docs: fix dependencies section in readme

Problem: time and timeout were listed as optional dependencies despite
being required for plugin initialization. nix was not mentioned as an
alternative to uv for the Python scraping environment.

Solution: rename section to "Dependencies", list time/timeout first,
and add nix as an alternative to uv for scraping.

.busted

@@ -1,13 +0,0 @@
-return {
-  _all = {
-    coverage = false,
-    lpath = 'lua/?.lua;lua/?/init.lua',
-    lua = 'nlua',
-  },
-  default = {
-    verbose = true,
-  },
-  tests = {
-    verbose = true,
-  },
-}

.github/ISSUE_TEMPLATE/bug_report.yaml

@@ -0,0 +1,78 @@
+name: Bug Report
+description: Report a bug
+title: 'bug: '
+labels: [bug]
+body:
+  - type: checkboxes
+    attributes:
+      label: Prerequisites
+      options:
+        - label:
+            I have searched [existing
+            issues](https://github.com/barrettruth/cp.nvim/issues)
+          required: true
+        - label: I have updated to the latest version
+          required: true
+
+  - type: textarea
+    attributes:
+      label: 'Neovim version'
+      description: 'Output of `nvim --version`'
+      render: text
+    validations:
+      required: true
+
+  - type: input
+    attributes:
+      label: 'Operating system'
+      placeholder: 'e.g. Arch Linux, macOS 15, Ubuntu 24.04'
+    validations:
+      required: true
+
+  - type: textarea
+    attributes:
+      label: Description
+      description: What happened? What did you expect?
+    validations:
+      required: true
+
+  - type: textarea
+    attributes:
+      label: Steps to reproduce
+      description: Minimal steps to trigger the bug
+      value: |
+        1.
+        2.
+        3.
+    validations:
+      required: true
+
+  - type: textarea
+    attributes:
+      label: 'Health check'
+      description: 'Output of `:checkhealth cp`'
+      render: text
+
+  - type: textarea
+    attributes:
+      label: Minimal reproduction
+      description: |
+        Save the script below as `repro.lua`, edit if needed, and run:
+        ```
+        nvim -u repro.lua
+        ```
+        Confirm the bug reproduces with this config before submitting.
+      render: lua
+      value: |
+        vim.env.LAZY_STDPATH = '.repro'
+        load(vim.fn.system('curl -s https://raw.githubusercontent.com/folke/lazy.nvim/main/bootstrap.lua'))()
+        require('lazy.nvim').setup({
+          spec = {
+            {
+              'barrett-ruth/cp.nvim',
+              opts = {},
+            },
+          },
+        })
+    validations:
+      required: true

.github/ISSUE_TEMPLATE/config.yaml

@@ -0,0 +1,5 @@
+blank_issues_enabled: false
+contact_links:
+  - name: Questions
+    url: https://github.com/barrettruth/cp.nvim/discussions
+    about: Ask questions and discuss ideas

.github/ISSUE_TEMPLATE/feature_request.yaml

@@ -0,0 +1,30 @@
+name: Feature Request
+description: Suggest a feature
+title: 'feat: '
+labels: [enhancement]
+body:
+  - type: checkboxes
+    attributes:
+      label: Prerequisites
+      options:
+        - label:
+            I have searched [existing
+            issues](https://github.com/barrettruth/cp.nvim/issues)
+          required: true
+
+  - type: textarea
+    attributes:
+      label: Problem
+      description: What problem does this solve?
+    validations:
+      required: true
+
+  - type: textarea
+    attributes:
+      label: Proposed solution
+    validations:
+      required: true
+
+  - type: textarea
+    attributes:
+      label: Alternatives considered

.github/workflows/luarocks.yaml

@@ -1,18 +1,21 @@
-name: Release
+name: luarocks
 
 on:
   push:
     tags:
-      - '*'
+      - 'v*'
-  workflow_dispatch:
 
 jobs:
-  publish-luarocks:
+  ci:
-    name: Publish to LuaRocks
+    uses: ./.github/workflows/ci.yaml
+
+  publish:
+    needs: ci
     runs-on: ubuntu-latest
+
     steps:
       - uses: actions/checkout@v4
-      - name: Publish to LuaRocks
+
-        uses: nvim-neorocks/luarocks-tag-release@v7
+      - uses: nvim-neorocks/luarocks-tag-release@v7
         env:
           LUAROCKS_API_KEY: ${{ secrets.LUAROCKS_API_KEY }}

.github/workflows/quality.yaml

@@ -1,4 +1,4 @@
-name: Code Quality
+name: quality
 
 on:
   pull_request:
@@ -115,10 +115,10 @@ jobs:
       - uses: actions/checkout@v4
       - name: Install uv
         uses: astral-sh/setup-uv@v4
-      - name: Install dependencies with mypy
+      - name: Install dependencies with uv
         run: uv sync --dev
-      - name: Type check Python files with mypy
+      - name: Type check Python files with ty
-        run: uv run mypy .
+        run: uvx ty check .
 
   markdown-format:
     name: Markdown Format Check

.github/workflows/test.yaml

@@ -1,4 +1,4 @@
-name: Tests
+name: tests
 
 on:
   pull_request:
@@ -35,21 +35,6 @@ jobs:
               - 'pyproject.toml'
               - 'uv.lock'
 
-  lua-test:
-    name: Lua Tests (${{ matrix.neovim_version }})
-    runs-on: ubuntu-latest
-    needs: changes
-    if: ${{ needs.changes.outputs.lua == 'true' }}
-    strategy:
-      matrix:
-        neovim_version: ['stable', 'nightly']
-    steps:
-      - uses: actions/checkout@v4
-      - name: Run Lua tests
-        uses: nvim-neorocks/nvim-busted-action@v1
-        with:
-          nvim_version: ${{ matrix.neovim_version }}
-
   python-test:
     name: Python Tests
     runs-on: ubuntu-latest
@@ -59,9 +44,7 @@ jobs:
       - uses: actions/checkout@v4
       - name: Install uv
         uses: astral-sh/setup-uv@v4
-      - name: Install dependencies with pytest
+      - name: Install dependencies
         run: uv sync --dev
-      - name: Fetch camoufox data
-        run: uv run camoufox fetch
       - name: Run Python tests
         run: uv run pytest tests/ -v

.gitignore

@@ -1,9 +1,19 @@
-.venv/
+.venv
+venv
 doc/tags
 *.log
 build
 io
 debug
-venv/
+create
+
+
+.*cache*
 CLAUDE.md
 __pycache__
+.claude/
+
+node_modules/
+
+.envrc
+.direnv/

.pre-commit-config.yaml

@@ -2,7 +2,7 @@ minimum_pre_commit_version: '3.5.0'
 
 repos:
   - repo: https://github.com/JohnnyMorganz/StyLua
-    rev: v2.1.0
+    rev: v2.3.1
     hooks:
       - id: stylua-github
         name: stylua (Lua formatter)
@@ -10,7 +10,7 @@ repos:
         pass_filenames: true
 
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.6.9
+    rev: v0.14.3
     hooks:
       - id: ruff-format
         name: ruff (format)
@@ -20,18 +20,17 @@ repos:
         args: ['--fix', '--select=I']
         files: \.py$
 
-  - repo: local
-    hooks:
-      - id: mypy
-        name: mypy (type check)
-        entry: uv run mypy
-        language: system
-        args: ['.']
-        pass_filenames: false
-
   - repo: https://github.com/pre-commit/mirrors-prettier
-    rev: v3.1.0
+    rev: v4.0.0-alpha.8
     hooks:
       - id: prettier
-        name: prettier (format markdown)
+        name: prettier
-        files: \.md$
+        files: \.(md|toml|ya?ml|sh)$
+
+  - repo: local
+    hooks:
+      - id: ty-type-check
+        name: ty (Python type checker)
+        language: system
+        entry: uv run ty check
+        types: [python]

README.md

@@ -5,12 +5,11 @@
 Scrape problems, run tests, and debug solutions across multiple platforms with
 zero configuration.
 
-https://github.com/user-attachments/assets/50b19481-8e6d-47b4-bebc-15e16c61a9c9
+https://github.com/user-attachments/assets/e81d8dfb-578f-4a79-9989-210164fc0148
 
 ## Features
 
-- **Multi-platform support**: AtCoder, Codeforces, CSES with consistent
+- **Multi-platform support**: AtCoder, CodeChef, Codeforces, and CSES
-  interface
 - **Automatic problem setup**: Scrape test cases and metadata in seconds
 - **Dual view modes**: Lightweight I/O view for quick feedback, full panel for
   detailed analysis
@@ -20,11 +19,21 @@ https://github.com/user-attachments/assets/50b19481-8e6d-47b4-bebc-15e16c61a9c9
 - **Language agnostic**: Works with any language
 - **Diff viewer**: Compare expected vs actual output with 3 diff modes
 
-## Optional Dependencies
+## Installation
+
+Install using your package manager of choice or via
+[luarocks](https://luarocks.org/modules/barrettruth/cp.nvim):
+
+```
+luarocks install cp.nvim
+```
+
+## Dependencies
 
-- [uv](https://docs.astral.sh/uv/) for problem scraping
 - GNU [time](https://www.gnu.org/software/time/) and
   [timeout](https://www.gnu.org/software/coreutils/manual/html_node/timeout-invocation.html)
+- [uv](https://docs.astral.sh/uv/) or [nix](https://nixos.org/) for problem
+  scraping
 
 ## Quick Start
 
@@ -69,9 +78,22 @@ cp.nvim follows a simple principle: **solve locally, submit remotely**.
 ```
 
 See
-[my config](https://github.com/barrett-ruth/dots/blob/main/nvim/lua/plugins/cp.lua)
+[my config](https://github.com/barrettruth/dots/blob/main/.config/nvim/lua/plugins/cp.lua)
 for the setup in the video shown above.
 
+## Motivation
+
+I could not find a neovim-centric, efficient, dependency-free, flexible, and
+easily customizable competitive programming workflow that "just works"--so I
+made it myself. I conferenced with top competitive programmers at Carnegie
+Mellon Univerity and the University of Virginia and covered their (and my) pain
+points:
+
+- Scraping: contests are automatically loaded asynchronously
+- Test Case Management: test case editor (`:CP edit`)
+- UI: both `run` and `panel` layouts cover common formats
+- Extensibility: snippet plugins, compilation, etc. are left to the programmer
+
 ## Similar Projects
 
 - [competitest.nvim](https://github.com/xeluxee/competitest.nvim)

cp.nvim-scm-1.rockspec

@@ -2,7 +2,7 @@ rockspec_format = '3.0'
 package = 'cp.nvim'
 version = 'scm-1'
 
-source = { url = 'git://github.com/barrett-ruth/cp.nvim' }
+source = { url = 'git://github.com/barrettruth/cp.nvim' }
 build = { type = 'builtin' }
 
 test_dependencies = {

doc/cp.nvim.txt

@@ -18,6 +18,243 @@ REQUIREMENTS                                                 *cp-requirements*
 - Unix-like operating system
 - uv package manager (https://docs.astral.sh/uv/)
 
+==============================================================================
+SETUP                                                              *cp-setup*
+
+Load cp.nvim with your package manager. For example, with lazy.nvim: >lua
+    { 'barrettruth/cp.nvim' }
+<
+The plugin works automatically with no configuration required. For
+customization, see |cp-config|.
+
+==============================================================================
+CONFIGURATION                                                      *cp-config*
+
+Configuration is done via `vim.g.cp`. Set this before using the plugin:
+>lua
+    vim.g.cp = {
+      languages = {
+        cpp = {
+          extension = 'cc',
+          commands = {
+            build = { 'g++', '-std=c++17', '{source}', '-o', '{binary}',
+            '-fdiagnostics-color=always' },
+            run   = { '{binary}' },
+            debug = { 'g++', '-std=c++17', '-fsanitize=address,undefined',
+                      '{source}', '-o', '{binary}' },
+          },
+        },
+        python = {
+          extension = 'py',
+          commands = {
+            run   = { 'python', '{source}' },
+            debug = { 'python', '{source}' },
+          },
+        },
+      },
+      platforms = {
+        cses = {
+          enabled_languages = { 'cpp', 'python' },
+          default_language  = 'cpp',
+          overrides = {
+            cpp = { extension = 'cpp', commands = { build = { ... } } }
+          },
+        },
+        atcoder = {
+          enabled_languages = { 'cpp', 'python' },
+          default_language  = 'cpp',
+        },
+        codeforces = {
+          enabled_languages = { 'cpp', 'python' },
+          default_language  = 'cpp',
+        },
+      },
+      open_url = true,
+      debug = false,
+      ui = {
+        ansi = true,
+        run = {
+          width = 0.3,
+          next_test_key = '<c-n>',  -- or nil to disable
+          prev_test_key = '<c-p>',  -- or nil to disable
+        },
+        panel = {
+          diff_modes = { 'side-by-side', 'git', 'vim' },
+          max_output_lines = 50,
+        },
+        diff = {
+          git = {
+            args = { 'diff', '--no-index', '--word-diff=plain',
+                     '--word-diff-regex=.', '--no-prefix' },
+          },
+        },
+        picker = 'telescope',
+      },
+    }
+<
+
+By default, C++ (g++ with ISO C++17) and Python are preconfigured under
+'languages'. Platforms select which languages are enabled and which one is
+the default; per-platform overrides can tweak 'extension' or 'commands'.
+
+For example, to run CodeForces contests with Python by default:
+>lua
+    vim.g.cp = {
+      platforms = {
+        codeforces = {
+          default_language  = 'python',
+        },
+      },
+    }
+<
+Any language is supported provided the proper configuration. For example, to
+run CSES problems with Rust using the single schema:
+>lua
+    vim.g.cp = {
+      languages = {
+        rust = {
+          extension = 'rs',
+          commands = {
+            build = { 'rustc', '{source}', '-o', '{binary}' },
+            run   = { '{binary}' },
+          },
+        },
+      },
+      platforms = {
+        cses = {
+          enabled_languages = { 'cpp', 'python', 'rust' },
+          default_language  = 'rust',
+        },
+      },
+    }
+<
+                                                                   *cp.Config*
+    Fields: ~
+        {languages}     (table<string,|CpLanguage|>) Global language registry.
+                        Each language provides an {extension} and {commands}.
+        {platforms}     (table<string,|CpPlatform|>) Per-platform enablement,
+                        default language, and optional overrides.
+        {hooks}         (|cp.Hooks|) Hook functions called at various stages.
+        {debug}         (boolean, default: false) Show info messages.
+        {scrapers}      (string[]) Supported platform ids.
+        {filename}      (function, optional)
+                        function(contest, contest_id, problem_id, config, language): string
+                        Should return full filename with extension.
+                        (default: concatenates contest_id and problem_id, lowercased)
+        {ui}            (|CpUI|) UI settings: panel, diff backend, picker.
+        {open_url}      (boolean) Open the contest & problem url in the browser
+                        when the contest is first opened.
+
+                                                                  *CpPlatform*
+    Fields: ~
+        {enabled_languages} (string[]) Language ids enabled on this platform.
+        {default_language}  (string)   One of {enabled_languages}.
+        {overrides}         (table<string,|CpPlatformOverrides|>, optional)
+                            Per-language overrides of {extension} and/or {commands}.
+
+                                                                  *CpLanguage*
+    Fields: ~
+        {extension}     (string) File extension without leading dot.
+        {commands}      (|CpLangCommands|) Command templates.
+
+                                                              *CpLangCommands*
+    Fields: ~
+        {build}         (string[], optional) For compiled languages.
+                         Must include {source} and {binary}.
+        {run}           (string[], optional) Runtime command.
+                         Compiled: must include {binary}.
+                         Interpreted: must include {source}.
+        {debug}         (string[], optional) Debug variant; same token rules
+                         as {build} (compiled) or {run} (interpreted).
+
+                                                                        *CpUI*
+    Fields: ~
+        {ansi}          (boolean, default: true) Enable ANSI color parsing
+                        and highlighting in both I/O view and panel.
+        {run}           (|RunConfig|) I/O view configuration.
+        {panel}         (|PanelConfig|) Test panel behavior configuration.
+        {diff}          (|DiffConfig|) Diff backend configuration.
+        {picker}        (string|nil) 'telescope', 'fzf-lua', or nil.
+
+                                                                  *RunConfig*
+    Fields: ~
+        {width}            (number, default: 0.3) Width of I/O view splits as
+                           fraction of screen (0.0 to 1.0).
+        {next_test_key}    (string|nil, default: '<c-n>') Keymap to navigate
+                           to next test in I/O view. Set to nil to disable.
+        {prev_test_key}    (string|nil, default: '<c-p>') Keymap to navigate
+                           to previous test in I/O view. Set to nil to disable.
+        {format_verdict}   (|VerdictFormatter|, default: nil) Custom verdict line
+                           formatter. See |cp-verdict-format|.
+
+                                                                *EditConfig*
+    Fields: ~
+        {next_test_key}      (string|nil, default: ']t') Jump to next test.
+        {prev_test_key}      (string|nil, default: '[t') Jump to previous test.
+        {delete_test_key}    (string|nil, default: 'gd') Delete current test.
+        {add_test_key}       (string|nil, default: 'ga') Add new test.
+        {save_and_exit_key}  (string|nil, default: 'q') Save and exit editor.
+                             All keys are nil-able. Set to nil to disable.
+
+                                                              *cp.PanelConfig*
+    Fields: ~
+        {diff_modes}       (string[], default: {'side-by-side', 'git', 'vim'})
+                           List of diff modes to cycle through with 't' key.
+                           First element is the default mode.
+                           Valid modes: 'side-by-side', 'git', 'vim'.
+        {max_output_lines} (number, default: 50) Maximum lines of test output.
+
+                                                               *cp.DiffConfig*
+    Fields: ~
+        {git}           (|cp.DiffGitConfig|) Git diff backend configuration.
+
+                                                            *cp.DiffGitConfig*
+    Fields: ~
+        {args}          (string[]) Command-line arguments for git diff.
+                        Default: { 'diff', '--no-index', '--word-diff=plain',
+                                  '--word-diff-regex=.', '--no-prefix' }
+                        • --no-index: Compare files outside git repository
+                        • --word-diff=plain: Character-level diff markers
+                        • --word-diff-regex=.: Split on every character
+                        • --no-prefix: Remove a/ b/ prefixes from output
+
+                                                                    *cp.Hooks*
+    Fields: ~
+        {before_run}       (function, optional) Called before test panel opens.
+                           function(state: cp.State)
+        {before_debug}     (function, optional) Called before debug build/run.
+                           function(state: cp.State)
+        {setup_code}       (function, optional) Called after source file is opened.
+                           function(state: cp.State)
+        {setup_io_input}   (function, optional) Called when I/O input buffer created.
+                           function(bufnr: integer, state: cp.State)
+                           Default: helpers.clearcol (removes line numbers/columns)
+        {setup_io_output}  (function, optional) Called when I/O output buffer created.
+                           function(bufnr: integer, state: cp.State)
+                           Default: helpers.clearcol (removes line numbers/columns)
+
+    Hook functions receive the cp.nvim state object (|cp.State|). See
+    |lua/cp/state.lua| for available methods and fields.
+
+    The I/O buffer hooks are called once when the buffers are first created
+    during problem setup. Use these to customize buffer appearance (e.g.,
+    remove line numbers, set custom options). Access helpers via:
+>lua
+        local helpers = require('cp').helpers
+<
+    Example usage:
+>lua
+        hooks = {
+          setup_code = function(state)
+            print("Setting up " .. state.get_base_name())
+            print("Source file: " .. state.get_source_file())
+          end,
+          setup_io_input = function(bufnr, state)
+            vim.api.nvim_set_option_value('number', false, { buf = bufnr })
+          end
+        }
+<
+
 ==============================================================================
 COMMANDS                                                         *cp-commands*
 
@@ -34,15 +271,30 @@ COMMANDS                                                         *cp-commands*
                                     :CP codeforces 1933 --lang python
 <
         View Commands ~
-            :CP run [--debug] [n]
+            :CP run [all|n|n,m,...] [--debug]
                                 Run tests in I/O view (see |cp-io-view|).
                                 Lightweight split showing test verdicts.
-                                Without [n]: runs all tests, shows verdict summary
+
-                                With [n]: runs test n, shows detailed output
+                                Execution modes:
+                                • :CP run              Combined: single execution with all tests
+                                                       (auto-switches to individual when multiple samples)
+                                • :CP run all          Individual: N separate executions
+                                • :CP run n            Individual: run test n only
+                                • :CP run n,m,...      Individual: run specific tests (e.g. nth and mth)
+
                                 --debug: Use debug build (builds to build/<name>.dbg)
+
+                                Combined mode runs all test inputs in one execution (matching
+                                platform behavior for multi-test problems). When a problem has
+                                multiple independent sample test cases, :CP run auto-switches to
+                                individual mode to run each sample separately.
+
                                 Examples: >
-                                    :CP run              " All tests
+                                    :CP run              " Combined: all tests, one execution
-                                    :CP run --debug 2    " Test 2, debug build
+                                    :CP run all          " Individual: all tests, N executions
+                                    :CP run 2            " Individual: test 2 only
+                                    :CP run 1,3,5        " Individual: tests 1, 3, and 5
+                                    :CP run all --debug  " Individual with debug build
 <
             :CP panel [--debug] [n]
                                 Open full-screen test panel (see |cp-panel|).
@@ -188,235 +440,40 @@ Debug Builds ~
 <
 
 ==============================================================================
-CONFIGURATION                                                      *cp-config*
+MAPPINGS                                                        *cp-mappings*
 
-Here's an example configuration with lazy.nvim:
+cp.nvim provides <Plug> mappings for all primary actions. These dispatch
->lua
+through the same code path as |:CP|.
-    {
-      'barrett-ruth/cp.nvim',
-      cmd = 'CP',
-      build = 'uv sync',
-      opts = {
-        languages = {
-          cpp = {
-            extension = 'cc',
-            commands = {
-              build = { 'g++', '-std=c++17', '{source}', '-o', '{binary}',
-              '-fdiagnostics-color=always' },
-              run   = { '{binary}' },
-              debug = { 'g++', '-std=c++17', '-fsanitize=address,undefined',
-                        '{source}', '-o', '{binary}' },
-            },
-          },
-          python = {
-            extension = 'py',
-            commands = {
-              run   = { 'python', '{source}' },
-              debug = { 'python', '{source}' },
-            },
-          },
-        },
-        platforms = {
-          cses = {
-            enabled_languages = { 'cpp', 'python' },
-            default_language  = 'cpp',
-            overrides = {
-              cpp = { extension = 'cpp', commands = { build = { ... } } }
-            },
-          },
-          atcoder = {
-            enabled_languages = { 'cpp', 'python' },
-            default_language  = 'cpp',
-          },
-          codeforces = {
-            enabled_languages = { 'cpp', 'python' },
-            default_language  = 'cpp',
-          },
-        },
-        open_url = true,
-        debug = false,
-        ui = {
-          ansi = true,
-          run = {
-            width = 0.3,
-            next_test_key = '<c-n>',  -- or nil to disable
-            prev_test_key = '<c-p>',  -- or nil to disable
-          },
-          panel = {
-            diff_mode = 'vim',
-            max_output_lines = 50,
-          },
-          diff = {
-            git = {
-              args = { 'diff', '--no-index', '--word-diff=plain',
-                       '--word-diff-regex=.', '--no-prefix' },
-            },
-          },
-          picker = 'telescope',
-        },
-      }
-    }
-<
 
-By default, C++ (g++ with ISO C++17) and Python are preconfigured under
+                                                              *<Plug>(cp-run)*
-'languages'. Platforms select which languages are enabled and which one is
+<Plug>(cp-run)          Run tests in I/O view. Equivalent to :CP run.
-the default; per-platform overrides can tweak 'extension' or 'commands'.
 
-For example, to run CodeForces contests with Python by default:
+                                                            *<Plug>(cp-panel)*
->lua
+<Plug>(cp-panel)        Open full-screen test panel. Equivalent to :CP panel.
-    {
-      platforms = {
-        codeforces = {
-          default_language  = 'python',
-        },
-      },
-    }
-<
-Any language is supported provided the proper configuration. For example, to
-run CSES problems with Rust using the single schema:
->lua
-    {
-      languages = {
-        rust = {
-          extension = 'rs',
-          commands = {
-            build = { 'rustc', '{source}', '-o', '{binary}' },
-            run   = { '{binary}' },
-          },
-        },
-      },
-      platforms = {
-        cses = {
-          enabled_languages = { 'cpp', 'python', 'rust' },
-          default_language  = 'rust',
-        },
-      },
-    }
-<
-                                                                   *cp.Config*
-    Fields: ~
-        {languages}     (table<string,|CpLanguage|>) Global language registry.
-                        Each language provides an {extension} and {commands}.
-        {platforms}     (table<string,|CpPlatform|>) Per-platform enablement,
-                        default language, and optional overrides.
-        {hooks}         (|cp.Hooks|) Hook functions called at various stages.
-        {debug}         (boolean, default: false) Show info messages.
-        {scrapers}      (string[]) Supported platform ids.
-        {filename}      (function, optional)
-                        function(contest, contest_id, problem_id, config, language): string
-                        Should return full filename with extension.
-                        (default: concatenates contest_id and problem_id, lowercased)
-        {ui}            (|CpUI|) UI settings: panel, diff backend, picker.
-        {open_url}      (boolean) Open the contest & problem url in the browser
-                        when the contest is first opened.
 
-                                                                  *CpPlatform*
+                                                             *<Plug>(cp-edit)*
-    Fields: ~
+<Plug>(cp-edit)         Open the test case editor. Equivalent to :CP edit.
-        {enabled_languages} (string[]) Language ids enabled on this platform.
-        {default_language}  (string)   One of {enabled_languages}.
-        {overrides}         (table<string,|CpPlatformOverrides|>, optional)
-                            Per-language overrides of {extension} and/or {commands}.
 
-                                                                  *CpLanguage*
+                                                             *<Plug>(cp-next)*
-    Fields: ~
+<Plug>(cp-next)         Navigate to the next problem. Equivalent to :CP next.
-        {extension}     (string) File extension without leading dot.
-        {commands}      (|CpLangCommands|) Command templates.
 
-                                                              *CpLangCommands*
+                                                             *<Plug>(cp-prev)*
-    Fields: ~
+<Plug>(cp-prev)         Navigate to the previous problem. Equivalent to :CP prev.
-        {build}         (string[], optional) For compiled languages.
-                         Must include {source} and {binary}.
-        {run}           (string[], optional) Runtime command.
-                         Compiled: must include {binary}.
-                         Interpreted: must include {source}.
-        {debug}         (string[], optional) Debug variant; same token rules
-                         as {build} (compiled) or {run} (interpreted).
 
-                                                                        *CpUI*
+                                                             *<Plug>(cp-pick)*
-    Fields: ~
+<Plug>(cp-pick)         Launch the contest picker. Equivalent to :CP pick.
-        {ansi}          (boolean, default: true) Enable ANSI color parsing
-                        and highlighting in both I/O view and panel.
-        {run}           (|RunConfig|) I/O view configuration.
-        {panel}         (|PanelConfig|) Test panel behavior configuration.
-        {diff}          (|DiffConfig|) Diff backend configuration.
-        {picker}        (string|nil) 'telescope', 'fzf-lua', or nil.
 
-                                                                  *RunConfig*
+                                                         *<Plug>(cp-interact)*
-    Fields: ~
+<Plug>(cp-interact)     Open interactive mode. Equivalent to :CP interact.
-        {width}            (number, default: 0.3) Width of I/O view splits as
-                           fraction of screen (0.0 to 1.0).
-        {next_test_key}    (string|nil, default: '<c-n>') Keymap to navigate
-                           to next test in I/O view. Set to nil to disable.
-        {prev_test_key}    (string|nil, default: '<c-p>') Keymap to navigate
-                           to previous test in I/O view. Set to nil to disable.
-        {format_verdict}   (|VerdictFormatter|, default: nil) Custom verdict line
-                           formatter. See |cp-verdict-format|.
 
-                                                                *EditConfig*
+Example configuration: >lua
-    Fields: ~
+    vim.keymap.set('n', '<leader>cr', '<Plug>(cp-run)')
-        {next_test_key}      (string|nil, default: ']t') Jump to next test.
+    vim.keymap.set('n', '<leader>cp', '<Plug>(cp-panel)')
-        {prev_test_key}      (string|nil, default: '[t') Jump to previous test.
+    vim.keymap.set('n', '<leader>ce', '<Plug>(cp-edit)')
-        {delete_test_key}    (string|nil, default: 'gd') Delete current test.
+    vim.keymap.set('n', '<leader>cn', '<Plug>(cp-next)')
-        {add_test_key}       (string|nil, default: 'ga') Add new test.
+    vim.keymap.set('n', '<leader>cN', '<Plug>(cp-prev)')
-        {save_and_exit_key}  (string|nil, default: 'q') Save and exit editor.
+    vim.keymap.set('n', '<leader>cc', '<Plug>(cp-pick)')
-                             All keys are nil-able. Set to nil to disable.
+    vim.keymap.set('n', '<leader>ci', '<Plug>(cp-interact)')
-
-                                                              *cp.PanelConfig*
-    Fields: ~
-        {diff_mode}        (string, default: "none") Diff backend: "none",
-                           "vim", or "git".
-        {max_output_lines} (number, default: 50) Maximum lines of test output.
-
-                                                               *cp.DiffConfig*
-    Fields: ~
-        {git}           (|cp.DiffGitConfig|) Git diff backend configuration.
-
-                                                            *cp.DiffGitConfig*
-    Fields: ~
-        {args}          (string[]) Command-line arguments for git diff.
-                        Default: { 'diff', '--no-index', '--word-diff=plain',
-                                  '--word-diff-regex=.', '--no-prefix' }
-                        • --no-index: Compare files outside git repository
-                        • --word-diff=plain: Character-level diff markers
-                        • --word-diff-regex=.: Split on every character
-                        • --no-prefix: Remove a/ b/ prefixes from output
-
-                                                                    *cp.Hooks*
-    Fields: ~
-        {before_run}       (function, optional) Called before test panel opens.
-                           function(state: cp.State)
-        {before_debug}     (function, optional) Called before debug build/run.
-                           function(state: cp.State)
-        {setup_code}       (function, optional) Called after source file is opened.
-                           function(state: cp.State)
-        {setup_io_input}   (function, optional) Called when I/O input buffer created.
-                           function(bufnr: integer, state: cp.State)
-                           Default: helpers.clearcol (removes line numbers/columns)
-        {setup_io_output}  (function, optional) Called when I/O output buffer created.
-                           function(bufnr: integer, state: cp.State)
-                           Default: helpers.clearcol (removes line numbers/columns)
-
-    Hook functions receive the cp.nvim state object (|cp.State|). See
-    |lua/cp/state.lua| for available methods and fields.
-
-    The I/O buffer hooks are called once when the buffers are first created
-    during problem setup. Use these to customize buffer appearance (e.g.,
-    remove line numbers, set custom options). Access helpers via:
->lua
-        local helpers = require('cp').helpers
-<
-    Example usage:
->lua
-        hooks = {
-          setup_code = function(state)
-            print("Setting up " .. state.get_base_name())
-            print("Source file: " .. state.get_source_file())
-          end,
-          setup_io_input = function(bufnr, state)
-            -- Custom setup for input buffer
-            vim.api.nvim_set_option_value('number', false, { buf = bufnr })
-          end
-        }
 <
 
 ==============================================================================
@@ -536,10 +593,27 @@ Example: Setting up and solving AtCoder contest ABC324
 I/O VIEW                                                          *cp-io-view*
 
 The I/O view provides lightweight test feedback in persistent side splits.
-All test outputs are concatenated with verdict summaries at the bottom.
+Test outputs are concatenated with verdict summaries at the bottom.
 The |cp-panel| offers more fine-grained analysis with diff modes.
 
-Access the I/O view with :CP run [n]
+Execution Modes ~
+
+The I/O view supports two execution modes:
+
+Combined Mode (:CP run with single sample)
+    • Single execution with all test inputs concatenated
+    • Matches platform behavior (e.g. Codeforces multi-test format)
+    • Shows one verdict for the entire execution
+    • Input split: All test inputs concatenated
+    • Output split: Single program output + verdict
+    • Used when problem has one sample containing multiple test cases
+
+Individual Mode (:CP run all / :CP run n / :CP run n,m,...)
+    • Separate execution for each test case
+    • Per-test verdicts for debugging
+    • Input split: Selected test inputs concatenated
+    • Output split: All test outputs concatenated + per-test verdicts
+    • Auto-selected when problem has multiple independent samples
 
 Layout ~
 
@@ -561,7 +635,7 @@ The I/O view appears as 30% width splits on the right side: >
     └──────────────────────────┴─────────────────────────────────────────────┘
 <
 The output split shows:
-1. Concatenated test outputs (separated by blank lines)
+1. Program output (raw, preserving all formatting)
 2. Space-aligned verdict summary with:
    - Test number and status (AC/WA/TLE/MLE/RTE with color highlighting)
    - Runtime: actual/limit in milliseconds
@@ -570,8 +644,10 @@ The output split shows:
 
 Usage ~
 
-    :CP run             Run all tests
+    :CP run             Combined mode: all tests in one execution
-    :CP run 3           Run test 3 only
+    :CP run all         Individual mode: all tests separately
+    :CP run 3           Individual mode: test 3 only
+    :CP run 1,3,5       Individual mode: specific tests (1, 3, and 5)
 
 Navigation ~
 
@@ -750,12 +826,15 @@ HIGHLIGHT GROUPS                                               *cp-highlights*
 
 Test Status Groups ~
 
-    CpTestAC        Green foreground for AC status
+All test status groups link to builtin highlight groups, automatically adapting
-    CpTestWA        Red foreground for WA status
+to your colorscheme:
-    CpTestTLE       Orange foreground for TLE status
+
-    CpTestMLE       Orange foreground for MLE status
+    CpTestAC        Links to DiagnosticOk (AC status)
-    CpTestRTE       Purple foreground for RTE status
+    CpTestWA        Links to DiagnosticError (WA status)
-    CpTestNA        Gray foreground for remaining state
+    CpTestTLE       Links to DiagnosticWarn (TLE status)
+    CpTestMLE       Links to DiagnosticWarn (MLE status)
+    CpTestRTE       Links to DiagnosticHint (RTE status)
+    CpTestNA        Links to Comment (pending/unknown status)
 
 ANSI Color Groups ~
 
@@ -814,18 +893,21 @@ PANEL KEYMAPS                                                  *cp-panel-keys*
 
 <c-n>   Navigate to next test case
 <c-p>   Navigate to previous test case
-t       Cycle through diff modes: none → git → vim
+t       Cycle through configured diff modes (see |cp.PanelConfig|)
 q       Exit panel and restore layout
 <c-q>   Exit interactive terminal and restore layout
 
 Diff Modes ~
 
-Three diff backends are available:
+Three diff modes are available:
 
-    none    Nothing
+    side-by-side    Expected and actual output shown side-by-side (default)
-    vim     Built-in vim diff (default, always available)
+    vim             Built-in vim diff (always available)
     git             Character-level git word-diff (requires git, more precise)
 
+Configure which modes to cycle through via |cp.PanelConfig|.diff_modes.
+The first element is used as the default mode.
+
 The git backend shows character-level changes with [-removed-] and {+added+}
 markers.
 

flake.lock

@@ -0,0 +1,43 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1771008912,
+        "narHash": "sha256-gf2AmWVTs8lEq7z/3ZAsgnZDhWIckkb+ZnAo5RzSxJg=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "a82ccc39b39b621151d6732718e3e250109076fa",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs",
+        "systems": "systems"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1689347949,
+        "narHash": "sha256-12tWmuL2zgBgZkdoB6qXZsgJEH9LR3oUgpaQq2RbI80=",
+        "owner": "nix-systems",
+        "repo": "default-linux",
+        "rev": "31732fcf5e8fea42e59c2488ad31a0e651500f68",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default-linux",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,72 @@
+{
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    systems.url = "github:nix-systems/default-linux";
+  };
+
+  outputs =
+    {
+      self,
+      nixpkgs,
+      systems,
+    }:
+    let
+      eachSystem = nixpkgs.lib.genAttrs (import systems);
+      pkgsFor = system: nixpkgs.legacyPackages.${system};
+
+      mkPythonEnv =
+        pkgs:
+        pkgs.python312.withPackages (ps: [
+          ps.backoff
+          ps.beautifulsoup4
+          ps.curl-cffi
+          ps.httpx
+          ps.ndjson
+          ps.pydantic
+          ps.requests
+        ]);
+
+      mkPlugin =
+        pkgs:
+        let
+          pythonEnv = mkPythonEnv pkgs;
+        in
+        pkgs.vimUtils.buildVimPlugin {
+          pname = "cp-nvim";
+          version = "0-unstable-${self.shortRev or self.dirtyShortRev or "dev"}";
+          src = self;
+          postPatch = ''
+            substituteInPlace lua/cp/utils.lua \
+              --replace-fail "local _nix_python = nil" \
+              "local _nix_python = '${pythonEnv.interpreter}'"
+          '';
+          nvimSkipModule = [
+            "cp.pickers.telescope"
+            "cp.version"
+          ];
+          passthru = { inherit pythonEnv; };
+          meta.description = "Competitive programming plugin for Neovim";
+        };
+    in
+    {
+      overlays.default = final: prev: {
+        vimPlugins = prev.vimPlugins // {
+          cp-nvim = mkPlugin final;
+        };
+      };
+
+      packages = eachSystem (system: {
+        default = mkPlugin (pkgsFor system);
+        pythonEnv = mkPythonEnv (pkgsFor system);
+      });
+
+      devShells = eachSystem (system: {
+        default = (pkgsFor system).mkShell {
+          packages = with (pkgsFor system); [
+            uv
+            python312
+          ];
+        };
+      });
+    };
+}

lua/cp/cache.lua

@@ -16,12 +16,18 @@
 ---@field name string
 ---@field id string
 
+---@class CombinedTest
+---@field input string
+---@field expected string
+
 ---@class Problem
 ---@field id string
 ---@field name? string
 ---@field interactive? boolean
+---@field multi_test? boolean
 ---@field memory_mb? number
 ---@field timeout_ms? number
+---@field combined_test? CombinedTest
 ---@field test_cases TestCase[]
 
 ---@class TestCase
@@ -180,38 +186,64 @@ function M.get_test_cases(platform, contest_id, problem_id)
   return cache_data[platform][contest_id].problems[index].test_cases or {}
 end
 
+---@param platform string
+---@param contest_id string
+---@param problem_id? string
+---@return CombinedTest?
+function M.get_combined_test(platform, contest_id, problem_id)
+  if
+    not cache_data[platform]
+    or not cache_data[platform][contest_id]
+    or not cache_data[platform][contest_id].problems
+    or not cache_data[platform][contest_id].index_map
+  then
+    return nil
+  end
+
+  local index = cache_data[platform][contest_id].index_map[problem_id]
+  return cache_data[platform][contest_id].problems[index].combined_test
+end
+
 ---@param platform string
 ---@param contest_id string
 ---@param problem_id string
+---@param combined_test? CombinedTest
 ---@param test_cases TestCase[]
 ---@param timeout_ms number
 ---@param memory_mb number
 ---@param interactive boolean
+---@param multi_test boolean
 function M.set_test_cases(
   platform,
   contest_id,
   problem_id,
+  combined_test,
   test_cases,
   timeout_ms,
   memory_mb,
-  interactive
+  interactive,
+  multi_test
 )
   vim.validate({
     platform = { platform, 'string' },
     contest_id = { contest_id, 'string' },
     problem_id = { problem_id, { 'string', 'nil' }, true },
+    combined_test = { combined_test, { 'table', 'nil' }, true },
     test_cases = { test_cases, 'table' },
     timeout_ms = { timeout_ms, { 'number', 'nil' }, true },
     memory_mb = { memory_mb, { 'number', 'nil' }, true },
     interactive = { interactive, { 'boolean', 'nil' }, true },
+    multi_test = { multi_test, { 'boolean', 'nil' }, true },
   })
 
   local index = cache_data[platform][contest_id].index_map[problem_id]
 
+  cache_data[platform][contest_id].problems[index].combined_test = combined_test
   cache_data[platform][contest_id].problems[index].test_cases = test_cases
   cache_data[platform][contest_id].problems[index].timeout_ms = timeout_ms
   cache_data[platform][contest_id].problems[index].memory_mb = memory_mb
   cache_data[platform][contest_id].problems[index].interactive = interactive
+  cache_data[platform][contest_id].problems[index].multi_test = multi_test
 
   M.save()
 end

lua/cp/commands/init.lua

@@ -17,8 +17,11 @@ local actions = constants.ACTIONS
 ---@field problem_id? string
 ---@field interactor_cmd? string
 ---@field test_index? integer
+---@field test_indices? integer[]
+---@field mode? string
 ---@field debug? boolean
 ---@field language? string
+---@field subcommand? string
 
 --- Turn raw args into normalized structure to later dispatch
 ---@param args string[] The raw command-line mode args
@@ -75,25 +78,84 @@ local function parse_command(args)
       return { type = 'action', action = 'edit', test_index = test_index }
     elseif first == 'run' or first == 'panel' then
       local debug = false
-      local test_index = nil
+      local test_indices = nil
+      local mode = 'combined'
 
       if #args == 2 then
         if args[2] == '--debug' then
           debug = true
+        elseif args[2] == 'all' then
+          mode = 'individual'
+        else
+          if args[2]:find(',') then
+            local indices = {}
+            for num in args[2]:gmatch('[^,]+') do
+              local idx = tonumber(num)
+              if not idx or idx < 1 or idx ~= math.floor(idx) then
+                return {
+                  type = 'error',
+                  message = ("Invalid test index '%s' in list"):format(num),
+                }
+              end
+              table.insert(indices, idx)
+            end
+            if #indices == 0 then
+              return { type = 'error', message = 'No valid test indices provided' }
+            end
+            test_indices = indices
+            mode = 'individual'
           else
             local idx = tonumber(args[2])
             if not idx then
               return {
                 type = 'error',
-              message = ("Invalid argument '%s': expected test number or --debug"):format(args[2]),
+                message = ("Invalid argument '%s': expected test number(s), 'all', or --debug"):format(
+                  args[2]
+                ),
               }
             end
             if idx < 1 or idx ~= math.floor(idx) then
               return { type = 'error', message = ("'%s' is not a valid test index"):format(idx) }
             end
-          test_index = idx
+            test_indices = { idx }
+            mode = 'individual'
+          end
         end
       elseif #args == 3 then
+        if args[2] == 'all' then
+          mode = 'individual'
+          if args[3] ~= '--debug' then
+            return {
+              type = 'error',
+              message = ("Invalid argument '%s': expected --debug"):format(args[3]),
+            }
+          end
+          debug = true
+        elseif args[2]:find(',') then
+          local indices = {}
+          for num in args[2]:gmatch('[^,]+') do
+            local idx = tonumber(num)
+            if not idx or idx < 1 or idx ~= math.floor(idx) then
+              return {
+                type = 'error',
+                message = ("Invalid test index '%s' in list"):format(num),
+              }
+            end
+            table.insert(indices, idx)
+          end
+          if #indices == 0 then
+            return { type = 'error', message = 'No valid test indices provided' }
+          end
+          if args[3] ~= '--debug' then
+            return {
+              type = 'error',
+              message = ("Invalid argument '%s': expected --debug"):format(args[3]),
+            }
+          end
+          test_indices = indices
+          mode = 'individual'
+          debug = true
+        else
           local idx = tonumber(args[2])
           if not idx then
             return {
@@ -110,16 +172,26 @@ local function parse_command(args)
               message = ("Invalid argument '%s': expected --debug"):format(args[3]),
             }
           end
-        test_index = idx
+          test_indices = { idx }
+          mode = 'individual'
           debug = true
+        end
       elseif #args > 3 then
         return {
           type = 'error',
-          message = 'Too many arguments. Usage: :CP ' .. first .. ' [test_num] [--debug]',
+          message = 'Too many arguments. Usage: :CP '
+            .. first
+            .. ' [all|test_num[,test_num...]] [--debug]',
         }
       end
 
-      return { type = 'action', action = first, test_index = test_index, debug = debug }
+      return {
+        type = 'action',
+        action = first,
+        test_indices = test_indices,
+        debug = debug,
+        mode = mode,
+      }
     else
       local language = nil
       if #args >= 3 and args[2] == '--lang' then
@@ -197,9 +269,12 @@ function M.handle_command(opts)
     if cmd.action == 'interact' then
       ui.toggle_interactive(cmd.interactor_cmd)
     elseif cmd.action == 'run' then
-      ui.run_io_view(cmd.test_index, cmd.debug)
+      ui.run_io_view(cmd.test_indices, cmd.debug, cmd.mode)
     elseif cmd.action == 'panel' then
-      ui.toggle_panel({ debug = cmd.debug, test_index = cmd.test_index })
+      ui.toggle_panel({
+        debug = cmd.debug,
+        test_index = cmd.test_indices and cmd.test_indices[1] or nil,
+      })
     elseif cmd.action == 'next' then
       setup.navigate_problem(1, cmd.language)
     elseif cmd.action == 'prev' then

lua/cp/commands/picker.lua

@@ -40,7 +40,7 @@ function M.handle_pick_action(language)
     local ok, _ = pcall(require, 'fzf-lua')
     if not ok then
       logger.log(
-        'fzf-lua is not available. Install fzf-lua xor change your picker config',
+        'fzf-lua is not available. Install fzf-lua or change your picker config',
         vim.log.levels.ERROR
       )
       return

lua/cp/config.lua

@@ -18,7 +18,7 @@
 ---@field overrides? table<string, CpPlatformOverrides>
 
 ---@class PanelConfig
----@field diff_mode "none"|"vim"|"git"
+---@field diff_modes string[]
 ---@field max_output_lines integer
 
 ---@class DiffGitConfig
@@ -139,6 +139,10 @@ M.defaults = {
       enabled_languages = { 'cpp', 'python' },
       default_language = 'cpp',
     },
+    codechef = {
+      enabled_languages = { 'cpp', 'python' },
+      default_language = 'cpp',
+    },
     cses = {
       enabled_languages = { 'cpp', 'python' },
       default_language = 'cpp',
@@ -169,7 +173,7 @@ M.defaults = {
       add_test_key = 'ga',
       save_and_exit_key = 'q',
     },
-    panel = { diff_mode = 'none', max_output_lines = 50 },
+    panel = { diff_modes = { 'side-by-side', 'git', 'vim' }, max_output_lines = 50 },
     diff = {
       git = {
         args = { 'diff', '--no-index', '--word-diff=plain', '--word-diff-regex=.', '--no-prefix' },
@@ -288,7 +292,15 @@ end
 ---@return cp.Config
 function M.setup(user_config)
   vim.validate({ user_config = { user_config, { 'table', 'nil' }, true } })
-  local cfg = vim.tbl_deep_extend('force', vim.deepcopy(M.defaults), user_config or {})
+  local defaults = vim.deepcopy(M.defaults)
+  if user_config and user_config.platforms then
+    for plat in pairs(defaults.platforms) do
+      if not user_config.platforms[plat] then
+        defaults.platforms[plat] = nil
+      end
+    end
+  end
+  local cfg = vim.tbl_deep_extend('force', defaults, user_config or {})
 
   if not next(cfg.languages) then
     error('[cp.nvim] At least one language must be configured')
@@ -301,7 +313,24 @@ function M.setup(user_config)
   vim.validate({
     hooks = { cfg.hooks, { 'table' } },
     ui = { cfg.ui, { 'table' } },
+    debug = { cfg.debug, { 'boolean', 'nil' }, true },
     open_url = { cfg.open_url, { 'boolean', 'nil' }, true },
+    filename = { cfg.filename, { 'function', 'nil' }, true },
+    scrapers = {
+      cfg.scrapers,
+      function(v)
+        if type(v) ~= 'table' then
+          return false
+        end
+        for _, s in ipairs(v) do
+          if not vim.tbl_contains(constants.PLATFORMS, s) then
+            return false
+          end
+        end
+        return true
+      end,
+      ('one of {%s}'):format(table.concat(constants.PLATFORMS, ',')),
+    },
     before_run = { cfg.hooks.before_run, { 'function', 'nil' }, true },
     before_debug = { cfg.hooks.before_debug, { 'function', 'nil' }, true },
     setup_code = { cfg.hooks.setup_code, { 'function', 'nil' }, true },
@@ -309,14 +338,23 @@ function M.setup(user_config)
     setup_io_output = { cfg.hooks.setup_io_output, { 'function', 'nil' }, true },
   })
 
+  local layouts = require('cp.ui.layouts')
   vim.validate({
     ansi = { cfg.ui.ansi, 'boolean' },
-    diff_mode = {
+    diff_modes = {
-      cfg.ui.panel.diff_mode,
+      cfg.ui.panel.diff_modes,
       function(v)
-        return vim.tbl_contains({ 'none', 'vim', 'git' }, v)
+        if type(v) ~= 'table' then
+          return false
+        end
+        for _, mode in ipairs(v) do
+          if not layouts.DIFF_MODES[mode] then
+            return false
+          end
+        end
+        return true
       end,
-      "diff_mode must be 'none', 'vim', or 'git'",
+      ('one of {%s}'):format(table.concat(vim.tbl_keys(layouts.DIFF_MODES), ',')),
     },
     max_output_lines = {
       cfg.ui.panel.max_output_lines,
@@ -326,6 +364,14 @@ function M.setup(user_config)
       'positive integer',
     },
     git = { cfg.ui.diff.git, { 'table' } },
+    git_args = { cfg.ui.diff.git.args, is_string_list, 'string[]' },
+    width = {
+      cfg.ui.run.width,
+      function(v)
+        return type(v) == 'number' and v > 0 and v <= 1
+      end,
+      'decimal between 0 and 1',
+    },
     next_test_key = {
       cfg.ui.run.next_test_key,
       function(v)
@@ -379,6 +425,13 @@ function M.setup(user_config)
       end,
       'nil or non-empty string',
     },
+    picker = {
+      cfg.ui.picker,
+      function(v)
+        return v == nil or v == 'telescope' or v == 'fzf-lua'
+      end,
+      "nil, 'telescope', or 'fzf-lua'",
+    },
   })
 
   for id, lang in pairs(cfg.languages) do
@@ -439,7 +492,18 @@ function M.get_language_for_platform(platform_id, language_id)
     }
   end
 
-  local effective = cfg.runtime.effective[platform_id][language_id]
+  local platform_effective = cfg.runtime.effective[platform_id]
+  if not platform_effective then
+    return {
+      valid = false,
+      error = string.format(
+        'No runtime config for platform %s (plugin not initialized)',
+        platform_id
+      ),
+    }
+  end
+
+  local effective = platform_effective[language_id]
   if not effective then
     return {
       valid = false,

lua/cp/constants.lua

@@ -1,10 +1,11 @@
 local M = {}
 
-M.PLATFORMS = { 'atcoder', 'codeforces', 'cses' }
+M.PLATFORMS = { 'atcoder', 'codechef', 'codeforces', 'cses' }
 M.ACTIONS = { 'run', 'panel', 'next', 'prev', 'pick', 'cache', 'interact', 'edit' }
 
 M.PLATFORM_DISPLAY_NAMES = {
   atcoder = 'AtCoder',
+  codechef = 'CodeChef',
   codeforces = 'CodeForces',
   cses = 'CSES',
 }

lua/cp/health.lua

@@ -5,6 +5,8 @@ local utils = require('cp.utils')
 local function check()
   vim.health.start('cp.nvim [required] ~')
 
+  utils.setup_python_env()
+
   if vim.fn.has('nvim-0.10.0') == 1 then
     vim.health.ok('Neovim 0.10.0+ detected')
   else
@@ -16,6 +18,16 @@ local function check()
     vim.health.error('Windows is not supported')
   end
 
+  if utils.is_nix_build() then
+    local source = utils.is_nix_discovered() and 'runtime discovery' or 'flake install'
+    vim.health.ok('Nix Python environment detected (' .. source .. ')')
+    local py = utils.get_nix_python()
+    vim.health.info('Python: ' .. py)
+    local r = vim.system({ py, '--version' }, { text = true }):wait()
+    if r.code == 0 then
+      vim.health.info('Python version: ' .. r.stdout:gsub('\n', ''))
+    end
+  else
     if vim.fn.executable('uv') == 1 then
       vim.health.ok('uv executable found')
       local r = vim.system({ 'uv', '--version' }, { text = true }):wait()
@@ -26,6 +38,10 @@ local function check()
       vim.health.warn('uv not found (install https://docs.astral.sh/uv/ for scraping)')
     end
 
+    if vim.fn.executable('nix') == 1 then
+      vim.health.info('nix available but Python environment not resolved via nix')
+    end
+
     local plugin_path = utils.get_plugin_path()
     local venv_dir = plugin_path .. '/.venv'
     if vim.fn.isdirectory(venv_dir) == 1 then
@@ -33,6 +49,7 @@ local function check()
     else
       vim.health.info('Python virtual environment not set up (created on first scrape)')
     end
+  end
 
   local time_cap = utils.time_capability()
   if time_cap.ok then
@@ -41,7 +58,7 @@ local function check()
     vim.health.error('GNU time not found: ' .. (time_cap.reason or ''))
   end
 
-  local timeout_cap = utils.time_capability()
+  local timeout_cap = utils.timeout_capability()
   if timeout_cap.ok then
     vim.health.ok('GNU timeout found: ' .. timeout_cap.path)
   else

lua/cp/init.lua

@@ -11,27 +11,44 @@ if vim.fn.has('nvim-0.10.0') == 0 then
   return {}
 end
 
-local user_config = {}
-local config = nil
 local initialized = false
 
+local function ensure_initialized()
+  if initialized then
+    return true
+  end
+  local user_config = vim.g.cp or {}
+  local ok, result = pcall(config_module.setup, user_config)
+  if not ok then
+    local msg = tostring(result):gsub('^.+:%d+: ', '')
+    vim.notify(msg, vim.log.levels.ERROR)
+    return false
+  end
+  config_module.set_current_config(result)
+  initialized = true
+  return true
+end
+
 ---@return nil
 function M.handle_command(opts)
+  if not ensure_initialized() then
+    return
+  end
   local commands = require('cp.commands')
   commands.handle_command(opts)
 end
 
-function M.setup(opts)
-  opts = opts or {}
-  user_config = opts
-  config = config_module.setup(user_config)
-  config_module.set_current_config(config)
-
-  initialized = true
-end
-
 function M.is_initialized()
   return initialized
 end
 
+---@deprecated Use `vim.g.cp` instead
+function M.setup(user_config)
+  vim.deprecate('require("cp").setup()', 'vim.g.cp', 'v0.7.7', 'cp.nvim', false)
+
+  if user_config then
+    vim.g.cp = vim.tbl_deep_extend('force', vim.g.cp or {}, user_config)
+  end
+end
+
 return M

lua/cp/pickers/fzf_lua.lua

@@ -51,8 +51,6 @@ local function contest_picker(platform, refresh, language)
         end
       end,
       ['ctrl-r'] = function()
-        local cache = require('cp.cache')
-        cache.clear_contest_list(platform)
         contest_picker(platform, true, language)
       end,
     },

lua/cp/runner/execute.lua

@@ -39,14 +39,15 @@ end
 
 ---@param compile_cmd string[]
 ---@param substitutions SubstitutableCommand
-function M.compile(compile_cmd, substitutions)
+---@param on_complete fun(r: {code: integer, stdout: string})
+function M.compile(compile_cmd, substitutions, on_complete)
   local cmd = substitute_template(compile_cmd, substitutions)
   local sh = table.concat(cmd, ' ') .. ' 2>&1'
+  logger.log('compile: ' .. sh)
 
   local t0 = vim.uv.hrtime()
-  local r = vim.system({ 'sh', '-c', sh }, { text = false }):wait()
+  vim.system({ 'sh', '-c', sh }, { text = false }, function(r)
     local dt = (vim.uv.hrtime() - t0) / 1e6
-
     local ansi = require('cp.ui.ansi')
     r.stdout = ansi.bytes_to_string(r.stdout or '')
 
@@ -56,7 +57,10 @@ function M.compile(compile_cmd, substitutions)
       logger.log(('Compilation failed in %.1fms.'):format(dt))
     end
 
-  return r
+    vim.schedule(function()
+      on_complete(r)
+    end)
+  end)
 end
 
 local function parse_and_strip_time_v(output)
@@ -73,14 +77,20 @@ local function parse_and_strip_time_v(output)
     return s, 0
   end
 
-  local k = last_i - 1
+  local tab_before_marker = s:find('\t[^\t]*Command being timed:', 1)
+  local k
+  if tab_before_marker then
+    k = tab_before_marker - 1
+  else
+    k = last_i - 1
     while k >= 1 do
       local ch = s:sub(k, k)
-    if ch ~= ' ' and ch ~= '\t' then
+      if ch == '\n' then
         break
       end
       k = k - 1
     end
+  end
 
   local head = s:sub(1, k)
   local tail = s:sub(last_i)
@@ -97,7 +107,8 @@ local function parse_and_strip_time_v(output)
   return head, peak_mb
 end
 
-function M.run(cmd, stdin, timeout_ms, memory_mb)
+---@param on_complete fun(result: ExecuteResult)
+function M.run(cmd, stdin, timeout_ms, memory_mb, on_complete)
   local time_bin = utils.time_path()
   local timeout_bin = utils.timeout_path()
 
@@ -109,14 +120,10 @@ function M.run(cmd, stdin, timeout_ms, memory_mb)
   local sec = math.ceil(timeout_ms / 1000)
   local timeout_prefix = ('%s -k 1s %ds '):format(timeout_bin, sec)
   local sh = prefix .. timeout_prefix .. ('%s -v sh -c %q 2>&1'):format(time_bin, prog)
+  logger.log('run: ' .. sh)
 
   local t0 = vim.uv.hrtime()
-  local r = vim
+  vim.system({ 'sh', '-c', sh }, { stdin = stdin, text = true }, function(r)
-    .system({ 'sh', '-c', sh }, {
-      stdin = stdin,
-      text = true,
-    })
-    :wait()
     local dt = (vim.uv.hrtime() - t0) / 1e6
 
     local code = r.code or 0
@@ -137,7 +144,7 @@ function M.run(cmd, stdin, timeout_ms, memory_mb)
       or lower:find('enomem', 1, true)
     local near_cap = peak_mb >= (0.90 * memory_mb)
 
-  local mled = (peak_mb >= memory_mb) or near_cap or (oom_hint and not tled)
+    local mled = (peak_mb >= memory_mb) or near_cap or (oom_hint ~= nil and not tled)
 
     if tled then
       logger.log(('Execution timed out in %.1fms.'):format(dt))
@@ -149,7 +156,8 @@ function M.run(cmd, stdin, timeout_ms, memory_mb)
       logger.log(('Execution successful in %.1fms.'):format(dt))
     end
 
-  return {
+    vim.schedule(function()
+      on_complete({
         stdout = cleaned,
         code = code,
         time_ms = dt,
@@ -157,30 +165,49 @@ function M.run(cmd, stdin, timeout_ms, memory_mb)
         mled = mled,
         peak_mb = peak_mb,
         signal = signal,
-  }
+      })
+    end)
+  end)
 end
 
-function M.compile_problem(debug)
+---@param debug boolean?
+---@param on_complete fun(result: {success: boolean, output: string?})
+function M.compile_problem(debug, on_complete)
   local state = require('cp.state')
   local config = require('cp.config').get_config()
   local platform = state.get_platform()
   local language = state.get_language() or config.platforms[platform].default_language
   local eff = config.runtime.effective[platform][language]
 
+  local source_file = state.get_source_file()
+  if source_file then
+    local buf = vim.fn.bufnr(source_file)
+    if buf ~= -1 and vim.api.nvim_buf_is_loaded(buf) and vim.bo[buf].modified then
+      vim.api.nvim_buf_call(buf, function()
+        vim.cmd.write({ mods = { silent = true, noautocmd = true } })
+      end)
+    end
+  end
+
   local compile_config = (debug and eff.commands.debug) or eff.commands.build
 
   if not compile_config then
-    return { success = true, output = nil }
+    on_complete({ success = true, output = nil })
+    return
   end
 
+  require('cp.utils').ensure_dirs()
+
   local binary = debug and state.get_debug_file() or state.get_binary_file()
   local substitutions = { source = state.get_source_file(), binary = binary }
-  local r = M.compile(compile_config, substitutions)
 
+  M.compile(compile_config, substitutions, function(r)
     if r.code ~= 0 then
-    return { success = false, output = r.stdout or 'unknown error' }
+      on_complete({ success = false, output = r.stdout or 'unknown error' })
+    else
+      on_complete({ success = true, output = nil })
     end
-  return { success = true, output = nil }
+  end)
 end
 
 return M

lua/cp/runner/run.lua

@@ -101,8 +101,8 @@ end
 
 ---@param test_case RanTestCase
 ---@param debug boolean?
----@return { status: "pass"|"fail"|"tle"|"mle", actual: string, actual_highlights: Highlight[], error: string, stderr: string, time_ms: number, code: integer, ok: boolean, signal: string, tled: boolean, mled: boolean, rss_mb: number }
+---@param on_complete fun(result: { status: "pass"|"fail"|"tle"|"mle", actual: string, actual_highlights: Highlight[], error: string, stderr: string, time_ms: number, code: integer, ok: boolean, signal: string?, tled: boolean, mled: boolean, rss_mb: number })
-local function run_single_test_case(test_case, debug)
+local function run_single_test_case(test_case, debug, on_complete)
   local source_file = state.get_source_file()
 
   local binary_file = debug and state.get_debug_file() or state.get_binary_file()
@@ -117,8 +117,7 @@ local function run_single_test_case(test_case, debug)
   local timeout_ms = (panel_state.constraints and panel_state.constraints.timeout_ms) or 0
   local memory_mb = panel_state.constraints and panel_state.constraints.memory_mb or 0
 
-  local r = execute.run(cmd, stdin_content, timeout_ms, memory_mb)
+  execute.run(cmd, stdin_content, timeout_ms, memory_mb, function(r)
-
     local ansi = require('cp.ui.ansi')
     local out = r.stdout or ''
     local highlights = {}
@@ -162,7 +161,7 @@ local function run_single_test_case(test_case, debug)
       status = 'fail'
     end
 
-  return {
+    on_complete({
       status = status,
       actual = out,
       actual_highlights = highlights,
@@ -175,7 +174,8 @@ local function run_single_test_case(test_case, debug)
       tled = r.tled or false,
       mled = r.mled or false,
       rss_mb = r.peak_mb or 0,
-  }
+    })
+  end)
 end
 
 ---@return boolean
@@ -198,18 +198,54 @@ function M.load_test_cases()
   return #tcs > 0
 end
 
+---@param debug boolean?
+---@param on_complete fun(result: RanTestCase?)
+function M.run_combined_test(debug, on_complete)
+  local combined = cache.get_combined_test(
+    state.get_platform() or '',
+    state.get_contest_id() or '',
+    state.get_problem_id()
+  )
+
+  if not combined then
+    logger.log('No combined test found', vim.log.levels.ERROR)
+    on_complete(nil)
+    return
+  end
+
+  local ran_test = {
+    index = 1,
+    input = combined.input,
+    expected = combined.expected,
+    status = 'running',
+    actual = nil,
+    time_ms = nil,
+    code = nil,
+    ok = nil,
+    signal = nil,
+    tled = false,
+    mled = false,
+    rss_mb = 0,
+    selected = true,
+  }
+
+  run_single_test_case(ran_test, debug, function(result)
+    on_complete(result)
+  end)
+end
+
 ---@param index number
 ---@param debug boolean?
----@return boolean
+---@param on_complete fun(success: boolean)
-function M.run_test_case(index, debug)
+function M.run_test_case(index, debug, on_complete)
   local tc = panel_state.test_cases[index]
   if not tc then
-    return false
+    on_complete(false)
+    return
   end
 
   tc.status = 'running'
-  local r = run_single_test_case(tc, debug)
+  run_single_test_case(tc, debug, function(r)
-
     tc.status = r.status
     tc.actual = r.actual
     tc.actual_highlights = r.actual_highlights
@@ -223,13 +259,15 @@ function M.run_test_case(index, debug)
     tc.mled = r.mled
     tc.rss_mb = r.rss_mb
 
-  return true
+    on_complete(true)
+  end)
 end
 
 ---@param indices? integer[]
 ---@param debug boolean?
----@return RanTestCase[]
+---@param on_each? fun(index: integer, total: integer)
-function M.run_all_test_cases(indices, debug)
+---@param on_done fun(results: RanTestCase[])
+function M.run_all_test_cases(indices, debug, on_each, on_done)
   local to_run = indices
   if not to_run then
     to_run = {}
@@ -238,11 +276,26 @@ function M.run_all_test_cases(indices, debug)
     end
   end
 
-  for _, i in ipairs(to_run) do
+  local function run_next(pos)
-    M.run_test_case(i, debug)
+    if pos > #to_run then
+      logger.log(
+        ('Finished %s %d test cases.'):format(debug and 'debugging' or 'running', #to_run),
+        vim.log.levels.INFO,
+        true
+      )
+      on_done(panel_state.test_cases)
+      return
     end
 
-  return panel_state.test_cases
+    M.run_test_case(to_run[pos], debug, function()
+      if on_each then
+        on_each(pos, #to_run)
+      end
+      run_next(pos + 1)
+    end)
+  end
+
+  run_next(1)
 end
 
 ---@return PanelState

lua/cp/runner/run_render.lua

@@ -4,6 +4,10 @@
 
 local M = {}
 
+local function strwidth(s)
+  return vim.api.nvim_strwidth(s)
+end
+
 local exit_code_names = {
   [128] = 'SIGHUP',
   [129] = 'SIGINT',
@@ -26,6 +30,12 @@ local exit_code_names = {
 ---@param ran_test_case RanTestCase
 ---@return StatusInfo
 function M.get_status_info(ran_test_case)
+  if ran_test_case.status == 'pending' then
+    return { text = '...', highlight_group = 'CpTestNA' }
+  elseif ran_test_case.status == 'running' then
+    return { text = 'RUN', highlight_group = 'CpTestNA' }
+  end
+
   if ran_test_case.ok then
     return { text = 'AC', highlight_group = 'CpTestAC' }
   end
@@ -34,7 +44,7 @@ function M.get_status_info(ran_test_case)
     return { text = 'TLE', highlight_group = 'CpTestTLE' }
   elseif ran_test_case.mled then
     return { text = 'MLE', highlight_group = 'CpTestMLE' }
-  elseif ran_test_case.code > 0 and ran_test_case.code >= 128 then
+  elseif ran_test_case.code and ran_test_case.code >= 128 then
     return { text = 'RTE', highlight_group = 'CpTestRTE' }
   elseif ran_test_case.code == 0 and not ran_test_case.ok then
     return { text = 'WA', highlight_group = 'CpTestWA' }
@@ -63,24 +73,24 @@ local function compute_cols(test_state)
 
   for i, tc in ipairs(test_state.test_cases) do
     local prefix = (i == test_state.current_index) and '>' or ' '
-    w.num = math.max(w.num, #(' ' .. prefix .. i .. ' '))
+    w.num = math.max(w.num, strwidth(' ' .. prefix .. i .. ' '))
-    w.status = math.max(w.status, #(' ' .. M.get_status_info(tc).text .. ' '))
+    w.status = math.max(w.status, strwidth(' ' .. M.get_status_info(tc).text .. ' '))
     local time_str = tc.time_ms and string.format('%.2f', tc.time_ms) or '—'
-    w.time = math.max(w.time, #(' ' .. time_str .. ' '))
+    w.time = math.max(w.time, strwidth(' ' .. time_str .. ' '))
-    w.timeout = math.max(w.timeout, #(' ' .. timeout_str .. ' '))
+    w.timeout = math.max(w.timeout, strwidth(' ' .. timeout_str .. ' '))
     local rss_str = (tc.rss_mb and string.format('%.0f', tc.rss_mb)) or '—'
-    w.rss = math.max(w.rss, #(' ' .. rss_str .. ' '))
+    w.rss = math.max(w.rss, strwidth(' ' .. rss_str .. ' '))
-    w.memory = math.max(w.memory, #(' ' .. memory_str .. ' '))
+    w.memory = math.max(w.memory, strwidth(' ' .. memory_str .. ' '))
-    w.exit = math.max(w.exit, #(' ' .. format_exit_code(tc.code) .. ' '))
+    w.exit = math.max(w.exit, strwidth(' ' .. format_exit_code(tc.code) .. ' '))
   end
 
-  w.num = math.max(w.num, #' # ')
+  w.num = math.max(w.num, strwidth(' # '))
-  w.status = math.max(w.status, #' Status ')
+  w.status = math.max(w.status, strwidth(' Status '))
-  w.time = math.max(w.time, #' Runtime (ms) ')
+  w.time = math.max(w.time, strwidth(' Runtime (ms) '))
-  w.timeout = math.max(w.timeout, #' Time (ms) ')
+  w.timeout = math.max(w.timeout, strwidth(' Time (ms) '))
-  w.rss = math.max(w.rss, #' RSS (MB) ')
+  w.rss = math.max(w.rss, strwidth(' RSS (MB) '))
-  w.memory = math.max(w.memory, #' Mem (MB) ')
+  w.memory = math.max(w.memory, strwidth(' Mem (MB) '))
-  w.exit = math.max(w.exit, #' Exit Code ')
+  w.exit = math.max(w.exit, strwidth(' Exit Code '))
 
   local sum = w.num + w.status + w.time + w.timeout + w.rss + w.memory + w.exit
   local inner = sum + 6
@@ -89,7 +99,7 @@ local function compute_cols(test_state)
 end
 
 local function center(text, width)
-  local pad = width - #text
+  local pad = width - strwidth(text)
   if pad <= 0 then
     return text
   end
@@ -101,7 +111,7 @@ local function format_num_column(prefix, idx, width)
   local num_str = tostring(idx)
   local content = (#num_str == 1) and (' ' .. prefix .. ' ' .. num_str .. ' ')
     or (' ' .. prefix .. num_str .. ' ')
-  local total_pad = width - #content
+  local total_pad = width - strwidth(content)
   if total_pad <= 0 then
     return content
   end
@@ -314,10 +324,10 @@ function M.render_test_list(test_state)
 
       for _, input_line in ipairs(vim.split(tc.input, '\n', { plain = true, trimempty = false })) do
         local s = input_line or ''
-        if #s > c.inner then
+        if strwidth(s) > c.inner then
           s = string.sub(s, 1, c.inner)
         end
-        local pad = c.inner - #s
+        local pad = c.inner - strwidth(s)
         table.insert(lines, '│' .. s .. string.rep(' ', pad) .. '│')
       end
 
@@ -357,14 +367,12 @@ end
 ---@return table<string, table>
 function M.get_highlight_groups()
   return {
-    CpTestAC = { fg = '#10b981' },
+    CpTestAC = { link = 'DiagnosticOk' },
-    CpTestWA = { fg = '#ef4444' },
+    CpTestWA = { link = 'DiagnosticError' },
-    CpTestTLE = { fg = '#f59e0b' },
+    CpTestTLE = { link = 'DiagnosticWarn' },
-    CpTestMLE = { fg = '#f59e0b' },
+    CpTestMLE = { link = 'DiagnosticWarn' },
-    CpTestRTE = { fg = '#8b5cf6' },
+    CpTestRTE = { link = 'DiagnosticHint' },
-    CpTestNA = { fg = '#6b7280' },
+    CpTestNA = { link = 'Comment' },
-    CpDiffRemoved = { fg = '#ef4444', bg = '#1f1f1f' },
-    CpDiffAdded = { fg = '#10b981', bg = '#1f1f1f' },
   }
 end
 

lua/cp/scraper.lua

@@ -25,10 +25,27 @@ end
 ---@param args string[]
 ---@param opts { sync?: boolean, ndjson?: boolean, on_event?: fun(ev: table), on_exit?: fun(result: table) }
 local function run_scraper(platform, subcommand, args, opts)
+  if not utils.setup_python_env() then
+    local msg = 'no Python environment available (install uv or nix)'
+    logger.log(msg, vim.log.levels.ERROR)
+    if opts and opts.on_exit then
+      opts.on_exit({ success = false, error = msg })
+    end
+    return { success = false, error = msg }
+  end
+
   local plugin_path = utils.get_plugin_path()
-  local cmd = { 'uv', 'run', '--directory', plugin_path, '-m', 'scrapers.' .. platform, subcommand }
+  local cmd = utils.get_python_cmd(platform, plugin_path)
+  vim.list_extend(cmd, { subcommand })
   vim.list_extend(cmd, args)
 
+  logger.log('scraper cmd: ' .. table.concat(cmd, ' '))
+
+  local env = vim.fn.environ()
+  env.VIRTUAL_ENV = ''
+  env.PYTHONPATH = ''
+  env.CONDA_PREFIX = ''
+
   if opts and opts.ndjson then
     local uv = vim.loop
     local stdout = uv.new_pipe(false)
@@ -36,10 +53,12 @@ local function run_scraper(platform, subcommand, args, opts)
     local buf = ''
 
     local handle
-    handle = uv.spawn(
+    handle = uv.spawn(cmd[1], {
-      cmd[1],
+      args = vim.list_slice(cmd, 2),
-      { args = vim.list_slice(cmd, 2), stdio = { nil, stdout, stderr } },
+      stdio = { nil, stdout, stderr },
-      function(code, signal)
+      env = env,
+      cwd = plugin_path,
+    }, function(code, signal)
       if buf ~= '' and opts.on_event then
         local ok_tail, ev_tail = pcall(vim.json.decode, buf)
         if ok_tail then
@@ -59,8 +78,7 @@ local function run_scraper(platform, subcommand, args, opts)
       if handle and not handle:is_closing() then
         handle:close()
       end
-      end
+    end)
-    )
 
     if not handle then
       logger.log('Failed to start scraper process', vim.log.levels.ERROR)
@@ -97,7 +115,7 @@ local function run_scraper(platform, subcommand, args, opts)
     return
   end
 
-  local sysopts = { text = true, timeout = 30000 }
+  local sysopts = { text = true, timeout = 30000, env = env, cwd = plugin_path }
   if opts and opts.sync then
     local result = vim.system(cmd, sysopts):wait()
     return syshandle(result)
@@ -181,7 +199,7 @@ function M.scrape_all_tests(platform, contest_id, callback)
         return
       end
       vim.schedule(function()
-        vim.system({ 'mkdir', '-p', 'build', 'io' }):wait()
+        require('cp.utils').ensure_dirs()
         local config = require('cp.config')
         local base_name = config.default_filename(contest_id, ev.problem_id)
         for i, t in ipairs(ev.tests) do
@@ -189,15 +207,17 @@ function M.scrape_all_tests(platform, contest_id, callback)
           local expected_file = 'io/' .. base_name .. '.' .. i .. '.cpout'
           local input_content = t.input:gsub('\r', '')
           local expected_content = t.expected:gsub('\r', '')
-          vim.fn.writefile(vim.split(input_content, '\n', { trimempty = true }), input_file)
+          vim.fn.writefile(vim.split(input_content, '\n'), input_file)
-          vim.fn.writefile(vim.split(expected_content, '\n', { trimempty = true }), expected_file)
+          vim.fn.writefile(vim.split(expected_content, '\n'), expected_file)
         end
         if type(callback) == 'function' then
           callback({
+            combined = ev.combined,
             tests = ev.tests,
             timeout_ms = ev.timeout_ms or 0,
             memory_mb = ev.memory_mb or 0,
             interactive = ev.interactive or false,
+            multi_test = ev.multi_test or false,
             problem_id = ev.problem_id,
           })
         end

lua/cp/setup.lua

@@ -82,7 +82,7 @@ local function start_tests(platform, contest_id, problems)
     return not vim.tbl_isempty(cache.get_test_cases(platform, contest_id, p.id))
   end, problems)
   if cached_len ~= #problems then
-    logger.log(('Fetching test cases... (%d/%d)'):format(cached_len, #problems))
+    logger.log(('Fetching %s/%s problem tests...'):format(cached_len, #problems))
     scraper.scrape_all_tests(platform, contest_id, function(ev)
       local cached_tests = {}
       if not ev.interactive and vim.tbl_isempty(ev.tests) then
@@ -95,23 +95,22 @@ local function start_tests(platform, contest_id, problems)
         platform,
         contest_id,
         ev.problem_id,
+        ev.combined,
         cached_tests,
         ev.timeout_ms or 0,
         ev.memory_mb or 0,
-        ev.interactive
+        ev.interactive,
+        ev.multi_test
       )
 
       local io_state = state.get_io_view_state()
       if io_state then
-        local test_cases = cache.get_test_cases(platform, contest_id, state.get_problem_id())
+        local combined_test = cache.get_combined_test(platform, contest_id, state.get_problem_id())
-        local input_lines = {}
+        if combined_test then
-        for _, tc in ipairs(test_cases) do
+          local input_lines = vim.split(combined_test.input, '\n')
-          for _, line in ipairs(vim.split(tc.input, '\n')) do
-            table.insert(input_lines, line)
-          end
-        end
           require('cp.utils').update_buffer_content(io_state.input_buf, input_lines, nil, nil)
         end
+      end
     end)
   end
 end
@@ -161,6 +160,8 @@ function M.setup_contest(platform, contest_id, problem_id, language)
     vim.bo[bufnr].buftype = ''
     vim.bo[bufnr].swapfile = false
 
+    state.set_language(lang)
+
     if cfg.hooks and cfg.hooks.setup_code and not vim.b[bufnr].cp_setup_done then
       local ok = pcall(cfg.hooks.setup_code, state)
       if ok then
@@ -217,7 +218,16 @@ function M.setup_problem(problem_id, language)
     return
   end
 
+  local old_problem_id = state.get_problem_id()
   state.set_problem_id(problem_id)
+
+  if old_problem_id ~= problem_id then
+    local io_state = state.get_io_view_state()
+    if io_state and io_state.output_buf and vim.api.nvim_buf_is_valid(io_state.output_buf) then
+      local utils = require('cp.utils')
+      utils.update_buffer_content(io_state.output_buf, {}, nil, nil)
+    end
+  end
   local config = config_module.get_config()
   local lang = language
     or (config.platforms[platform] and config.platforms[platform].default_language)
@@ -242,6 +252,11 @@ function M.setup_problem(problem_id, language)
   local prov = state.get_provisional()
   if prov and prov.platform == platform and prov.contest_id == (state.get_contest_id() or '') then
     if vim.api.nvim_buf_is_valid(prov.bufnr) then
+      local existing_bufnr = vim.fn.bufnr(source_file)
+      if existing_bufnr ~= -1 then
+        vim.api.nvim_buf_delete(prov.bufnr, { force = true })
+        state.set_provisional(nil)
+      else
         vim.api.nvim_buf_set_name(prov.bufnr, source_file)
         vim.bo[prov.bufnr].swapfile = true
         -- selene: allow(mixed_table)
@@ -268,16 +283,19 @@ function M.setup_problem(problem_id, language)
           lang
         )
         require('cp.ui.views').ensure_io_view()
-    end
         state.set_provisional(nil)
         return
       end
+    else
+      state.set_provisional(nil)
+    end
+  end
 
-  vim.schedule(function()
   vim.cmd.only({ mods = { silent = true } })
   vim.cmd.e(source_file)
   local bufnr = vim.api.nvim_get_current_buf()
   state.set_solution_win(vim.api.nvim_get_current_win())
+  require('cp.ui.views').ensure_io_view()
   if config.hooks and config.hooks.setup_code and not vim.b[bufnr].cp_setup_done then
     local ok = pcall(config.hooks.setup_code, state)
     if ok then
@@ -294,8 +312,6 @@ function M.setup_problem(problem_id, language)
     state.get_problem_id() or '',
     lang
   )
-    require('cp.ui.views').ensure_io_view()
-  end)
 end
 
 ---@param direction integer
@@ -334,6 +350,8 @@ function M.navigate_problem(direction, language)
     return
   end
 
+  logger.log(('navigate_problem: %s -> %s'):format(current_problem_id, problems[new_index].id))
+
   local active_panel = state.get_active_panel()
   if active_panel == 'run' then
     require('cp.ui.views').disable()
@@ -364,6 +382,12 @@ function M.navigate_problem(direction, language)
     end
   end
 
+  local io_state = state.get_io_view_state()
+  if io_state and io_state.output_buf and vim.api.nvim_buf_is_valid(io_state.output_buf) then
+    local utils = require('cp.utils')
+    utils.update_buffer_content(io_state.output_buf, {}, nil, nil)
+  end
+
   M.setup_contest(platform, contest_id, problems[new_index].id, lang)
 end
 

lua/cp/state.lua

@@ -9,9 +9,8 @@
 ---@class cp.IoViewState
 ---@field output_buf integer
 ---@field input_buf integer
----@field output_win integer
----@field input_win integer
 ---@field current_test_index integer?
+---@field source_buf integer?
 
 ---@class cp.State
 ---@field get_platform fun(): string?
@@ -200,19 +199,7 @@ end
 
 ---@return cp.IoViewState?
 function M.get_io_view_state()
-  if not state.io_view_state then
+  return state.io_view_state
-    return nil
-  end
-  local s = state.io_view_state
-  if
-    vim.api.nvim_buf_is_valid(s.output_buf)
-    and vim.api.nvim_buf_is_valid(s.input_buf)
-    and vim.api.nvim_win_is_valid(s.output_win)
-    and vim.api.nvim_win_is_valid(s.input_win)
-  then
-    return s
-  end
-  return nil
 end
 
 ---@param s cp.IoViewState?

lua/cp/ui/edit.lua

@@ -90,7 +90,7 @@ local function delete_current_test()
     return
   end
   if #edit_state.test_buffers == 1 then
-    logger.log('Cannot have 0 problem tests.', vim.log.levels.ERROR)
+    logger.log('Problems must have at least one test case.', vim.log.levels.ERROR)
     return
   end
 
@@ -217,6 +217,32 @@ setup_keybindings = function(buf)
       { buffer = buf, silent = true, desc = 'Add test' }
     )
   end
+
+  local augroup = vim.api.nvim_create_augroup('cp_edit_guard', { clear = false })
+  vim.api.nvim_create_autocmd({ 'BufDelete', 'BufWipeout' }, {
+    group = augroup,
+    buffer = buf,
+    callback = function()
+      vim.schedule(function()
+        if not edit_state then
+          return
+        end
+
+        local is_tracked = false
+        for _, pair in ipairs(edit_state.test_buffers) do
+          if pair.input_buf == buf or pair.expected_buf == buf then
+            is_tracked = true
+            break
+          end
+        end
+
+        if is_tracked then
+          logger.log('Test buffer closed unexpectedly. Exiting editor.', vim.log.levels.WARN)
+          M.toggle_edit()
+        end
+      end)
+    end,
+  })
 end
 
 local function save_all_tests()
@@ -244,14 +270,34 @@ local function save_all_tests()
     end
   end
 
+  local contest_data = cache.get_contest_data(platform, contest_id)
+  local is_multi_test = contest_data.problems[contest_data.index_map[problem_id]].multi_test
+    or false
+
+  -- Generate combined test from individual test cases
+  local combined_input = table.concat(
+    vim.tbl_map(function(tc)
+      return tc.input
+    end, edit_state.test_cases),
+    '\n'
+  )
+  local combined_expected = table.concat(
+    vim.tbl_map(function(tc)
+      return tc.expected
+    end, edit_state.test_cases),
+    '\n'
+  )
+
   cache.set_test_cases(
     platform,
     contest_id,
     problem_id,
+    { input = combined_input, expected = combined_expected },
     edit_state.test_cases,
     edit_state.constraints and edit_state.constraints.timeout_ms or 0,
     edit_state.constraints and edit_state.constraints.memory_mb or 0,
-    false
+    false,
+    is_multi_test
   )
 
   local config = config_module.get_config()
@@ -279,6 +325,8 @@ function M.toggle_edit(test_index)
     save_all_tests()
     edit_state = nil
 
+    pcall(vim.api.nvim_clear_autocmds, { group = 'cp_edit_guard' })
+
     local saved = state.get_saved_session()
     if saved then
       vim.fn.delete(saved)

lua/cp/ui/highlight.lua

@@ -26,7 +26,7 @@ local function parse_diff_line(text)
         line = 0,
         col_start = highlight_start,
         col_end = #result_text,
-        highlight_group = 'CpDiffRemoved',
+        highlight_group = 'DiffDelete',
       })
       pos = removed_end + 1
     else
@@ -38,7 +38,7 @@ local function parse_diff_line(text)
           line = 0,
           col_start = highlight_start,
           col_end = #result_text,
-          highlight_group = 'CpDiffAdded',
+          highlight_group = 'DiffAdd',
         })
         pos = added_end + 1
       else

lua/cp/ui/layouts.lua

@@ -3,7 +3,13 @@ local M = {}
 local helpers = require('cp.helpers')
 local utils = require('cp.utils')
 
-local function create_none_diff_layout(parent_win, expected_content, actual_content)
+M.DIFF_MODES = {
+  ['side-by-side'] = 'side-by-side',
+  vim = 'vim',
+  git = 'git',
+}
+
+local function create_side_by_side_layout(parent_win, expected_content, actual_content)
   local expected_buf = utils.create_buffer_with_options()
   local actual_buf = utils.create_buffer_with_options()
   helpers.clearcol(expected_buf)
@@ -21,8 +27,13 @@ local function create_none_diff_layout(parent_win, expected_content, actual_cont
 
   vim.api.nvim_set_option_value('filetype', 'cp', { buf = expected_buf })
   vim.api.nvim_set_option_value('filetype', 'cp', { buf = actual_buf })
-  vim.api.nvim_set_option_value('winbar', 'Expected', { win = expected_win })
+  local label = M.DIFF_MODES['side-by-side']
-  vim.api.nvim_set_option_value('winbar', 'Actual', { win = actual_win })
+  vim.api.nvim_set_option_value(
+    'winbar',
+    ('expected (diff: %s)'):format(label),
+    { win = expected_win }
+  )
+  vim.api.nvim_set_option_value('winbar', ('actual (diff: %s)'):format(label), { win = actual_win })
 
   local expected_lines = vim.split(expected_content, '\n', { plain = true, trimempty = true })
   local actual_lines = vim.split(actual_content, '\n', { plain = true })
@@ -33,6 +44,7 @@ local function create_none_diff_layout(parent_win, expected_content, actual_cont
   return {
     buffers = { expected_buf, actual_buf },
     windows = { expected_win, actual_win },
+    mode = 'side-by-side',
     cleanup = function()
       pcall(vim.api.nvim_win_close, expected_win, true)
       pcall(vim.api.nvim_win_close, actual_win, true)
@@ -60,8 +72,13 @@ local function create_vim_diff_layout(parent_win, expected_content, actual_conte
 
   vim.api.nvim_set_option_value('filetype', 'cp', { buf = expected_buf })
   vim.api.nvim_set_option_value('filetype', 'cp', { buf = actual_buf })
-  vim.api.nvim_set_option_value('winbar', 'Expected', { win = expected_win })
+  local label = M.DIFF_MODES.vim
-  vim.api.nvim_set_option_value('winbar', 'Actual', { win = actual_win })
+  vim.api.nvim_set_option_value(
+    'winbar',
+    ('expected (diff: %s)'):format(label),
+    { win = expected_win }
+  )
+  vim.api.nvim_set_option_value('winbar', ('actual (diff: %s)'):format(label), { win = actual_win })
 
   local expected_lines = vim.split(expected_content, '\n', { plain = true, trimempty = true })
   local actual_lines = vim.split(actual_content, '\n', { plain = true })
@@ -83,6 +100,7 @@ local function create_vim_diff_layout(parent_win, expected_content, actual_conte
   return {
     buffers = { expected_buf, actual_buf },
     windows = { expected_win, actual_win },
+    mode = 'vim',
     cleanup = function()
       pcall(vim.api.nvim_win_close, expected_win, true)
       pcall(vim.api.nvim_win_close, actual_win, true)
@@ -103,7 +121,8 @@ local function create_git_diff_layout(parent_win, expected_content, actual_conte
   vim.api.nvim_win_set_buf(diff_win, diff_buf)
 
   vim.api.nvim_set_option_value('filetype', 'cp', { buf = diff_buf })
-  vim.api.nvim_set_option_value('winbar', 'Expected vs Actual', { win = diff_win })
+  local label = M.DIFF_MODES.git
+  vim.api.nvim_set_option_value('winbar', ('diff: %s'):format(label), { win = diff_win })
 
   local diff_backend = require('cp.ui.diff')
   local backend = diff_backend.get_best_backend('git')
@@ -121,6 +140,7 @@ local function create_git_diff_layout(parent_win, expected_content, actual_conte
   return {
     buffers = { diff_buf },
     windows = { diff_win },
+    mode = 'git',
     cleanup = function()
       pcall(vim.api.nvim_win_close, diff_win, true)
       pcall(vim.api.nvim_buf_delete, diff_buf, { force = true })
@@ -143,6 +163,7 @@ local function create_single_layout(parent_win, content)
   return {
     buffers = { buf },
     windows = { win },
+    mode = 'single',
     cleanup = function()
       pcall(vim.api.nvim_win_close, win, true)
       pcall(vim.api.nvim_buf_delete, buf, { force = true })
@@ -153,12 +174,14 @@ end
 function M.create_diff_layout(mode, parent_win, expected_content, actual_content)
   if mode == 'single' then
     return create_single_layout(parent_win, actual_content)
-  elseif mode == 'none' then
+  elseif mode == 'side-by-side' then
-    return create_none_diff_layout(parent_win, expected_content, actual_content)
+    return create_side_by_side_layout(parent_win, expected_content, actual_content)
   elseif mode == 'git' then
     return create_git_diff_layout(parent_win, expected_content, actual_content)
-  else
+  elseif mode == 'vim' then
     return create_vim_diff_layout(parent_win, expected_content, actual_content)
+  else
+    return create_side_by_side_layout(parent_win, expected_content, actual_content)
   end
 end
 
@@ -191,12 +214,13 @@ function M.update_diff_panes(
     actual_content = actual_content
   end
 
-  local desired_mode = is_compilation_failure and 'single' or config.ui.panel.diff_mode
+  local default_mode = config.ui.panel.diff_modes[1]
+  local desired_mode = is_compilation_failure and 'single' or (current_mode or default_mode)
   local highlight = require('cp.ui.highlight')
   local diff_namespace = highlight.create_namespace()
   local ansi_namespace = vim.api.nvim_create_namespace('cp_ansi_highlights')
 
-  if current_diff_layout and current_mode ~= desired_mode then
+  if current_diff_layout and current_diff_layout.mode ~= desired_mode then
     local saved_pos = vim.api.nvim_win_get_cursor(0)
     current_diff_layout.cleanup()
     current_diff_layout = nil
@@ -251,7 +275,7 @@ function M.update_diff_panes(
           ansi_namespace
         )
       end
-    elseif desired_mode == 'none' then
+    elseif desired_mode == 'side-by-side' then
       local expected_lines = vim.split(expected_content, '\n', { plain = true, trimempty = true })
       local actual_lines = vim.split(actual_content, '\n', { plain = true })
       utils.update_buffer_content(current_diff_layout.buffers[1], expected_lines, {})

lua/cp/ui/views.lua

@@ -13,6 +13,7 @@ local utils = require('cp.utils')
 
 local current_diff_layout = nil
 local current_mode = nil
+local io_view_running = false
 
 function M.disable()
   local active_panel = state.get_active_panel()
@@ -81,15 +82,26 @@ function M.toggle_interactive(interactor_cmd)
 
   local execute = require('cp.runner.execute')
   local run = require('cp.runner.run')
-  local compile_result = execute.compile_problem()
+
+  local function restore_session()
+    if state.saved_interactive_session then
+      vim.cmd.source(state.saved_interactive_session)
+      vim.fn.delete(state.saved_interactive_session)
+      state.saved_interactive_session = nil
+    end
+  end
+
+  execute.compile_problem(false, function(compile_result)
     if not compile_result.success then
       run.handle_compilation_failure(compile_result.output)
+      restore_session()
       return
     end
 
     local binary = state.get_binary_file()
     if not binary or binary == '' then
       logger.log('No binary produced.', vim.log.levels.ERROR)
+      restore_session()
       return
     end
 
@@ -104,14 +116,19 @@ function M.toggle_interactive(interactor_cmd)
           ("Interactor '%s' is not executable."):format(interactor_cmd),
           vim.log.levels.ERROR
         )
-      if state.saved_interactive_session then
+        restore_session()
-        vim.cmd.source(state.saved_interactive_session)
-        vim.fn.delete(state.saved_interactive_session)
-        state.saved_interactive_session = nil
-      end
         return
       end
-    local orchestrator = vim.fn.fnamemodify(utils.get_plugin_path() .. '/scripts/interact.py', ':p')
+      local orchestrator =
+        vim.fn.fnamemodify(utils.get_plugin_path() .. '/scripts/interact.py', ':p')
+      if utils.is_nix_build() then
+        cmdline = table.concat({
+          vim.fn.shellescape(utils.get_nix_python()),
+          vim.fn.shellescape(orchestrator),
+          vim.fn.shellescape(interactor),
+          vim.fn.shellescape(binary),
+        }, ' ')
+      else
         cmdline = table.concat({
           'uv',
           'run',
@@ -119,6 +136,7 @@ function M.toggle_interactive(interactor_cmd)
           vim.fn.shellescape(interactor),
           vim.fn.shellescape(binary),
         }, ' ')
+      end
     else
       cmdline = vim.fn.shellescape(binary)
     end
@@ -139,11 +157,7 @@ function M.toggle_interactive(interactor_cmd)
           pcall(vim.fn.jobstop, job)
         end
       end
-    if state.saved_interactive_session then
+      restore_session()
-      vim.cmd.source(state.saved_interactive_session)
-      vim.fn.delete(state.saved_interactive_session)
-      state.saved_interactive_session = nil
-    end
       state.interactive_buf = nil
       state.interactive_win = nil
       state.set_active_panel(nil)
@@ -151,9 +165,7 @@ function M.toggle_interactive(interactor_cmd)
 
     vim.api.nvim_create_autocmd({ 'BufWipeout', 'BufUnload' }, {
       buffer = term_buf,
-    callback = function()
+      callback = cleanup,
-      cleanup()
-    end,
     })
 
     vim.api.nvim_create_autocmd('WinClosed', {
@@ -191,93 +203,119 @@ function M.toggle_interactive(interactor_cmd)
     state.interactive_buf = term_buf
     state.interactive_win = term_win
     state.set_active_panel('interactive')
+  end)
 end
 
-function M.ensure_io_view()
+---@return integer, integer
-  local platform, contest_id, problem_id =
+local function get_or_create_io_buffers()
-    state.get_platform(), state.get_contest_id(), state.get_problem_id()
-  if not platform or not contest_id or not problem_id then
-    logger.log(
-      'No platform/contest/problem configured. Use :CP <platform> <contest> [...] first.',
-      vim.log.levels.ERROR
-    )
-    return
-  end
-
-  cache.load()
-  local contest_data = cache.get_contest_data(platform, contest_id)
-  if
-    contest_data
-    and contest_data.index_map
-    and contest_data.problems[contest_data.index_map[problem_id]].interactive
-  then
-    logger.log('This problem is not interactive. Use :CP {run,panel}.', vim.log.levels.ERROR)
-    return
-  end
-
-  local solution_win = state.get_solution_win()
   local io_state = state.get_io_view_state()
-  local output_buf, input_buf, output_win, input_win
+  local solution_win = state.get_solution_win()
+  local current_source_buf = vim.api.nvim_win_get_buf(solution_win)
 
   if io_state then
-    output_buf = io_state.output_buf
+    local output_valid = io_state.output_buf and vim.api.nvim_buf_is_valid(io_state.output_buf)
-    input_buf = io_state.input_buf
+    local input_valid = io_state.input_buf and vim.api.nvim_buf_is_valid(io_state.input_buf)
-    output_win = io_state.output_win
+    local same_source = io_state.source_buf == current_source_buf
-    input_win = io_state.input_win
-  else
-    vim.api.nvim_set_current_win(solution_win)
 
-    vim.cmd.vsplit()
+    if output_valid and input_valid and same_source then
-    output_win = vim.api.nvim_get_current_win()
+      return io_state.output_buf, io_state.input_buf
-    local cfg = config_module.get_config()
+    end
-    local width = math.floor(vim.o.columns * (cfg.ui.run.width or 0.3))
-    vim.api.nvim_win_set_width(output_win, width)
-    output_buf = utils.create_buffer_with_options('cpout')
-    vim.api.nvim_win_set_buf(output_win, output_buf)
 
-    vim.cmd.split()
+    if io_state.source_buf then
-    input_win = vim.api.nvim_get_current_win()
+      pcall(vim.api.nvim_del_augroup_by_name, 'cp_io_cleanup_buf' .. io_state.source_buf)
-    input_buf = utils.create_buffer_with_options('cpin')
+    end
-    vim.api.nvim_win_set_buf(input_win, input_buf)
+    if output_valid then
+      pcall(vim.api.nvim_buf_delete, io_state.output_buf, { force = true })
+    end
+    if input_valid then
+      pcall(vim.api.nvim_buf_delete, io_state.input_buf, { force = true })
+    end
+  end
+
+  local output_buf = utils.create_buffer_with_options('cpout')
+  local input_buf = utils.create_buffer_with_options('cpin')
 
   state.set_io_view_state({
     output_buf = output_buf,
     input_buf = input_buf,
-      output_win = output_win,
-      input_win = input_win,
     current_test_index = 1,
+    source_buf = current_source_buf,
   })
 
-    local source_buf = vim.api.nvim_win_get_buf(solution_win)
+  local source_buf = current_source_buf
+
+  local group_name = 'cp_io_cleanup_buf' .. source_buf
+  vim.api.nvim_create_augroup(group_name, { clear = true })
   vim.api.nvim_create_autocmd('BufDelete', {
+    group = group_name,
     buffer = source_buf,
     callback = function()
       local io = state.get_io_view_state()
-        if io then
+
+      if not io then
+        return
+      end
+
       if io.output_buf and vim.api.nvim_buf_is_valid(io.output_buf) then
         vim.api.nvim_buf_delete(io.output_buf, { force = true })
       end
       if io.input_buf and vim.api.nvim_buf_is_valid(io.input_buf) then
         vim.api.nvim_buf_delete(io.input_buf, { force = true })
       end
+
       state.set_io_view_state(nil)
-        end
     end,
   })
 
-    if cfg.hooks and cfg.hooks.setup_io_output then
+  vim.api.nvim_create_autocmd({ 'BufWinEnter', 'BufWinLeave' }, {
-      pcall(cfg.hooks.setup_io_output, output_buf, state)
+    group = group_name,
+    buffer = source_buf,
+    callback = function()
+      vim.schedule(function()
+        local io = state.get_io_view_state()
+        if not io then
+          return
         end
 
-    if cfg.hooks and cfg.hooks.setup_io_input then
+        if io.source_buf ~= source_buf then
-      pcall(cfg.hooks.setup_io_input, input_buf, state)
+          return
         end
 
+        local wins = vim.api.nvim_list_wins()
+        for _, win in ipairs(wins) do
+          if vim.api.nvim_win_get_buf(win) == source_buf then
+            return
+          end
+        end
+
+        for _, win in ipairs(wins) do
+          local buf = vim.api.nvim_win_get_buf(win)
+          if buf == io.output_buf or buf == io.input_buf then
+            if #vim.api.nvim_list_wins() > 1 then
+              pcall(vim.api.nvim_win_close, win, true)
+            else
+              local replacement = vim.api.nvim_create_buf(false, true)
+              vim.api.nvim_win_set_buf(win, replacement)
+            end
+          end
+        end
+      end)
+    end,
+  })
+
+  local cfg = config_module.get_config()
+  local platform = state.get_platform()
+  local contest_id = state.get_contest_id()
+  local problem_id = state.get_problem_id()
+
   local function navigate_test(delta)
     local io_view_state = state.get_io_view_state()
     if not io_view_state then
       return
     end
+    if not platform or not contest_id or not problem_id then
+      return
+    end
     local test_cases = cache.get_test_cases(platform, contest_id, problem_id)
     if not test_cases or #test_cases == 0 then
       return
@@ -307,26 +345,51 @@ function M.ensure_io_view()
       navigate_test(-1)
     end, { buffer = input_buf, silent = true, desc = 'Previous test' })
   end
+
+  return output_buf, input_buf
 end
 
-  utils.update_buffer_content(input_buf, {})
+---@param output_buf integer
-  utils.update_buffer_content(output_buf, {})
+---@param input_buf integer
+---@return boolean
+local function buffers_are_displayed(output_buf, input_buf)
+  local output_displayed = false
+  local input_displayed = false
 
-  local test_cases = cache.get_test_cases(platform, contest_id, problem_id)
+  for _, win in ipairs(vim.api.nvim_list_wins()) do
-  if test_cases and #test_cases > 0 then
+    local buf = vim.api.nvim_win_get_buf(win)
-    local input_lines = {}
+    if buf == output_buf then
-    for _, tc in ipairs(test_cases) do
+      output_displayed = true
-      for _, line in ipairs(vim.split(tc.input, '\n')) do
+    end
-        table.insert(input_lines, line)
+    if buf == input_buf then
+      input_displayed = true
     end
   end
-    utils.update_buffer_content(input_buf, input_lines, nil, nil)
+
+  return output_displayed and input_displayed
 end
 
+---@param output_buf integer
+---@param input_buf integer
+local function create_window_layout(output_buf, input_buf)
+  local solution_win = state.get_solution_win()
+  vim.api.nvim_set_current_win(solution_win)
+
+  vim.cmd.vsplit()
+  local output_win = vim.api.nvim_get_current_win()
+  local cfg = config_module.get_config()
+  local width = math.floor(vim.o.columns * (cfg.ui.run.width or 0.3))
+  vim.api.nvim_win_set_width(output_win, width)
+  vim.api.nvim_win_set_buf(output_win, output_buf)
+
+  vim.cmd.split()
+  local input_win = vim.api.nvim_get_current_win()
+  vim.api.nvim_win_set_buf(input_win, input_buf)
+
   vim.api.nvim_set_current_win(solution_win)
 end
 
-function M.run_io_view(test_index, debug)
+function M.ensure_io_view()
   local platform, contest_id, problem_id =
     state.get_platform(), state.get_contest_id(), state.get_problem_id()
   if not platform or not contest_id or not problem_id then
@@ -337,91 +400,146 @@ function M.run_io_view(test_index, debug)
     return
   end
 
+  require('cp.utils').ensure_dirs()
+
+  local source_file = state.get_source_file()
+  if source_file then
+    local source_file_abs = vim.fn.fnamemodify(source_file, ':p')
+    for _, win in ipairs(vim.api.nvim_list_wins()) do
+      local buf = vim.api.nvim_win_get_buf(win)
+      local buf_name = vim.api.nvim_buf_get_name(buf)
+      if buf_name == source_file_abs then
+        state.set_solution_win(win)
+        break
+      end
+    end
+  else
+    state.set_solution_win(vim.api.nvim_get_current_win())
+  end
+
   cache.load()
   local contest_data = cache.get_contest_data(platform, contest_id)
-  if not contest_data or not contest_data.index_map then
+  if
-    logger.log('No test cases available.', vim.log.levels.ERROR)
+    contest_data
+    and contest_data.index_map
+    and contest_data.problems[contest_data.index_map[problem_id]].interactive
+  then
+    logger.log('This problem is not interactive. Use :CP {run,panel}.', vim.log.levels.ERROR)
     return
   end
 
-  M.ensure_io_view()
+  local output_buf, input_buf = get_or_create_io_buffers()
 
+  if not buffers_are_displayed(output_buf, input_buf) then
+    local solution_win = state.get_solution_win()
+
+    for _, win in ipairs(vim.api.nvim_list_wins()) do
+      if win ~= solution_win then
+        pcall(vim.api.nvim_win_close, win, true)
+      end
+    end
+
+    create_window_layout(output_buf, input_buf)
+  end
+
+  local cfg = config_module.get_config()
+
+  if cfg.hooks and cfg.hooks.setup_io_output then
+    pcall(cfg.hooks.setup_io_output, output_buf, state)
+  end
+
+  if cfg.hooks and cfg.hooks.setup_io_input then
+    pcall(cfg.hooks.setup_io_input, input_buf, state)
+  end
+
+  local test_cases = cache.get_test_cases(platform, contest_id, problem_id)
+  if test_cases and #test_cases > 0 then
+    local input_lines = {}
+    local is_multi_test = contest_data
+        and contest_data.problems
+        and contest_data.index_map
+        and contest_data.index_map[problem_id]
+        and contest_data.problems[contest_data.index_map[problem_id]].multi_test
+      or false
+
+    if is_multi_test and #test_cases > 1 then
+      table.insert(input_lines, tostring(#test_cases))
+      for _, tc in ipairs(test_cases) do
+        local stripped = tc.input:gsub('^1\n', '')
+        for _, line in ipairs(vim.split(stripped, '\n')) do
+          table.insert(input_lines, line)
+        end
+      end
+    else
+      for _, tc in ipairs(test_cases) do
+        for _, line in ipairs(vim.split(tc.input, '\n')) do
+          table.insert(input_lines, line)
+        end
+      end
+    end
+    utils.update_buffer_content(input_buf, input_lines, nil, nil)
+  end
+end
+
+local function render_io_view_results(io_state, test_indices, mode, combined_result, combined_input)
   local run = require('cp.runner.run')
-  if not run.load_test_cases() then
-    logger.log('No test cases available', vim.log.levels.ERROR)
-    return
-  end
-
-  local test_state = run.get_panel_state()
-  local test_indices = {}
-
-  if test_index then
-    if test_index < 1 or test_index > #test_state.test_cases then
-      logger.log(
-        string.format(
-          'Test %d does not exist (only %d tests available)',
-          test_index,
-          #test_state.test_cases
-        ),
-        vim.log.levels.WARN
-      )
-      return
-    end
-    test_indices = { test_index }
-  else
-    for i = 1, #test_state.test_cases do
-      test_indices[i] = i
-    end
-  end
-
-  local io_state = state.get_io_view_state()
-  if not io_state then
-    return
-  end
-
-  local config = config_module.get_config()
-
-  if config.ui.ansi then
-    require('cp.ui.ansi').setup_highlight_groups()
-  end
-
-  local execute = require('cp.runner.execute')
-  local compile_result = execute.compile_problem(debug)
-  if not compile_result.success then
-    local ansi = require('cp.ui.ansi')
-    local output = compile_result.output or ''
-    local lines, highlights
-
-    if config.ui.ansi then
-      local parsed = ansi.parse_ansi_text(output)
-      lines = parsed.lines
-      highlights = parsed.highlights
-    else
-      lines = vim.split(output:gsub('\027%[[%d;]*[a-zA-Z]', ''), '\n')
-      highlights = {}
-    end
-
-    local ns = vim.api.nvim_create_namespace('cp_io_view_compile_error')
-    utils.update_buffer_content(io_state.output_buf, lines, highlights, ns)
-    return
-  end
-
-  run.run_all_test_cases(test_indices, debug)
-
   local run_render = require('cp.runner.run_render')
+  local cfg = config_module.get_config()
+
   run_render.setup_highlights()
 
   local input_lines = {}
   local output_lines = {}
   local verdict_lines = {}
   local verdict_highlights = {}
+  local formatter = cfg.ui.run.format_verdict
+  local test_state = run.get_panel_state()
 
-  local formatter = config.ui.run.format_verdict
+  if mode == 'combined' and combined_result then
+    input_lines = vim.split(combined_input, '\n')
 
-  local max_time_actual = 0
+    if combined_result.actual and combined_result.actual ~= '' then
-  local max_time_limit = 0
+      output_lines = vim.split(combined_result.actual, '\n')
-  local max_mem_actual = 0
+    end
-  local max_mem_limit = 0
+
+    local status = run_render.get_status_info(combined_result)
+    local format_data = {
+      index = 1,
+      status = status,
+      time_ms = combined_result.time_ms or 0,
+      time_limit_ms = test_state.constraints and test_state.constraints.timeout_ms or 0,
+      memory_mb = combined_result.rss_mb or 0,
+      memory_limit_mb = test_state.constraints and test_state.constraints.memory_mb or 0,
+      exit_code = combined_result.code or 0,
+      signal = (combined_result.code and combined_result.code >= 128)
+          and require('cp.constants').signal_codes[combined_result.code]
+        or nil,
+      time_actual_width = #string.format('%.2f', combined_result.time_ms or 0),
+      time_limit_width = #tostring(
+        test_state.constraints and test_state.constraints.timeout_ms or 0
+      ),
+      mem_actual_width = #string.format('%.0f', combined_result.rss_mb or 0),
+      mem_limit_width = #string.format(
+        '%.0f',
+        test_state.constraints and test_state.constraints.memory_mb or 0
+      ),
+    }
+
+    local verdict_result = formatter(format_data)
+    table.insert(verdict_lines, verdict_result.line)
+
+    if verdict_result.highlights then
+      for _, hl in ipairs(verdict_result.highlights) do
+        table.insert(verdict_highlights, {
+          line_offset = #verdict_lines - 1,
+          col_start = hl.col_start,
+          col_end = hl.col_end,
+          group = hl.group,
+        })
+      end
+    end
+  else
+    local max_time_actual, max_time_limit, max_mem_actual, max_mem_limit = 0, 0, 0, 0
 
     for _, idx in ipairs(test_indices) do
       local tc = test_state.test_cases[idx]
@@ -437,21 +555,28 @@ function M.run_io_view(test_index, debug)
       )
     end
 
+    local all_outputs = {}
     for _, idx in ipairs(test_indices) do
       local tc = test_state.test_cases[idx]
-
+      for _, line in ipairs(vim.split(tc.input, '\n')) do
+        table.insert(input_lines, line)
+      end
       if tc.actual then
-      for _, line in ipairs(vim.split(tc.actual, '\n', { plain = true, trimempty = false })) do
+        table.insert(all_outputs, tc.actual)
+      end
+    end
+
+    local combined_output = table.concat(all_outputs, '')
+    if combined_output ~= '' then
+      for _, line in ipairs(vim.split(combined_output, '\n')) do
         table.insert(output_lines, line)
       end
     end
-    if idx < #test_indices then
-      table.insert(output_lines, '')
-    end
 
+    for _, idx in ipairs(test_indices) do
+      local tc = test_state.test_cases[idx]
       local status = run_render.get_status_info(tc)
 
-    ---@type VerdictFormatData
       local format_data = {
         index = idx,
         status = status,
@@ -481,12 +606,6 @@ function M.run_io_view(test_index, debug)
           })
         end
       end
-
-    for _, line in ipairs(vim.split(tc.input, '\n')) do
-      table.insert(input_lines, line)
-    end
-    if idx < #test_indices then
-      table.insert(input_lines, '')
     end
   end
 
@@ -510,11 +629,169 @@ function M.run_io_view(test_index, debug)
   end
 
   utils.update_buffer_content(io_state.input_buf, input_lines, nil, nil)
-
   local output_ns = vim.api.nvim_create_namespace('cp_io_view_output')
   utils.update_buffer_content(io_state.output_buf, output_lines, final_highlights, output_ns)
 end
 
+function M.run_io_view(test_indices_arg, debug, mode)
+  if io_view_running then
+    logger.log('Tests already running', vim.log.levels.WARN)
+    return
+  end
+  io_view_running = true
+
+  logger.log(('%s tests...'):format(debug and 'Debugging' or 'Running'), vim.log.levels.INFO, true)
+
+  mode = mode or 'combined'
+
+  local platform, contest_id, problem_id =
+    state.get_platform(), state.get_contest_id(), state.get_problem_id()
+  if not platform or not contest_id or not problem_id then
+    logger.log(
+      'No platform/contest/problem configured. Use :CP <platform> <contest> [...] first.',
+      vim.log.levels.ERROR
+    )
+    io_view_running = false
+    return
+  end
+
+  cache.load()
+  local contest_data = cache.get_contest_data(platform, contest_id)
+  if not contest_data or not contest_data.index_map then
+    logger.log('No test cases available.', vim.log.levels.ERROR)
+    io_view_running = false
+    return
+  end
+
+  if mode == 'combined' then
+    local problem_data = contest_data.problems[contest_data.index_map[problem_id]]
+    if not problem_data.multi_test then
+      mode = 'individual'
+    end
+  end
+
+  local run = require('cp.runner.run')
+
+  if mode == 'combined' then
+    local combined = cache.get_combined_test(platform, contest_id, problem_id)
+    if not combined then
+      logger.log('No combined test available', vim.log.levels.ERROR)
+      io_view_running = false
+      return
+    end
+  else
+    if not run.load_test_cases() then
+      logger.log('No test cases available', vim.log.levels.ERROR)
+      io_view_running = false
+      return
+    end
+  end
+
+  local test_indices = {}
+
+  if mode == 'individual' then
+    local test_state = run.get_panel_state()
+
+    if test_indices_arg then
+      for _, idx in ipairs(test_indices_arg) do
+        if idx < 1 or idx > #test_state.test_cases then
+          logger.log(
+            string.format(
+              'Test %d does not exist (only %d tests available)',
+              idx,
+              #test_state.test_cases
+            ),
+            vim.log.levels.WARN
+          )
+          io_view_running = false
+          return
+        end
+      end
+      test_indices = test_indices_arg
+    else
+      for i = 1, #test_state.test_cases do
+        test_indices[i] = i
+      end
+    end
+  end
+
+  if not test_indices_arg then
+    M.ensure_io_view()
+  end
+
+  local io_state = state.get_io_view_state()
+  if not io_state then
+    io_view_running = false
+    return
+  end
+
+  local cfg = config_module.get_config()
+
+  if cfg.ui.ansi then
+    require('cp.ui.ansi').setup_highlight_groups()
+  end
+
+  local execute = require('cp.runner.execute')
+
+  execute.compile_problem(debug, function(compile_result)
+    if not vim.api.nvim_buf_is_valid(io_state.output_buf) then
+      io_view_running = false
+      return
+    end
+
+    if not compile_result.success then
+      local ansi = require('cp.ui.ansi')
+      local output = compile_result.output or ''
+      local lines, highlights
+
+      if cfg.ui.ansi then
+        local parsed = ansi.parse_ansi_text(output)
+        lines = parsed.lines
+        highlights = parsed.highlights
+      else
+        lines = vim.split(output:gsub('\027%[[%d;]*[a-zA-Z]', ''), '\n')
+        highlights = {}
+      end
+
+      local ns = vim.api.nvim_create_namespace('cp_io_view_compile_error')
+      utils.update_buffer_content(io_state.output_buf, lines, highlights, ns)
+      io_view_running = false
+      return
+    end
+
+    if mode == 'combined' then
+      local combined = cache.get_combined_test(platform, contest_id, problem_id)
+      if not combined then
+        logger.log('No combined test found', vim.log.levels.ERROR)
+        io_view_running = false
+        return
+      end
+
+      run.load_test_cases()
+
+      run.run_combined_test(debug, function(result)
+        if not result then
+          logger.log('Failed to run combined test', vim.log.levels.ERROR)
+          io_view_running = false
+          return
+        end
+
+        if vim.api.nvim_buf_is_valid(io_state.output_buf) then
+          render_io_view_results(io_state, test_indices, mode, result, combined.input)
+        end
+        io_view_running = false
+      end)
+    else
+      run.run_all_test_cases(test_indices, debug, nil, function()
+        if vim.api.nvim_buf_is_valid(io_state.output_buf) then
+          render_io_view_results(io_state, test_indices, mode, nil, nil)
+        end
+        io_view_running = false
+      end)
+    end
+  end)
+end
+
 ---@param panel_opts? PanelOpts
 function M.toggle_panel(panel_opts)
   if state.get_active_panel() == 'run' then
@@ -572,13 +849,14 @@ function M.toggle_panel(panel_opts)
 
   local io_state = state.get_io_view_state()
   if io_state then
-    if vim.api.nvim_win_is_valid(io_state.output_win) then
+    for _, win in ipairs(vim.api.nvim_list_wins()) do
-      vim.api.nvim_win_close(io_state.output_win, true)
+      local buf = vim.api.nvim_win_get_buf(win)
+      if buf == io_state.output_buf or buf == io_state.input_buf then
+        if vim.api.nvim_win_is_valid(win) then
+          vim.api.nvim_win_close(win, true)
+        end
       end
-    if vim.api.nvim_win_is_valid(io_state.input_win) then
-      vim.api.nvim_win_close(io_state.input_win, true)
     end
-    state.set_io_view_state(nil)
   end
 
   local session_file = vim.fn.tempname()
@@ -611,6 +889,9 @@ function M.toggle_panel(panel_opts)
   end
 
   local function refresh_panel()
+    if state.get_active_panel() ~= 'run' then
+      return
+    end
     if not test_buffers.tab_buf or not vim.api.nvim_buf_is_valid(test_buffers.tab_buf) then
       return
     end
@@ -636,6 +917,10 @@ function M.toggle_panel(panel_opts)
         vim.cmd.normal({ 'zz', bang = true })
       end)
     end
+
+    if test_windows.tab_win and vim.api.nvim_win_is_valid(test_windows.tab_win) then
+      vim.api.nvim_set_current_win(test_windows.tab_win)
+    end
   end
 
   local function navigate_test_case(delta)
@@ -652,15 +937,15 @@ function M.toggle_panel(panel_opts)
       M.toggle_panel()
     end, { buffer = buf, silent = true })
     vim.keymap.set('n', 't', function()
-      local modes = { 'none', 'git', 'vim' }
+      local modes = config.ui.panel.diff_modes
       local current_idx = 1
       for i, mode in ipairs(modes) do
-        if config.ui.panel.diff_mode == mode then
+        if current_mode == mode then
           current_idx = i
           break
         end
       end
-      config.ui.panel.diff_mode = modes[(current_idx % #modes) + 1]
+      current_mode = modes[(current_idx % #modes) + 1]
       refresh_panel()
     end, { buffer = buf, silent = true })
     vim.keymap.set('n', '<c-n>', function()
@@ -684,17 +969,19 @@ function M.toggle_panel(panel_opts)
     end)
   end
 
-  local execute = require('cp.runner.execute')
+  vim.api.nvim_set_current_win(test_windows.tab_win)
-  local compile_result = execute.compile_problem(panel_opts and panel_opts.debug)
+  state.test_buffers = test_buffers
-  if compile_result.success then
+  state.test_windows = test_windows
-    run.run_all_test_cases(nil, panel_opts and panel_opts.debug)
+  state.set_active_panel('run')
-  else
+  logger.log('test panel opened')
-    run.handle_compilation_failure(compile_result.output)
-  end
 
   refresh_panel()
 
+  local function finalize_panel()
     vim.schedule(function()
+      if state.get_active_panel() ~= 'run' then
+        return
+      end
       if config.ui.ansi then
         require('cp.ui.ansi').setup_highlight_groups()
       end
@@ -702,12 +989,27 @@ function M.toggle_panel(panel_opts)
         update_diff_panes()
       end
     end)
+  end
 
-  vim.api.nvim_set_current_win(test_windows.tab_win)
+  local execute = require('cp.runner.execute')
-  state.test_buffers = test_buffers
+  execute.compile_problem(panel_opts and panel_opts.debug, function(compile_result)
-  state.test_windows = test_windows
+    if not test_buffers.tab_buf or not vim.api.nvim_buf_is_valid(test_buffers.tab_buf) then
-  state.set_active_panel('run')
+      return
-  logger.log('test panel opened')
+    end
+
+    if compile_result.success then
+      run.run_all_test_cases(nil, panel_opts and panel_opts.debug, function()
+        refresh_panel()
+      end, function()
+        refresh_panel()
+        finalize_panel()
+      end)
+    else
+      run.handle_compilation_failure(compile_result.output)
+      refresh_panel()
+      finalize_panel()
+    end
+  end)
 end
 
 return M

lua/cp/utils.lua

@@ -2,6 +2,9 @@ local M = {}
 
 local logger = require('cp.log')
 
+local _nix_python = nil
+local _nix_discovered = false
+
 local uname = vim.loop.os_uname()
 
 local _time_cached = false
@@ -57,7 +60,11 @@ local function find_gnu_time()
 
   _time_cached = true
   _time_path = nil
+  if uname and uname.sysname == 'Darwin' then
+    _time_reason = 'GNU time not found (install via: brew install coreutils)'
+  else
     _time_reason = 'GNU time not found'
+  end
   return _time_path, _time_reason
 end
 
@@ -79,46 +86,146 @@ function M.get_plugin_path()
   return vim.fn.fnamemodify(plugin_path, ':h:h:h')
 end
 
+---@return boolean
+function M.is_nix_build()
+  return _nix_python ~= nil
+end
+
+---@return string|nil
+function M.get_nix_python()
+  return _nix_python
+end
+
+---@return boolean
+function M.is_nix_discovered()
+  return _nix_discovered
+end
+
+---@param module string
+---@param plugin_path string
+---@return string[]
+function M.get_python_cmd(module, plugin_path)
+  if _nix_python then
+    return { _nix_python, '-m', 'scrapers.' .. module }
+  end
+  return { 'uv', 'run', '--directory', plugin_path, '-m', 'scrapers.' .. module }
+end
+
 local python_env_setup = false
 
+---@return boolean
+local function discover_nix_python()
+  local cache_dir = vim.fn.stdpath('cache') .. '/cp-nvim'
+  local cache_file = cache_dir .. '/nix-python'
+
+  local f = io.open(cache_file, 'r')
+  if f then
+    local cached = f:read('*l')
+    f:close()
+    if cached and vim.fn.executable(cached) == 1 then
+      _nix_python = cached
+      return true
+    end
+  end
+
+  local plugin_path = M.get_plugin_path()
+  vim.notify('[cp.nvim] Building Python environment with nix...', vim.log.levels.INFO)
+  vim.cmd.redraw()
+  local result = vim
+    .system(
+      { 'nix', 'build', plugin_path .. '#pythonEnv', '--no-link', '--print-out-paths' },
+      { text = true }
+    )
+    :wait()
+
+  if result.code ~= 0 then
+    logger.log('nix build #pythonEnv failed: ' .. (result.stderr or ''), vim.log.levels.WARN)
+    return false
+  end
+
+  local store_path = result.stdout:gsub('%s+$', '')
+  local python_path = store_path .. '/bin/python3'
+
+  if vim.fn.executable(python_path) ~= 1 then
+    logger.log('nix python not executable at ' .. python_path, vim.log.levels.WARN)
+    return false
+  end
+
+  vim.fn.mkdir(cache_dir, 'p')
+  f = io.open(cache_file, 'w')
+  if f then
+    f:write(python_path)
+    f:close()
+  end
+
+  _nix_python = python_path
+  _nix_discovered = true
+  return true
+end
+
 ---@return boolean success
 function M.setup_python_env()
   if python_env_setup then
     return true
   end
 
-  local plugin_path = M.get_plugin_path()
+  if _nix_python then
-  local venv_dir = plugin_path .. '/.venv'
+    logger.log('Python env: nix (python=' .. _nix_python .. ')')
+    python_env_setup = true
+    return true
+  end
 
-  if vim.fn.executable('uv') == 0 then
+  if vim.fn.executable('uv') == 1 then
+    local plugin_path = M.get_plugin_path()
+    logger.log('Python env: uv sync (dir=' .. plugin_path .. ')')
+    vim.notify('[cp.nvim] Setting up Python environment...', vim.log.levels.INFO)
+    vim.cmd.redraw()
+
+    local env = vim.fn.environ()
+    env.VIRTUAL_ENV = ''
+    env.PYTHONPATH = ''
+    env.CONDA_PREFIX = ''
+    local result = vim
+      .system({ 'uv', 'sync' }, { cwd = plugin_path, text = true, env = env })
+      :wait()
+    if result.code ~= 0 then
       logger.log(
-      'uv is not installed. Install it to enable problem scraping: https://docs.astral.sh/uv/',
+        'Failed to setup Python environment: ' .. (result.stderr or ''),
-      vim.log.levels.WARN
+        vim.log.levels.ERROR
       )
       return false
     end
-
+    if result.stderr and result.stderr ~= '' then
-  if vim.fn.isdirectory(venv_dir) == 0 then
+      logger.log('uv sync stderr: ' .. result.stderr:gsub('%s+$', ''))
-    logger.log('Setting up Python environment for scrapers...')
-    local result = vim.system({ 'uv', 'sync' }, { cwd = plugin_path, text = true }):wait()
-    if result.code ~= 0 then
-      logger.log('Failed to setup Python environment: ' .. result.stderr, vim.log.levels.ERROR)
-      return false
-    end
-    logger.log('Python environment setup complete.')
     end
 
     python_env_setup = true
     return true
   end
 
+  if vim.fn.executable('nix') == 1 then
+    logger.log('Python env: nix discovery')
+    if discover_nix_python() then
+      python_env_setup = true
+      return true
+    end
+  end
+
+  logger.log(
+    'No Python environment available. Install uv (https://docs.astral.sh/uv/) or use nix.',
+    vim.log.levels.WARN
+  )
+  return false
+end
+
 --- Configure the buffer with good defaults
 ---@param filetype? string
 function M.create_buffer_with_options(filetype)
   local buf = vim.api.nvim_create_buf(false, true)
-  vim.api.nvim_set_option_value('bufhidden', 'wipe', { buf = buf })
+  vim.api.nvim_set_option_value('bufhidden', 'hide', { buf = buf })
   vim.api.nvim_set_option_value('readonly', true, { buf = buf })
   vim.api.nvim_set_option_value('modifiable', false, { buf = buf })
+
   if filetype then
     vim.api.nvim_set_option_value('filetype', filetype, { buf = buf })
   end
@@ -155,20 +262,12 @@ function M.check_required_runtime()
 
   local time = M.time_capability()
   if not time.ok then
-    return false, 'GNU time not found: ' .. (time.reason or '')
+    return false, time.reason
   end
 
   local timeout = M.timeout_capability()
   if not timeout.ok then
-    return false, 'GNU timeout not found: ' .. (timeout.reason or '')
+    return false, timeout.reason
-  end
-
-  if vim.fn.executable('uv') ~= 1 then
-    return false, 'uv not found (https://docs.astral.sh/uv/)'
-  end
-
-  if not M.setup_python_env() then
-    return false, 'failed to set up Python virtual environment'
   end
 
   return true
@@ -218,7 +317,11 @@ local function find_gnu_timeout()
 
   _timeout_cached = true
   _timeout_path = nil
+  if uname and uname.sysname == 'Darwin' then
+    _timeout_reason = 'GNU timeout not found (install via: brew install coreutils)'
+  else
     _timeout_reason = 'GNU timeout not found'
+  end
   return _timeout_path, _timeout_reason
 end
 
@@ -255,4 +358,8 @@ function M.cwd_executables()
   return out
 end
 
+function M.ensure_dirs()
+  vim.system({ 'mkdir', '-p', 'build', 'io' }):wait()
+end
+
 return M

plugin/cp.lua

@@ -154,3 +154,17 @@ end, {
     return {}
   end,
 })
+
+local function cp_action(action)
+  return function()
+    require('cp').handle_command({ fargs = { action } })
+  end
+end
+
+vim.keymap.set('n', '<Plug>(cp-run)', cp_action('run'), { desc = 'CP run tests' })
+vim.keymap.set('n', '<Plug>(cp-panel)', cp_action('panel'), { desc = 'CP open panel' })
+vim.keymap.set('n', '<Plug>(cp-edit)', cp_action('edit'), { desc = 'CP edit test cases' })
+vim.keymap.set('n', '<Plug>(cp-next)', cp_action('next'), { desc = 'CP next problem' })
+vim.keymap.set('n', '<Plug>(cp-prev)', cp_action('prev'), { desc = 'CP previous problem' })
+vim.keymap.set('n', '<Plug>(cp-pick)', cp_action('pick'), { desc = 'CP pick contest' })
+vim.keymap.set('n', '<Plug>(cp-interact)', cp_action('interact'), { desc = 'CP interactive mode' })

pyproject.toml

@@ -1,7 +1,7 @@
 [project]
 name = "scrapers"
 version = "0.1.0"
-description = "Add your description here"
+description = "Competitive programming scrapers for a variety of web platforms."
 readme = "README.md"
 requires-python = ">=3.11"
 dependencies = [
@@ -12,18 +12,18 @@ dependencies = [
     "ndjson>=0.3.1",
     "pydantic>=2.11.10",
     "requests>=2.32.5",
-    "scrapling[fetchers]>=0.3.5",
 ]
 
 [dependency-groups]
 dev = [
-    "mypy>=1.18.2",
     "types-beautifulsoup4>=4.12.0.20250516",
     "types-requests>=2.32.4.20250913",
     "pytest>=8.0.0",
     "pytest-mock>=3.12.0",
     "pre-commit>=4.3.0",
     "basedpyright>=1.31.6",
+    "ruff>=0.14.2",
+    "ty>=0.0.1a32",
 ]
 
 [tool.pytest.ini_options]

scrapers/atcoder.py

@@ -16,6 +16,7 @@ from urllib3.util.retry import Retry
 
 from .base import BaseScraper
 from .models import (
+    CombinedTest,
     ContestListResult,
     ContestSummary,
     MetadataResult,
@@ -242,7 +243,7 @@ def _to_problem_summaries(rows: list[dict[str, str]]) -> list[ProblemSummary]:
 
 async def _fetch_all_contests_async() -> list[ContestSummary]:
     async with httpx.AsyncClient(
-        limits=httpx.Limits(max_connections=100, max_keepalive_connections=100)
+        limits=httpx.Limits(max_connections=100, max_keepalive_connections=100),
     ) as client:
         first_html = await _get_async(client, ARCHIVE_URL)
         last = _parse_last_page(first_html)
@@ -265,43 +266,31 @@ class AtcoderScraper(BaseScraper):
         return "atcoder"
 
     async def scrape_contest_metadata(self, contest_id: str) -> MetadataResult:
-        async def impl(cid: str) -> MetadataResult:
         try:
-                rows = await asyncio.to_thread(_scrape_tasks_sync, cid)
+            rows = await asyncio.to_thread(_scrape_tasks_sync, contest_id)
-            except requests.HTTPError as e:
-                if e.response is not None and e.response.status_code == 404:
-                    return self._create_metadata_error(
-                        f"No problems found for contest {cid}", cid
-                    )
-                raise
-
             problems = _to_problem_summaries(rows)
             if not problems:
-                return self._create_metadata_error(
+                return self._metadata_error(
-                    f"No problems found for contest {cid}", cid
+                    f"No problems found for contest {contest_id}"
                 )
-
             return MetadataResult(
                 success=True,
                 error="",
-                contest_id=cid,
+                contest_id=contest_id,
                 problems=problems,
                 url=f"https://atcoder.jp/contests/{contest_id}/tasks/{contest_id}_%s",
             )
-
+        except Exception as e:
-        return await self._safe_execute("metadata", impl, contest_id)
+            return self._metadata_error(str(e))
 
     async def scrape_contest_list(self) -> ContestListResult:
-        async def impl() -> ContestListResult:
         try:
             contests = await _fetch_all_contests_async()
-            except Exception as e:
-                return self._create_contests_error(str(e))
             if not contests:
-                return self._create_contests_error("No contests found")
+                return self._contests_error("No contests found")
             return ContestListResult(success=True, error="", contests=contests)
-
+        except Exception as e:
-        return await self._safe_execute("contests", impl)
+            return self._contests_error(str(e))
 
     async def stream_tests_for_category_async(self, category_id: str) -> None:
         rows = await asyncio.to_thread(_scrape_tasks_sync, category_id)
@@ -313,16 +302,23 @@ class AtcoderScraper(BaseScraper):
                 return
             data = await asyncio.to_thread(_scrape_problem_page_sync, category_id, slug)
             tests: list[TestCase] = data.get("tests", [])
+            combined_input = "\n".join(t.input for t in tests) if tests else ""
+            combined_expected = "\n".join(t.expected for t in tests) if tests else ""
             print(
                 json.dumps(
                     {
                         "problem_id": letter,
+                        "combined": {
+                            "input": combined_input,
+                            "expected": combined_expected,
+                        },
                         "tests": [
                             {"input": t.input, "expected": t.expected} for t in tests
                         ],
                         "timeout_ms": data.get("timeout_ms", 0),
                         "memory_mb": data.get("memory_mb", 0),
                         "interactive": bool(data.get("interactive")),
+                        "multi_test": False,
                     }
                 ),
                 flush=True,
@@ -364,6 +360,7 @@ async def main_async() -> int:
                 success=False,
                 error="Usage: atcoder.py tests <contest_id>",
                 problem_id="",
+                combined=CombinedTest(input="", expected=""),
                 tests=[],
                 timeout_ms=0,
                 memory_mb=0,

scrapers/base.py

@@ -1,9 +1,8 @@
+import asyncio
+import sys
 from abc import ABC, abstractmethod
-from typing import Any, Awaitable, Callable, ParamSpec, cast
 
-from .models import ContestListResult, MetadataResult, TestsResult
+from .models import CombinedTest, ContestListResult, MetadataResult, TestsResult
-
-P = ParamSpec("P")
 
 
 class BaseScraper(ABC):
@@ -20,54 +19,65 @@ class BaseScraper(ABC):
     @abstractmethod
     async def stream_tests_for_category_async(self, category_id: str) -> None: ...
 
-    def _create_metadata_error(
+    def _usage(self) -> str:
-        self, error_msg: str, contest_id: str = ""
+        name = self.platform_name
-    ) -> MetadataResult:
+        return f"Usage: {name}.py metadata <id> | tests <id> | contests"
-        return MetadataResult(
-            success=False,
-            error=f"{self.platform_name}: {error_msg}",
-            contest_id=contest_id,
-            problems=[],
-            url="",
-        )
 
-    def _create_tests_error(
+    def _metadata_error(self, msg: str) -> MetadataResult:
-        self, error_msg: str, problem_id: str = "", url: str = ""
+        return MetadataResult(success=False, error=msg, url="")
-    ) -> TestsResult:
+
+    def _tests_error(self, msg: str) -> TestsResult:
         return TestsResult(
             success=False,
-            error=f"{self.platform_name}: {error_msg}",
+            error=msg,
-            problem_id=problem_id,
+            problem_id="",
+            combined=CombinedTest(input="", expected=""),
             tests=[],
             timeout_ms=0,
             memory_mb=0,
-            interactive=False,
         )
 
-    def _create_contests_error(self, error_msg: str) -> ContestListResult:
+    def _contests_error(self, msg: str) -> ContestListResult:
-        return ContestListResult(
+        return ContestListResult(success=False, error=msg)
-            success=False,
-            error=f"{self.platform_name}: {error_msg}",
-            contests=[],
-        )
 
-    async def _safe_execute(
+    async def _run_cli_async(self, args: list[str]) -> int:
-        self,
+        if len(args) < 2:
-        operation: str,
+            print(self._metadata_error(self._usage()).model_dump_json())
-        func: Callable[P, Awaitable[Any]],
+            return 1
-        *args: P.args,
+
-        **kwargs: P.kwargs,
+        mode = args[1]
-    ):
+
-        try:
+        match mode:
-            return await func(*args, **kwargs)
+            case "metadata":
-        except Exception as e:
+                if len(args) != 3:
-            if operation == "metadata":
+                    print(self._metadata_error(self._usage()).model_dump_json())
-                contest_id = cast(str, args[0]) if args else ""
+                    return 1
-                return self._create_metadata_error(str(e), contest_id)
+                result = await self.scrape_contest_metadata(args[2])
-            elif operation == "tests":
+                print(result.model_dump_json())
-                problem_id = cast(str, args[1]) if len(args) > 1 else ""
+                return 0 if result.success else 1
-                return self._create_tests_error(str(e), problem_id)
+
-            elif operation == "contests":
+            case "tests":
-                return self._create_contests_error(str(e))
+                if len(args) != 3:
-            else:
+                    print(self._tests_error(self._usage()).model_dump_json())
-                raise
+                    return 1
+                await self.stream_tests_for_category_async(args[2])
+                return 0
+
+            case "contests":
+                if len(args) != 2:
+                    print(self._contests_error(self._usage()).model_dump_json())
+                    return 1
+                result = await self.scrape_contest_list()
+                print(result.model_dump_json())
+                return 0 if result.success else 1
+
+            case _:
+                print(
+                    self._metadata_error(
+                        f"Unknown mode: {mode}. {self._usage()}"
+                    ).model_dump_json()
+                )
+                return 1
+
+    def run_cli(self) -> None:
+        sys.exit(asyncio.run(self._run_cli_async(sys.argv)))

scrapers/codechef.py

@@ -0,0 +1,253 @@
+#!/usr/bin/env python3
+
+import asyncio
+import json
+import re
+from typing import Any
+
+import httpx
+from curl_cffi import requests as curl_requests
+
+from .base import BaseScraper
+from .models import (
+    ContestListResult,
+    ContestSummary,
+    MetadataResult,
+    ProblemSummary,
+    TestCase,
+)
+
+BASE_URL = "https://www.codechef.com"
+API_CONTESTS_ALL = "/api/list/contests/all"
+API_CONTEST = "/api/contests/{contest_id}"
+API_PROBLEM = "/api/contests/{contest_id}/problems/{problem_id}"
+PROBLEM_URL = "https://www.codechef.com/problems/{problem_id}"
+HEADERS = {
+    "User-Agent": "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36"
+}
+TIMEOUT_S = 15.0
+CONNECTIONS = 8
+MEMORY_LIMIT_RE = re.compile(
+    r"Memory\s+[Ll]imit.*?([0-9.]+)\s*(MB|GB)", re.IGNORECASE | re.DOTALL
+)
+
+
+async def fetch_json(client: httpx.AsyncClient, path: str) -> dict:
+    r = await client.get(BASE_URL + path, headers=HEADERS, timeout=TIMEOUT_S)
+    r.raise_for_status()
+    return r.json()
+
+
+def _extract_memory_limit(html: str) -> float:
+    m = MEMORY_LIMIT_RE.search(html)
+    if not m:
+        return 256.0
+    value = float(m.group(1))
+    unit = m.group(2).upper()
+    if unit == "GB":
+        return value * 1024.0
+    return value
+
+
+def _fetch_html_sync(url: str) -> str:
+    response = curl_requests.get(url, impersonate="chrome", timeout=TIMEOUT_S)
+    response.raise_for_status()
+    return response.text
+
+
+class CodeChefScraper(BaseScraper):
+    @property
+    def platform_name(self) -> str:
+        return "codechef"
+
+    async def scrape_contest_metadata(self, contest_id: str) -> MetadataResult:
+        try:
+            async with httpx.AsyncClient() as client:
+                data = await fetch_json(
+                    client, API_CONTEST.format(contest_id=contest_id)
+                )
+            if not data.get("problems"):
+                return self._metadata_error(
+                    f"No problems found for contest {contest_id}"
+                )
+            problems = []
+            for problem_code, problem_data in data["problems"].items():
+                if problem_data.get("category_name") == "main":
+                    problems.append(
+                        ProblemSummary(
+                            id=problem_code,
+                            name=problem_data.get("name", problem_code),
+                        )
+                    )
+            return MetadataResult(
+                success=True,
+                error="",
+                contest_id=contest_id,
+                problems=problems,
+                url=f"{BASE_URL}/{contest_id}",
+            )
+        except Exception as e:
+            return self._metadata_error(f"Failed to fetch contest {contest_id}: {e}")
+
+    async def scrape_contest_list(self) -> ContestListResult:
+        async with httpx.AsyncClient() as client:
+            try:
+                data = await fetch_json(client, API_CONTESTS_ALL)
+            except httpx.HTTPStatusError as e:
+                return self._contests_error(f"Failed to fetch contests: {e}")
+            all_contests = data.get("future_contests", []) + data.get(
+                "past_contests", []
+            )
+            max_num = 0
+            for contest in all_contests:
+                contest_code = contest.get("contest_code", "")
+                if contest_code.startswith("START"):
+                    match = re.match(r"START(\d+)", contest_code)
+                    if match:
+                        num = int(match.group(1))
+                        max_num = max(max_num, num)
+            if max_num == 0:
+                return self._contests_error("No Starters contests found")
+            contests = []
+            sem = asyncio.Semaphore(CONNECTIONS)
+
+            async def fetch_divisions(i: int) -> list[ContestSummary]:
+                parent_id = f"START{i}"
+                async with sem:
+                    try:
+                        parent_data = await fetch_json(
+                            client, API_CONTEST.format(contest_id=parent_id)
+                        )
+                    except Exception as e:
+                        import sys
+
+                        print(f"Error fetching {parent_id}: {e}", file=sys.stderr)
+                        return []
+                child_contests = parent_data.get("child_contests", {})
+                if not child_contests:
+                    return []
+                base_name = f"Starters {i}"
+                divisions = []
+                for div_key, div_data in child_contests.items():
+                    div_code = div_data.get("contest_code", "")
+                    div_num = div_data.get("div", {}).get("div_number", "")
+                    if div_code and div_num:
+                        divisions.append(
+                            ContestSummary(
+                                id=div_code,
+                                name=base_name,
+                                display_name=f"{base_name} (Div. {div_num})",
+                            )
+                        )
+                return divisions
+
+            tasks = [fetch_divisions(i) for i in range(1, max_num + 1)]
+            for coro in asyncio.as_completed(tasks):
+                divisions = await coro
+                contests.extend(divisions)
+        return ContestListResult(success=True, error="", contests=contests)
+
+    async def stream_tests_for_category_async(self, category_id: str) -> None:
+        async with httpx.AsyncClient(
+            limits=httpx.Limits(max_connections=CONNECTIONS)
+        ) as client:
+            try:
+                contest_data = await fetch_json(
+                    client, API_CONTEST.format(contest_id=category_id)
+                )
+            except Exception as e:
+                print(
+                    json.dumps(
+                        {"error": f"Failed to fetch contest {category_id}: {str(e)}"}
+                    ),
+                    flush=True,
+                )
+                return
+            all_problems = contest_data.get("problems", {})
+            if not all_problems:
+                print(
+                    json.dumps(
+                        {"error": f"No problems found for contest {category_id}"}
+                    ),
+                    flush=True,
+                )
+                return
+            problems = {
+                code: data
+                for code, data in all_problems.items()
+                if data.get("category_name") == "main"
+            }
+            if not problems:
+                print(
+                    json.dumps(
+                        {"error": f"No main problems found for contest {category_id}"}
+                    ),
+                    flush=True,
+                )
+                return
+            sem = asyncio.Semaphore(CONNECTIONS)
+
+            async def run_one(problem_code: str) -> dict[str, Any]:
+                async with sem:
+                    try:
+                        problem_data = await fetch_json(
+                            client,
+                            API_PROBLEM.format(
+                                contest_id=category_id, problem_id=problem_code
+                            ),
+                        )
+                        sample_tests = (
+                            problem_data.get("problemComponents", {}).get(
+                                "sampleTestCases", []
+                            )
+                            or []
+                        )
+                        tests = [
+                            TestCase(
+                                input=t.get("input", "").strip(),
+                                expected=t.get("output", "").strip(),
+                            )
+                            for t in sample_tests
+                            if not t.get("isDeleted", False)
+                        ]
+                        time_limit_str = problem_data.get("max_timelimit", "1")
+                        timeout_ms = int(float(time_limit_str) * 1000)
+                        problem_url = PROBLEM_URL.format(problem_id=problem_code)
+                        loop = asyncio.get_event_loop()
+                        html = await loop.run_in_executor(
+                            None, _fetch_html_sync, problem_url
+                        )
+                        memory_mb = _extract_memory_limit(html)
+                        interactive = False
+                    except Exception:
+                        tests = []
+                        timeout_ms = 1000
+                        memory_mb = 256.0
+                        interactive = False
+                    combined_input = "\n".join(t.input for t in tests) if tests else ""
+                    combined_expected = (
+                        "\n".join(t.expected for t in tests) if tests else ""
+                    )
+                    return {
+                        "problem_id": problem_code,
+                        "combined": {
+                            "input": combined_input,
+                            "expected": combined_expected,
+                        },
+                        "tests": [
+                            {"input": t.input, "expected": t.expected} for t in tests
+                        ],
+                        "timeout_ms": timeout_ms,
+                        "memory_mb": memory_mb,
+                        "interactive": interactive,
+                        "multi_test": False,
+                    }
+
+            tasks = [run_one(problem_code) for problem_code in problems.keys()]
+            for coro in asyncio.as_completed(tasks):
+                payload = await coro
+                print(json.dumps(payload), flush=True)
+
+
+if __name__ == "__main__":
+    CodeChefScraper().run_cli()

scrapers/codeforces.py

@@ -2,14 +2,12 @@
 
 import asyncio
 import json
-import logging
 import re
-import sys
 from typing import Any
 
 import requests
 from bs4 import BeautifulSoup, Tag
-from scrapling.fetchers import StealthyFetcher
+from curl_cffi import requests as curl_requests
 
 from .base import BaseScraper
 from .models import (
@@ -18,13 +16,8 @@ from .models import (
     MetadataResult,
     ProblemSummary,
     TestCase,
-    TestsResult,
 )
 
-# suppress scrapling logging - https://github.com/D4Vinci/Scrapling/issues/31)
-logging.getLogger("scrapling").setLevel(logging.CRITICAL)
-
-
 BASE_URL = "https://codeforces.com"
 API_CONTEST_LIST_URL = f"{BASE_URL}/api/contest.list"
 TIMEOUT_SECONDS = 30
@@ -83,19 +76,19 @@ def _extract_title(block: Tag) -> tuple[str, str]:
     return parts[0].strip().upper(), parts[1].strip()
 
 
-def _extract_samples(block: Tag) -> list[TestCase]:
+def _extract_samples(block: Tag) -> tuple[list[TestCase], bool]:
     st = block.find("div", class_="sample-test")
-    if not st:
+    if not isinstance(st, Tag):
-        return []
+        return [], False
 
-    input_pres: list[Tag] = [  # type: ignore[misc]
+    input_pres: list[Tag] = [
-        inp.find("pre")  # type: ignore[misc]
+        inp.find("pre")
-        for inp in st.find_all("div", class_="input")  # type: ignore[union-attr]
+        for inp in st.find_all("div", class_="input")
         if isinstance(inp, Tag) and inp.find("pre")
     ]
     output_pres: list[Tag] = [
-        out.find("pre")  # type: ignore[misc]
+        out.find("pre")
-        for out in st.find_all("div", class_="output")  # type: ignore[union-attr]
+        for out in st.find_all("div", class_="output")
         if isinstance(out, Tag) and out.find("pre")
     ]
     input_pres = [p for p in input_pres if isinstance(p, Tag)]
@@ -119,18 +112,19 @@ def _extract_samples(block: Tag) -> list[TestCase]:
         outputs_by_gid.pop(0, None)
         keys = sorted(set(inputs_by_gid.keys()) & set(outputs_by_gid.keys()))
         if keys:
-            return [
+            samples = [
                 TestCase(
                     input="\n".join(inputs_by_gid[k]).strip(),
                     expected="\n".join(outputs_by_gid[k]).strip(),
                 )
                 for k in keys
             ]
+            return samples, True
 
     inputs = [_text_from_pre(p) for p in input_pres]
     outputs = [_text_from_pre(p) for p in output_pres]
     n = min(len(inputs), len(outputs))
-    return [TestCase(input=inputs[i], expected=outputs[i]) for i in range(n)]
+    return [TestCase(input=inputs[i], expected=outputs[i]) for i in range(n)], False
 
 
 def _is_interactive(block: Tag) -> bool:
@@ -141,12 +135,9 @@ def _is_interactive(block: Tag) -> bool:
 
 def _fetch_problems_html(contest_id: str) -> str:
     url = f"{BASE_URL}/contest/{contest_id}/problems"
-    page = StealthyFetcher.fetch(
+    response = curl_requests.get(url, impersonate="chrome", timeout=TIMEOUT_SECONDS)
-        url,
+    response.raise_for_status()
-        headless=True,
+    return response.text
-        solve_cloudflare=True,
-    )
-    return page.html_content
 
 
 def _parse_all_blocks(html: str) -> list[dict[str, Any]]:
@@ -156,20 +147,38 @@ def _parse_all_blocks(html: str) -> list[dict[str, Any]]:
     for b in blocks:
         holder = b.find_parent("div", class_="problemindexholder")
         letter = (holder.get("problemindex") if holder else "").strip().upper()
-        name = _extract_title(b)[1]  # keep your name extraction
+        name = _extract_title(b)[1]
         if not letter:
             continue
-        tests = _extract_samples(b)
+        raw_samples, is_grouped = _extract_samples(b)
         timeout_ms, memory_mb = _extract_limits(b)
         interactive = _is_interactive(b)
+
+        if is_grouped and raw_samples:
+            combined_input = f"{len(raw_samples)}\n" + "\n".join(
+                tc.input for tc in raw_samples
+            )
+            combined_expected = "\n".join(tc.expected for tc in raw_samples)
+            individual_tests = [
+                TestCase(input=f"1\n{tc.input}", expected=tc.expected)
+                for tc in raw_samples
+            ]
+        else:
+            combined_input = "\n".join(tc.input for tc in raw_samples)
+            combined_expected = "\n".join(tc.expected for tc in raw_samples)
+            individual_tests = raw_samples
+
         out.append(
             {
                 "letter": letter,
                 "name": name,
-                "tests": tests,
+                "combined_input": combined_input,
+                "combined_expected": combined_expected,
+                "tests": individual_tests,
                 "timeout_ms": timeout_ms,
                 "memory_mb": memory_mb,
                 "interactive": interactive,
+                "multi_test": is_grouped,
             }
         )
     return out
@@ -191,30 +200,31 @@ class CodeforcesScraper(BaseScraper):
         return "codeforces"
 
     async def scrape_contest_metadata(self, contest_id: str) -> MetadataResult:
-        async def impl(cid: str) -> MetadataResult:
+        try:
-            problems = await asyncio.to_thread(_scrape_contest_problems_sync, cid)
+            problems = await asyncio.to_thread(
+                _scrape_contest_problems_sync, contest_id
+            )
             if not problems:
-                return self._create_metadata_error(
+                return self._metadata_error(
-                    f"No problems found for contest {cid}", cid
+                    f"No problems found for contest {contest_id}"
                 )
             return MetadataResult(
                 success=True,
                 error="",
-                contest_id=cid,
+                contest_id=contest_id,
                 problems=problems,
-                url=f"https://codeforces.com/contest/{contest_id}/%s",
+                url=f"https://codeforces.com/contest/{contest_id}/problem/%s",
             )
-
+        except Exception as e:
-        return await self._safe_execute("metadata", impl, contest_id)
+            return self._metadata_error(str(e))
 
     async def scrape_contest_list(self) -> ContestListResult:
-        async def impl() -> ContestListResult:
         try:
             r = requests.get(API_CONTEST_LIST_URL, timeout=TIMEOUT_SECONDS)
             r.raise_for_status()
             data = r.json()
             if data.get("status") != "OK":
-                    return self._create_contests_error("Invalid API response")
+                return self._contests_error("Invalid API response")
 
             contests: list[ContestSummary] = []
             for c in data["result"]:
@@ -222,18 +232,14 @@ class CodeforcesScraper(BaseScraper):
                     continue
                 cid = str(c["id"])
                 name = c["name"]
-                    contests.append(
+                contests.append(ContestSummary(id=cid, name=name, display_name=name))
-                        ContestSummary(id=cid, name=name, display_name=name)
-                    )
 
             if not contests:
-                    return self._create_contests_error("No contests found")
+                return self._contests_error("No contests found")
 
             return ContestListResult(success=True, error="", contests=contests)
         except Exception as e:
-                return self._create_contests_error(str(e))
+            return self._contests_error(str(e))
-
-        return await self._safe_execute("contests", impl)
 
     async def stream_tests_for_category_async(self, category_id: str) -> None:
         html = await asyncio.to_thread(_fetch_problems_html, category_id)
@@ -246,84 +252,22 @@ class CodeforcesScraper(BaseScraper):
                 json.dumps(
                     {
                         "problem_id": pid,
+                        "combined": {
+                            "input": b.get("combined_input", ""),
+                            "expected": b.get("combined_expected", ""),
+                        },
                         "tests": [
                             {"input": t.input, "expected": t.expected} for t in tests
                         ],
                         "timeout_ms": b.get("timeout_ms", 0),
                         "memory_mb": b.get("memory_mb", 0),
                         "interactive": bool(b.get("interactive")),
+                        "multi_test": bool(b.get("multi_test", False)),
                     }
                 ),
                 flush=True,
             )
 
 
-async def main_async() -> int:
-    if len(sys.argv) < 2:
-        result = MetadataResult(
-            success=False,
-            error="Usage: codeforces.py metadata <contest_id> OR codeforces.py tests <contest_id> OR codeforces.py contests",
-            url="",
-        )
-        print(result.model_dump_json())
-        return 1
-
-    mode: str = sys.argv[1]
-    scraper = CodeforcesScraper()
-
-    if mode == "metadata":
-        if len(sys.argv) != 3:
-            result = MetadataResult(
-                success=False,
-                error="Usage: codeforces.py metadata <contest_id>",
-                url="",
-            )
-            print(result.model_dump_json())
-            return 1
-        contest_id = sys.argv[2]
-        result = await scraper.scrape_contest_metadata(contest_id)
-        print(result.model_dump_json())
-        return 0 if result.success else 1
-
-    if mode == "tests":
-        if len(sys.argv) != 3:
-            tests_result = TestsResult(
-                success=False,
-                error="Usage: codeforces.py tests <contest_id>",
-                problem_id="",
-                tests=[],
-                timeout_ms=0,
-                memory_mb=0,
-            )
-            print(tests_result.model_dump_json())
-            return 1
-        contest_id = sys.argv[2]
-        await scraper.stream_tests_for_category_async(contest_id)
-        return 0
-
-    if mode == "contests":
-        if len(sys.argv) != 2:
-            contest_result = ContestListResult(
-                success=False, error="Usage: codeforces.py contests"
-            )
-            print(contest_result.model_dump_json())
-            return 1
-        contest_result = await scraper.scrape_contest_list()
-        print(contest_result.model_dump_json())
-        return 0 if contest_result.success else 1
-
-    result = MetadataResult(
-        success=False,
-        error="Unknown mode. Use 'metadata <contest_id>', 'tests <contest_id>', or 'contests'",
-        url="",
-    )
-    print(result.model_dump_json())
-    return 1
-
-
-def main() -> None:
-    sys.exit(asyncio.run(main_async()))
-
-
 if __name__ == "__main__":
-    main()
+    CodeforcesScraper().run_cli()

scrapers/cses.py

@@ -3,7 +3,6 @@
 import asyncio
 import json
 import re
-import sys
 from typing import Any
 
 import httpx
@@ -15,7 +14,6 @@ from .models import (
     MetadataResult,
     ProblemSummary,
     TestCase,
-    TestsResult,
 )
 
 BASE_URL = "https://cses.fi"
@@ -233,14 +231,25 @@ class CSESScraper(BaseScraper):
                     except Exception:
                         tests = []
                         timeout_ms, memory_mb, interactive = 0, 0, False
+
+                    combined_input = "\n".join(t.input for t in tests) if tests else ""
+                    combined_expected = (
+                        "\n".join(t.expected for t in tests) if tests else ""
+                    )
+
                     return {
                         "problem_id": pid,
+                        "combined": {
+                            "input": combined_input,
+                            "expected": combined_expected,
+                        },
                         "tests": [
                             {"input": t.input, "expected": t.expected} for t in tests
                         ],
                         "timeout_ms": timeout_ms,
                         "memory_mb": memory_mb,
                         "interactive": interactive,
+                        "multi_test": False,
                     }
 
             tasks = [run_one(p.id) for p in problems]
@@ -249,72 +258,5 @@ class CSESScraper(BaseScraper):
                 print(json.dumps(payload), flush=True)
 
 
-async def main_async() -> int:
-    if len(sys.argv) < 2:
-        result = MetadataResult(
-            success=False,
-            error="Usage: cses.py metadata <category_id> OR cses.py tests <category> OR cses.py contests",
-            url="",
-        )
-        print(result.model_dump_json())
-        return 1
-
-    mode: str = sys.argv[1]
-    scraper = CSESScraper()
-
-    if mode == "metadata":
-        if len(sys.argv) != 3:
-            result = MetadataResult(
-                success=False,
-                error="Usage: cses.py metadata <category_id>",
-                url="",
-            )
-            print(result.model_dump_json())
-            return 1
-        category_id = sys.argv[2]
-        result = await scraper.scrape_contest_metadata(category_id)
-        print(result.model_dump_json())
-        return 0 if result.success else 1
-
-    if mode == "tests":
-        if len(sys.argv) != 3:
-            tests_result = TestsResult(
-                success=False,
-                error="Usage: cses.py tests <category>",
-                problem_id="",
-                tests=[],
-                timeout_ms=0,
-                memory_mb=0,
-            )
-            print(tests_result.model_dump_json())
-            return 1
-        category = sys.argv[2]
-        await scraper.stream_tests_for_category_async(category)
-        return 0
-
-    if mode == "contests":
-        if len(sys.argv) != 2:
-            contest_result = ContestListResult(
-                success=False, error="Usage: cses.py contests"
-            )
-            print(contest_result.model_dump_json())
-            return 1
-        contest_result = await scraper.scrape_contest_list()
-        print(contest_result.model_dump_json())
-        return 0 if contest_result.success else 1
-
-    result = MetadataResult(
-        success=False,
-        error=f"Unknown mode: {mode}. Use 'metadata <category>', 'tests <category>', or 'contests'",
-        url="",
-    )
-    print(result.model_dump_json())
-    return 1
-
-
-def main() -> None:
-    sys.exit(asyncio.run(main_async()))
-
-
 if __name__ == "__main__":
-    main()
+    CSESScraper().run_cli()

scrapers/models.py

@@ -8,6 +8,13 @@ class TestCase(BaseModel):
     model_config = ConfigDict(extra="forbid")
 
 
+class CombinedTest(BaseModel):
+    input: str
+    expected: str
+
+    model_config = ConfigDict(extra="forbid")
+
+
 class ProblemSummary(BaseModel):
     id: str
     name: str
@@ -46,10 +53,12 @@ class ContestListResult(ScrapingResult):
 
 class TestsResult(ScrapingResult):
     problem_id: str
+    combined: CombinedTest
     tests: list[TestCase] = Field(default_factory=list)
     timeout_ms: int
     memory_mb: float
     interactive: bool = False
+    multi_test: bool = False
 
     model_config = ConfigDict(extra="forbid")
 

spec/execute_spec.lua

@@ -1,11 +0,0 @@
-describe('run module', function()
-  local run = require('cp.runner.run')
-
-  describe('basic functionality', function()
-    it('can get panel state', function()
-      local state = run.get_panel_state()
-      assert.is_table(state)
-      assert.is_table(state.test_cases)
-    end)
-  end)
-end)

tests/conftest.py

@@ -10,7 +10,7 @@ from typing import Any
 import httpx
 import pytest
 import requests
-from scrapling import fetchers
+from curl_cffi import requests as curl_requests
 
 ROOT = Path(__file__).resolve().parent.parent
 FIX = Path(__file__).resolve().parent / "fixtures"
@@ -63,13 +63,13 @@ def run_scraper_offline(fixture_text):
             target = target.removeprefix("https://cses.fi")
 
         if target.strip("/") == "problemset":
-            return fixture_text("cses_contests.html")
+            return fixture_text("cses/contests.html")
 
         if target.startswith("/problemset/task/") or target.startswith(
             "problemset/task/"
         ):
             pid = target.rstrip("/").split("/")[-1]
-            return fixture_text(f"cses_task_{pid}.html")
+            return fixture_text(f"cses/task_{pid}.html")
 
         raise AssertionError(f"No fixture for CSES path={path!r} url={url!r}")
 
@@ -77,12 +77,12 @@ def run_scraper_offline(fixture_text):
         if not url:
             raise AssertionError("AtCoder expects url routing")
         if "/contests/archive" in url:
-            return fixture_text("atcoder_contests.html")
+            return fixture_text("atcoder/contests.html")
         if url.endswith("/tasks"):
-            return fixture_text("atcoder_abc100_tasks.html")
+            return fixture_text("atcoder/abc100_tasks.html")
         if "/tasks/" in url:
             slug = url.rsplit("/", 1)[-1]
-            return fixture_text(f"atcoder_task_{slug}.html")
+            return fixture_text(f"atcoder/task_{slug}.html")
         raise AssertionError(f"No fixture for AtCoder url={url!r}")
 
     def _router_codeforces(*, path: str | None = None, url: str | None = None) -> str:
@@ -90,17 +90,17 @@ def run_scraper_offline(fixture_text):
             raise AssertionError("Codeforces expects url routing")
         if "/contest/" in url and url.endswith("/problems"):
             contest_id = url.rstrip("/").split("/")[-2]
-            return fixture_text(f"codeforces_{contest_id}_problems.html")
+            return fixture_text(f"codeforces/{contest_id}_problems.html")
         if "/contests" in url and "/problem/" not in url:
-            return fixture_text("codeforces_contests.html")
+            return fixture_text("codeforces/contests.html")
         if "/problem/" in url:
             parts = url.rstrip("/").split("/")
             contest_id, index = parts[-3], parts[-1]
-            return fixture_text(f"codeforces_{contest_id}_{index}.html")
+            return fixture_text(f"codeforces/{contest_id}_{index}.html")
         if "/problemset/problem/" in url:
             parts = url.rstrip("/").split("/")
             contest_id, index = parts[-2], parts[-1]
-            return fixture_text(f"codeforces_{contest_id}_{index}.html")
+            return fixture_text(f"codeforces/{contest_id}_{index}.html")
 
         raise AssertionError(f"No fixture for Codeforces url={url!r}")
 
@@ -136,12 +136,15 @@ def run_scraper_offline(fixture_text):
 
             case "codeforces":
 
-                class MockPage:
+                class MockCurlResponse:
                     def __init__(self, html: str):
-                        self.html_content = html
+                        self.text = html
 
-                def _mock_stealthy_fetch(url: str, **kwargs):
+                    def raise_for_status(self):
-                    return MockPage(_router_codeforces(url=url))
+                        pass
+
+                def _mock_curl_get(url: str, **kwargs):
+                    return MockCurlResponse(_router_codeforces(url=url))
 
                 def _mock_requests_get(url: str, **kwargs):
                     if "api/contest.list" in url:
@@ -172,37 +175,97 @@ def run_scraper_offline(fixture_text):
                     raise AssertionError(f"Unexpected requests.get call: {url}")
 
                 return {
-                    "StealthyFetcher.fetch": _mock_stealthy_fetch,
+                    "curl_requests.get": _mock_curl_get,
                     "requests.get": _mock_requests_get,
                 }
 
+            case "codechef":
+
+                class MockResponse:
+                    def __init__(self, json_data):
+                        self._json_data = json_data
+                        self.status_code = 200
+
+                    def json(self):
+                        return self._json_data
+
+                    def raise_for_status(self):
+                        pass
+
+                async def __offline_get_async(client, url: str, **kwargs):
+                    if "/api/list/contests/all" in url:
+                        data = json.loads(fixture_text("codechef/contests.json"))
+                        return MockResponse(data)
+                    if "/api/contests/START" in url and "/problems/" not in url:
+                        contest_id = url.rstrip("/").split("/")[-1]
+                        try:
+                            data = json.loads(
+                                fixture_text(f"codechef/{contest_id}.json")
+                            )
+                            return MockResponse(data)
+                        except FileNotFoundError:
+                            raise AssertionError(f"No fixture for CodeChef url={url!r}")
+                    if "/api/contests/START" in url and "/problems/" in url:
+                        parts = url.rstrip("/").split("/")
+                        contest_id = parts[-3]
+                        problem_id = parts[-1]
+                        data = json.loads(
+                            fixture_text(f"codechef/{contest_id}_{problem_id}.json")
+                        )
+                        return MockResponse(data)
+                    raise AssertionError(f"No fixture for CodeChef url={url!r}")
+
+                class MockCodeChefCurlResponse:
+                    def __init__(self, html: str):
+                        self.text = html
+
+                    def raise_for_status(self):
+                        pass
+
+                def _mock_curl_get(url: str, **kwargs):
+                    if "/problems/" in url:
+                        problem_id = url.rstrip("/").split("/")[-1]
+                        html = fixture_text(f"codechef/{problem_id}.html")
+                        return MockCodeChefCurlResponse(html)
+                    raise AssertionError(f"No fixture for CodeChef url={url!r}")
+
+                return {
+                    "__offline_get_async": __offline_get_async,
+                    "curl_requests.get": _mock_curl_get,
+                }
+
             case _:
                 raise AssertionError(f"Unknown scraper: {scraper_name}")
 
+    scraper_classes = {
+        "cses": "CSESScraper",
+        "atcoder": "AtcoderScraper",
+        "codeforces": "CodeforcesScraper",
+        "codechef": "CodeChefScraper",
+    }
+
     def _run(scraper_name: str, mode: str, *args: str):
         mod_path = ROOT / "scrapers" / f"{scraper_name}.py"
         ns = _load_scraper_module(mod_path, scraper_name)
         offline_fetches = _make_offline_fetches(scraper_name)
 
         if scraper_name == "codeforces":
-            fetchers.StealthyFetcher.fetch = offline_fetches["StealthyFetcher.fetch"]  # type: ignore[assignment]
+            curl_requests.get = offline_fetches["curl_requests.get"]
             requests.get = offline_fetches["requests.get"]
         elif scraper_name == "atcoder":
             ns._fetch = offline_fetches["_fetch"]
             ns._get_async = offline_fetches["_get_async"]
         elif scraper_name == "cses":
-            httpx.AsyncClient.get = offline_fetches["__offline_fetch_text"]  # type: ignore[assignment]
+            httpx.AsyncClient.get = offline_fetches["__offline_fetch_text"]
+        elif scraper_name == "codechef":
+            httpx.AsyncClient.get = offline_fetches["__offline_get_async"]
+            curl_requests.get = offline_fetches["curl_requests.get"]
 
-        main_async = getattr(ns, "main_async")
+        scraper_class = getattr(ns, scraper_classes[scraper_name])
-        assert callable(main_async), f"main_async not found in {scraper_name}"
+        scraper = scraper_class()
 
         argv = [str(mod_path), mode, *args]
-        old_argv = sys.argv
+        rc, out = _capture_stdout(scraper._run_cli_async(argv))
-        sys.argv = argv
-        try:
-            rc, out = _capture_stdout(main_async())
-        finally:
-            sys.argv = old_argv
 
         json_lines: list[Any] = []
         for line in (_line for _line in out.splitlines() if _line.strip()):

tests/fixtures/codechef/START209.json

@@ -0,0 +1,116 @@
+{
+  "status": "success",
+  "user": { "username": null },
+  "code": "START209",
+  "isRatedContest": "1",
+  "isParentContestRated": "0",
+  "name": "Starters 209 (Rated till 5 star)",
+  "problems": [],
+  "banner": "https:\/\/cdn.codechef.com\/download\/small-banner\/START209\/1760933061.png",
+  "rules": "<h4>CodeChef: A Platform for Aspiring Programmers<\/h4>\n<p class=\"last\">CodeChef was created as a platform to help programmers make it big in the world of algorithms, computer programming, and programming contests. At CodeChef, our dedicated efforts are aimed at reviving the inner geek within you, as we proudly host a thrilling programming (coding) contest every Wednesday.<\/p>\n<h4>About CodeChef Starters:<\/h4>\n<p>CodeChef Starters is a short programming contest which takes place on every Wednesday\u00a0<\/p>\n<h4>Contest Details:<\/h4>\n<ul class=\"last\">\n<li><strong>D<\/strong><strong>uration: <\/strong>\u00a02.00 hours\u00a0<\/li>\n<li><strong>Start Date: <\/strong>Wednesday, 22nd October , 2025 at 20:00 HRS (IST)<\/li>\n<li><strong>End Date: <\/strong>Wednesday, 22nd October, 2025 at 22:00 HRS (IST)<\/li>\n<li>Check your timezone <a href=\"https:\/\/www.timeanddate.com\/worldclock\/fixedtime.html?msg=CodeChef+Starters+209&amp;iso=20251022T20&amp;p1=44&amp;ah=2\" target=\"_blank\" rel=\"nofollow noreferrer noopener\">here<\/a>.<\/li>\n<\/ul>\n<h4>Eligibility Criteria: Anyone with a knack for programming<\/h4>\n<p class=\"last\">Our contests are open to all programmers across the globe.<\/p>\n<h4>What's in it for you?<\/h4>\n<p>The idea behind these programming contests is that we want you to learn while competing. Also, we believe that it is alright to refer to tutorials, books, and other materials, learn a concept, and then apply the same to solve a problem during a contest. But it is <strong>not alright to copy other people's solutions or seek other people's help to solve a problem. <\/strong>All the participants are expected to abide to <a class=\"button blue\" href=\"..\/codeofconduct\">CodeChef's Code Of Conduct<\/a>.<\/p>\n<h4>Rules and Regulations:<\/h4>\n<ul>\n<li>This is an IOI-style contest. This means that the problems will be partially graded. You will get the score for passing certain test data.<\/li>\n<li>The details of the failed test cases will also be visible on your solution page.<\/li>\n<li>You can submit solutions as many times as you'd like, there are no penalties for incorrect submissions. Only your best correct submission will be considered.<\/li>\n<li>Those who achieve the score first will be placed higher in the ranklist in case of a tie.<\/li>\n<li><strong>We have removed all the Institutions that we could not identify from our database. We request you to update your institutions once again by going to your profile page.<\/strong><\/li>\n<li>You can also send in your queries in an email to <a href=\"mailto:help@codechef.com\" target=\"_blank\" rel=\"noreferrer noopener\">help@codechef.com<\/a>, during the contest.<\/li>\n<li>Please do not discuss strategy, suggestions, or tips in the comments during a live contest. Posting questions clarifying the problem statement is ok. If you are unsure, email us at <a href=\"mailto:feedback@codechef.com\" target=\"_blank\" rel=\"noreferrer noopener\"> feedback@codechef.com<\/a>.<\/li>\n<li>Discussing CodeChef's problems or any aspect of a problem, on any other platform on the web, on identification, could lead to the disabling of the respective account and banning from the community.<\/li>\n<\/ul>\n<p><strong>Note: You can now \"Code, Compile, and Run\" your codes on our <a href=\"..\/ide\">Online IDE<\/a>.<\/strong><\/p>\n<p>However, if you are using any other online development environment, make sure that other contestants don't have access to your code. As a contestant, you are responsible for making sure others don't access the code that you submit. If you use Ideone, make sure to mark your submission \"private\" (not secret)\".<\/p>",
+  "time": {
+    "start": 1761143400,
+    "end": 1761150600,
+    "freezing": 0,
+    "current": 1761370410
+  },
+  "ip": "2603:7000:3900:1358:3959:b692:6cf3:cb03",
+  "announcements": "<p><strong>CodeChef \u00d7 Coding Club League (2025-26)<\/strong><br \/><br \/>Partner with CodeChef to build a strong coding culture on campus!<\/p>\n<p><strong>Benefits for Clubs:<\/strong><\/p>\n<ul>\n<li>Platform access and support for Annual Technical events \/ hackathons<\/li>\n<li>Pro access for winners<\/li>\n<li>Dashboard to track member progress<\/li>\n<li>Discounts on CodeChef Pro for all members<\/li>\n<li>Co-branding &amp; promotion on CodeChef channels<br \/><br \/>\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0<strong style=\"text-align:center;\"><a class=\"button blue\" href=\"codechef-coding-club\" target=\"_blank\" rel=\"noreferrer noopener\">\u00a0Click Here To Know More<\/a><\/strong><\/li>\n<\/ul>\n<p><strong>\u00a0<\/strong><\/p>",
+  "problemsstats": {
+    "attempted": [],
+    "partially_solved": [],
+    "solved": [],
+    "locked": []
+  },
+  "todos": [],
+  "stats": null,
+  "partial_scores": [],
+  "isRanklistFrozen": false,
+  "rank_and_score": { "score": "NA", "rank": "NA" },
+  "is_a_parent_contest": true,
+  "is_contest_elements_visible": true,
+  "is_OTP_required": false,
+  "is_linked_problems_contest": "0",
+  "custom_contest_page_title": "",
+  "custom_contest_page_meta_desc": "",
+  "contest_introduction": "https:\/\/discuss.codechef.com\/t\/invitation-to-codechef-starters-209-rated-upto-5-stars-22nd-october\/124401",
+  "contest_editorials": "https:\/\/discuss.codechef.com\/tag\/start209",
+  "contest_video_editorials": "",
+  "is_older_rating_based_division_system": false,
+  "division_generation": 3,
+  "isAssessmentContest": false,
+  "penalisedUsersCount": 0,
+  "ttl": 60,
+  "child_contests": {
+    "div_1": {
+      "div": {
+        "div_number": "1",
+        "code": "div_1",
+        "min_rating": 2000,
+        "max_rating": 50000,
+        "name": "Division 1",
+        "description": "Users with rating above 2000"
+      },
+      "division_generation": 3,
+      "contest_code": "START209A",
+      "contest_link": "\/START209A"
+    },
+    "div_2": {
+      "div": {
+        "div_number": "2",
+        "code": "div_2",
+        "min_rating": 1600,
+        "max_rating": 1999,
+        "name": "Division 2",
+        "description": "Users with rating between 1600 and 1999"
+      },
+      "division_generation": 3,
+      "contest_code": "START209B",
+      "contest_link": "\/START209B"
+    },
+    "div_3": {
+      "div": {
+        "div_number": "3",
+        "code": "div_3",
+        "min_rating": 1400,
+        "max_rating": 1599,
+        "name": "Division 3",
+        "description": "Users with rating upto 1599"
+      },
+      "division_generation": 3,
+      "contest_code": "START209C",
+      "contest_link": "\/START209C"
+    },
+    "div_4": {
+      "div": {
+        "div_number": "4",
+        "code": "div_4",
+        "min_rating": 0,
+        "max_rating": 1399,
+        "name": "Division 4",
+        "description": "Users with rating upto 1399"
+      },
+      "division_generation": 3,
+      "contest_code": "START209D",
+      "contest_link": "\/START209D"
+    }
+  },
+  "user_rating_div": {
+    "rating": -1,
+    "div": {
+      "code": "all",
+      "min_rating": 0,
+      "max_rating": 50000,
+      "name": "All",
+      "description": "All the users"
+    }
+  },
+  "user_contest_code": null,
+  "show_div_based_contest": false,
+  "is_registration_enabled_contest": false,
+  "is_flexi_time_contest": false,
+  "duration": "120",
+  "is_proctored": false,
+  "autoRefresh": true,
+  "visitedContests": []
+}

tests/fixtures/codechef/START209D.json

@@ -0,0 +1,202 @@
+{
+  "status": "success",
+  "user": { "username": null },
+  "code": "START209D",
+  "isRatedContest": "1",
+  "isParentContestRated": "1",
+  "name": "Starters 209 (Rated)",
+  "problems": {
+    "P1209": {
+      "code": "P1209",
+      "name": "Bitcoin Market",
+      "type": "3",
+      "successful_submissions": "25131",
+      "allow_submission": false,
+      "accuracy": 85.680000000000007,
+      "problem_url": "\/problems\/P1209",
+      "submit_url": "\/problems\/P1209",
+      "status_url": "\/status\/P1209",
+      "is_added_to_practice": true,
+      "total_submissions": "33093",
+      "category_name": "main",
+      "is_direct_submittable": false
+    },
+    "P2209": {
+      "code": "P2209",
+      "name": "Divisible Duel",
+      "type": "3",
+      "successful_submissions": "21888",
+      "allow_submission": false,
+      "accuracy": 64.159999999999997,
+      "problem_url": "\/problems\/P2209",
+      "submit_url": "\/problems\/P2209",
+      "status_url": "\/status\/P2209",
+      "is_added_to_practice": true,
+      "total_submissions": "37437",
+      "category_name": "main",
+      "is_direct_submittable": false
+    },
+    "P3209": {
+      "code": "P3209",
+      "name": "Small GCD Sort",
+      "type": "3",
+      "successful_submissions": "13450",
+      "allow_submission": false,
+      "accuracy": 76.239999999999995,
+      "problem_url": "\/problems\/P3209",
+      "submit_url": "\/problems\/P3209",
+      "status_url": "\/status\/P3209",
+      "is_added_to_practice": true,
+      "total_submissions": "19164",
+      "category_name": "main",
+      "is_direct_submittable": false
+    },
+    "P4209": {
+      "code": "P4209",
+      "name": "Tactical Conversion",
+      "type": "3",
+      "successful_submissions": "1567",
+      "allow_submission": false,
+      "accuracy": 8.4499999999999993,
+      "problem_url": "\/problems\/P4209",
+      "submit_url": "\/problems\/P4209",
+      "status_url": "\/status\/P4209",
+      "is_added_to_practice": true,
+      "total_submissions": "20535",
+      "category_name": "main",
+      "is_direct_submittable": false
+    },
+    "P5209": {
+      "code": "P5209",
+      "name": "Binary Love",
+      "type": "3",
+      "successful_submissions": "3271",
+      "allow_submission": false,
+      "accuracy": 33.530000000000001,
+      "problem_url": "\/problems\/P5209",
+      "submit_url": "\/problems\/P5209",
+      "status_url": "\/status\/P5209",
+      "is_added_to_practice": true,
+      "total_submissions": "11128",
+      "category_name": "main",
+      "is_direct_submittable": false
+    },
+    "P6209E": {
+      "code": "P6209E",
+      "name": "High Score (Easy Version)",
+      "type": "3",
+      "successful_submissions": "285",
+      "allow_submission": false,
+      "accuracy": 7.2800000000000002,
+      "problem_url": "\/problems\/P6209E",
+      "submit_url": "\/problems\/P6209E",
+      "status_url": "\/status\/P6209E",
+      "is_added_to_practice": true,
+      "total_submissions": "4535",
+      "category_name": "main",
+      "is_direct_submittable": false
+    },
+    "P6209": {
+      "code": "P6209",
+      "name": "High Score (Hard Version)",
+      "type": "3",
+      "successful_submissions": "34",
+      "allow_submission": false,
+      "accuracy": 3.1899999999999999,
+      "problem_url": "\/problems\/P6209",
+      "submit_url": "\/problems\/P6209",
+      "status_url": "\/status\/P6209",
+      "is_added_to_practice": true,
+      "total_submissions": "1159",
+      "category_name": "main",
+      "is_direct_submittable": false
+    },
+    "P7209": {
+      "code": "P7209",
+      "name": "Easy Grid Game",
+      "type": "3",
+      "successful_submissions": "80",
+      "allow_submission": false,
+      "accuracy": 5.1100000000000003,
+      "problem_url": "\/problems\/P7209",
+      "submit_url": "\/problems\/P7209",
+      "status_url": "\/status\/P7209",
+      "is_added_to_practice": true,
+      "total_submissions": "1740",
+      "category_name": "main",
+      "is_direct_submittable": false
+    },
+    "P8209": {
+      "code": "P8209",
+      "name": "Counting Is Fun",
+      "type": "3",
+      "successful_submissions": "22",
+      "allow_submission": false,
+      "accuracy": 1.8200000000000001,
+      "problem_url": "\/problems\/P8209",
+      "submit_url": "\/problems\/P8209",
+      "status_url": "\/status\/P8209",
+      "is_added_to_practice": true,
+      "total_submissions": "1261",
+      "category_name": "main",
+      "is_direct_submittable": false
+    }
+  },
+  "banner": "https:\/\/cdn.codechef.com\/download\/small-banner\/START209D\/1760933097.png",
+  "rules": "<h4>CodeChef: A Platform for Aspiring Programmers<\/h4>\n<p class=\"last\">CodeChef was created as a platform to help programmers make it big in the world of algorithms, computer programming, and programming contests. At CodeChef, our dedicated efforts are aimed at reviving the inner geek within you, as we proudly host a thrilling programming (coding) contest every Wednesday.<\/p>\n<h4>About CodeChef Starters:<\/h4>\n<p>CodeChef Starters is a short programming contest which takes place on every Wednesday\u00a0<\/p>\n<h4>Contest Details:<\/h4>\n<ul class=\"last\">\n<li><strong>D<\/strong><strong>uration: <\/strong>\u00a02.00 hours\u00a0<\/li>\n<li><strong>Start Date: <\/strong>Wednesday, 22nd October , 2025 at 20:00 HRS (IST)<\/li>\n<li><strong>End Date: <\/strong>Wednesday, 22nd October, 2025 at 22:00 HRS (IST)<\/li>\n<li>Check your timezone <a href=\"https:\/\/www.timeanddate.com\/worldclock\/fixedtime.html?msg=CodeChef+Starters+209&amp;iso=20251022T20&amp;p1=44&amp;ah=2\" target=\"_blank\" rel=\"nofollow noreferrer noopener\">here<\/a>.<\/li>\n<\/ul>\n<h4>Eligibility Criteria: Anyone with a knack for programming<\/h4>\n<p class=\"last\">Our contests are open to all programmers across the globe.<\/p>\n<h4>What's in it for you?<\/h4>\n<p>The idea behind these programming contests is that we want you to learn while competing. Also, we believe that it is alright to refer to tutorials, books, and other materials, learn a concept, and then apply the same to solve a problem during a contest. But it is <strong>not alright to copy other people's solutions or seek other people's help to solve a problem. <\/strong>All the participants are expected to abide to <a class=\"button blue\" href=\"..\/codeofconduct\">CodeChef's Code Of Conduct<\/a>.<\/p>\n<h4>Rules and Regulations:<\/h4>\n<ul>\n<li>This is an IOI-style contest. This means that the problems will be partially graded. You will get the score for passing certain test data.<\/li>\n<li>The details of the failed test cases will also be visible on your solution page.<\/li>\n<li>You can submit solutions as many times as you'd like, there are no penalties for incorrect submissions. Only your best correct submission will be considered.<\/li>\n<li>Those who achieve the score first will be placed higher in the ranklist in case of a tie.<\/li>\n<li><strong>We have removed all the Institutions that we could not identify from our database. We request you to update your institutions once again by going to your profile page.<\/strong><\/li>\n<li>You can also send in your queries in an email to <a href=\"mailto:help@codechef.com\" target=\"_blank\" rel=\"noreferrer noopener\">help@codechef.com<\/a>, during the contest.<\/li>\n<li>Please do not discuss strategy, suggestions, or tips in the comments during a live contest. Posting questions clarifying the problem statement is ok. If you are unsure, email us at <a href=\"mailto:feedback@codechef.com\" target=\"_blank\" rel=\"noreferrer noopener\"> feedback@codechef.com<\/a>.<\/li>\n<li>Discussing CodeChef's problems or any aspect of a problem, on any other platform on the web, on identification, could lead to the disabling of the respective account and banning from the community.<\/li>\n<\/ul>\n<p><strong>Note: You can now \"Code, Compile, and Run\" your codes on our <a href=\"..\/ide\">Online IDE<\/a>.<\/strong><\/p>\n<p>However, if you are using any other online development environment, make sure that other contestants don't have access to your code. As a contestant, you are responsible for making sure others don't access the code that you submit. If you use Ideone, make sure to mark your submission \"private\" (not secret)\".<\/p>",
+  "time": {
+    "start": 1761143406,
+    "end": 1761150606,
+    "freezing": 0,
+    "current": 1761365589
+  },
+  "ip": "2603:7000:3900:1358:3959:b692:6cf3:cb03",
+  "announcements": "<p><strong>CodeChef \u00d7 Coding Club League (2025-26)<\/strong><br \/><br \/>Partner with CodeChef to build a strong coding culture on campus!<\/p>\n<p><strong>Benefits for Clubs:<\/strong><\/p>\n<ul>\n<li>Platform access and support for Annual Technical events \/ hackathons<\/li>\n<li>Pro access for winners<\/li>\n<li>Dashboard to track member progress<\/li>\n<li>Discounts on CodeChef Pro for all members<\/li>\n<li>Co-branding &amp; promotion on CodeChef channels<br \/><br \/>\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0<strong style=\"text-align:center;\"><a class=\"button blue\" href=\"codechef-coding-club\" target=\"_blank\" rel=\"noreferrer noopener\">\u00a0Click Here To Know More<\/a><\/strong><\/li>\n<\/ul>\n<p><strong>\u00a0<\/strong><\/p>\n<p>\u00a0<\/p>",
+  "problemsstats": {
+    "attempted": [],
+    "partially_solved": [],
+    "solved": [],
+    "locked": []
+  },
+  "todos": [],
+  "stats": null,
+  "partial_scores": {
+    "P7209": [{ "score": "100", "count": "80" }],
+    "P5209": [{ "score": "100", "count": "3271" }],
+    "P4209": [{ "score": "100", "count": "1567" }],
+    "P1209": [{ "score": "100", "count": "25131" }],
+    "P3209": [{ "score": "100", "count": "13450" }],
+    "P2209": [{ "score": "100", "count": "21888" }],
+    "P8209": [{ "score": "100", "count": "22" }],
+    "P6209": [{ "score": "100", "count": "34" }],
+    "P6209E": [{ "score": "100", "count": "285" }]
+  },
+  "isRanklistFrozen": false,
+  "rank_and_score": { "score": "NA", "rank": "NA" },
+  "is_a_parent_contest": false,
+  "is_contest_elements_visible": true,
+  "is_OTP_required": false,
+  "is_linked_problems_contest": "0",
+  "custom_contest_page_title": "",
+  "custom_contest_page_meta_desc": "",
+  "contest_introduction": "https:\/\/discuss.codechef.com\/t\/invitation-to-codechef-starters-209-rated-upto-5-stars-22nd-october\/124401",
+  "contest_editorials": "https:\/\/discuss.codechef.com\/tag\/start209",
+  "contest_video_editorials": "",
+  "is_older_rating_based_division_system": false,
+  "division_generation": 3,
+  "isAssessmentContest": false,
+  "penalisedUsersCount": 0,
+  "ttl": 60,
+  "scorable_heading": "Scorable Problems for Division 4",
+  "scorable_message": "",
+  "division": "Division 4",
+  "non_scorable_heading": "Non Scorable Problems for Practice",
+  "non_scorable_message": "<p>The following problems are <b>NOT part of the contest<\/b>, and will not be counted towards your rankings and ratings. These are problems from the other Division(s), made available for you to practice. Click <a href='\/blogs\/how-does-codechef-rating-system-work'>here<\/a> to know more. They will be considered for plagiarism though.<\/p>",
+  "is_registration_enabled_contest": false,
+  "is_flexi_time_contest": false,
+  "duration": "120",
+  "is_proctored": false,
+  "autoRefresh": true,
+  "visitedContests": [],
+  "user_live_ratings_update_frequency": 15
+}

tests/fixtures/codechef/START209D_P1209.json

@@ -0,0 +1,99 @@
+{
+  "category_name": "main",
+  "contest_code": "START209D",
+  "contest_name": "Starters 209 (Rated)",
+  "status": "success",
+  "submit_error": "You need to login to submit.",
+  "is_verified": false,
+  "problem_code": "P1209",
+  "contest_category": "9",
+  "problem_name": "Bitcoin Market",
+  "intended_contest_code": "START209",
+  "body": "This is an example problem statement in markdown, and a mini guide on writing statements. Please make sure to remove everything here before publishing your problem.\n\n- Codechef uses markdown for its problem statements. Markdown syntax can be found [here](https:\/\/github.com\/showdownjs\/showdown\/wiki\/Showdown's-Markdown-syntax). Note the `[text](link)` syntax to insert a hyperlink.\n- Codechef also uses $\\LaTeX$ to render mathematical expressions, and you are advised to make liberal use of it to make your statement look good.\n- Text can be made **bold** or *italicized*.\n- **Do not** use HTML tags (p, ul, li, pre, br, ...) in the statement.\n- To insert an image, first upload it to an online hosting service (for an official contest, ask a Codechef admin to do this for you \u2014 this is important) and then use the following syntax: `![alt text](link-to-image)`.\n- If your problem doesn't contain subtasks, ensure that the Subtasks section below is disabled and **all content is deleted from it**.\n\nIf you face any issues, either contact a Codechef admin directly or send us an email at help@codechef.com.\n\nBelow is an example problem statement that uses some of the above-mentioned features.\n\n---------\n\nChef has a simple undirected graph $G$ with $N$ vertices and $M$ edges. A [subgraph](https:\/\/mathworld.wolfram.com\/Subgraph.html) $H$ of $G$ is called *good* if:\n- $H$ is connected\n- $H$ contains all $N$ vertices of $G$\n- There is a unique path between any two vertices in $H$, using only edges in $H$\n\nCount the number of *good* subgraphs of $G$. Since this number might be large, report it modulo $10^9 + 7$.\n\nIn other news, here's a completely unrelated image:\n\n![](https:\/\/s3.amazonaws.com\/codechef_shared\/download\/Images\/START41\/ss3.png).\n\n\n<aside style='background: #f8f8f8;padding: 10px 15px;'><div>All submissions for this problem are available.<\/div><\/aside>",
+  "problemComponents": {
+    "constraints": "- $1 \\leq R \\leq 10$",
+    "constraintsState": true,
+    "subtasks": "- **Subtask 1 (10 points):** $1 \\leq M \\leq 10$\n- **Subtask 2 (20 points):** The sum of $N$ across all test cases won't exceed $20$.\n- **Subtask 3 (70 points):** No further constraints.",
+    "subtasksState": false,
+    "statement": "Chef has recently started investing in **Bitcoin**.  \nHe assigns a **market risk level** $R$ (from $1$ to $10$), where:  \n\n- $1$ means the market is *very safe*,  \n- $10$ means the market is *very risky*.  \n\nChef will **buy Bitcoin** only if the risk level is **$4$ or less**.  \n\nGiven the current risk level $R$, determine whether Chef should buy Bitcoin.\n\nPrint **\"YES\"** if Chef should buy, otherwise print **\"NO\"**.",
+    "inputFormat": "- The first and only line of input contains a single integer $R$ \u2014 the current market risk level.",
+    "inputFormatState": true,
+    "outputFormat": "Print `YES` if Chef should buy Bitcoin, Otherwise, print `NO`.\n\nYou may print each character of the string in uppercase or lowercase (for example, the strings `YES`, `yEs`, `yes`, and `yeS` will all be treated as identical).\n",
+    "outputFormatState": true,
+    "sampleTestCases": [
+      {
+        "id": "1",
+        "input": "2",
+        "output": "YES",
+        "explanation": "The current market risk is $2$.  \nSince $2$ is not larger than $4$, the risk is small enough, and Chef will buy Bitcoin.",
+        "isDeleted": false
+      },
+      {
+        "id": "2",
+        "input": "4",
+        "output": "YES",
+        "explanation": "The current market risk is $4$.  \nSince $4$ is not larger than $4$, the risk is small enough, and Chef will buy Bitcoin.",
+        "isDeleted": false
+      },
+      {
+        "id": "3",
+        "input": "5",
+        "output": "NO",
+        "explanation": "The current market risk is $5$.  \nSince $5$ is larger than $4$, the risk is too much, and Chef will **not** buy Bitcoin.",
+        "isDeleted": false
+      }
+    ]
+  },
+  "gumlet_video_url": "",
+  "video_editorial_url": "https:\/\/youtu.be\/tjUCV9Ld1Kw?si=minop9943wecj1bh",
+  "text_editorial_body": "<h1><a name=\"problem-link-1\" class=\"anchor\" href=\"#problem-link-1\"><\/a>PROBLEM LINK:<\/h1>\n<p><a href=\"https:\/\/www.codechef.com\/problems\/P1209\">Practice<\/a><br>\n<a href=\"https:\/\/www.codechef.com\/START209A\/problems\/P1209\">Contest: Division 1<\/a><br>\n<a href=\"https:\/\/www.codechef.com\/START209B\/problems\/P1209\">Contest: Division 2<\/a><br>\n<a href=\"https:\/\/www.codechef.com\/START209C\/problems\/P1209\">Contest: Division 3<\/a><br>\n<a href=\"https:\/\/www.codechef.com\/START209D\/problems\/P1209\">Contest: Division 4<\/a><\/p>\n<p><em><strong>Author:<\/strong><\/em> <a href=\"https:\/\/www.codechef.com\/users\/pols_agyi_pols\">pols_agyi_pols<\/a><br>\n<em><strong>Tester:<\/strong><\/em> <a href=\"https:\/\/www.codechef.com\/users\/kingmessi\">kingmessi<\/a><br>\n<em><strong>Editorialist:<\/strong><\/em> <a href=\"https:\/\/www.codechef.com\/users\/iceknight1093\">iceknight1093<\/a><\/p>\n<h1><a name=\"difficulty-2\" class=\"anchor\" href=\"#difficulty-2\"><\/a>DIFFICULTY:<\/h1>\n<p>Cakewalk<\/p>\n<h1><a name=\"prerequisites-3\" class=\"anchor\" href=\"#prerequisites-3\"><\/a>PREREQUISITES:<\/h1>\n<p>None<\/p>\n<h1><a name=\"problem-4\" class=\"anchor\" href=\"#problem-4\"><\/a>PROBLEM:<\/h1>\n<p>Chef will buy bitcoin if the market risk level is no more than <span class=\"math\">4<\/span>.<br>\nThe current market risk level is <span class=\"math\">R<\/span>.<br>\nWill Chef buy bitcoin?<\/p>\n<h1><a name=\"explanation-5\" class=\"anchor\" href=\"#explanation-5\"><\/a>EXPLANATION:<\/h1>\n<p>The answer is <code>Yes<\/code> if <span class=\"math\">R \\le 4<\/span> and <code>No<\/code> otherwise.<br>\nThis can be checked using an <code>if<\/code> condition.<\/p>\n<h1><a name=\"time-complexity-6\" class=\"anchor\" href=\"#time-complexity-6\"><\/a>TIME COMPLEXITY:<\/h1>\n<p><span class=\"math\">\\mathcal{O}(1)<\/span> per testcase.<\/p>\n<h1><a name=\"code-7\" class=\"anchor\" href=\"#code-7\"><\/a>CODE:<\/h1>\n<details>\n<summary>\nEditorialist's code (PyPy3)<\/summary>\n<pre><code class=\"lang-python\">r = int(input())\nprint('Yes' if r &lt;= 4 else 'No')\n<\/code><\/pre>\n<\/details>",
+  "text_editorial_is_markdown": 0,
+  "text_editorial_topic_id": 124410,
+  "languages_supported": "CPP20, PYTH 3, C, JAVA, PYP3, CS2, NODEJS, GO, TS, PHP, kotlin, rust, R",
+  "max_timelimit": "1",
+  "source_sizelimit": "50000",
+  "problem_author": "archit_adm",
+  "problem_display_authors": ["archit_adm"],
+  "problem_display_authors_html_handle": "<div class=\"multiple-usernames-container\"><a href='\/users\/archit_adm'>archit_adm<\/a><\/div>",
+  "problem_tester": null,
+  "problem_testers_usernames": ["kingmessi"],
+  "problem_tester_html_handle": "<div class=\"multiple-usernames-container\"><a href='\/users\/kingmessi'><span \n            class='rating' \n            style='display: inline-block; \n                    font-size: 10px; \n                    background: #D0011B;\n                    padding: 0 3px; \n                    line-height: 1.3; \n                    color: white;\n                    margin-right: 2px;'>7&#9733;<\/span><span class='m-username--link'>kingmessi<\/span><\/a><\/div>",
+  "problem_editorialist": "iceknight1093",
+  "date_added": "20-10-2025",
+  "ready_for_debug": false,
+  "problem_stats": {
+    "accuracy": 85.780000000000001,
+    "successful_submissions": "25325",
+    "total_submissions": "33327"
+  },
+  "user_tags": ["archit_adm", "cakewalk", "start209"],
+  "computed_tags": [],
+  "difficulty_rating": "172",
+  "best_tag": "",
+  "editorial_url": "",
+  "time": {
+    "view_start_date": 1761143406,
+    "submit_start_date": 1761143406,
+    "visible_start_date": 1761150606,
+    "end_date": 1761150606,
+    "current": 1761365589,
+    "practice_submission_allowed": false
+  },
+  "user": { "username": null, "access": "default", "isPremiumUser": false },
+  "bookmark_status": false,
+  "contest_problem_status": "unattempted",
+  "problem_status": "unattempted",
+  "is_direct_submittable": false,
+  "problemDiscussURL": "https:\/\/discuss.codechef.com\/search?q=P1209",
+  "is_a_practice_or_college_contest": false,
+  "votes_data": {
+    "SolutionVoteData": { "upvote_count": 0, "user_vote": 0 },
+    "HintsVoteData": { "upvote_count": 0, "user_vote": 0 },
+    "ProblemStatementVoteData": { "upvote_count": 26, "user_vote": 0 },
+    "DoubtSupportVoteData": { "upvote_count": 0, "user_vote": 0 }
+  },
+  "is_proctored": false,
+  "is_user_verified_for_proctoring": false,
+  "visitedContests": [],
+  "isSupportedByJudge": true
+}

tests/fixtures/codechef/contests.json

@@ -0,0 +1,330 @@
+{
+  "status": "success",
+  "message": "All contests list",
+  "present_contests": [
+    {
+      "contest_code": "DEVWEEKEND21",
+      "contest_name": "Weekend Dev Challenge 21: Full Stack Projects using MERN",
+      "contest_start_date": "25 Oct 2025  00:00:00",
+      "contest_end_date": "27 Oct 2025  00:00:00",
+      "contest_start_date_iso": "2025-10-25T00:00:00+05:30",
+      "contest_end_date_iso": "2025-10-27T00:00:00+05:30",
+      "contest_duration": "2880",
+      "distinct_users": 8
+    }
+  ],
+  "future_contests": [
+    {
+      "contest_code": "START210",
+      "contest_name": "Starters 210",
+      "contest_start_date": "29 Oct 2025  20:00:00",
+      "contest_end_date": "29 Oct 2025  22:00:00",
+      "contest_start_date_iso": "2025-10-29T20:00:00+05:30",
+      "contest_end_date_iso": "2025-10-29T22:00:00+05:30",
+      "contest_duration": "120",
+      "distinct_users": 0
+    },
+    {
+      "contest_code": "START211",
+      "contest_name": "Starters 211",
+      "contest_start_date": "05 Nov 2025  20:00:00",
+      "contest_end_date": "05 Nov 2025  22:00:00",
+      "contest_start_date_iso": "2025-11-05T20:00:00+05:30",
+      "contest_end_date_iso": "2025-11-05T22:00:00+05:30",
+      "contest_duration": "120",
+      "distinct_users": 0
+    }
+  ],
+  "practice_contests": [],
+  "past_contests": [
+    {
+      "contest_code": "START209",
+      "contest_name": "Starters 209 (Rated till 5 star)",
+      "contest_start_date": "22 Oct 2025  20:00:00",
+      "contest_end_date": "22 Oct 2025  22:00:00",
+      "contest_start_date_iso": "2025-10-22T20:00:00+05:30",
+      "contest_end_date_iso": "2025-10-22T22:00:00+05:30",
+      "contest_duration": "120",
+      "distinct_users": 30408
+    },
+    {
+      "contest_code": "DSAMONDAY08",
+      "contest_name": "Monday Munch - DSA Challenge 08",
+      "contest_start_date": "20 Oct 2025  18:00:31",
+      "contest_end_date": "20 Oct 2025  21:00:31",
+      "contest_start_date_iso": "2025-10-20T18:00:31+05:30",
+      "contest_end_date_iso": "2025-10-20T21:00:31+05:30",
+      "contest_duration": "180",
+      "distinct_users": 653
+    },
+    {
+      "contest_code": "DEVWEEKEND20",
+      "contest_name": "Weekend Dev Challenge 20: Full Stack Projects using MERN",
+      "contest_start_date": "18 Oct 2025  00:00:00",
+      "contest_end_date": "20 Oct 2025  00:00:00",
+      "contest_start_date_iso": "2025-10-18T00:00:00+05:30",
+      "contest_end_date_iso": "2025-10-20T00:00:00+05:30",
+      "contest_duration": "2880",
+      "distinct_users": 318
+    },
+    {
+      "contest_code": "START208",
+      "contest_name": "Starters 208 (Rated till 6 star)",
+      "contest_start_date": "15 Oct 2025  20:00:00",
+      "contest_end_date": "15 Oct 2025  22:00:00",
+      "contest_start_date_iso": "2025-10-15T20:00:00+05:30",
+      "contest_end_date_iso": "2025-10-15T22:00:00+05:30",
+      "contest_duration": "120",
+      "distinct_users": 37727
+    },
+    {
+      "contest_code": "DSAMONDAY07",
+      "contest_name": "Monday Munch - DSA Challenge 07",
+      "contest_start_date": "13 Oct 2025  18:00:00",
+      "contest_end_date": "13 Oct 2025  21:00:00",
+      "contest_start_date_iso": "2025-10-13T18:00:00+05:30",
+      "contest_end_date_iso": "2025-10-13T21:00:00+05:30",
+      "contest_duration": "180",
+      "distinct_users": 4934
+    },
+    {
+      "contest_code": "DEVWEEKEND19",
+      "contest_name": "Weekend Dev Challenge 19: Full Stack Projects using MERN",
+      "contest_start_date": "11 Oct 2025  00:00:00",
+      "contest_end_date": "13 Oct 2025  00:00:00",
+      "contest_start_date_iso": "2025-10-11T00:00:00+05:30",
+      "contest_end_date_iso": "2025-10-13T00:00:00+05:30",
+      "contest_duration": "2880",
+      "distinct_users": 5376
+    },
+    {
+      "contest_code": "START207",
+      "contest_name": "Starters 207 (Rated till 5 star)",
+      "contest_start_date": "08 Oct 2025  20:00:00",
+      "contest_end_date": "08 Oct 2025  22:00:00",
+      "contest_start_date_iso": "2025-10-08T20:00:00+05:30",
+      "contest_end_date_iso": "2025-10-08T22:00:00+05:30",
+      "contest_duration": "120",
+      "distinct_users": 32785
+    },
+    {
+      "contest_code": "DSAMONDAY06",
+      "contest_name": "Monday Munch - DSA Challenge 06",
+      "contest_start_date": "06 Oct 2025  18:00:02",
+      "contest_end_date": "06 Oct 2025  21:00:02",
+      "contest_start_date_iso": "2025-10-06T18:00:02+05:30",
+      "contest_end_date_iso": "2025-10-06T21:00:02+05:30",
+      "contest_duration": "180",
+      "distinct_users": 892
+    },
+    {
+      "contest_code": "DEVWEEKEND18",
+      "contest_name": "Weekend Dev Challenge 18: Full Stack Projects using MERN",
+      "contest_start_date": "04 Oct 2025  00:00:00",
+      "contest_end_date": "06 Oct 2025  00:00:00",
+      "contest_start_date_iso": "2025-10-04T00:00:00+05:30",
+      "contest_end_date_iso": "2025-10-06T00:00:00+05:30",
+      "contest_duration": "2880",
+      "distinct_users": 223
+    },
+    {
+      "contest_code": "START206",
+      "contest_name": "Starters 206 (Rated till 5 star)",
+      "contest_start_date": "01 Oct 2025  20:00:00",
+      "contest_end_date": "01 Oct 2025  22:00:00",
+      "contest_start_date_iso": "2025-10-01T20:00:00+05:30",
+      "contest_end_date_iso": "2025-10-01T22:00:00+05:30",
+      "contest_duration": "120",
+      "distinct_users": 23977
+    },
+    {
+      "contest_code": "DSAMONDAY05",
+      "contest_name": "Monday Munch - DSA Challenge 05",
+      "contest_start_date": "29 Sep 2025  18:00:00",
+      "contest_end_date": "29 Sep 2025  21:00:00",
+      "contest_start_date_iso": "2025-09-29T18:00:00+05:30",
+      "contest_end_date_iso": "2025-09-29T21:00:00+05:30",
+      "contest_duration": "180",
+      "distinct_users": 1160
+    },
+    {
+      "contest_code": "DEVWEEKEND17",
+      "contest_name": "Weekend Dev Challenge 17: GenAI Projects using LLM",
+      "contest_start_date": "27 Sep 2025  00:00:00",
+      "contest_end_date": "29 Sep 2025  00:00:00",
+      "contest_start_date_iso": "2025-09-27T00:00:00+05:30",
+      "contest_end_date_iso": "2025-09-29T00:00:00+05:30",
+      "contest_duration": "2880",
+      "distinct_users": 130
+    },
+    {
+      "contest_code": "START205",
+      "contest_name": "Starters 205 (Rated till 6 star)",
+      "contest_start_date": "24 Sep 2025  20:00:00",
+      "contest_end_date": "24 Sep 2025  22:00:00",
+      "contest_start_date_iso": "2025-09-24T20:00:00+05:30",
+      "contest_end_date_iso": "2025-09-24T22:00:00+05:30",
+      "contest_duration": "120",
+      "distinct_users": 32552
+    },
+    {
+      "contest_code": "DSAMONDAY04",
+      "contest_name": "Monday Munch - DSA Challenge 04",
+      "contest_start_date": "22 Sep 2025  18:00:00",
+      "contest_end_date": "22 Sep 2025  21:00:00",
+      "contest_start_date_iso": "2025-09-22T18:00:00+05:30",
+      "contest_end_date_iso": "2025-09-22T21:00:00+05:30",
+      "contest_duration": "180",
+      "distinct_users": 759
+    },
+    {
+      "contest_code": "DEVWEEKEND16",
+      "contest_name": "Weekend Dev Challenge 16: GenAI Projects using LLM",
+      "contest_start_date": "20 Sep 2025  00:00:00",
+      "contest_end_date": "22 Sep 2025  00:00:00",
+      "contest_start_date_iso": "2025-09-20T00:00:00+05:30",
+      "contest_end_date_iso": "2025-09-22T00:00:00+05:30",
+      "contest_duration": "2880",
+      "distinct_users": 171
+    },
+    {
+      "contest_code": "START204",
+      "contest_name": "Starters 204 (Rated till 5 star)",
+      "contest_start_date": "17 Sep 2025  20:00:00",
+      "contest_end_date": "17 Sep 2025  22:00:00",
+      "contest_start_date_iso": "2025-09-17T20:00:00+05:30",
+      "contest_end_date_iso": "2025-09-17T22:00:00+05:30",
+      "contest_duration": "120",
+      "distinct_users": 36282
+    },
+    {
+      "contest_code": "DSAMONDAY03",
+      "contest_name": "Monday Munch - DSA Challenge 03",
+      "contest_start_date": "15 Sep 2025  18:00:00",
+      "contest_end_date": "15 Sep 2025  21:00:00",
+      "contest_start_date_iso": "2025-09-15T18:00:00+05:30",
+      "contest_end_date_iso": "2025-09-15T21:00:00+05:30",
+      "contest_duration": "180",
+      "distinct_users": 657
+    },
+    {
+      "contest_code": "DEVWEEKEND15",
+      "contest_name": "Weekend Dev Challenge 15: Classify images using Deep Learning",
+      "contest_start_date": "13 Sep 2025  00:00:00",
+      "contest_end_date": "14 Sep 2025  00:00:00",
+      "contest_start_date_iso": "2025-09-13T00:00:00+05:30",
+      "contest_end_date_iso": "2025-09-14T00:00:00+05:30",
+      "contest_duration": "1440",
+      "distinct_users": 112
+    },
+    {
+      "contest_code": "START203",
+      "contest_name": "Starters 203 (Rated till 5 star)",
+      "contest_start_date": "10 Sep 2025  20:00:00",
+      "contest_end_date": "10 Sep 2025  22:00:00",
+      "contest_start_date_iso": "2025-09-10T20:00:00+05:30",
+      "contest_end_date_iso": "2025-09-10T22:00:00+05:30",
+      "contest_duration": "120",
+      "distinct_users": 36512
+    },
+    {
+      "contest_code": "DSAMONDAY02",
+      "contest_name": "Monday Munch - DSA Challenge 02",
+      "contest_start_date": "08 Sep 2025  18:00:00",
+      "contest_end_date": "08 Sep 2025  21:00:00",
+      "contest_start_date_iso": "2025-09-08T18:00:00+05:30",
+      "contest_end_date_iso": "2025-09-08T21:00:00+05:30",
+      "contest_duration": "180",
+      "distinct_users": 737
+    }
+  ],
+  "skill_tests": [
+    {
+      "contest_code": "basic-python",
+      "contest_name": "Python Online Test & Quiz",
+      "contest_start_date": "27 Mar 2024  15:00:00",
+      "contest_end_date": "01 Jan 2027  01:30:00",
+      "contest_start_date_iso": "2024-03-27T15:00:00+05:30",
+      "contest_end_date_iso": "2027-01-01T01:30:00+05:30",
+      "contest_duration": "90",
+      "problem_count": 30,
+      "distinct_users": 61244
+    },
+    {
+      "contest_code": "basic-java",
+      "contest_name": "Java Online Test & Quiz",
+      "contest_start_date": "28 Mar 2024  00:00:00",
+      "contest_end_date": "01 Jan 2027  01:30:00",
+      "contest_start_date_iso": "2024-03-28T00:00:00+05:30",
+      "contest_end_date_iso": "2027-01-01T01:30:00+05:30",
+      "contest_duration": "90",
+      "problem_count": 30,
+      "distinct_users": 49993
+    },
+    {
+      "contest_code": "basic-c-language",
+      "contest_name": "C language online test",
+      "contest_start_date": "28 Mar 2024  00:00:00",
+      "contest_end_date": "01 Jan 2027  01:30:00",
+      "contest_start_date_iso": "2024-03-28T00:00:00+05:30",
+      "contest_end_date_iso": "2027-01-01T01:30:00+05:30",
+      "contest_duration": "90",
+      "problem_count": 30,
+      "distinct_users": 41373
+    },
+    {
+      "contest_code": "basic-c-plus-plus",
+      "contest_name": "C++ Online Test and Quiz",
+      "contest_start_date": "28 Mar 2024  00:00:00",
+      "contest_end_date": "01 Jan 2027  01:30:00",
+      "contest_start_date_iso": "2024-03-28T00:00:00+05:30",
+      "contest_end_date_iso": "2027-01-01T01:30:00+05:30",
+      "contest_duration": "90",
+      "problem_count": 30,
+      "distinct_users": 32507
+    },
+    {
+      "contest_code": "basic-sql",
+      "contest_name": "SQL Online Test and Quiz",
+      "contest_start_date": "01 Jun 2024  00:00:00",
+      "contest_end_date": "01 Jan 2027  01:00:00",
+      "contest_start_date_iso": "2024-06-01T00:00:00+05:30",
+      "contest_end_date_iso": "2027-01-01T01:00:00+05:30",
+      "contest_duration": "60",
+      "problem_count": 17,
+      "distinct_users": 17426
+    },
+    {
+      "contest_code": "operating-systems",
+      "contest_name": "Operating Systems Skill Test",
+      "contest_start_date": "01 Jun 2024  00:00:00",
+      "contest_end_date": "01 Jan 2027  00:45:00",
+      "contest_start_date_iso": "2024-06-01T00:00:00+05:30",
+      "contest_end_date_iso": "2027-01-01T00:45:00+05:30",
+      "contest_duration": "45",
+      "problem_count": 30,
+      "distinct_users": 8751
+    },
+    {
+      "contest_code": "c-language-dsa",
+      "contest_name": "Data structures and Algorithms in C test",
+      "contest_start_date": "01 Apr 2024  12:00:00",
+      "contest_end_date": "01 Jan 2027  02:00:00",
+      "contest_start_date_iso": "2024-04-01T12:00:00+05:30",
+      "contest_end_date_iso": "2027-01-01T02:00:00+05:30",
+      "contest_duration": "120",
+      "problem_count": 28,
+      "distinct_users": 6611
+    }
+  ],
+  "banners": [
+    {
+      "image": "1760933050.png",
+      "link": "https:\/\/www.codechef.com\/START209"
+    },
+    {
+      "image": "1719492535.png",
+      "link": "https:\/\/www.codechef.com\/roadmap\/data-structures-and-algorithms"
+    }
+  ]
+}

tests/fixtures/cses/contests.html

@@ -27,7 +27,7 @@
         <a href="/" class="logo"><img src="/logo.png?1" alt="CSES" /></a>
         <a
           class="menu-toggle"
-          onclick="document.body.classList.toggle('menu-open');"
+          onclick="document.body.classList.toggle('menu-open')"
         >
           <i class="fas fa-bars"></i>
         </a>

tests/fixtures/cses/task_1068.html

@@ -27,7 +27,7 @@
         <a href="/" class="logo"><img src="/logo.png?1" alt="CSES" /></a>
         <a
           class="menu-toggle"
-          onclick="document.body.classList.toggle('menu-open');"
+          onclick="document.body.classList.toggle('menu-open')"
         >
           <i class="fas fa-bars"></i>
         </a>

tests/fixtures/cses/task_1621.html

@@ -27,7 +27,7 @@
         <a href="/" class="logo"><img src="/logo.png?1" alt="CSES" /></a>
         <a
           class="menu-toggle"
-          onclick="document.body.classList.toggle('menu-open');"
+          onclick="document.body.classList.toggle('menu-open')"
         >
           <i class="fas fa-bars"></i>
         </a>

tests/test_scrapers.py

@@ -6,11 +6,6 @@ from scrapers.models import (
     TestsResult,
 )
 
-MODEL_FOR_MODE = {
-    "metadata": MetadataResult,
-    "contests": ContestListResult,
-}
-
 MATRIX = {
     "cses": {
         "metadata": ("introductory_problems",),
@@ -27,6 +22,11 @@ MATRIX = {
         "tests": ("1550",),
         "contests": tuple(),
     },
+    "codechef": {
+        "metadata": ("START209D",),
+        "tests": ("START209D",),
+        "contests": tuple(),
+    },
 }
 
 
@@ -38,24 +38,34 @@ def test_scraper_offline_fixture_matrix(run_scraper_offline, scraper, mode):
     assert rc in (0, 1), f"Bad exit code {rc}"
     assert objs, f"No JSON output for {scraper}:{mode}"
 
-    if mode in ("metadata", "contests"):
-        Model = MODEL_FOR_MODE[mode]
-        model = Model.model_validate(objs[-1])
-        assert model is not None
-        assert model.success is True
     if mode == "metadata":
+        model = MetadataResult.model_validate(objs[-1])
+        assert model.success is True
         assert model.url
         assert len(model.problems) >= 1
         assert all(isinstance(p.id, str) and p.id for p in model.problems)
-        else:
+    elif mode == "contests":
+        model = ContestListResult.model_validate(objs[-1])
+        assert model.success is True
         assert len(model.contests) >= 1
     else:
+        assert len(objs) >= 1, "No test objects returned"
         validated_any = False
         for obj in objs:
             if "success" in obj and "tests" in obj and "problem_id" in obj:
                 tr = TestsResult.model_validate(obj)
                 assert tr.problem_id != ""
                 assert isinstance(tr.tests, list)
+                assert hasattr(tr, "combined"), "Missing combined field"
+                assert tr.combined is not None, "combined field is None"
+                assert hasattr(tr.combined, "input"), "combined missing input"
+                assert hasattr(tr.combined, "expected"), "combined missing expected"
+                assert isinstance(tr.combined.input, str), "combined.input not string"
+                assert isinstance(tr.combined.expected, str), (
+                    "combined.expected not string"
+                )
+                assert hasattr(tr, "multi_test"), "Missing multi_test field"
+                assert isinstance(tr.multi_test, bool), "multi_test not boolean"
                 validated_any = True
             else:
                 assert "problem_id" in obj
@@ -63,5 +73,17 @@ def test_scraper_offline_fixture_matrix(run_scraper_offline, scraper, mode):
                 assert (
                     "timeout_ms" in obj and "memory_mb" in obj and "interactive" in obj
                 )
+                assert "combined" in obj, "Missing combined field in raw JSON"
+                assert isinstance(obj["combined"], dict), "combined not a dict"
+                assert "input" in obj["combined"], "combined missing input key"
+                assert "expected" in obj["combined"], "combined missing expected key"
+                assert isinstance(obj["combined"]["input"], str), (
+                    "combined.input not string"
+                )
+                assert isinstance(obj["combined"]["expected"], str), (
+                    "combined.expected not string"
+                )
+                assert "multi_test" in obj, "Missing multi_test field in raw JSON"
+                assert isinstance(obj["multi_test"], bool), "multi_test not boolean"
                 validated_any = True
         assert validated_any, "No valid tests payloads validated"