/**
 * Tests for git-based extension updates, specifically handling force-push scenarios.
 *
 * These tests verify that DefaultPackageManager.update() handles:
 * - Normal git updates (no force-push)
 * - Force-pushed remotes gracefully (currently fails, fix needed)
 */

import { spawnSync } from "node:child_process";
import { createHash } from "node:crypto";
import {
  existsSync,
  mkdirSync,
  readFileSync,
  rmSync,
  writeFileSync,
} from "node:fs";
import { tmpdir } from "node:os";
import { join } from "node:path";
import { afterEach, beforeEach, describe, expect, it } from "vitest";
import { DefaultPackageManager } from "../src/core/package-manager.js";
import { SettingsManager } from "../src/core/settings-manager.js";

// Helper to run git commands in a directory
function git(args: string[], cwd: string): string {
  const result = spawnSync("git", args, {
    cwd,
    encoding: "utf-8",
  });
  if (result.status !== 0) {
    throw new Error(`Command failed: git ${args.join(" ")}\n${result.stderr}`);
  }
  return result.stdout.trim();
}

// Helper to create a commit with a file
function createCommit(
  repoDir: string,
  filename: string,
  content: string,
  message: string,
): string {
  writeFileSync(join(repoDir, filename), content);
  git(["add", filename], repoDir);
  git(["commit", "-m", message], repoDir);
  return git(["rev-parse", "HEAD"], repoDir);
}

// Helper to get current commit hash
function getCurrentCommit(repoDir: string): string {
  return git(["rev-parse", "HEAD"], repoDir);
}

// Helper to get file content
function getFileContent(repoDir: string, filename: string): string {
  return readFileSync(join(repoDir, filename), "utf-8");
}

describe("DefaultPackageManager git update", () => {
  let tempDir: string;
  let remoteDir: string; // Simulates the "remote" repository
  let agentDir: string; // The agent directory where extensions are installed
  let installedDir: string; // The installed extension directory
  let settingsManager: SettingsManager;
  let packageManager: DefaultPackageManager;

  // Git source that maps to our installed directory structure.
  // Must use "git:" prefix so parseSource() treats it as a git source
  // (bare "github.com/..." is not recognized as a git URL).
  const gitSource = "git:github.com/test/extension";

  beforeEach(() => {
    tempDir = join(
      tmpdir(),
      `git-update-test-${Date.now()}-${Math.random().toString(36).slice(2)}`,
    );
    mkdirSync(tempDir, { recursive: true });
    remoteDir = join(tempDir, "remote");
    agentDir = join(tempDir, "agent");

    // This matches the path structure: agentDir/git/<host>/<path>
    installedDir = join(agentDir, "git", "github.com", "test", "extension");

    mkdirSync(agentDir, { recursive: true });

    settingsManager = SettingsManager.inMemory();
    packageManager = new DefaultPackageManager({
      cwd: tempDir,
      agentDir,
      settingsManager,
    });
  });

  afterEach(() => {
    if (tempDir && existsSync(tempDir)) {
      rmSync(tempDir, { recursive: true, force: true });
    }
  });

  /**
   * Sets up a "remote" repository and clones it to the installed directory.
   * This simulates what packageManager.install() would do.
   * @param sourceOverride Optional source string to use instead of gitSource (e.g., with @ref for pinned tests)
   */
  function setupRemoteAndInstall(sourceOverride?: string): void {
    // Create "remote" repository
    mkdirSync(remoteDir, { recursive: true });
    git(["init"], remoteDir);
    git(["config", "--local", "user.email", "test@test.com"], remoteDir);
    git(["config", "--local", "user.name", "Test"], remoteDir);
    createCommit(remoteDir, "extension.ts", "// v1", "Initial commit");

    // Clone to installed directory (simulating what install() does)
    mkdirSync(join(agentDir, "git", "github.com", "test"), { recursive: true });
    git(["clone", remoteDir, installedDir], tempDir);
    git(["config", "--local", "user.email", "test@test.com"], installedDir);
    git(["config", "--local", "user.name", "Test"], installedDir);

    // Add to global packages so update() processes this source
    settingsManager.setPackages([sourceOverride ?? gitSource]);
  }

  describe("normal updates (no force-push)", () => {
    it("should update to latest commit when remote has new commits", async () => {
      setupRemoteAndInstall();
      expect(getFileContent(installedDir, "extension.ts")).toBe("// v1");

      // Add a new commit to remote
      const newCommit = createCommit(
        remoteDir,
        "extension.ts",
        "// v2",
        "Second commit",
      );

      // Update via package manager (no args = uses settings)
      await packageManager.update();

      // Verify update succeeded
      expect(getCurrentCommit(installedDir)).toBe(newCommit);
      expect(getFileContent(installedDir, "extension.ts")).toBe("// v2");
    });

    it("should handle multiple commits ahead", async () => {
      setupRemoteAndInstall();

      // Add multiple commits to remote
      createCommit(remoteDir, "extension.ts", "// v2", "Second commit");
      createCommit(remoteDir, "extension.ts", "// v3", "Third commit");
      const latestCommit = createCommit(
        remoteDir,
        "extension.ts",
        "// v4",
        "Fourth commit",
      );

      await packageManager.update();

      expect(getCurrentCommit(installedDir)).toBe(latestCommit);
      expect(getFileContent(installedDir, "extension.ts")).toBe("// v4");
    });

    it("should update even when local checkout has no upstream", async () => {
      setupRemoteAndInstall();
      createCommit(remoteDir, "extension.ts", "// v2", "Second commit");
      const latestCommit = createCommit(
        remoteDir,
        "extension.ts",
        "// v3",
        "Third commit",
      );

      const detachedCommit = getCurrentCommit(installedDir);
      git(["checkout", detachedCommit], installedDir);

      await packageManager.update();

      expect(getCurrentCommit(installedDir)).toBe(latestCommit);
      expect(getFileContent(installedDir, "extension.ts")).toBe("// v3");
    });
  });

  describe("force-push scenarios", () => {
    it("should recover when remote history is rewritten", async () => {
      setupRemoteAndInstall();
      const initialCommit = getCurrentCommit(remoteDir);

      // Add commit to remote
      createCommit(remoteDir, "extension.ts", "// v2", "Commit to keep");

      // Update to get the new commit
      await packageManager.update();
      expect(getFileContent(installedDir, "extension.ts")).toBe("// v2");

      // Now force-push to rewrite history on remote
      git(["reset", "--hard", initialCommit], remoteDir);
      const rewrittenCommit = createCommit(
        remoteDir,
        "extension.ts",
        "// v2-rewritten",
        "Rewritten commit",
      );

      // Update should succeed despite force-push
      await packageManager.update();

      expect(getCurrentCommit(installedDir)).toBe(rewrittenCommit);
      expect(getFileContent(installedDir, "extension.ts")).toBe(
        "// v2-rewritten",
      );
    });

    it("should recover when local commit no longer exists in remote", async () => {
      setupRemoteAndInstall();

      // Add commits to remote
      createCommit(remoteDir, "extension.ts", "// v2", "Commit A");
      createCommit(remoteDir, "extension.ts", "// v3", "Commit B");

      // Update to get all commits
      await packageManager.update();
      expect(getFileContent(installedDir, "extension.ts")).toBe("// v3");

      // Force-push remote to remove commits A and B
      git(["reset", "--hard", "HEAD~2"], remoteDir);
      const newCommit = createCommit(
        remoteDir,
        "extension.ts",
        "// v2-new",
        "New commit replacing A and B",
      );

      // Update should succeed - the commits we had locally no longer exist
      await packageManager.update();

      expect(getCurrentCommit(installedDir)).toBe(newCommit);
      expect(getFileContent(installedDir, "extension.ts")).toBe("// v2-new");
    });

    it("should handle complete history rewrite", async () => {
      setupRemoteAndInstall();

      // Remote gets several commits
      createCommit(remoteDir, "extension.ts", "// v2", "v2");
      createCommit(remoteDir, "extension.ts", "// v3", "v3");

      await packageManager.update();
      expect(getFileContent(installedDir, "extension.ts")).toBe("// v3");

      // Maintainer force-pushes completely different history
      git(["reset", "--hard", "HEAD~2"], remoteDir);
      createCommit(remoteDir, "extension.ts", "// rewrite-a", "Rewrite A");
      const finalCommit = createCommit(
        remoteDir,
        "extension.ts",
        "// rewrite-b",
        "Rewrite B",
      );

      // Should handle this gracefully
      await packageManager.update();

      expect(getCurrentCommit(installedDir)).toBe(finalCommit);
      expect(getFileContent(installedDir, "extension.ts")).toBe("// rewrite-b");
    });
  });

  describe("pinned sources", () => {
    it("should not update pinned git sources (with @ref)", async () => {
      // Create remote repo first to get the initial commit
      mkdirSync(remoteDir, { recursive: true });
      git(["init"], remoteDir);
      git(["config", "--local", "user.email", "test@test.com"], remoteDir);
      git(["config", "--local", "user.name", "Test"], remoteDir);
      const initialCommit = createCommit(
        remoteDir,
        "extension.ts",
        "// v1",
        "Initial commit",
      );

      // Install with pinned ref from the start - full clone to ensure commit is available
      mkdirSync(join(agentDir, "git", "github.com", "test"), {
        recursive: true,
      });
      git(["clone", remoteDir, installedDir], tempDir);
      git(["checkout", initialCommit], installedDir);
      git(["config", "--local", "user.email", "test@test.com"], installedDir);
      git(["config", "--local", "user.name", "Test"], installedDir);

      // Add to global packages with pinned ref
      settingsManager.setPackages([`${gitSource}@${initialCommit}`]);

      // Add new commit to remote
      createCommit(remoteDir, "extension.ts", "// v2", "Second commit");

      // Update should be skipped for pinned sources
      await packageManager.update();

      // Should still be on initial commit
      expect(getCurrentCommit(installedDir)).toBe(initialCommit);
      expect(getFileContent(installedDir, "extension.ts")).toBe("// v1");
    });
  });

  describe("temporary git sources", () => {
    it("should refresh cached temporary git sources when resolving", async () => {
      const gitHost = "github.com";
      const gitPath = "test/extension";
      const hash = createHash("sha256")
        .update(`git-${gitHost}-${gitPath}`)
        .digest("hex")
        .slice(0, 8);
      const cachedDir = join(
        tmpdir(),
        "clanker-extensions",
        `git-${gitHost}`,
        hash,
        gitPath,
      );
      const extensionFile = join(
        cachedDir,
        "clanker-extensions",
        "session-breakdown.ts",
      );

      rmSync(cachedDir, { recursive: true, force: true });
      mkdirSync(join(cachedDir, "clanker-extensions"), { recursive: true });
      writeFileSync(
        join(cachedDir, "package.json"),
        JSON.stringify({ clanker: { extensions: ["./clanker-extensions"] } }, null, 2),
      );
      writeFileSync(extensionFile, "// stale");

      const executedCommands: string[] = [];
      const managerWithInternals = packageManager as unknown as {
        runCommand: (
          command: string,
          args: string[],
          options?: { cwd?: string },
        ) => Promise<void>;
      };
      managerWithInternals.runCommand = async (command, args) => {
        executedCommands.push(`${command} ${args.join(" ")}`);
        if (command === "git" && args[0] === "reset") {
          writeFileSync(extensionFile, "// fresh");
        }
      };

      await packageManager.resolveExtensionSources([gitSource], {
        temporary: true,
      });

      expect(executedCommands).toContain("git fetch --prune origin");
      expect(
        getFileContent(cachedDir, "clanker-extensions/session-breakdown.ts"),
      ).toBe("// fresh");
    });

    it("should not refresh pinned temporary git sources", async () => {
      const gitHost = "github.com";
      const gitPath = "test/extension";
      const hash = createHash("sha256")
        .update(`git-${gitHost}-${gitPath}`)
        .digest("hex")
        .slice(0, 8);
      const cachedDir = join(
        tmpdir(),
        "clanker-extensions",
        `git-${gitHost}`,
        hash,
        gitPath,
      );
      const extensionFile = join(
        cachedDir,
        "clanker-extensions",
        "session-breakdown.ts",
      );

      rmSync(cachedDir, { recursive: true, force: true });
      mkdirSync(join(cachedDir, "clanker-extensions"), { recursive: true });
      writeFileSync(
        join(cachedDir, "package.json"),
        JSON.stringify({ clanker: { extensions: ["./clanker-extensions"] } }, null, 2),
      );
      writeFileSync(extensionFile, "// pinned");

      const executedCommands: string[] = [];
      const managerWithInternals = packageManager as unknown as {
        runCommand: (
          command: string,
          args: string[],
          options?: { cwd?: string },
        ) => Promise<void>;
      };
      managerWithInternals.runCommand = async (command, args) => {
        executedCommands.push(`${command} ${args.join(" ")}`);
      };

      await packageManager.resolveExtensionSources([`${gitSource}@main`], {
        temporary: true,
      });

      expect(executedCommands).toEqual([]);
      expect(
        getFileContent(cachedDir, "clanker-extensions/session-breakdown.ts"),
      ).toBe("// pinned");
    });
  });

  describe("scope-aware update", () => {
    it("should not install locally when source is only registered globally", async () => {
      setupRemoteAndInstall();

      // Add a new commit to remote
      createCommit(remoteDir, "extension.ts", "// v2", "Second commit");

      // The project-scope install path should not exist before or after update
      const projectGitDir = join(
        tempDir,
        ".clanker",
        "git",
        "github.com",
        "test",
        "extension",
      );
      expect(existsSync(projectGitDir)).toBe(false);

      await packageManager.update(gitSource);

      // Global install should be updated
      expect(getFileContent(installedDir, "extension.ts")).toBe("// v2");

      // Project-scope directory should NOT have been created
      expect(existsSync(projectGitDir)).toBe(false);
    });
  });
});