import * as fs from "node:fs";
import * as os from "node:os";
import * as path from "node:path";
import { fileURLToPath } from "node:url";
import { afterEach, beforeEach, describe, expect, it } from "vitest";
import { discoverAndLoadExtensions } from "../src/core/extensions/loader.js";

const __dirname = path.dirname(fileURLToPath(import.meta.url));

describe("extensions discovery", () => {
  let tempDir: string;
  let extensionsDir: string;

  beforeEach(() => {
    tempDir = fs.mkdtempSync(path.join(os.tmpdir(), "companion-ext-test-"));
    extensionsDir = path.join(tempDir, "extensions");
    fs.mkdirSync(extensionsDir);
  });

  afterEach(() => {
    fs.rmSync(tempDir, { recursive: true, force: true });
  });

  const extensionCode = `
		export default function(companion) {
			companion.registerCommand("test", { handler: async () => {} });
		}
	`;

  const extensionCodeWithTool = (toolName: string) => `
		import { Type } from "@sinclair/typebox";
		export default function(companion) {
			companion.registerTool({
				name: "${toolName}",
				label: "${toolName}",
				description: "Test tool",
				parameters: Type.Object({}),
				execute: async () => ({ content: [{ type: "text", text: "ok" }] }),
			});
		}
	`;

  it("discovers direct .ts files in extensions/", async () => {
    fs.writeFileSync(path.join(extensionsDir, "foo.ts"), extensionCode);
    fs.writeFileSync(path.join(extensionsDir, "bar.ts"), extensionCode);

    const result = await discoverAndLoadExtensions([], tempDir, tempDir);

    expect(result.errors).toHaveLength(0);
    expect(result.extensions).toHaveLength(2);
    expect(result.extensions.map((e) => path.basename(e.path)).sort()).toEqual([
      "bar.ts",
      "foo.ts",
    ]);
  });

  it("discovers direct .js files in extensions/", async () => {
    fs.writeFileSync(path.join(extensionsDir, "foo.js"), extensionCode);

    const result = await discoverAndLoadExtensions([], tempDir, tempDir);

    expect(result.errors).toHaveLength(0);
    expect(result.extensions).toHaveLength(1);
    expect(path.basename(result.extensions[0].path)).toBe("foo.js");
  });

  it("discovers subdirectory with index.ts", async () => {
    const subdir = path.join(extensionsDir, "my-extension");
    fs.mkdirSync(subdir);
    fs.writeFileSync(path.join(subdir, "index.ts"), extensionCode);

    const result = await discoverAndLoadExtensions([], tempDir, tempDir);

    expect(result.errors).toHaveLength(0);
    expect(result.extensions).toHaveLength(1);
    expect(result.extensions[0].path).toContain("my-extension");
    expect(result.extensions[0].path).toContain("index.ts");
  });

  it("discovers subdirectory with index.js", async () => {
    const subdir = path.join(extensionsDir, "my-extension");
    fs.mkdirSync(subdir);
    fs.writeFileSync(path.join(subdir, "index.js"), extensionCode);

    const result = await discoverAndLoadExtensions([], tempDir, tempDir);

    expect(result.errors).toHaveLength(0);
    expect(result.extensions).toHaveLength(1);
    expect(result.extensions[0].path).toContain("index.js");
  });

  it("prefers index.ts over index.js", async () => {
    const subdir = path.join(extensionsDir, "my-extension");
    fs.mkdirSync(subdir);
    fs.writeFileSync(path.join(subdir, "index.ts"), extensionCode);
    fs.writeFileSync(path.join(subdir, "index.js"), extensionCode);

    const result = await discoverAndLoadExtensions([], tempDir, tempDir);

    expect(result.errors).toHaveLength(0);
    expect(result.extensions).toHaveLength(1);
    expect(result.extensions[0].path).toContain("index.ts");
  });

  it("discovers subdirectory with package.json companion field", async () => {
    const subdir = path.join(extensionsDir, "my-package");
    const srcDir = path.join(subdir, "src");
    fs.mkdirSync(subdir);
    fs.mkdirSync(srcDir);
    fs.writeFileSync(path.join(srcDir, "main.ts"), extensionCode);
    fs.writeFileSync(
      path.join(subdir, "package.json"),
      JSON.stringify({
        name: "my-package",
        companion: {
          extensions: ["./src/main.ts"],
        },
      }),
    );

    const result = await discoverAndLoadExtensions([], tempDir, tempDir);

    expect(result.errors).toHaveLength(0);
    expect(result.extensions).toHaveLength(1);
    expect(result.extensions[0].path).toContain("src");
    expect(result.extensions[0].path).toContain("main.ts");
  });

  it("package.json can declare multiple extensions", async () => {
    const subdir = path.join(extensionsDir, "my-package");
    fs.mkdirSync(subdir);
    fs.writeFileSync(path.join(subdir, "ext1.ts"), extensionCode);
    fs.writeFileSync(path.join(subdir, "ext2.ts"), extensionCode);
    fs.writeFileSync(
      path.join(subdir, "package.json"),
      JSON.stringify({
        name: "my-package",
        companion: {
          extensions: ["./ext1.ts", "./ext2.ts"],
        },
      }),
    );

    const result = await discoverAndLoadExtensions([], tempDir, tempDir);

    expect(result.errors).toHaveLength(0);
    expect(result.extensions).toHaveLength(2);
  });

  it("package.json with companion field takes precedence over index.ts", async () => {
    const subdir = path.join(extensionsDir, "my-package");
    fs.mkdirSync(subdir);
    fs.writeFileSync(
      path.join(subdir, "index.ts"),
      extensionCodeWithTool("from-index"),
    );
    fs.writeFileSync(
      path.join(subdir, "custom.ts"),
      extensionCodeWithTool("from-custom"),
    );
    fs.writeFileSync(
      path.join(subdir, "package.json"),
      JSON.stringify({
        name: "my-package",
        companion: {
          extensions: ["./custom.ts"],
        },
      }),
    );

    const result = await discoverAndLoadExtensions([], tempDir, tempDir);

    expect(result.errors).toHaveLength(0);
    expect(result.extensions).toHaveLength(1);
    expect(result.extensions[0].path).toContain("custom.ts");
    // Verify the right tool was registered
    expect(result.extensions[0].tools.has("from-custom")).toBe(true);
    expect(result.extensions[0].tools.has("from-index")).toBe(false);
  });

  it("ignores package.json without companion field, falls back to index.ts", async () => {
    const subdir = path.join(extensionsDir, "my-package");
    fs.mkdirSync(subdir);
    fs.writeFileSync(path.join(subdir, "index.ts"), extensionCode);
    fs.writeFileSync(
      path.join(subdir, "package.json"),
      JSON.stringify({
        name: "my-package",
        version: "1.0.0",
      }),
    );

    const result = await discoverAndLoadExtensions([], tempDir, tempDir);

    expect(result.errors).toHaveLength(0);
    expect(result.extensions).toHaveLength(1);
    expect(result.extensions[0].path).toContain("index.ts");
  });

  it("ignores subdirectory without index or package.json", async () => {
    const subdir = path.join(extensionsDir, "not-an-extension");
    fs.mkdirSync(subdir);
    fs.writeFileSync(path.join(subdir, "helper.ts"), extensionCode);
    fs.writeFileSync(path.join(subdir, "utils.ts"), extensionCode);

    const result = await discoverAndLoadExtensions([], tempDir, tempDir);

    expect(result.errors).toHaveLength(0);
    expect(result.extensions).toHaveLength(0);
  });

  it("does not recurse beyond one level", async () => {
    const subdir = path.join(extensionsDir, "container");
    const nested = path.join(subdir, "nested");
    fs.mkdirSync(subdir);
    fs.mkdirSync(nested);
    fs.writeFileSync(path.join(nested, "index.ts"), extensionCode);
    // No index.ts or package.json in container/

    const result = await discoverAndLoadExtensions([], tempDir, tempDir);

    expect(result.errors).toHaveLength(0);
    expect(result.extensions).toHaveLength(0);
  });

  it("handles mixed direct files and subdirectories", async () => {
    // Direct file
    fs.writeFileSync(path.join(extensionsDir, "direct.ts"), extensionCode);

    // Subdirectory with index
    const subdir1 = path.join(extensionsDir, "with-index");
    fs.mkdirSync(subdir1);
    fs.writeFileSync(path.join(subdir1, "index.ts"), extensionCode);

    // Subdirectory with package.json
    const subdir2 = path.join(extensionsDir, "with-manifest");
    fs.mkdirSync(subdir2);
    fs.writeFileSync(path.join(subdir2, "entry.ts"), extensionCode);
    fs.writeFileSync(
      path.join(subdir2, "package.json"),
      JSON.stringify({ companion: { extensions: ["./entry.ts"] } }),
    );

    const result = await discoverAndLoadExtensions([], tempDir, tempDir);

    expect(result.errors).toHaveLength(0);
    expect(result.extensions).toHaveLength(3);
  });

  it("skips non-existent paths declared in package.json", async () => {
    const subdir = path.join(extensionsDir, "my-package");
    fs.mkdirSync(subdir);
    fs.writeFileSync(path.join(subdir, "exists.ts"), extensionCode);
    fs.writeFileSync(
      path.join(subdir, "package.json"),
      JSON.stringify({
        companion: {
          extensions: ["./exists.ts", "./missing.ts"],
        },
      }),
    );

    const result = await discoverAndLoadExtensions([], tempDir, tempDir);

    expect(result.errors).toHaveLength(0);
    expect(result.extensions).toHaveLength(1);
    expect(result.extensions[0].path).toContain("exists.ts");
  });

  it("loads extensions and registers commands", async () => {
    fs.writeFileSync(
      path.join(extensionsDir, "with-command.ts"),
      extensionCode,
    );

    const result = await discoverAndLoadExtensions([], tempDir, tempDir);

    expect(result.errors).toHaveLength(0);
    expect(result.extensions).toHaveLength(1);
    expect(result.extensions[0].commands.has("test")).toBe(true);
  });

  it("loads extensions and registers tools", async () => {
    fs.writeFileSync(
      path.join(extensionsDir, "with-tool.ts"),
      extensionCodeWithTool("my-tool"),
    );

    const result = await discoverAndLoadExtensions([], tempDir, tempDir);

    expect(result.errors).toHaveLength(0);
    expect(result.extensions).toHaveLength(1);
    expect(result.extensions[0].tools.has("my-tool")).toBe(true);
  });

  it("reports errors for invalid extension code", async () => {
    fs.writeFileSync(
      path.join(extensionsDir, "invalid.ts"),
      "this is not valid typescript export",
    );

    const result = await discoverAndLoadExtensions([], tempDir, tempDir);

    expect(result.errors).toHaveLength(1);
    expect(result.errors[0].path).toContain("invalid.ts");
    expect(result.extensions).toHaveLength(0);
  });

  it("handles explicitly configured paths", async () => {
    const customPath = path.join(tempDir, "custom-location", "my-ext.ts");
    fs.mkdirSync(path.dirname(customPath), { recursive: true });
    fs.writeFileSync(customPath, extensionCode);

    const result = await discoverAndLoadExtensions(
      [customPath],
      tempDir,
      tempDir,
    );

    expect(result.errors).toHaveLength(0);
    expect(result.extensions).toHaveLength(1);
    expect(result.extensions[0].path).toContain("my-ext.ts");
  });

  it("resolves dependencies from extension's own node_modules", async () => {
    const extPath = path.join(tempDir, "custom-location", "with-deps");
    const nodeModulesDir = path.join(extPath, "node_modules", "ms");
    fs.mkdirSync(nodeModulesDir, { recursive: true });
    fs.writeFileSync(
      path.join(extPath, "index.ts"),
      `
				import { Type } from "@sinclair/typebox";
				import ms from "ms";
				export default function(companion) {
					companion.registerTool({
						name: "parse_duration",
						label: "parse_duration",
						description: "Parse a duration string",
						parameters: Type.Object({ value: Type.String() }),
						execute: async (_toolCallId, params) => ({
							content: [{ type: "text", text: String(ms(params.value)) }],
						}),
					});
				}
			`,
    );
    fs.writeFileSync(
      path.join(extPath, "package.json"),
      JSON.stringify({
        name: "with-deps",
        type: "module",
      }),
    );
    fs.writeFileSync(
      path.join(nodeModulesDir, "package.json"),
      JSON.stringify({
        name: "ms",
        type: "module",
        exports: "./index.js",
      }),
    );
    fs.writeFileSync(
      path.join(nodeModulesDir, "index.js"),
      `export default function ms(value) { return value === "1m" ? 60000 : 0; }`,
    );

    const result = await discoverAndLoadExtensions([extPath], tempDir, tempDir);

    expect(result.errors).toHaveLength(0);
    expect(result.extensions).toHaveLength(1);
    expect(result.extensions[0].path).toContain("with-deps");
    // The extension registers a 'parse_duration' tool
    expect(result.extensions[0].tools.has("parse_duration")).toBe(true);
  });

  it("registers message renderers", async () => {
    const extCode = `
			export default function(companion) {
				companion.registerMessageRenderer("my-custom-type", (message, options, theme) => {
					return null; // Use default rendering
				});
			}
		`;
    fs.writeFileSync(path.join(extensionsDir, "with-renderer.ts"), extCode);

    const result = await discoverAndLoadExtensions([], tempDir, tempDir);

    expect(result.errors).toHaveLength(0);
    expect(result.extensions).toHaveLength(1);
    expect(result.extensions[0].messageRenderers.has("my-custom-type")).toBe(
      true,
    );
  });

  it("reports error when extension throws during initialization", async () => {
    const extCode = `
			export default function(companion) {
				throw new Error("Initialization failed!");
			}
		`;
    fs.writeFileSync(path.join(extensionsDir, "throws.ts"), extCode);

    const result = await discoverAndLoadExtensions([], tempDir, tempDir);

    expect(result.errors).toHaveLength(1);
    expect(result.errors[0].error).toContain("Initialization failed!");
    expect(result.extensions).toHaveLength(0);
  });

  it("reports error when extension has no default export", async () => {
    const extCode = `
			export function notDefault(companion) {
				companion.registerCommand("test", { handler: async () => {} });
			}
		`;
    fs.writeFileSync(path.join(extensionsDir, "no-default.ts"), extCode);

    const result = await discoverAndLoadExtensions([], tempDir, tempDir);

    expect(result.errors).toHaveLength(1);
    expect(result.errors[0].error).toContain(
      "does not export a valid factory function",
    );
    expect(result.extensions).toHaveLength(0);
  });

  it("allows multiple extensions to register different tools", async () => {
    fs.writeFileSync(
      path.join(extensionsDir, "tool-a.ts"),
      extensionCodeWithTool("tool-a"),
    );
    fs.writeFileSync(
      path.join(extensionsDir, "tool-b.ts"),
      extensionCodeWithTool("tool-b"),
    );

    const result = await discoverAndLoadExtensions([], tempDir, tempDir);

    expect(result.errors).toHaveLength(0);
    expect(result.extensions).toHaveLength(2);

    const allTools = new Set<string>();
    for (const ext of result.extensions) {
      for (const name of ext.tools.keys()) {
        allTools.add(name);
      }
    }
    expect(allTools.has("tool-a")).toBe(true);
    expect(allTools.has("tool-b")).toBe(true);
  });

  it("loads extension with event handlers", async () => {
    const extCode = `
			export default function(companion) {
				companion.on("agent_start", async () => {});
				companion.on("tool_call", async (event) => undefined);
				companion.on("agent_end", async () => {});
			}
		`;
    fs.writeFileSync(path.join(extensionsDir, "with-handlers.ts"), extCode);

    const result = await discoverAndLoadExtensions([], tempDir, tempDir);

    expect(result.errors).toHaveLength(0);
    expect(result.extensions).toHaveLength(1);
    expect(result.extensions[0].handlers.has("agent_start")).toBe(true);
    expect(result.extensions[0].handlers.has("tool_call")).toBe(true);
    expect(result.extensions[0].handlers.has("agent_end")).toBe(true);
  });

  it("loads extension with shortcuts", async () => {
    const extCode = `
			export default function(companion) {
				companion.registerShortcut("ctrl+t", {
					description: "Test shortcut",
					handler: async (ctx) => {},
				});
			}
		`;
    fs.writeFileSync(path.join(extensionsDir, "with-shortcut.ts"), extCode);

    const result = await discoverAndLoadExtensions([], tempDir, tempDir);

    expect(result.errors).toHaveLength(0);
    expect(result.extensions).toHaveLength(1);
    expect(result.extensions[0].shortcuts.has("ctrl+t")).toBe(true);
  });

  it("loads extension with flags", async () => {
    const extCode = `
			export default function(companion) {
				companion.registerFlag("my-flag", {
					description: "My custom flag",
					handler: async (value) => {},
				});
			}
		`;
    fs.writeFileSync(path.join(extensionsDir, "with-flag.ts"), extCode);

    const result = await discoverAndLoadExtensions([], tempDir, tempDir);

    expect(result.errors).toHaveLength(0);
    expect(result.extensions).toHaveLength(1);
    expect(result.extensions[0].flags.has("my-flag")).toBe(true);
  });

  it("loadExtensions only loads explicit paths without discovery", async () => {
    // Create discoverable extensions (would be found by discoverAndLoadExtensions)
    fs.writeFileSync(
      path.join(extensionsDir, "discovered.ts"),
      extensionCodeWithTool("discovered"),
    );

    // Create explicit extension outside discovery path
    const explicitPath = path.join(tempDir, "explicit.ts");
    fs.writeFileSync(explicitPath, extensionCodeWithTool("explicit"));

    // Use loadExtensions directly to skip discovery
    const { loadExtensions } = await import("../src/core/extensions/loader.js");
    const result = await loadExtensions([explicitPath], tempDir);

    expect(result.errors).toHaveLength(0);
    expect(result.extensions).toHaveLength(1);
    expect(result.extensions[0].tools.has("explicit")).toBe(true);
    expect(result.extensions[0].tools.has("discovered")).toBe(false);
  });

  it("loadExtensions with no paths loads nothing", async () => {
    // Create discoverable extensions (would be found by discoverAndLoadExtensions)
    fs.writeFileSync(path.join(extensionsDir, "discovered.ts"), extensionCode);

    // Use loadExtensions directly with empty paths
    const { loadExtensions } = await import("../src/core/extensions/loader.js");
    const result = await loadExtensions([], tempDir);

    expect(result.errors).toHaveLength(0);
    expect(result.extensions).toHaveLength(0);
  });
});