import { mkdtemp, mkdir, readdir, readFile, rm, stat, writeFile } from "node:fs/promises";
import { tmpdir } from "node:os";
import path from "node:path";

import { describe, expect, it } from "vitest";

import { linkFixtureNodeModules } from "../../scripts/lib/fixture-node-modules.ts";

/**
 * A removal or provider fixture runs `pnpm` inside a throwaway copy of the
 * repository. pnpm does not recognise the modules directory it finds there and
 * purges it, and with `CI=true` it does so without a prompt. When
 * `<fixture>/node_modules` was a single directory symlink, that purge followed
 * the link and deleted the repository's own installed dependencies mid-run —
 * a test suite uninstalling the workspace it was running in.
 */
describe("fixture node_modules linking", () => {
  async function sourceTree() {
    const source = await mkdtemp(path.join(tmpdir(), "fixture-source-"));
    const modules = path.join(source, "node_modules");
    await mkdir(path.join(modules, "left", "lib"), { recursive: true });
    await mkdir(path.join(modules, "@scope", "right"), { recursive: true });
    await mkdir(path.join(modules, ".bin"), { recursive: true });
    await writeFile(path.join(modules, "left", "lib", "index.js"), "export default 1;\n");
    await writeFile(path.join(modules, "@scope", "right", "package.json"), "{}\n");
    await writeFile(path.join(modules, ".modules.yaml"), "{}\n");
    return source;
  }

  it("survives a recursive delete of the fixture's node_modules", async () => {
    const source = await sourceTree();
    const fixture = await mkdtemp(path.join(tmpdir(), "fixture-root-"));
    try {
      await linkFixtureNodeModules(fixture, source);

      // The fixture resolves the same packages...
      expect(
        await readFile(
          path.join(fixture, "node_modules/left/lib/index.js"),
          "utf8",
        ),
      ).toContain("export default 1;");
      expect(
        (await readdir(path.join(fixture, "node_modules"))).sort(),
      ).toEqual([".bin", ".modules.yaml", "@scope", "left"]);

      // ...and this is exactly what pnpm's purge does.
      await rm(path.join(fixture, "node_modules"), {
        recursive: true,
        force: true,
      });

      // The repository's real dependencies are untouched.
      expect(
        await readFile(
          path.join(source, "node_modules/left/lib/index.js"),
          "utf8",
        ),
      ).toContain("export default 1;");
      expect(
        await stat(path.join(source, "node_modules/@scope/right/package.json")),
      ).toBeDefined();
      expect(
        (await readdir(path.join(source, "node_modules"))).sort(),
      ).toEqual([".bin", ".modules.yaml", "@scope", "left"]);
    } finally {
      await rm(source, { recursive: true, force: true });
      await rm(fixture, { recursive: true, force: true });
    }
  });

  it("creates node_modules as a real directory, never a symlink", async () => {
    const source = await sourceTree();
    const fixture = await mkdtemp(path.join(tmpdir(), "fixture-root-"));
    try {
      await linkFixtureNodeModules(fixture, source);
      const { lstat } = await import("node:fs/promises");
      const entry = await lstat(path.join(fixture, "node_modules"));
      expect(entry.isSymbolicLink()).toBe(false);
      expect(entry.isDirectory()).toBe(true);
      expect(
        (await lstat(path.join(fixture, "node_modules/left"))).isSymbolicLink(),
      ).toBe(true);
    } finally {
      await rm(source, { recursive: true, force: true });
      await rm(fixture, { recursive: true, force: true });
    }
  });
});