import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
import { mkdirSafe, existsSafe } from '@automaker/utils';
import fs from 'fs/promises';
import path from 'path';
import os from 'os';

describe('fs-utils.ts', () => {
  let testDir: string;

  beforeEach(async () => {
    // Create a temporary test directory
    testDir = path.join(os.tmpdir(), `fs-utils-test-${Date.now()}`);
    await fs.mkdir(testDir, { recursive: true });
  });

  afterEach(async () => {
    // Clean up test directory
    try {
      await fs.rm(testDir, { recursive: true, force: true });
    } catch {
      // Ignore cleanup errors
    }
  });

  describe('mkdirSafe', () => {
    it('should create a new directory', async () => {
      const newDir = path.join(testDir, 'new-directory');
      await mkdirSafe(newDir);

      const stats = await fs.stat(newDir);
      expect(stats.isDirectory()).toBe(true);
    });

    it('should succeed if directory already exists', async () => {
      const existingDir = path.join(testDir, 'existing');
      await fs.mkdir(existingDir);

      // Should not throw
      await expect(mkdirSafe(existingDir)).resolves.toBeUndefined();
    });

    it('should create nested directories', async () => {
      const nestedDir = path.join(testDir, 'a', 'b', 'c');
      await mkdirSafe(nestedDir);

      const stats = await fs.stat(nestedDir);
      expect(stats.isDirectory()).toBe(true);
    });

    it('should throw if path exists as a file', async () => {
      const filePath = path.join(testDir, 'file.txt');
      await fs.writeFile(filePath, 'content');

      await expect(mkdirSafe(filePath)).rejects.toThrow('Path exists and is not a directory');
    });

    it('should succeed if path is a symlink to a directory', async () => {
      const realDir = path.join(testDir, 'real-dir');
      const symlinkPath = path.join(testDir, 'link-to-dir');
      await fs.mkdir(realDir);
      await fs.symlink(realDir, symlinkPath);

      // Should not throw
      await expect(mkdirSafe(symlinkPath)).resolves.toBeUndefined();
    });

    it('should handle ELOOP error gracefully when checking path', async () => {
      // Mock lstat to throw ELOOP error
      const originalLstat = fs.lstat;
      const mkdirSafePath = path.join(testDir, 'eloop-path');

      vi.spyOn(fs, 'lstat').mockRejectedValueOnce({ code: 'ELOOP' });

      // Should not throw, should return gracefully
      await expect(mkdirSafe(mkdirSafePath)).resolves.toBeUndefined();

      vi.restoreAllMocks();
    });

    it('should handle EEXIST error gracefully when creating directory', async () => {
      const newDir = path.join(testDir, 'race-condition-dir');

      // Mock lstat to return ENOENT (path doesn't exist)
      // Then mock mkdir to throw EEXIST (race condition)
      vi.spyOn(fs, 'lstat').mockRejectedValueOnce({ code: 'ENOENT' });
      vi.spyOn(fs, 'mkdir').mockRejectedValueOnce({ code: 'EEXIST' });

      // Should not throw, should return gracefully
      await expect(mkdirSafe(newDir)).resolves.toBeUndefined();

      vi.restoreAllMocks();
    });

    it('should handle ELOOP error gracefully when creating directory', async () => {
      const newDir = path.join(testDir, 'eloop-create-dir');

      // Mock lstat to return ENOENT (path doesn't exist)
      // Then mock mkdir to throw ELOOP
      vi.spyOn(fs, 'lstat').mockRejectedValueOnce({ code: 'ENOENT' });
      vi.spyOn(fs, 'mkdir').mockRejectedValueOnce({ code: 'ELOOP' });

      // Should not throw, should return gracefully
      await expect(mkdirSafe(newDir)).resolves.toBeUndefined();

      vi.restoreAllMocks();
    });
  });

  describe('existsSafe', () => {
    it('should return true for existing file', async () => {
      const filePath = path.join(testDir, 'test-file.txt');
      await fs.writeFile(filePath, 'content');

      const exists = await existsSafe(filePath);
      expect(exists).toBe(true);
    });

    it('should return true for existing directory', async () => {
      const dirPath = path.join(testDir, 'test-dir');
      await fs.mkdir(dirPath);

      const exists = await existsSafe(dirPath);
      expect(exists).toBe(true);
    });

    it('should return false for non-existent path', async () => {
      const nonExistent = path.join(testDir, 'does-not-exist');

      const exists = await existsSafe(nonExistent);
      expect(exists).toBe(false);
    });

    it('should return true for symlink', async () => {
      const realFile = path.join(testDir, 'real-file.txt');
      const symlinkPath = path.join(testDir, 'link-to-file');
      await fs.writeFile(realFile, 'content');
      await fs.symlink(realFile, symlinkPath);

      const exists = await existsSafe(symlinkPath);
      expect(exists).toBe(true);
    });

    it("should return true for broken symlink (symlink exists even if target doesn't)", async () => {
      const symlinkPath = path.join(testDir, 'broken-link');
      const nonExistent = path.join(testDir, 'non-existent-target');
      await fs.symlink(nonExistent, symlinkPath);

      const exists = await existsSafe(symlinkPath);
      expect(exists).toBe(true);
    });

    it('should return true for ELOOP error (symlink loop)', async () => {
      // Mock lstat to throw ELOOP error
      vi.spyOn(fs, 'lstat').mockRejectedValueOnce({ code: 'ELOOP' });

      const exists = await existsSafe('/some/path/with/loop');
      expect(exists).toBe(true);

      vi.restoreAllMocks();
    });

    it('should throw for other errors', async () => {
      // Mock lstat to throw a non-ENOENT, non-ELOOP error
      vi.spyOn(fs, 'lstat').mockRejectedValueOnce({ code: 'EACCES' });

      await expect(existsSafe('/some/path')).rejects.toMatchObject({ code: 'EACCES' });

      vi.restoreAllMocks();
    });
  });
});