/**
 * SimpleGitBranchManager Tests
 *
 * Tests for remoteBranchExists validation used when setting
 * a project's default branch.
 */

import { describe, it, expect, beforeEach, afterEach, beforeAll, afterAll } from 'vitest';
import { mkdtemp, rm, writeFile } from 'node:fs/promises';
import { tmpdir } from 'node:os';
import path from 'node:path';
import { simpleGit } from 'simple-git';
import { SimpleGitBranchManager } from './simple-git-branch-manager.js';

/**
 * Create a "remote" bare repo and a clone of it for testing.
 * The bare repo has branches that the clone can see as remote tracking branches.
 */
async function createTestRepoWithRemote(): Promise<{
  clonePath: string;
  barePath: string;
  cleanup: () => Promise<void>;
}> {
  const tmpBase = await mkdtemp(path.join(tmpdir(), 'cw-branch-test-'));
  const barePath = path.join(tmpBase, 'bare.git');
  const workPath = path.join(tmpBase, 'work');
  const clonePath = path.join(tmpBase, 'clone');

  // Create a bare repo
  const bareGit = simpleGit();
  await bareGit.init([barePath, '--bare']);

  // Clone it to a working directory, add commits and branches, push
  await simpleGit().clone(barePath, workPath);
  const workGit = simpleGit(workPath);
  await workGit.addConfig('user.email', 'test@example.com');
  await workGit.addConfig('user.name', 'Test User');
  await writeFile(path.join(workPath, 'README.md'), '# Test\n');
  await workGit.add('README.md');
  await workGit.commit('Initial commit');
  await workGit.push('origin', 'main');

  // Create additional branches
  await workGit.checkoutLocalBranch('develop');
  await writeFile(path.join(workPath, 'dev.txt'), 'dev\n');
  await workGit.add('dev.txt');
  await workGit.commit('Dev commit');
  await workGit.push('origin', 'develop');

  await workGit.checkoutLocalBranch('feature/auth');
  await writeFile(path.join(workPath, 'auth.txt'), 'auth\n');
  await workGit.add('auth.txt');
  await workGit.commit('Auth commit');
  await workGit.push('origin', 'feature/auth');

  // Clone from bare to simulate what project registration does
  await simpleGit().clone(barePath, clonePath);

  return {
    clonePath,
    barePath,
    cleanup: async () => {
      await rm(tmpBase, { recursive: true, force: true });
    },
  };
}

/**
 * Create a repo pair for testing diff operations.
 * Sets up bare + clone with a 'feature' branch that has known changes vs 'main'.
 */
async function createTestRepoForDiff(): Promise<{
  clonePath: string;
  cleanup: () => Promise<void>;
}> {
  const tmpBase = await mkdtemp(path.join(tmpdir(), 'cw-diff-test-'));
  const barePath = path.join(tmpBase, 'bare.git');
  const workPath = path.join(tmpBase, 'work');
  const clonePath = path.join(tmpBase, 'clone');

  // Create bare repo
  await simpleGit().init([barePath, '--bare']);

  // Set up main branch in work dir
  await simpleGit().clone(barePath, workPath);
  const workGit = simpleGit(workPath);
  await workGit.addConfig('user.email', 'test@example.com');
  await workGit.addConfig('user.name', 'Test User');
  await writeFile(path.join(workPath, 'README.md'), '# README\n');
  await writeFile(path.join(workPath, 'to-delete.txt'), 'delete me\n');
  await workGit.add(['README.md', 'to-delete.txt']);
  await workGit.commit('Initial commit');
  await workGit.push('origin', 'main');

  // Clone and create feature branch with changes
  await simpleGit().clone(barePath, clonePath);
  const cloneGit = simpleGit(clonePath);
  await cloneGit.addConfig('user.email', 'test@example.com');
  await cloneGit.addConfig('user.name', 'Test User');
  await cloneGit.checkoutLocalBranch('feature');

  // Add new text file
  await writeFile(path.join(clonePath, 'added.txt'), 'new content\n');
  await cloneGit.add('added.txt');

  // Modify existing file
  await writeFile(path.join(clonePath, 'README.md'), '# README\n\nModified content\n');
  await cloneGit.add('README.md');

  // Delete a file
  await cloneGit.rm(['to-delete.txt']);

  // Add binary file
  await writeFile(path.join(clonePath, 'image.bin'), Buffer.alloc(16));
  await cloneGit.add('image.bin');

  // Add file with space in name
  await writeFile(path.join(clonePath, 'has space.txt'), 'content\n');
  await cloneGit.add('has space.txt');

  await cloneGit.commit('Feature branch changes');

  return {
    clonePath,
    cleanup: async () => {
      await rm(tmpBase, { recursive: true, force: true });
    },
  };
}

describe('SimpleGitBranchManager', () => {
  let clonePath: string;
  let cleanup: () => Promise<void>;
  let branchManager: SimpleGitBranchManager;

  beforeAll(async () => {
    const setup = await createTestRepoWithRemote();
    clonePath = setup.clonePath;
    cleanup = setup.cleanup;
    branchManager = new SimpleGitBranchManager();
  });

  afterAll(async () => {
    await cleanup();
  });

  describe('remoteBranchExists', () => {
    it('should return true for a branch that exists on the remote', async () => {
      expect(await branchManager.remoteBranchExists(clonePath, 'main')).toBe(true);
      expect(await branchManager.remoteBranchExists(clonePath, 'develop')).toBe(true);
      expect(await branchManager.remoteBranchExists(clonePath, 'feature/auth')).toBe(true);
    });

    it('should return false for a branch that does not exist', async () => {
      expect(await branchManager.remoteBranchExists(clonePath, 'nonexistent')).toBe(false);
      expect(await branchManager.remoteBranchExists(clonePath, 'feature/nope')).toBe(false);
    });

    it('should return false for an invalid repo path', async () => {
      expect(await branchManager.remoteBranchExists('/tmp/no-such-repo', 'main')).toBe(false);
    });

    it('should detect remote branches not checked out locally', async () => {
      // After clone, only 'main' is checked out locally.
      // 'develop' exists only as origin/develop.
      const localExists = await branchManager.branchExists(clonePath, 'develop');
      const remoteExists = await branchManager.remoteBranchExists(clonePath, 'develop');

      expect(localExists).toBe(false);
      expect(remoteExists).toBe(true);
    });
  });
});

describe('SimpleGitBranchManager - diffBranchesStat and diffFileSingle', () => {
  let clonePath: string;
  let cleanup: () => Promise<void>;
  let branchManager: SimpleGitBranchManager;

  beforeAll(async () => {
    const setup = await createTestRepoForDiff();
    clonePath = setup.clonePath;
    cleanup = setup.cleanup;
    branchManager = new SimpleGitBranchManager();
  });

  afterAll(async () => {
    await cleanup();
  });

  describe('diffBranchesStat', () => {
    it('returns correct entries for added, modified, and deleted text files', async () => {
      const entries = await branchManager.diffBranchesStat(clonePath, 'main', 'feature');
      const added = entries.find(e => e.path === 'added.txt');
      const modified = entries.find(e => e.path === 'README.md');
      const deleted = entries.find(e => e.path === 'to-delete.txt');

      expect(added?.status).toBe('added');
      expect(added?.additions).toBeGreaterThan(0);
      expect(modified?.status).toBe('modified');
      expect(deleted?.status).toBe('deleted');
      expect(deleted?.deletions).toBeGreaterThan(0);
    });

    it('marks binary files as status=binary with additions=0, deletions=0', async () => {
      const entries = await branchManager.diffBranchesStat(clonePath, 'main', 'feature');
      const binary = entries.find(e => e.path === 'image.bin');
      expect(binary?.status).toBe('binary');
      expect(binary?.additions).toBe(0);
      expect(binary?.deletions).toBe(0);
    });

    it('returns empty array when there are no changes', async () => {
      const entries = await branchManager.diffBranchesStat(clonePath, 'main', 'main');
      expect(entries).toEqual([]);
    });

    it('handles files with spaces in their names', async () => {
      const entries = await branchManager.diffBranchesStat(clonePath, 'main', 'feature');
      const spaced = entries.find(e => e.path === 'has space.txt');
      expect(spaced).toBeDefined();
      expect(spaced?.status).toBe('added');
    });
  });

  describe('diffFileSingle', () => {
    it('returns unified diff containing addition hunks for an added file', async () => {
      const diff = await branchManager.diffFileSingle(clonePath, 'main', 'feature', 'added.txt');
      expect(diff).toContain('+');
      expect(diff).toContain('added.txt');
    });

    it('returns unified diff with removal hunks for a deleted file', async () => {
      const diff = await branchManager.diffFileSingle(clonePath, 'main', 'feature', 'to-delete.txt');
      expect(diff).toContain('-');
      expect(diff).toContain('to-delete.txt');
    });

    it('returns string for a binary file', async () => {
      const diff = await branchManager.diffFileSingle(clonePath, 'main', 'feature', 'image.bin');
      // git diff returns empty or a "Binary files differ" line — no hunk content
      expect(typeof diff).toBe('string');
    });

    it('handles file paths with spaces', async () => {
      const diff = await branchManager.diffFileSingle(clonePath, 'main', 'feature', 'has space.txt');
      expect(diff).toContain('has space.txt');
    });
  });
});