import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
import { mkdtemp, readFile, rm, readdir, stat } from 'node:fs/promises';
import path from 'node:path';
import { tmpdir } from 'node:os';
import type { PostData } from '../../src/main/engine/PostEngine';

const generatedFileHashes = new Map<string, string>();
const getGeneratedFileHashMock = vi.fn(async (projectId: string, relativePath: string) => {
  const key = `${projectId}:${relativePath}`;
  return generatedFileHashes.get(key) ?? null;
});
const setGeneratedFileHashMock = vi.fn(async (projectId: string, relativePath: string, hash: string) => {
  const key = `${projectId}:${relativePath}`;
  generatedFileHashes.set(key, hash);
});
const executeDbSql = vi.fn(async (input: { sql: string; args?: unknown[] }) => {
  const sqlText = input.sql.replace(/\s+/g, ' ').trim();
  const args = input.args ?? [];

  if (sqlText.startsWith('CREATE TABLE IF NOT EXISTS generated_file_hashes')) {
    return { rows: [] };
  }

  if (sqlText.startsWith('SELECT content_hash FROM generated_file_hashes')) {
    const key = `${String(args[0] ?? '')}:${String(args[1] ?? '')}`;
    const hash = generatedFileHashes.get(key);
    return { rows: hash ? [{ content_hash: hash }] : [] };
  }

  if (sqlText.startsWith('INSERT INTO generated_file_hashes')) {
    const key = `${String(args[0] ?? '')}:${String(args[1] ?? '')}`;
    generatedFileHashes.set(key, String(args[2] ?? ''));
    return { rows: [] };
  }

  return { rows: [] };
});

vi.mock('../../src/main/database/generatedFileHashStore', () => ({
  getGeneratedFileHash: getGeneratedFileHashMock,
  setGeneratedFileHash: setGeneratedFileHashMock,
}));

vi.mock('../../src/main/database', () => ({
  getDatabase: vi.fn(() => ({
    getLocalClient: vi.fn(() => ({
      execute: executeDbSql,
    })),
  })),
}));

vi.mock('../../src/main/engine/PostEngine', async (importOriginal) => {
  const actual = await importOriginal<typeof import('../../src/main/engine/PostEngine')>();
  const mockPostEngine = {
    getPostsFiltered: vi.fn(async () => []),
    getPublishedVersion: vi.fn(async () => null),
    getPost: vi.fn(async () => null),
    setProjectContext: vi.fn(),
  };
  return {
    ...actual,
    getPostEngine: vi.fn(() => mockPostEngine),
    __mockPostEngine: mockPostEngine,
  };
});

vi.mock('../../src/main/engine/MediaEngine', () => {
  const mockMediaEngine = {
    getAllMedia: vi.fn(async () => []),
    setProjectContext: vi.fn(),
  };
  return {
    getMediaEngine: vi.fn(() => mockMediaEngine),
    __mockMediaEngine: mockMediaEngine,
  };
});

vi.mock('../../src/main/engine/PostMediaEngine', () => {
  const mockPostMediaEngine = {
    getLinkedMediaDataForPost: vi.fn(async () => []),
    setProjectContext: vi.fn(),
  };
  return {
    getPostMediaEngine: vi.fn(() => mockPostMediaEngine),
    __mockPostMediaEngine: mockPostMediaEngine,
  };
});

function makePost(overrides: Partial<PostData> = {}): PostData {
  const createdAt = overrides.createdAt ?? new Date('2025-01-15T10:00:00.000Z');
  const updatedAt = overrides.updatedAt ?? createdAt;
  return {
    id: overrides.id ?? 'post-1',
    projectId: overrides.projectId ?? 'default',
    title: overrides.title ?? 'Test Post',
    slug: overrides.slug ?? 'test-post',
    excerpt: overrides.excerpt,
    content: overrides.content ?? '# Test\n\nBody text',
    status: overrides.status ?? 'published',
    author: overrides.author,
    createdAt,
    updatedAt,
    publishedAt: overrides.publishedAt ?? createdAt,
    tags: overrides.tags ?? [],
    categories: overrides.categories ?? [],
  };
}

async function fileExists(filePath: string): Promise<boolean> {
  try {
    await stat(filePath);
    return true;
  } catch {
    return false;
  }
}

async function listFiles(dir: string, prefix = ''): Promise<string[]> {
  const files: string[] = [];
  try {
    const entries = await readdir(dir, { withFileTypes: true });
    for (const entry of entries) {
      const relative = prefix ? `${prefix}/${entry.name}` : entry.name;
      if (entry.isDirectory()) {
        files.push(...await listFiles(path.join(dir, entry.name), relative));
      } else {
        files.push(relative);
      }
    }
  } catch {
    // dir doesn't exist
  }
  return files.sort();
}

describe('BlogGenerationEngine', () => {
  let tempDir: string;
  let mockPostEngine: any;

  beforeEach(async () => {
    vi.clearAllMocks();
    generatedFileHashes.clear();
    tempDir = await mkdtemp(path.join(tmpdir(), 'bds-gen-'));

    const { __mockPostEngine } = await import('../../src/main/engine/PostEngine') as any;
    mockPostEngine = __mockPostEngine;
  });

  afterEach(async () => {
    if (tempDir) {
      await rm(tempDir, { recursive: true, force: true });
    }
  });

  function setupPosts(posts: PostData[]): void {
    mockPostEngine.getPostsFiltered.mockImplementation(async (filter: { status?: string }) => {
      return posts.filter((p) => p.status === (filter.status ?? p.status));
    });
    mockPostEngine.getPublishedVersion.mockResolvedValue(null);
    mockPostEngine.getPost.mockImplementation(async (id: string) => {
      return posts.find((p) => p.id === id) ?? null;
    });
  }

  async function generate(posts: PostData[], options?: Partial<{ maxPostsPerPage: number; language: string; pageTitle: string }>) {
    setupPosts(posts);
    const { BlogGenerationEngine } = await import('../../src/main/engine/BlogGenerationEngine');
    const engine = new BlogGenerationEngine();
    const onProgress = vi.fn();
    return engine.generate({
      projectId: 'test',
      projectName: 'Test Blog',
      dataDir: tempDir,
      baseUrl: 'https://example.com',
      maxPostsPerPage: options?.maxPostsPerPage,
      language: options?.language,
      pageTitle: options?.pageTitle,
    }, onProgress);
  }

  it('copies all required asset files to html/assets/ and html/images/', async () => {
    const result = await generate([]);

    expect(await fileExists(path.join(tempDir, 'html', 'assets', 'pico.min.css'))).toBe(true);
    expect(await fileExists(path.join(tempDir, 'html', 'assets', 'lightbox.min.css'))).toBe(true);
    expect(await fileExists(path.join(tempDir, 'html', 'assets', 'lightbox.min.js'))).toBe(true);
    expect(await fileExists(path.join(tempDir, 'html', 'assets', 'tag-cloud.js'))).toBe(true);
    expect(await fileExists(path.join(tempDir, 'html', 'images', 'prev.png'))).toBe(true);
    expect(await fileExists(path.join(tempDir, 'html', 'images', 'next.png'))).toBe(true);
    expect(await fileExists(path.join(tempDir, 'html', 'images', 'close.png'))).toBe(true);
    expect(await fileExists(path.join(tempDir, 'html', 'images', 'loading.gif'))).toBe(true);

    const picoContent = await readFile(path.join(tempDir, 'html', 'assets', 'pico.min.css'), 'utf-8');
    expect(picoContent.length).toBeGreaterThan(0);
  });

  it('generates root index.html for published posts', async () => {
    const posts = [
      makePost({ id: '1', slug: 'first', title: 'First Post', createdAt: new Date('2025-01-15T10:00:00Z') }),
      makePost({ id: '2', slug: 'second', title: 'Second Post', createdAt: new Date('2025-01-14T10:00:00Z') }),
    ];

    const result = await generate(posts);

    expect(result.pagesGenerated).toBeGreaterThan(0);
    const indexPath = path.join(tempDir, 'html', 'index.html');
    expect(await fileExists(indexPath)).toBe(true);

    const html = await readFile(indexPath, 'utf-8');
    expect(html).toContain('data-template="post-list"');
    expect(html).toContain('/assets/pico.min.css');
    expect(html).toContain('/assets/lightbox.min.css');
    expect(html).toContain('/assets/tag-cloud.js');
    expect(html).not.toContain('function parseWords(');
    expect(html).toContain('archive-day-marker');
    expect(html).toContain('15.01.2025');
    expect(html).toContain('14.01.2025');
  });

  it('generates single post pages at /{year}/{month}/{day}/{slug}/index.html', async () => {
    const posts = [
      makePost({ id: '1', slug: 'hello-world', createdAt: new Date('2025-03-15T10:00:00Z') }),
    ];

    await generate(posts);

    const postPath = path.join(tempDir, 'html', '2025', '03', '15', 'hello-world', 'index.html');
    expect(await fileExists(postPath)).toBe(true);

    const html = await readFile(postPath, 'utf-8');
    expect(html).toContain('data-template="single-post"');
  });

  it('generates category pages with correct archive context', async () => {
    const posts = [
      makePost({ id: '1', slug: 'news-1', title: 'News 1', categories: ['news'] }),
      makePost({ id: '2', slug: 'tech-1', title: 'Tech 1', categories: ['tech'] }),
    ];

    await generate(posts);

    const newsPath = path.join(tempDir, 'html', 'category', 'news', 'index.html');
    const techPath = path.join(tempDir, 'html', 'category', 'tech', 'index.html');
    expect(await fileExists(newsPath)).toBe(true);
    expect(await fileExists(techPath)).toBe(true);

    const newsHtml = await readFile(newsPath, 'utf-8');
    expect(newsHtml).toContain('news');
    expect(newsHtml).toContain('data-template="post-list"');
  });

  it('generates tag pages with correct archive context', async () => {
    const posts = [
      makePost({ id: '1', slug: 'tagged-1', title: 'Tagged 1', tags: ['javascript'] }),
      makePost({ id: '2', slug: 'tagged-2', title: 'Tagged 2', tags: ['typescript'] }),
    ];

    await generate(posts);

    const jsPath = path.join(tempDir, 'html', 'tag', 'javascript', 'index.html');
    const tsPath = path.join(tempDir, 'html', 'tag', 'typescript', 'index.html');
    expect(await fileExists(jsPath)).toBe(true);
    expect(await fileExists(tsPath)).toBe(true);

    const jsHtml = await readFile(jsPath, 'utf-8');
    expect(jsHtml).toContain('javascript');
    expect(jsHtml).toContain('data-template="post-list"');
  });

  it('generates pagination pages for categories with many posts', async () => {
    const posts: PostData[] = [];
    for (let i = 0; i < 5; i++) {
      posts.push(makePost({
        id: `post-${i}`,
        slug: `post-${i}`,
        title: `Post ${i}`,
        categories: ['big-category'],
        createdAt: new Date(`2025-01-${String(i + 1).padStart(2, '0')}T10:00:00Z`),
      }));
    }

    await generate(posts, { maxPostsPerPage: 2 });

    expect(await fileExists(path.join(tempDir, 'html', 'category', 'big-category', 'index.html'))).toBe(true);
    expect(await fileExists(path.join(tempDir, 'html', 'category', 'big-category', 'page', '2', 'index.html'))).toBe(true);
    expect(await fileExists(path.join(tempDir, 'html', 'category', 'big-category', 'page', '3', 'index.html'))).toBe(true);
  });

  it('generates pagination pages for tags with many posts', async () => {
    const posts: PostData[] = [];
    for (let i = 0; i < 4; i++) {
      posts.push(makePost({
        id: `post-${i}`,
        slug: `post-${i}`,
        title: `Post ${i}`,
        tags: ['popular'],
        createdAt: new Date(`2025-01-${String(i + 1).padStart(2, '0')}T10:00:00Z`),
      }));
    }

    await generate(posts, { maxPostsPerPage: 2 });

    expect(await fileExists(path.join(tempDir, 'html', 'tag', 'popular', 'index.html'))).toBe(true);
    expect(await fileExists(path.join(tempDir, 'html', 'tag', 'popular', 'page', '2', 'index.html'))).toBe(true);
  });

  it('generates root pagination pages', async () => {
    const posts: PostData[] = [];
    for (let i = 0; i < 4; i++) {
      posts.push(makePost({
        id: `post-${i}`,
        slug: `post-${i}`,
        title: `Post ${i}`,
        createdAt: new Date(`2025-01-${String(i + 1).padStart(2, '0')}T10:00:00Z`),
      }));
    }

    await generate(posts, { maxPostsPerPage: 2 });

    expect(await fileExists(path.join(tempDir, 'html', 'index.html'))).toBe(true);
    expect(await fileExists(path.join(tempDir, 'html', 'page', '2', 'index.html'))).toBe(true);
  });

  it('generates year, month, and day archive pages', async () => {
    const posts = [
      makePost({ id: '1', slug: 'jan-post', createdAt: new Date('2025-01-15T10:00:00Z') }),
      makePost({ id: '2', slug: 'feb-post', createdAt: new Date('2025-02-20T10:00:00Z') }),
    ];

    await generate(posts);

    // Year archive
    expect(await fileExists(path.join(tempDir, 'html', '2025', 'index.html'))).toBe(true);
    // Month archives
    expect(await fileExists(path.join(tempDir, 'html', '2025', '01', 'index.html'))).toBe(true);
    expect(await fileExists(path.join(tempDir, 'html', '2025', '02', 'index.html'))).toBe(true);
    // Day archives
    expect(await fileExists(path.join(tempDir, 'html', '2025', '01', '15', 'index.html'))).toBe(true);
    expect(await fileExists(path.join(tempDir, 'html', '2025', '02', '20', 'index.html'))).toBe(true);
  });

  it('excludes draft-only posts from generated pages', async () => {
    const posts = [
      makePost({ id: '1', slug: 'published', title: 'Published', status: 'published' }),
      makePost({ id: '2', slug: 'draft-only', title: 'Draft Only', status: 'draft' }),
    ];

    const result = await generate(posts);

    expect(result.postCount).toBe(1);
    expect(await fileExists(path.join(tempDir, 'html', '2025', '01', '15', 'published', 'index.html'))).toBe(true);
    expect(await fileExists(path.join(tempDir, 'html', '2025', '01', '15', 'draft-only', 'index.html'))).toBe(false);
  });

  it('includes draft posts that have a published version', async () => {
    const publishedPost = makePost({ id: '1', slug: 'with-published', title: 'Published Version', status: 'published' });
    const draftWithPublished = makePost({ id: '2', slug: 'draft-has-pub', title: 'Draft Has Published', status: 'draft' });
    const publishedVersion = makePost({ id: '2', slug: 'draft-has-pub', title: 'Published Version of Draft', status: 'published', createdAt: new Date('2025-02-10T10:00:00Z') });

    mockPostEngine.getPostsFiltered.mockImplementation(async (filter: { status?: string }) => {
      if (filter.status === 'published') return [publishedPost];
      if (filter.status === 'draft') return [draftWithPublished];
      return [];
    });
    mockPostEngine.getPublishedVersion.mockImplementation(async (id: string) => {
      if (id === '2') return publishedVersion;
      return null;
    });
    mockPostEngine.getPost.mockImplementation(async (id: string) => {
      if (id === '1') return publishedPost;
      if (id === '2') return publishedVersion;
      return null;
    });

    const { BlogGenerationEngine } = await import('../../src/main/engine/BlogGenerationEngine');
    const engine = new BlogGenerationEngine();
    const result = await engine.generate({
      projectId: 'test',
      projectName: 'Test Blog',
      dataDir: tempDir,
      baseUrl: 'https://example.com',
    }, vi.fn());

    expect(result.postCount).toBe(2);
    expect(await fileExists(path.join(tempDir, 'html', '2025', '02', '10', 'draft-has-pub', 'index.html'))).toBe(true);
  });

  it('returns correct pagesGenerated count', async () => {
    const posts = [
      makePost({ id: '1', slug: 'post-a', categories: ['news'], tags: ['js'], createdAt: new Date('2025-01-15T10:00:00Z') }),
    ];

    const result = await generate(posts);

    // Should have: root(1) + single(1) + category/news(1) + tag/js(1) + year(1) + month(1) + day(1) = 7
    expect(result.pagesGenerated).toBe(7);
  });

  it('generates HTML that references local assets not CDN', async () => {
    const posts = [makePost({ id: '1', slug: 'test' })];
    await generate(posts);

    const indexHtml = await readFile(path.join(tempDir, 'html', 'index.html'), 'utf-8');
    expect(indexHtml).toContain('href="/assets/pico.min.css"');
    expect(indexHtml).toContain('href="/assets/lightbox.min.css"');
    expect(indexHtml).toContain('src="/assets/lightbox.min.js"');
    expect(indexHtml).not.toContain('cdn.jsdelivr.net');
    expect(indexHtml).not.toContain('cdnjs.cloudflare.com');
  });

  it('handles categories with special characters via URL encoding', async () => {
    const posts = [
      makePost({ id: '1', slug: 'special', categories: ['my category'] }),
    ];

    await generate(posts);

    expect(await fileExists(path.join(tempDir, 'html', 'category', 'my%20category', 'index.html'))).toBe(true);
  });

  it('generates static page routes at /{slug}/index.html for posts in category page', async () => {
    const posts = [
      makePost({ id: 'page-1', slug: 'about', title: 'About', categories: ['page'] }),
      makePost({ id: 'post-1', slug: 'hello-world', title: 'Hello World', categories: ['blog'] }),
    ];

    await generate(posts);

    expect(await fileExists(path.join(tempDir, 'html', 'about', 'index.html'))).toBe(true);
    expect(await fileExists(path.join(tempDir, 'html', 'hello-world', 'index.html'))).toBe(false);
  });

  it('generates canonical post routes only and does not generate aliases', async () => {
    const posts = [
      makePost({ id: '1', slug: 'alias-test', createdAt: new Date('2025-03-15T10:00:00Z') }),
    ];

    await generate(posts);

    expect(await fileExists(path.join(tempDir, 'html', '2025', '03', '15', 'alias-test', 'index.html'))).toBe(true);
    expect(await fileExists(path.join(tempDir, 'html', 'posts', 'alias-test', 'index.html'))).toBe(false);
    expect(await fileExists(path.join(tempDir, 'html', 'posts', '2025', '03', 'alias-test', 'index.html'))).toBe(false);
    expect(await fileExists(path.join(tempDir, 'html', 'post', 'alias-test', 'index.html'))).toBe(false);
    expect(await fileExists(path.join(tempDir, 'html', 'post', '2025', '03', 'alias-test', 'index.html'))).toBe(false);
  });

  it('does not overwrite unchanged html files on subsequent generation runs', async () => {
    const posts = [
      makePost({ id: '1', slug: 'stable-post', createdAt: new Date('2025-03-15T10:00:00Z') }),
    ];

    await generate(posts);

    const canonicalPath = path.join(tempDir, 'html', '2025', '03', '15', 'stable-post', 'index.html');
    const beforeStat = await stat(canonicalPath);

    await new Promise((resolve) => setTimeout(resolve, 20));
    await generate(posts);

    const afterStat = await stat(canonicalPath);
    expect(afterStat.mtimeMs).toBe(beforeStat.mtimeMs);
  });

  it('delegates hash reads/writes to generated file hash store module', async () => {
    const posts = [makePost({ id: '1', slug: 'delegation-check' })];

    await generate(posts);

    expect(getGeneratedFileHashMock).toHaveBeenCalled();
    expect(setGeneratedFileHashMock).toHaveBeenCalled();
  });

  it('does not execute CREATE TABLE statements during generation runtime', async () => {
    const posts = [makePost({ id: '1', slug: 'runtime-ddl-test' })];

    await generate(posts);

    const createTableCalls = executeDbSql.mock.calls.filter(([input]) => {
      const sql = typeof input?.sql === 'string' ? input.sql : '';
      return sql.toUpperCase().includes('CREATE TABLE');
    });

    expect(createTableCalls).toHaveLength(0);
  });

  it('does not create html/media folder during generation', async () => {
    const posts = [makePost({ id: '1', slug: 'test' })];

    await generate(posts);

    expect(await fileExists(path.join(tempDir, 'html', 'media'))).toBe(false);
  });

  it('generates zero pages when there are no published posts', async () => {
    const result = await generate([]);
    expect(result.pagesGenerated).toBe(0);
    expect(result.postCount).toBe(0);
  });

  it('generates pagination links in list pages', async () => {
    const posts: PostData[] = [];
    for (let i = 0; i < 4; i++) {
      posts.push(makePost({
        id: `p-${i}`,
        slug: `p-${i}`,
        title: `Post ${i}`,
        tags: ['paginated'],
        createdAt: new Date(`2025-01-${String(i + 1).padStart(2, '0')}T10:00:00Z`),
      }));
    }

    await generate(posts, { maxPostsPerPage: 2 });

    const page1 = await readFile(path.join(tempDir, 'html', 'tag', 'paginated', 'index.html'), 'utf-8');
    expect(page1).toContain('/tag/paginated/page/2/');

    const page2 = await readFile(path.join(tempDir, 'html', 'tag', 'paginated', 'page', '2', 'index.html'), 'utf-8');
    expect(page2).toContain('/tag/paginated/');
  });
});