import dotenv from 'dotenv';
import express from 'express';
import cors from 'cors';
import session from 'express-session';
import fs from 'fs-extra';
import path from 'path';
import { fileURLToPath } from 'url';
import { v4 as uuidv4 } from 'uuid';

// Load environment variables
dotenv.config();
import { authenticateUser, getUserByUsername, changeUserPassword } from './auth.js';
import { 
  getAllThemes, 
  getActiveTheme, 
  setActiveTheme, 
  createCustomTheme, 
  updateCustomTheme, 
  deleteCustomTheme, 
  exportTheme 
} from './themes.js';

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


const app = express();
const PORT = process.env.PORT || 3001;

// Paths
const POSTS_DIR = path.resolve(__dirname, process.env.POSTS_DIR || '../public/posts');
const INDEX_FILE = path.join(POSTS_DIR, 'index.json');

// Middleware
app.use(cors({
  origin: ['http://localhost:5173', 'https://goonblog.thevakhovske.eu.org'],
  credentials: true // Enable cookies
}));
app.use(express.json());
app.use(express.urlencoded({ extended: true }));

// Session configuration - Simple as fuck
app.use(session({
  secret: 'your-secret-key-here-change-this',
  resave: true,
  saveUninitialized: true,
  cookie: { 
    secure: false, // Disable secure for now to test
    maxAge: 24 * 60 * 60 * 1000
  }
}));

// Ensure posts directory exists
await fs.ensureDir(POSTS_DIR);

// Authentication middleware
function requireAuth(req, res, next) {
  if (req.session && req.session.user && req.session.user.role === 'admin') {
    return next();
  }
  return res.status(401).json({ error: 'Authentication required' });
}

// Check if user is authenticated
function isAuthenticated(req, res, next) {
  req.isAuthenticated = !!(req.session && req.session.user);
  req.user = req.session?.user || null;
  next();
}

// Helper function to generate index.json
async function generateIndex() {
  try {
    const files = await fs.readdir(POSTS_DIR);
    const mdFiles = files.filter(f => f.endsWith('.md'));
    await fs.writeJSON(INDEX_FILE, mdFiles, { spaces: 2 });
    console.log(`Index updated: ${mdFiles.length} posts`);
    return mdFiles;
  } catch (error) {
    console.error('Error generating index:', error);
    throw error;
  }
}

// Helper function to parse post metadata
function parsePostMetadata(content) {
  const titleMatch = content.match(/title:\s*(.*)/);
  const descMatch = content.match(/desc:\s*(.*)/);
  const tagsMatch = content.match(/tags:\s*(.*)/);
  
  return {
    title: titleMatch ? titleMatch[1].trim() : 'Untitled',
    description: descMatch ? descMatch[1].trim() : '',
    tags: tagsMatch ? tagsMatch[1].split(',').map(tag => tag.trim()) : []
  };
}

// Helper function to generate filename from title
function generateFilename(title) {
  // Create date-based filename similar to existing pattern
  const date = new Date();
  const dateStr = date.toISOString().slice(0, 10).replace(/-/g, '');
  const slug = title.toLowerCase()
    .replace(/[^a-z0-9]+/g, '-')
    .replace(/^-|-$/g, '')
    .slice(0, 30);
  
  return slug ? `${dateStr}-${slug}.md` : `${dateStr}.md`;
}

// Authentication Routes

// POST /api/auth/login - Login
app.post('/api/auth/login', async (req, res) => {
  try {
    const { username, password } = req.body;
    
    if (!username || !password) {
      return res.status(400).json({ error: 'Username and password are required' });
    }
    
    const user = await authenticateUser(username, password);
    if (!user) {
      return res.status(401).json({ error: 'Invalid username or password' });
    }
    
    // Store user in session
    req.session.user = user;
    
    res.json({ 
      success: true, 
      user: {
        username: user.username,
        role: user.role
      }
    });
  } catch (error) {
    console.error('Login error:', error);
    res.status(500).json({ error: 'Login failed' });
  }
});

// POST /api/auth/logout - Logout
app.post('/api/auth/logout', (req, res) => {
  req.session.destroy((err) => {
    if (err) {
      return res.status(500).json({ error: 'Logout failed' });
    }
    res.clearCookie('connect.sid'); // Default session cookie name
    res.json({ success: true, message: 'Logged out successfully' });
  });
});

// GET /api/auth/me - Get current user
app.get('/api/auth/me', isAuthenticated, (req, res) => {
  if (req.isAuthenticated) {
    res.json({ 
      user: {
        username: req.user.username,
        role: req.user.role
      }
    });
  } else {
    res.json({ user: null });
  }
});

// POST /api/auth/change-password - Change password
app.post('/api/auth/change-password', requireAuth, async (req, res) => {
  try {
    const { currentPassword, newPassword } = req.body;
    
    if (!currentPassword || !newPassword) {
      return res.status(400).json({ error: 'Current password and new password are required' });
    }
    
    if (newPassword.length < 6) {
      return res.status(400).json({ error: 'New password must be at least 6 characters long' });
    }
    
    const result = await changeUserPassword(req.user.username, currentPassword, newPassword);
    
    if (result.success) {
      res.json({ success: true, message: result.message });
    } else {
      res.status(400).json({ error: result.message });
    }
  } catch (error) {
    console.error('Change password error:', error);
    res.status(500).json({ error: 'Failed to change password' });
  }
});

// API Routes

// GET /api/posts - Get all posts with metadata
app.get('/api/posts', async (req, res) => {
  try {
    const files = await generateIndex();
    const posts = [];
    
    for (const filename of files) {
      const filePath = path.join(POSTS_DIR, filename);
      const content = await fs.readFile(filePath, 'utf8');
      const metadata = parsePostMetadata(content);
      const slug = filename.replace('.md', '');
      
      posts.push({
        slug,
        filename,
        ...metadata,
        content,
        createdAt: (await fs.stat(filePath)).birthtime,
        updatedAt: (await fs.stat(filePath)).mtime
      });
    }
    
    // Sort by creation date, newest first
    posts.sort((a, b) => new Date(b.createdAt) - new Date(a.createdAt));
    
    res.json(posts);
  } catch (error) {
    console.error('Error fetching posts:', error);
    res.status(500).json({ error: 'Failed to fetch posts' });
  }
});

// GET /api/posts/:slug - Get specific post
app.get('/api/posts/:slug', async (req, res) => {
  try {
    const { slug } = req.params;
    const filename = `${slug}.md`;
    const filePath = path.join(POSTS_DIR, filename);
    
    if (!(await fs.pathExists(filePath))) {
      return res.status(404).json({ error: 'Post not found' });
    }
    
    const content = await fs.readFile(filePath, 'utf8');
    const metadata = parsePostMetadata(content);
    const stats = await fs.stat(filePath);
    
    res.json({
      slug,
      filename,
      ...metadata,
      content,
      createdAt: stats.birthtime,
      updatedAt: stats.mtime
    });
  } catch (error) {
    console.error('Error fetching post:', error);
    res.status(500).json({ error: 'Failed to fetch post' });
  }
});

// POST /api/posts - Create new post
app.post('/api/posts', requireAuth, async (req, res) => {
  try {
    const { title, description, content, tags } = req.body;
    
    if (!title || !content) {
      return res.status(400).json({ error: 'Title and content are required' });
    }
    
    // Generate filename
    const filename = generateFilename(title);
    const filePath = path.join(POSTS_DIR, filename);
    
    // Check if file already exists
    if (await fs.pathExists(filePath)) {
      return res.status(409).json({ error: 'Post with similar title already exists' });
    }
    
    // Format the post content
    let postContent = '';
    postContent += `title: ${title}\n`;
    if (description) postContent += `desc: ${description}\n`;
    if (tags && tags.length > 0) postContent += `tags: ${tags.join(', ')}\n`;
    postContent += '\n' + content;
    
    // Write the file
    await fs.writeFile(filePath, postContent, 'utf8');
    
    // Update index
    await generateIndex();
    
    const slug = filename.replace('.md', '');
    const stats = await fs.stat(filePath);
    
    res.status(201).json({
      slug,
      filename,
      title,
      description: description || '',
      tags: tags || [],
      content: postContent,
      createdAt: stats.birthtime,
      updatedAt: stats.mtime
    });
  } catch (error) {
    console.error('Error creating post:', error);
    res.status(500).json({ error: 'Failed to create post' });
  }
});

// PUT /api/posts/:slug - Update existing post
app.put('/api/posts/:slug', requireAuth, async (req, res) => {
  try {
    const { slug } = req.params;
    const { title, description, content, tags } = req.body;
    
    const oldFilename = `${slug}.md`;
    const oldFilePath = path.join(POSTS_DIR, oldFilename);
    
    if (!(await fs.pathExists(oldFilePath))) {
      return res.status(404).json({ error: 'Post not found' });
    }
    
    if (!title || !content) {
      return res.status(400).json({ error: 'Title and content are required' });
    }
    
    // Generate new filename if title changed
    const newFilename = generateFilename(title);
    const newFilePath = path.join(POSTS_DIR, newFilename);
    
    // Format the post content
    let postContent = '';
    postContent += `title: ${title}\n`;
    if (description) postContent += `desc: ${description}\n`;
    if (tags && tags.length > 0) postContent += `tags: ${tags.join(', ')}\n`;
    postContent += '\n' + content;
    
    // Write to new file
    await fs.writeFile(newFilePath, postContent, 'utf8');
    
    // If filename changed, remove old file
    if (oldFilename !== newFilename) {
      await fs.remove(oldFilePath);
    }
    
    // Update index
    await generateIndex();
    
    const newSlug = newFilename.replace('.md', '');
    const stats = await fs.stat(newFilePath);
    
    res.json({
      slug: newSlug,
      filename: newFilename,
      title,
      description: description || '',
      tags: tags || [],
      content: postContent,
      createdAt: stats.birthtime,
      updatedAt: stats.mtime
    });
  } catch (error) {
    console.error('Error updating post:', error);
    res.status(500).json({ error: 'Failed to update post' });
  }
});

// DELETE /api/posts/:slug - Delete post
app.delete('/api/posts/:slug', requireAuth, async (req, res) => {
  try {
    const { slug } = req.params;
    const filename = `${slug}.md`;
    const filePath = path.join(POSTS_DIR, filename);
    
    if (!(await fs.pathExists(filePath))) {
      return res.status(404).json({ error: 'Post not found' });
    }
    
    await fs.remove(filePath);
    await generateIndex();
    
    res.json({ message: 'Post deleted successfully' });
  } catch (error) {
    console.error('Error deleting post:', error);
    res.status(500).json({ error: 'Failed to delete post' });
  }
});

// Theme API Routes

// GET /api/themes - Get all themes
app.get('/api/themes', async (req, res) => {
  try {
    const themesData = await getAllThemes();
    res.json(themesData);
  } catch (error) {
    console.error('Error fetching themes:', error);
    res.status(500).json({ error: 'Failed to fetch themes' });
  }
});

// GET /api/themes/active - Get active theme
app.get('/api/themes/active', async (req, res) => {
  try {
    const activeTheme = await getActiveTheme();
    res.json(activeTheme);
  } catch (error) {
    console.error('Error fetching active theme:', error);
    res.status(500).json({ error: 'Failed to fetch active theme' });
  }
});

// PUT /api/themes/active - Set active theme
app.put('/api/themes/active', requireAuth, async (req, res) => {
  try {
    const { themeId } = req.body;
    
    if (!themeId) {
      return res.status(400).json({ error: 'Theme ID is required' });
    }
    
    const activeTheme = await setActiveTheme(themeId);
    res.json({ success: true, theme: activeTheme });
  } catch (error) {
    console.error('Error setting active theme:', error);
    res.status(400).json({ error: error.message });
  }
});

// POST /api/themes - Create custom theme
app.post('/api/themes', requireAuth, async (req, res) => {
  try {
    const themeData = req.body;
    const newTheme = await createCustomTheme(themeData);
    res.status(201).json(newTheme);
  } catch (error) {
    console.error('Error creating theme:', error);
    res.status(400).json({ error: error.message });
  }
});

// PUT /api/themes/:themeId - Update custom theme
app.put('/api/themes/:themeId', requireAuth, async (req, res) => {
  try {
    const { themeId } = req.params;
    const themeData = req.body;
    
    const updatedTheme = await updateCustomTheme(themeId, themeData);
    res.json(updatedTheme);
  } catch (error) {
    console.error('Error updating theme:', error);
    res.status(400).json({ error: error.message });
  }
});

// DELETE /api/themes/:themeId - Delete custom theme
app.delete('/api/themes/:themeId', requireAuth, async (req, res) => {
  try {
    const { themeId } = req.params;
    await deleteCustomTheme(themeId);
    res.json({ success: true, message: 'Theme deleted successfully' });
  } catch (error) {
    console.error('Error deleting theme:', error);
    res.status(400).json({ error: error.message });
  }
});

// GET /api/themes/:themeId/export - Export theme
app.get('/api/themes/:themeId/export', requireAuth, async (req, res) => {
  try {
    const { themeId } = req.params;
    const themeData = await exportTheme(themeId);
    
    res.setHeader('Content-Type', 'application/json');
    res.setHeader('Content-Disposition', `attachment; filename="theme-${themeId}.json"`);
    res.json(themeData);
  } catch (error) {
    console.error('Error exporting theme:', error);
    res.status(400).json({ error: error.message });
  }
});

// Health check endpoint
app.get('/api/health', (req, res) => {
  res.json({ status: 'OK', timestamp: new Date().toISOString() });
});

// Generate initial index on startup
await generateIndex();

app.listen(PORT, () => {
  console.log(`🚀 Backend server running on http://localhost:${PORT}`);
  console.log(`📁 Posts directory: ${POSTS_DIR}`);
});