import express from 'express';
import bcrypt from 'bcrypt';
import jwt from 'jsonwebtoken';
import db from '../database.js';
import { authenticateToken } from '../middleware/auth.js';

const router = express.Router();

// Register new user
router.post('/register', async (req, res) => {
  const { username, email, password } = req.body;

  if (!username || !email || !password) {
    return res.status(400).json({ error: 'Username, email, and password are required' });
  }

  if (password.length < 6) {
    return res.status(400).json({ error: 'Password must be at least 6 characters long' });
  }

  try {
    const hashedPassword = await bcrypt.hash(password, 10);

    const query = 'INSERT INTO users (username, email, password_hash) VALUES (?, ?, ?)';

    db.run(query, [username, email, hashedPassword], function (err) {
      if (err) {
        if (err.message.includes('UNIQUE')) {
          return res.status(400).json({ error: 'Username or email already exists' });
        }
        return res.status(500).json({ error: err.message });
      }

      const token = jwt.sign(
        { id: this.lastID, username, email },
        process.env.JWT_SECRET,
        { expiresIn: '7d' }
      );

      res.status(201).json({
        message: 'User registered successfully',
        token,
        user: {
          id: this.lastID,
          username,
          email
        }
      });
    });
  } catch (error) {
    res.status(500).json({ error: 'Error hashing password' });
  }
});

// Login
router.post('/login', (req, res) => {
  const { username, password } = req.body;

  if (!username || !password) {
    return res.status(400).json({ error: 'Username and password are required' });
  }

  const query = 'SELECT * FROM users WHERE username = ?';

  db.get(query, [username], async (err, user) => {
    if (err) {
      return res.status(500).json({ error: err.message });
    }

    if (!user) {
      return res.status(401).json({ error: 'Invalid username or password' });
    }

    try {
      const validPassword = await bcrypt.compare(password, user.password_hash);

      if (!validPassword) {
        return res.status(401).json({ error: 'Invalid username or password' });
      }

      const token = jwt.sign(
        { id: user.id, username: user.username, email: user.email },
        process.env.JWT_SECRET,
        { expiresIn: '7d' }
      );

      res.json({
        message: 'Login successful',
        token,
        user: {
          id: user.id,
          username: user.username,
          email: user.email
        }
      });
    } catch (error) {
      res.status(500).json({ error: 'Error verifying password' });
    }
  });
});

// Get current user
router.get('/me', authenticateToken, (req, res) => {
  const query = 'SELECT id, username, email, theme, created_at FROM users WHERE id = ?';

  db.get(query, [req.user.id], (err, user) => {
    if (err) {
      return res.status(500).json({ error: err.message });
    }

    if (!user) {
      return res.status(404).json({ error: 'User not found' });
    }

    res.json({ user });
  });
});

// Update user theme preference
router.put('/me/theme', authenticateToken, (req, res) => {
  const { theme } = req.body;

  if (!['light', 'dark'].includes(theme)) {
    return res.status(400).json({ error: 'Theme must be "light" or "dark"' });
  }

  const query = 'UPDATE users SET theme = ? WHERE id = ?';

  db.run(query, [theme, req.user.id], (err) => {
    if (err) {
      return res.status(500).json({ error: err.message });
    }

    res.json({ message: 'Theme updated', theme });
  });
});

// Update user email
router.put('/me/email', authenticateToken, async (req, res) => {
  const { newEmail, password } = req.body;

  if (!newEmail || !password) {
    return res.status(400).json({ error: 'New email and password are required' });
  }

  try {
    // Get current user
    const userQuery = 'SELECT * FROM users WHERE id = ?';
    
    db.get(userQuery, [req.user.id], async (err, user) => {
      if (err) {
        return res.status(500).json({ error: err.message });
      }

      if (!user) {
        return res.status(404).json({ error: 'User not found' });
      }

      // Verify password
      const validPassword = await bcrypt.compare(password, user.password_hash);

      if (!validPassword) {
        return res.status(401).json({ error: 'Invalid password' });
      }

      // Check if email already exists
      const emailCheckQuery = 'SELECT id FROM users WHERE email = ? AND id != ?';
      
      db.get(emailCheckQuery, [newEmail, req.user.id], (err, existingUser) => {
        if (err) {
          return res.status(500).json({ error: err.message });
        }

        if (existingUser) {
          return res.status(400).json({ error: 'Email already in use' });
        }

        // Update email
        const updateQuery = 'UPDATE users SET email = ? WHERE id = ?';
        
        db.run(updateQuery, [newEmail, req.user.id], (err) => {
          if (err) {
            return res.status(500).json({ error: err.message });
          }

          res.json({ message: 'Email updated successfully', email: newEmail });
        });
      });
    });
  } catch (error) {
    res.status(500).json({ error: 'Error updating email' });
  }
});

// Update user password
router.put('/me/password', authenticateToken, async (req, res) => {
  const { currentPassword, newPassword } = req.body;

  if (!currentPassword || !newPassword) {
    return res.status(400).json({ error: 'Current and new password are required' });
  }

  if (newPassword.length < 6) {
    return res.status(400).json({ error: 'New password must be at least 6 characters long' });
  }

  try {
    // Get current user
    const userQuery = 'SELECT * FROM users WHERE id = ?';
    
    db.get(userQuery, [req.user.id], async (err, user) => {
      if (err) {
        return res.status(500).json({ error: err.message });
      }

      if (!user) {
        return res.status(404).json({ error: 'User not found' });
      }

      // Verify current password
      const validPassword = await bcrypt.compare(currentPassword, user.password_hash);

      if (!validPassword) {
        return res.status(401).json({ error: 'Invalid current password' });
      }

      // Hash new password
      const hashedPassword = await bcrypt.hash(newPassword, 10);

      // Update password
      const updateQuery = 'UPDATE users SET password_hash = ? WHERE id = ?';
      
      db.run(updateQuery, [hashedPassword, req.user.id], (err) => {
        if (err) {
          return res.status(500).json({ error: err.message });
        }

        res.json({ message: 'Password updated successfully' });
      });
    });
  } catch (error) {
    res.status(500).json({ error: 'Error updating password' });
  }
});

export default router;