const express = require('express');
const router = express.Router();
const { body, validationResult } = require('express-validator');
const bcrypt = require('bcrypt');
const jwt = require('jsonwebtoken');
const db = require('../db');
const requireRole = require('../middleware/requireRole');

// Register a new user
router.post('/register', [
  body('email').isEmail().normalizeEmail(),
  body('password').isLength({ min: 8 }),
  body('name').notEmpty()
], async (req, res) => {
  const errors = validationResult(req);
  if (!errors.isEmpty()) {
    return res.status(400).json({ errors: errors.array() });
  }

  const { email, password, name } = req.body;

  try {
    // Check if user already exists
    const existingUser = await db.query('SELECT id FROM users WHERE email = $1', [email]);
    if (existingUser.rows.length > 0) {
      return res.status(409).json({ error: 'User already exists' });
    }

    // Hash password
    const hashedPassword = await bcrypt.hash(password, 12);

    // Insert new user with default role 'user'
    const newUser = await db.query(
      'INSERT INTO users (email, password_hash, name, role) VALUES ($1, $2, $3, $4) RETURNING id, email, name, role',
      [email, hashedPassword, name, 'user']
    );

    res.status(201).json({ user: newUser.rows[0] });
  } catch (err) {
    console.error(err);
    res.status(500).json({ error: 'Internal server error' });
  }
});

// Login user
router.post('/login', [
  body('email').isEmail().normalizeEmail(),
  body('password').notEmpty()
], async (req, res) => {
  const errors = validationResult(req);
  if (!errors.isEmpty()) {
    return res.status(400).json({ errors: errors.array() });
  }

  const { email, password } = req.body;

  try {
    // Find user by email
    const user = await db.query('SELECT id, email, password_hash, name, role FROM users WHERE email = $1', [email]);
    
    if (user.rows.length === 0) {
      return res.status(401).json({ error: 'Invalid credentials' });
    }

    // Compare passwords
    const isValidPassword = await bcrypt.compare(password, user.rows[0].password_hash);
    
    if (!isValidPassword) {
      return res.status(401).json({ error: 'Invalid credentials' });
    }

    // Generate JWT token with role
    const token = jwt.sign(
      { userId: user.rows[0].id, email: user.rows[0].email, role: user.rows[0].role },
      process.env.JWT_SECRET || 'default_secret',
      { expiresIn: '24h' }
    );

    res.json({ 
      token,
      user: {
        id: user.rows[0].id,
        email: user.rows[0].email,
        name: user.rows[0].name,
        role: user.rows[0].role
      }
    });
  } catch (err) {
    console.error(err);
    res.status(500).json({ error: 'Internal server error' });
  }
});

// Get current user profile (requires authentication)
router.get('/profile', requireRole(['user', 'moderator', 'admin']), async (req, res) => {
  try {
    const user = await db.query('SELECT id, email, name, role FROM users WHERE id = $1', [req.user.userId]);
    
    if (user.rows.length === 0) {
      return res.status(404).json({ error: 'User not found' });
    }

    res.json({ user: user.rows[0] });
  } catch (err) {
    console.error(err);
    res.status(500).json({ error: 'Internal server error' });
  }
});

// Update current user profile (requires authentication)
router.put('/profile', requireRole(['user', 'moderator', 'admin']), [
  body('name').optional().notEmpty()
], async (req, res) => {
  const errors = validationResult(req);
  if (!errors.isEmpty()) {
    return res.status(400).json({ errors: errors.array() });
  }

  try {
    const { name } = req.body;
    const userId = req.user.userId;

    // Update user profile
    const updatedUser = await db.query(
      'UPDATE users SET name = $1 WHERE id = $2 RETURNING id, email, name, role',
      [name, userId]
    );

    if (updatedUser.rows.length === 0) {
      return res.status(404).json({ error: 'User not found' });
    }

    res.json({ user: updatedUser.rows[0] });
  } catch (err) {
    console.error(err);
    res.status(500).json({ error: 'Internal server error' });
  }
});

module.exports = router;