const express = require('express');
const { body, validationResult } = require('express-validator');
const { protect, generateToken, hashPassword, comparePassword, authRateLimit, logAuthAttempt } = require('../middleware/auth');
const database = require('../config/database');
const redis = require('../config/redis');
const logger = require('../utils/logger');

const router = express.Router();

// Register new user
router.post('/register', [
  body('username').isLength({ min: 3 }).withMessage('Username must be at least 3 characters'),
  body('email').isEmail().withMessage('Must be a valid email'),
  body('password').isLength({ min: 6 }).withMessage('Password must be at least 6 characters'),
  body('role').optional().isIn(['admin', 'operator', 'viewer']).withMessage('Invalid role')
], async (req, res) => {
  try {
    const errors = validationResult(req);
    if (!errors.isEmpty()) {
      return res.status(400).json({
        success: false,
        errors: errors.array()
      });
    }

    const { username, email, password, role = 'viewer' } = req.body;

    // Check if user already exists
    const existingUsers = await database.query(
      'SELECT id FROM users WHERE username = ? OR email = ?',
      [username, email]
    );

    if (existingUsers.length > 0) {
      return res.status(400).json({
        success: false,
        message: 'Username or email already exists'
      });
    }

    // Hash password
    const passwordHash = await hashPassword(password);

    // Create user
    const result = await database.query(
      'INSERT INTO users (username, email, password_hash, role) VALUES (?, ?, ?, ?)',
      [username, email, passwordHash, role]
    );

    const userId = result.insertId;

    // Generate token
    const token = generateToken(userId);

    // Store session in Redis
    await redis.cacheUserSession(userId, {
      userId,
      username,
      email,
      role,
      loginTime: new Date().toISOString()
    });

    logger.logSecurity('user_registered', { username, email, role }, 'info');

    res.status(201).json({
      success: true,
      message: 'User registered successfully',
      data: {
        user: {
          id: userId,
          username,
          email,
          role
        },
        token
      }
    });
  } catch (error) {
    logger.error('Registration error:', error);
    res.status(500).json({
      success: false,
      message: 'Registration failed'
    });
  }
});

// Login user
router.post('/login', [
  body('username').notEmpty().withMessage('Username is required'),
  body('password').notEmpty().withMessage('Password is required')
], authRateLimit, logAuthAttempt, async (req, res) => {
  try {
    const errors = validationResult(req);
    if (!errors.isEmpty()) {
      return res.status(400).json({
        success: false,
        errors: errors.array()
      });
    }

    const { username, password } = req.body;

    // Find user
    const users = await database.query(
      'SELECT id, username, email, password_hash, role, status FROM users WHERE username = ? OR email = ?',
      [username, username]
    );

    if (users.length === 0) {
      return res.status(401).json({
        success: false,
        message: 'Invalid credentials'
      });
    }

    const user = users[0];

    // Check if user is active
    if (user.status !== 'active') {
      return res.status(401).json({
        success: false,
        message: 'Account is not active'
      });
    }

    // Verify password
    const isValidPassword = await comparePassword(password, user.password_hash);
    if (!isValidPassword) {
      return res.status(401).json({
        success: false,
        message: 'Invalid credentials'
      });
    }

    // Generate token
    const token = generateToken(user.id);

    // Store session in Redis
    await redis.cacheUserSession(user.id, {
      userId: user.id,
      username: user.username,
      email: user.email,
      role: user.role,
      loginTime: new Date().toISOString()
    });

    // Update last login
    await database.query(
      'UPDATE users SET last_login = NOW() WHERE id = ?',
      [user.id]
    );

    logger.logSecurity('user_login', { username: user.username, userId: user.id }, 'info');

    res.json({
      success: true,
      message: 'Login successful',
      data: {
        user: {
          id: user.id,
          username: user.username,
          email: user.email,
          role: user.role
        },
        token
      }
    });
  } catch (error) {
    logger.error('Login error:', error);
    res.status(500).json({
      success: false,
      message: 'Login failed'
    });
  }
});

// Get current user profile
router.get('/profile', protect, async (req, res) => {
  try {
    const user = await database.query(
      'SELECT id, username, email, role, status, created_at, last_login FROM users WHERE id = ?',
      [req.user.id]
    );

    if (user.length === 0) {
      return res.status(404).json({
        success: false,
        message: 'User not found'
      });
    }

    res.json({
      success: true,
      data: user[0]
    });
  } catch (error) {
    logger.error('Get profile error:', error);
    res.status(500).json({
      success: false,
      message: 'Failed to get profile'
    });
  }
});

// Update user profile
router.put('/profile', protect, [
  body('email').optional().isEmail().withMessage('Must be a valid email'),
  body('currentPassword').optional().notEmpty().withMessage('Current password is required for changes')
], async (req, res) => {
  try {
    const errors = validationResult(req);
    if (!errors.isEmpty()) {
      return res.status(400).json({
        success: false,
        errors: errors.array()
      });
    }

    const { email, currentPassword, newPassword } = req.body;
    const updates = {};
    const params = [];

    // Check if user wants to change password
    if (newPassword) {
      if (!currentPassword) {
        return res.status(400).json({
          success: false,
          message: 'Current password is required to change password'
        });
      }

      // Verify current password
      const user = await database.query(
        'SELECT password_hash FROM users WHERE id = ?',
        [req.user.id]
      );

      const isValidPassword = await comparePassword(currentPassword, user[0].password_hash);
      if (!isValidPassword) {
        return res.status(400).json({
          success: false,
          message: 'Current password is incorrect'
        });
      }

      // Hash new password
      const newPasswordHash = await hashPassword(newPassword);
      updates.password_hash = newPasswordHash;
      params.push(newPasswordHash);
    }

    // Update email if provided
    if (email) {
      // Check if email is already taken
      const existingUser = await database.query(
        'SELECT id FROM users WHERE email = ? AND id != ?',
        [email, req.user.id]
      );

      if (existingUser.length > 0) {
        return res.status(400).json({
          success: false,
          message: 'Email is already taken'
        });
      }

      updates.email = email;
      params.push(email);
    }

    if (Object.keys(updates).length === 0) {
      return res.status(400).json({
        success: false,
        message: 'No updates provided'
      });
    }

    // Build update query
    const updateFields = Object.keys(updates).map(key => `${key} = ?`).join(', ');
    params.push(req.user.id);

    await database.query(
      `UPDATE users SET ${updateFields} WHERE id = ?`,
      params
    );

    logger.logSecurity('profile_updated', { userId: req.user.id }, 'info');

    res.json({
      success: true,
      message: 'Profile updated successfully'
    });
  } catch (error) {
    logger.error('Update profile error:', error);
    res.status(500).json({
      success: false,
      message: 'Failed to update profile'
    });
  }
});

// Logout user
router.post('/logout', protect, async (req, res) => {
  try {
    // Invalidate session in Redis
    await redis.invalidateUserSession(req.user.id);

    logger.logSecurity('user_logout', { userId: req.user.id }, 'info');

    res.json({
      success: true,
      message: 'Logout successful'
    });
  } catch (error) {
    logger.error('Logout error:', error);
    res.status(500).json({
      success: false,
      message: 'Logout failed'
    });
  }
});

// Refresh token
router.post('/refresh', protect, async (req, res) => {
  try {
    // Generate new token
    const newToken = generateToken(req.user.id);

    // Update session in Redis
    await redis.cacheUserSession(req.user.id, {
      userId: req.user.id,
      username: req.user.username,
      email: req.user.email,
      role: req.user.role,
      loginTime: new Date().toISOString()
    });

    res.json({
      success: true,
      message: 'Token refreshed successfully',
      data: {
        token: newToken
      }
    });
  } catch (error) {
    logger.error('Token refresh error:', error);
    res.status(500).json({
      success: false,
      message: 'Token refresh failed'
    });
  }
});

// Change password
router.post('/change-password', protect, [
  body('currentPassword').notEmpty().withMessage('Current password is required'),
  body('newPassword').isLength({ min: 6 }).withMessage('New password must be at least 6 characters')
], async (req, res) => {
  try {
    const errors = validationResult(req);
    if (!errors.isEmpty()) {
      return res.status(400).json({
        success: false,
        errors: errors.array()
      });
    }

    const { currentPassword, newPassword } = req.body;

    // Get current user
    const user = await database.query(
      'SELECT password_hash FROM users WHERE id = ?',
      [req.user.id]
    );

    // Verify current password
    const isValidPassword = await comparePassword(currentPassword, user[0].password_hash);
    if (!isValidPassword) {
      return res.status(400).json({
        success: false,
        message: 'Current password is incorrect'
      });
    }

    // Hash new password
    const newPasswordHash = await hashPassword(newPassword);

    // Update password
    await database.query(
      'UPDATE users SET password_hash = ? WHERE id = ?',
      [newPasswordHash, req.user.id]
    );

    logger.logSecurity('password_changed', { userId: req.user.id }, 'info');

    res.json({
      success: true,
      message: 'Password changed successfully'
    });
  } catch (error) {
    logger.error('Change password error:', error);
    res.status(500).json({
      success: false,
      message: 'Failed to change password'
    });
  }
});

module.exports = router;