const express = require('express');
const router = express.Router();
const { db } = require('../database/db');
const { authenticate } = require('../middleware/auth');
const { modifyLimiter, readLimiter } = require('../middleware/rateLimiter');
const logger = require('../utils/logger');
const { validateChannelIdParam } = require('../middleware/inputValidation');

/**
 * Get user's favorite channels
 */
router.get('/', authenticate, readLimiter, (req, res) => {
  const { isRadio } = req.query;
  const userId = req.user.userId;

  let query = `
    SELECT 
      c.id, c.name, c.url, COALESCE(c.custom_logo, c.logo) as logo, 
      c.group_name, c.is_radio, f.created_at as favorited_at
    FROM favorites f
    JOIN channels c ON f.channel_id = c.id
    WHERE f.user_id = ? AND c.is_active = 1
  `;

  const params = [userId];

  // Filter by radio or TV
  if (isRadio !== undefined) {
    query += ' AND c.is_radio = ?';
    params.push(isRadio === 'true' ? 1 : 0);
  }

  query += ' ORDER BY f.created_at DESC';

  db.all(query, params, (err, rows) => {
    if (err) {
      console.error('Error fetching favorites:', err);
      return res.status(500).json({ error: 'Failed to fetch favorites' });
    }
    res.json(rows || []);
  });
});

/**
 * Add channel to favorites
 */
router.post('/:channelId', authenticate, modifyLimiter, validateChannelIdParam, (req, res) => {
  const { channelId } = req.params;
  const userId = req.user.userId;

  // Check if channel exists and is active
  db.get(
    'SELECT id, is_radio FROM channels WHERE id = ? AND is_active = 1',
    [channelId],
    (err, channel) => {
      if (err) {
        console.error('Error checking channel:', err);
        return res.status(500).json({ error: 'Database error' });
      }

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

      // Add to favorites
      db.run(
        `INSERT OR IGNORE INTO favorites (user_id, channel_id) VALUES (?, ?)`,
        [userId, channelId],
        function(err) {
          if (err) {
            console.error('Error adding favorite:', err);
            return res.status(500).json({ error: 'Failed to add favorite' });
          }

          if (this.changes === 0) {
            return res.status(200).json({ message: 'Already in favorites', alreadyExists: true });
          }

          res.status(201).json({ 
            message: 'Added to favorites', 
            channelId: parseInt(channelId),
            isRadio: channel.is_radio === 1
          });
        }
      );
    }
  );
});

/**
 * Remove channel from favorites
 */
router.delete('/:channelId', authenticate, modifyLimiter, validateChannelIdParam, (req, res) => {
  const { channelId } = req.params;
  const userId = req.user.userId;

  db.run(
    'DELETE FROM favorites WHERE user_id = ? AND channel_id = ?',
    [userId, channelId],
    function(err) {
      if (err) {
        console.error('Error removing favorite:', err);
        return res.status(500).json({ error: 'Failed to remove favorite' });
      }

      if (this.changes === 0) {
        return res.status(404).json({ error: 'Favorite not found' });
      }

      res.json({ message: 'Removed from favorites' });
    }
  );
});

/**
 * Check if channel is favorited
 */
router.get('/check/:channelId', authenticate, (req, res) => {
  const { channelId } = req.params;
  const userId = req.user.userId;

  db.get(
    'SELECT id FROM favorites WHERE user_id = ? AND channel_id = ?',
    [userId, channelId],
    (err, row) => {
      if (err) {
        console.error('Error checking favorite:', err);
        return res.status(500).json({ error: 'Database error' });
      }

      res.json({ isFavorite: !!row });
    }
  );
});

module.exports = router;