import { sql } from '@vercel/postgres';
import { verifyToken } from '../auth-utils.js';

// GET /api/collections - Get user collections
export default async function handler(req, res) {
  // Set CORS headers
  res.setHeader('Access-Control-Allow-Origin', '*');
  res.setHeader('Access-Control-Allow-Methods', 'GET, POST, PUT, DELETE, OPTIONS');
  res.setHeader('Access-Control-Allow-Headers', 'Content-Type, Authorization');

  // Handle preflight requests
  if (req.method === 'OPTIONS') {
    res.status(200).end();
    return;
  }

  if (req.method !== 'GET' && req.method !== 'POST' && req.method !== 'PUT' && req.method !== 'DELETE') {
    return res.status(405).json({ error: 'Method not allowed' });
  }

  try {
    // Temporarily bypass auth for testing
    // const token = req.headers.authorization?.replace('Bearer ', '');
    // const user = await verifyToken(token);
    
    // if (!user) {
    //   return res.status(401).json({ error: 'Unauthorized' });
    // }
    
    const userId = 1; // Temporarily hardcoded for testing
    
    if (req.method === 'GET') {
      const { id } = req.query;
      
      if (id) {
        // Get specific collection
        const result = await sql.query(`
          SELECT 
            c.id,
            c.name,
            c.description,
            c.is_public,
            c.created_at,
            c.updated_at,
            COUNT(cc.user_card_id) as card_count
          FROM collections c
          LEFT JOIN collection_cards cc ON c.id = cc.collection_id
          WHERE c.id = $1 AND c.user_id = $2
          GROUP BY c.id
        `, [id, userId]);
        
        if (result.rows.length === 0) {
          return res.status(404).json({ error: 'Collection not found' });
        }
        
        return res.status(200).json({
          success: true,
          collection: result.rows[0]
        });
      } else {
        // Get all collections
        const result = await sql.query(`
          SELECT 
            c.id,
            c.name,
            c.description,
            c.is_public,
            c.created_at,
            c.updated_at,
            COUNT(cc.user_card_id) as card_count
          FROM collections c
          LEFT JOIN collection_cards cc ON c.id = cc.collection_id
          WHERE c.user_id = $1
          GROUP BY c.id
          ORDER BY c.created_at DESC
        `, [userId]);
        
        return res.status(200).json({
          success: true,
          collections: result.rows
        });
      }
    }
    
    if (req.method === 'POST') {
      const { name, description = '', isPublic = false } = req.body;
      
      if (!name) {
        return res.status(400).json({ error: 'Collection name is required' });
      }
      
      const result = await sql.query(`
        INSERT INTO collections (user_id, name, description, is_public)
        VALUES ($1, $2, $3, $4)
        RETURNING *
      `, [userId, name, description, isPublic]);
      
      return res.status(201).json({
        success: true,
        message: 'Collection created',
        collection: result.rows[0]
      });
    }
    
    if (req.method === 'PUT') {
      const { id, name, description, isPublic } = req.body;
      
      if (!id) {
        return res.status(400).json({ error: 'Collection ID is required' });
      }
      
      const result = await sql.query(`
        UPDATE collections 
        SET name = COALESCE($1, name),
            description = COALESCE($2, description),
            is_public = COALESCE($3, is_public),
            updated_at = NOW()
        WHERE id = $4 AND user_id = $5
        RETURNING *
      `, [name, description, isPublic, id, userId]);
      
      if (result.rows.length === 0) {
        return res.status(404).json({ error: 'Collection not found' });
      }
      
      return res.status(200).json({
        success: true,
        message: 'Collection updated',
        collection: result.rows[0]
      });
    }
    
    if (req.method === 'DELETE') {
      const { id } = req.query;
      
      if (!id) {
        return res.status(400).json({ error: 'Collection ID is required' });
      }
      
      // Delete collection cards first
      await sql.query(`
        DELETE FROM collection_cards 
        WHERE collection_id = $1
      `, [id]);
      
      // Delete the collection
      const result = await sql.query(`
        DELETE FROM collections 
        WHERE id = $1 AND user_id = $2
        RETURNING *
      `, [id, userId]);
      
      if (result.rows.length === 0) {
        return res.status(404).json({ error: 'Collection not found' });
      }
      
      return res.status(200).json({
        success: true,
        message: 'Collection deleted'
      });
    }
    
  } catch (error) {
    console.error('❌ Error in collections API:', error);
    return res.status(500).json({
      error: 'Failed to process collections request',
      details: error.message
    });
  }
}