import { sql } from '@vercel/postgres';
import { getUserFromRequest } from '../../../lib/permission-middleware';
import { checkImportRateLimit } from '../../../lib/rate-limit.js';

// Helper function to delay execution
const delay = (ms) => new Promise(resolve => setTimeout(resolve, ms));

// Helper function to fetch with retry logic
async function fetchWithRetry(url, maxRetries = 3, delayMs = 2000) {
  for (let attempt = 1; attempt <= maxRetries; attempt++) {
    try {
      const response = await fetch(url, {
        headers: {
          'User-Agent': 'TCG-Vault/1.0',
          'Accept': 'application/json'
        },
        timeout: 30000 // 30 second timeout
      });
      
      if (response.ok) {
        return response;
      }
      
      // If it's a 404, don't retry
      if (response.status === 404) {
        throw new Error(`Set not found: ${response.status}`);
      }
      
      // If it's a 504 or 503, wait longer before retry
      if (response.status === 504 || response.status === 503) {
        console.log(`Attempt ${attempt}: Got ${response.status}, waiting ${delayMs * attempt}ms before retry...`);
        await delay(delayMs * attempt);
        continue;
      }
      
      throw new Error(`Pokemon TCG API error: ${response.status}`);
    } catch (error) {
      if (attempt === maxRetries) {
        throw error;
      }
      console.log(`Attempt ${attempt} failed:`, error.message);
      await delay(delayMs * attempt);
    }
  }
}

export default async function handler(req, res) {
  if (req.method !== 'POST') {
    return res.status(405).json({ error: 'Method not allowed' });
  }

  const user = await getUserFromRequest(req);
  if (!user) {
    return res.status(401).json({ error: 'Authentication required' });
  }
  if (user.role !== 'admin') {
    return res.status(403).json({ error: 'Admin access required' });
  }

  const { allowed, reset } = await checkImportRateLimit(req, user.userId);
  if (!allowed) {
    res.setHeader('Retry-After', Math.ceil((reset - Date.now()) / 1000));
    return res.status(429).json({ error: 'Too many attempts. Try again later.' });
  }

  try {
    const { setCode } = req.body;
    
    if (!setCode) {
      return res.status(400).json({ error: 'Set code is required' });
    }

    console.log(`Starting import for Pokemon set: ${setCode}`);

    // Fetch cards from Pokemon TCG API with retry logic
    const response = await fetchWithRetry(`https://api.pokemontcg.io/v2/cards?q=set.id:${setCode}&pageSize=250`);
    
    const data = await response.json();
    const cards = data.data || [];

    if (cards.length === 0) {
      return res.status(200).json({
        success: true,
        message: `No cards found for set ${setCode}`,
        imported: 0,
        skipped: 0,
        total: 0
      });
    }

    console.log(`Found ${cards.length} cards for set ${setCode}`);

    let importedCount = 0;
    let skippedCount = 0;

    for (const card of cards) {
      try {
        // Check if card already exists
        const existingCard = await sql`
          SELECT id FROM cards WHERE scryfall_id = ${card.id}
        `;

        if (existingCard.rows.length > 0) {
          skippedCount++;
          continue;
        }

        // Extract price data from TCGPlayer
        let currentPrice = null;
        if (card.tcgplayer?.prices?.normal?.market) {
          currentPrice = parseFloat(card.tcgplayer.prices.normal.market);
        } else if (card.tcgplayer?.prices?.holofoil?.market) {
          currentPrice = parseFloat(card.tcgplayer.prices.holofoil.market);
        }

        // Determine rarity
        let rarity = card.rarity || 'Unknown';
        if (rarity.includes('Holo')) {
          rarity = 'Holographic';
        } else if (rarity.includes('Secret')) {
          rarity = 'Secret Rare';
        } else if (rarity.includes('Ultra')) {
          rarity = 'Ultra Rare';
        }

        // Insert card into database
        await sql`
          INSERT INTO cards (
            name, set_name, set_code, card_number, rarity, game,
            mana_cost, cmc, card_type, colors, oracle_text,
            power, toughness, image_url, stock_image_url,
            current_price, market_price, scryfall_id, verified
          ) VALUES (
            ${card.name}, ${card.set.name}, ${card.set.id}, ${card.number},
            ${rarity}, 'Pokemon', null, null, ${card.supertype || 'Pokemon'},
            ${JSON.stringify(card.types || [])}, ${card.flavorText || null},
            ${card.attacks?.[0]?.damage || null}, null,
            ${card.images?.small || null}, ${card.images?.large || null},
            ${currentPrice}, null, ${card.id}, true
          )
        `;

        importedCount++;
      } catch (error) {
        console.error(`Error importing card ${card.name}:`, error);
        skippedCount++;
      }
    }

    console.log(`Import completed for set ${setCode}: ${importedCount} imported, ${skippedCount} skipped`);

    res.status(200).json({
      success: true,
      message: `Import completed for set ${setCode}`,
      imported: importedCount,
      skipped: skippedCount,
      total: cards.length
    });

  } catch (error) {
    console.error('Card import error:', error);
    res.status(500).json({ 
      error: 'Import failed', 
      details: error.message 
    });
  }
}