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

export default async function handler(req, res) {
  try {
    const user = await getUserFromRequest(req);
    if (!user) {
      return res.status(401).json({ error: 'Authentication required' });
    }

    const { id: deckId } = req.query;

    if (req.method === 'GET') {
      // Get deck details with cards
      const deckResult = await sql`
        SELECT d.*, u.username as creator_username
        FROM decks d
        JOIN users u ON d.user_id = u.id
        WHERE d.id = ${deckId} AND (d.user_id = ${user.userId} OR d.is_public = true)
      `;

      if (deckResult.rows.length === 0) {
        return res.status(404).json({ error: 'Deck not found or access denied' });
      }

      const deck = deckResult.rows[0];

      // Get deck cards with details
      const cardsResult = await sql`
        SELECT dc.*, c.name, c.set_name, c.rarity, c.mana_cost, c.cmc, 
               c.card_type, c.colors, c.image_url, c.oracle_text
        FROM deck_cards dc
        JOIN cards c ON dc.card_id = c.id
        WHERE dc.deck_id = ${deckId}
        ORDER BY c.name ASC
      `;

      deck.cards = cardsResult.rows;
      deck.card_count = cardsResult.rows.reduce((sum, card) => sum + card.quantity, 0);

      return res.status(200).json(deck);

    } else if (req.method === 'PUT') {
      // Update deck (only owner can update)
      const deckResult = await sql`
        SELECT * FROM decks WHERE id = ${deckId} AND user_id = ${user.userId}
      `;

      if (deckResult.rows.length === 0) {
        return res.status(404).json({ error: 'Deck not found or access denied' });
      }

      const { name, description, format, is_public, commander_id } = req.body;

      const updatedDeck = await sql`
        UPDATE decks 
        SET name = ${name}, description = ${description}, format = ${format}, 
            is_public = ${is_public}, commander_id = ${commander_id}, updated_at = CURRENT_TIMESTAMP
        WHERE id = ${deckId} AND user_id = ${user.userId}
        RETURNING *
      `;

      return res.status(200).json(updatedDeck.rows[0]);

    } else if (req.method === 'DELETE') {
      // Delete deck (only owner can delete)
      const deckResult = await sql`
        SELECT * FROM decks WHERE id = ${deckId} AND user_id = ${user.userId}
      `;

      if (deckResult.rows.length === 0) {
        return res.status(404).json({ error: 'Deck not found or access denied' });
      }

      // Delete deck cards first (foreign key constraint)
      await sql`DELETE FROM deck_cards WHERE deck_id = ${deckId}`;
      
      // Delete deck
      await sql`DELETE FROM decks WHERE id = ${deckId} AND user_id = ${user.userId}`;

      return res.status(200).json({ message: 'Deck deleted successfully' });

    } else {
      return res.status(405).json({ error: 'Method not allowed' });
    }

  } catch (error) {
    console.error('Error in deck API:', error);
    return res.status(500).json({ error: 'Internal server error' });
  }
}