import { NextRequest, NextResponse } from 'next/server';
import { Pool } from 'pg';

const pool = new Pool({
  connectionString: process.env.DATABASE_URL,
  ssl: process.env.NODE_ENV === 'production' ? { rejectUnauthorized: false } : false,
});

export default async function handler(req: NextRequest) {
  if (req.method !== 'GET') {
    return new NextResponse(JSON.stringify({ error: 'Method not allowed' }), {
      status: 405,
      headers: { 'Content-Type': 'application/json' },
    });
  }

  const client = await pool.connect();
  
  try {
    console.log('Testing database connection...');

    // Test basic connection
    const result = await client.query('SELECT NOW() as current_time, version() as postgres_version');
    
    // Check if users table exists
    const tableCheck = await client.query(`
      SELECT EXISTS (
        SELECT FROM information_schema.tables 
        WHERE table_schema = 'public' 
        AND table_name = 'users'
      ) as users_table_exists;
    `);

    // Check if cards table exists
    const cardsCheck = await client.query(`
      SELECT EXISTS (
        SELECT FROM information_schema.tables 
        WHERE table_schema = 'public' 
        AND table_name = 'cards'
      ) as cards_table_exists;
    `);

    // Get table counts
    let userCount = 0;
    let cardCount = 0;

    if (tableCheck.rows[0].users_table_exists) {
      const userCountResult = await client.query('SELECT COUNT(*) as count FROM users');
      userCount = parseInt(userCountResult.rows[0].count);
    }

    if (cardsCheck.rows[0].cards_table_exists) {
      const cardCountResult = await client.query('SELECT COUNT(*) as count FROM cards');
      cardCount = parseInt(cardCountResult.rows[0].count);
    }

    return new NextResponse(JSON.stringify({
      success: true,
      message: 'Database connection successful',
      database_info: {
        current_time: result.rows[0].current_time,
        postgres_version: result.rows[0].postgres_version,
        users_table_exists: tableCheck.rows[0].users_table_exists,
        cards_table_exists: cardsCheck.rows[0].cards_table_exists,
        user_count: userCount,
        card_count: cardCount
      }
    }), {
      status: 200,
      headers: { 'Content-Type': 'application/json' },
    });

  } catch (error) {
    console.error('Database connection failed:', error);
    return new NextResponse(JSON.stringify({ 
      success: false,
      error: 'Database connection failed',
      details: (error as Error).message
    }), {
      status: 500,
      headers: { 'Content-Type': 'application/json' },
    });
  } finally {
    client.release();
  }
}