// lib/db.ts
// Database connection pool - reuses connections efficiently

import { Pool } from 'pg';

// Singleton pattern - only create one pool for the entire app
let pool: Pool | null = null;

export function getPool(): Pool {
  if (!pool) {
    pool = new Pool({
      host: process.env.DB_HOST || 'localhost',
      port: parseInt(process.env.DB_PORT || '5432'),
      database: process.env.DB_NAME || 'openwheels',
      user: process.env.DB_USER || 'postgres',
      password: process.env.DB_PASSWORD,
      max: 20, // Maximum number of connections
      idleTimeoutMillis: 30000,
      connectionTimeoutMillis: 2000,
    });

    // Log pool errors
    pool.on('error', (err) => {
      console.error('Unexpected database error:', err);
    });
  }

  return pool;
}

// Helper function for queries - handles errors nicely
export async function query<T = any>(
  text: string,
  params?: any[]
): Promise<T[]> {
  const pool = getPool();
  try {
    const result = await pool.query(text, params);
    return result.rows;
  } catch (error) {
    console.error('Database query error:', error);
    throw error;
  }
}

// Helper for single row queries
export async function queryOne<T = any>(
  text: string,
  params?: any[]
): Promise<T | null> {
  const rows = await query<T>(text, params);
  return rows.length > 0 ? rows[0] : null;
}

// Graceful shutdown
export async function closePool(): Promise<void> {
  if (pool) {
    await pool.end();
    pool = null;
  }
}