import { Pool } from 'pg'

let pool: Pool | null = null

/**
 * Get development database connection pool (singleton)
 * Reads configuration from environment variables:
 * - DB_HOST (default: localhost)
 * - DB_PORT (default: 5432)
 * - DB_NAME
 * - DB_USER
 * - DB_PASSWORD
 */
export function getDevDbPool(): Pool {
  if (!pool) {
    pool = new Pool({
      host: process.env.DB_HOST || 'localhost',
      port: parseInt(process.env.DB_PORT || '5432', 10),
      database: process.env.DB_NAME,
      user: process.env.DB_USER,
      password: process.env.DB_PASSWORD,
      max: 10,
      idleTimeoutMillis: 30_000,
      connectionTimeoutMillis: 5_000,
    })

    pool.on('error', (err) => {
      console.error('[stago-dev-db] Pool error:', err.message)
    })
  }
  return pool
}

/**
 * Close database connection pool
 */
export async function closeDevDbPool(): Promise<void> {
  if (pool) {
    await pool.end()
    pool = null
  }
}