<?php
// Database configuration using environment variables with fallbacks
define('DB_HOST', getenv('DB_HOST') ?: '127.0.0.1');
define('DB_NAME', getenv('DB_NAME') ?: 'app_38314');
define('DB_USER', getenv('DB_USER') ?: 'app_38314');
define('DB_PASS', getenv('DB_PASS') ?: '5cd20aed-3235-4569-bf9a-d9a4b56ea0a4');

function db() {
  static $pdo;
  if (!$pdo) {
    try {
      $pdo = new PDO('mysql:host='.DB_HOST.';dbname='.DB_NAME.';charset=utf8mb4', DB_USER, DB_PASS, [
        PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
        PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
      ]);
    } catch (PDOException $e) {
      error_log("Database connection failed: " . $e->getMessage());
      return null;
    }
  }
  return $pdo;
}