db.php

<?php

function get_config(): array
{
    static $config = null;
    if ($config === null) {
        $config = require __DIR__ . '/../config.php';
    }
    return $config;
}

function db(): PDO
{
    static $pdo = null;
    if ($pdo !== null) {
        return $pdo;
    }

    $cfg = get_config();
    $dsn = sprintf(
        'mysql:host=%s;port=%d;dbname=%s;charset=utf8mb4',
        $cfg['db_host'],
        $cfg['db_port'],
        $cfg['db_name']
    );

    try {
        $pdo = new PDO($dsn, $cfg['db_user'], $cfg['db_pass'], [
            PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
            PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
            PDO::ATTR_EMULATE_PREPARES => false,
        ]);
    } catch (PDOException $e) {
        http_response_code(500);
        header('Content-Type: application/json');
        echo json_encode([
            'message' => 'Database connection failed. Run setup.php first and verify config.php.',
            'error' => $e->getMessage(),
        ]);
        exit;
    }

    return $pdo;
}