<?php

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

    $cfg = require __DIR__ . '/../../config.php';
    $dsn = "mysql:host={$cfg['db_host']};dbname={$cfg['db_name']};charset=utf8mb4";
    $pdo = new PDO($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,
    ]);
    return $pdo;
}

function cfg(string $key, string $default = ''): string {
    static $cache = [];
    if (!isset($cache[$key])) {
        $st = db()->prepare('SELECT value FROM config WHERE `key` = ?');
        $st->execute([$key]);
        $row = $st->fetch();
        $cache[$key] = $row ? $row['value'] : $default;
    }
    return $cache[$key];
}

function cfg_set(string $key, string $value): void {
    db()->prepare('INSERT INTO config (`key`, value) VALUES (?, ?) ON DUPLICATE KEY UPDATE value = ?')
        ->execute([$key, $value, $value]);
}