<?php
class JarvisDB {
    private static ?PDO $pdo = null;

    public static function get(): PDO {
        if (self::$pdo === null) {
            self::$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,
                 PDO::ATTR_EMULATE_PREPARES => false]
            );
        }
        return self::$pdo;
    }

    public static function query(string $sql, array $params = []): array {
        $stmt = self::get()->prepare($sql);
        $stmt->execute($params);
        return $stmt->fetchAll();
    }

    public static function execute(string $sql, array $params = []): int {
        $stmt = self::get()->prepare($sql);
        $stmt->execute($params);
        return $stmt->rowCount();
    }

    public static function single(string $sql, array $params = []): ?array {
        $rows = self::query($sql, $params);
        return $rows[0] ?? null;
    }

    public static function insert(string $sql, array $params = []): int {
        $stmt = self::get()->prepare($sql);
        $stmt->execute($params);
        return (int)self::get()->lastInsertId();
    }
}