<?php
/**
 * GeoGraSim — Thin Database Wrapper
 */

require_once __DIR__ . '/../config/db.php';

class Database {
    private PDO $pdo;
    private static ?Database $instance = null;

    private function __construct() {
        $this->pdo = getDB();
    }

    public static function get(): Database {
        if (self::$instance === null) {
            self::$instance = new Database();
        }
        return self::$instance;
    }

    public function query(string $sql, array $params = []): PDOStatement {
        $stmt = $this->pdo->prepare($sql);
        $stmt->execute($params);
        return $stmt;
    }

    public function fetchOne(string $sql, array $params = []): ?array {
        $stmt = $this->query($sql, $params);
        $row = $stmt->fetch();
        return $row ?: null;
    }

    public function fetchAll(string $sql, array $params = []): array {
        return $this->query($sql, $params)->fetchAll();
    }

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

    public function lastInsertId(): string {
        return $this->pdo->lastInsertId();
    }

    // ── Transaktionen (fuer Bulk-Operationen, z.B. Chargen-Vergabe) ──
    public function begin(): void    { $this->pdo->beginTransaction(); }
    public function commit(): void   { $this->pdo->commit(); }
    public function rollBack(): void { if ($this->pdo->inTransaction()) $this->pdo->rollBack(); }
    public function inTransaction(): bool { return $this->pdo->inTransaction(); }
}