<?php
require_once __DIR__ . '/../../includes/config.php';

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

    public static function get(): PDO {
        if (self::$pdo === null) {
            $dsn = 'mysql:host=' . DB_HOST . ';dbname=' . DB_NAME . ';charset=utf8mb4';
            self::$pdo = new PDO($dsn, DB_USER, DB_PASS, [
                PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
                PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
                PDO::ATTR_EMULATE_PREPARES => false,
            ]);
        }
        return self::$pdo;
    }

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

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

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

    public function insert(string $table, array $data) {
        $columns = implode(', ', array_keys($data));
        $placeholders = ':' . implode(', :', array_keys($data));
        $this->query("INSERT INTO {$table} ({$columns}) VALUES ({$placeholders})", $data);
        return self::get()->lastInsertId();
    }

    public function update(string $table, array $data, string $where, array $whereParams = []) {
        $set = [];
        foreach (array_keys($data) as $column) {
            $set[] = "{$column} = :{$column}";
        }
        $sql = "UPDATE {$table} SET " . implode(', ', $set) . " WHERE {$where}";
        return $this->query($sql, array_merge($data, $whereParams))->rowCount();
    }
}

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