<?php

const ADMIN_USERNAME = 'admin';
const ADMIN_PASSWORD = 'karczma2026!';

function startAdminSession(): void
{
    if (session_status() === PHP_SESSION_NONE) {
        session_start();
    }
}

function isAdminLoggedIn(): bool
{
    startAdminSession();
    return !empty($_SESSION['staff_logged_in']) && $_SESSION['staff_logged_in'] === true;
}

function requireAdminAuth(bool $redirectToLogin = true): void
{
    if (isAdminLoggedIn()) {
        return;
    }

    if ($redirectToLogin) {
        header('Location: login.php');
        exit;
    }

    http_response_code(401);
    header('Content-Type: application/json; charset=utf-8');
    echo json_encode([
        'status' => 'error',
        'message' => 'Unauthorized',
    ], JSON_UNESCAPED_UNICODE);
    exit;
}

function attemptAdminLogin(string $username, string $password): bool
{
    startAdminSession();

    $userOk = hash_equals(ADMIN_USERNAME, $username);
    $passOk = strlen($password) === strlen(ADMIN_PASSWORD)
        && hash_equals(ADMIN_PASSWORD, $password);

    if ($userOk && $passOk) {
        session_regenerate_id(true);
        $_SESSION['staff_logged_in'] = true;
        $_SESSION['staff_username'] = ADMIN_USERNAME;
        return true;
    }

    return false;
}

function adminLogout(): void
{
    startAdminSession();
    $_SESSION = [];
    if (ini_get('session.use_cookies')) {
        $params = session_get_cookie_params();
        setcookie(session_name(), '', time() - 42000, $params['path'], $params['domain'], $params['secure'], $params['httponly']);
    }
    session_destroy();
}