<?php
require_once 'config.php';
require_once __DIR__ . '/error_config.php';
start_secure_session();
set_json_headers();

$method = $_SERVER['REQUEST_METHOD'];
$action = $_GET['action'] ?? '';

// =====================================================
// 로그인
// =====================================================
if ($method === 'POST' && $action === 'login') {
    $input = get_json_input();
    $password = $input['password'] ?? '';
    
    if (empty($password)) {
        json_response(['error' => '비밀번호를 입력하세요'], 400);
    }
    
    // 무차별 대입 방지 - 간단한 딜레이
    usleep(500000); // 0.5초
    
    if (ADMIN_PASSWORD_HASH === '') {
        json_response(['error' => 'Admin password is not configured'], 500);
    }

    if (password_verify($password, ADMIN_PASSWORD_HASH)) {
        // 세션 고정 공격 방지
        session_regenerate_id(true);
        $_SESSION['authenticated'] = true;
        $_SESSION['login_time'] = time();
        json_response(['success' => true, 'message' => '로그인 성공', 'csrf_token' => ensure_csrf_token()]);
    } else {
        json_response(['error' => '비밀번호가 일치하지 않습니다'], 401);
    }
}

// =====================================================
// 로그아웃
// =====================================================
if ($method === 'POST' && $action === 'logout') {
    require_auth();
    require_csrf();
    session_destroy();
    json_response(['success' => true]);
}

// =====================================================
// 인증 상태 확인
// =====================================================
if ($method === 'GET' && $action === 'check') {
    $authenticated = isset($_SESSION['authenticated']) && $_SESSION['authenticated'] === true;
    
    // 타임아웃 체크
    if ($authenticated && isset($_SESSION['login_time'])) {
        if ((time() - $_SESSION['login_time']) > SESSION_LIFETIME) {
            session_destroy();
            $authenticated = false;
        }
    }
    
    $response = ['authenticated' => $authenticated];
    if ($authenticated) {
        $response['csrf_token'] = ensure_csrf_token();
    }
    json_response($response);
}

json_response(['error' => 'Invalid action'], 400);