<?php

declare(strict_types=1);

header('Content-Type: application/json; charset=utf-8');

require_once __DIR__ . '/menu_helpers.php';

if ($_SERVER['REQUEST_METHOD'] !== 'GET') {
    http_response_code(405);
    echo json_encode([
        'status' => 'error',
        'message' => 'Method not allowed',
    ], JSON_UNESCAPED_UNICODE);
    exit;
}

$config = require __DIR__ . '/../config/menu.php';
$languages = is_array($config['languages'] ?? null) ? $config['languages'] : [];
$lang = strtolower(trim((string) ($_GET['lang'] ?? 'pl')));

if ($lang === '' || !isset($languages[$lang])) {
    http_response_code(422);
    echo json_encode([
        'status' => 'error',
        'message' => 'Unsupported language',
        'allowed' => array_keys($languages),
    ], JSON_UNESCAPED_UNICODE);
    exit;
}

$langConfig = $languages[$lang];
$source = (string) ($langConfig['source'] ?? 'upstream');
$ttl = max(60, (int) ($config['ttl_seconds'] ?? 86400));
$timeout = max(3, (int) ($config['timeout_seconds'] ?? 12));
$cacheFile = menuCachePath($lang);

$cached = readMenuCache($cacheFile);
$now = time();
$cachedAtTs = 0;
if ($cached && !empty($cached['cachedAt'])) {
    $cachedAtTs = strtotime((string) $cached['cachedAt']) ?: 0;
}
$isFresh = $cached && $cachedAtTs > 0 && ($now - $cachedAtTs) < $ttl;

if ($isFresh) {
    echo json_encode($cached, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
    exit;
}

if ($source === 'ai') {
    if ($cached) {
        // Stary AI-cache jest OK dłużej niż TTL — cron i tak odświeża raz/dzień.
        echo json_encode($cached, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
        exit;
    }

    $from = strtolower((string) ($langConfig['from'] ?? 'pl'));
    $fallback = readMenuCache(menuCachePath($from));
    if ($fallback) {
        $fallback['lang'] = $lang;
        $fallback['source'] = 'ai_fallback_pl';
        echo json_encode($fallback, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
        exit;
    }

    http_response_code(503);
    echo json_encode([
        'status' => 'error',
        'message' => 'AI menu not available yet — run scripts/refresh_menu_cache.php',
        'lang' => $lang,
    ], JSON_UNESCAPED_UNICODE);
    exit;
}

$base = rtrim((string) ($config['upstream_base'] ?? ''), '/');
$url = $base . '/' . rawurlencode($lang);
$raw = fetchUpstreamMenu($url, $timeout);

if ($raw === null) {
    if ($cached) {
        echo json_encode($cached, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
        exit;
    }
    http_response_code(502);
    echo json_encode([
        'status' => 'error',
        'message' => 'Failed to fetch menu',
        'lang' => $lang,
    ], JSON_UNESCAPED_UNICODE);
    exit;
}

$mapped = mapUpstreamMenu($raw, $lang, 'upstream');
writeMenuCache($cacheFile, $mapped);

echo json_encode($mapped, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);