(function() {
    var CHECK_INTERVAL = 60000; // 每60秒检查一次
    var STORAGE_KEY = 'app_version_cache';

    function getStoredVersion() {
        try { return localStorage.getItem(STORAGE_KEY) || ''; } catch(e) { return ''; }
    }

    function setStoredVersion(v) {
        try { localStorage.setItem(STORAGE_KEY, v); } catch(e) {}
    }

    function checkVersion() {
        var prefix = (typeof SITE_PREFIX !== 'undefined' && SITE_PREFIX) ? SITE_PREFIX : '';
        fetch(prefix + '/api/version.php?_=' + Date.now(), { cache: 'no-store' })
            .then(function(r) { return r.json(); })
            .then(function(d) {
                if (!d.success) return;
                var serverVersion = d.version;
                var localVersion = getStoredVersion();
                if (!localVersion) {
                    setStoredVersion(serverVersion);
                    return;
                }
                if (localVersion !== serverVersion) {
                    setStoredVersion(serverVersion);
                    // 清除缓存并强制刷新获取最新资源
                    var url = window.location.href.replace(/[?&]_cv=\d+/, '');
                    var sep = url.indexOf('?') > -1 ? '&' : '?';
                    window.location.href = url + sep + '_cv=' + Date.now();
                }
            })
            .catch(function() {});
    }

    if (document.readyState === 'loading') {
        document.addEventListener('DOMContentLoaded', function() {
            checkVersion();
            setInterval(checkVersion, CHECK_INTERVAL);
        });
    } else {
        checkVersion();
        setInterval(checkVersion, CHECK_INTERVAL);
    }
})();