window.beforeBoot = function () {
    cc.log("游戏正在启动中.")
    if (window.remoteUrl) {
        const settings = window._CCSettings;
        settings.server = window.remoteUrl;
        cc.log("远程资源地址:", settings.server);
    }
    let url = window.updateUrl || false;
    if (!url) {
        cc.log("未配置版本更新地址,跳过更新.")
        window.boot();
        return;
    }
    url += `?_t=${Math.random()}`;
    cc.log("请求更新地址:", url);

    get(url, function (err, asset) {
        cc.log("请求更新信息:", url, err && err.toLocaleString(), JSON.stringify(asset));
        if (err || !asset) {
            window.boot();
            return;
        }
        window.mergeVersion(asset);
        window.boot();
        cc.log("游戏已启动.");
    });
};
window.mergeVersion = function (updateInfo) {
    const currentVer = cc.sys.localStorage.getItem("currentVer");
    let isFirstRun = false;
    let newVerFlag = false;
    if (!currentVer) {
        isFirstRun = true;
        cc.log("当前为首次运行");
    } else {
        const oldVerInfo = JSON.parse(currentVer);
        if (oldVerInfo && oldVerInfo.versionCode != updateInfo.versionCode) {
            newVerFlag = true;
            cc.log("发现新版本信息:", updateInfo.versionCode, oldVerInfo.versionCode);
        }
    }
    const settings = window._CCSettings;
    if (updateInfo.server) {
        settings.server = updateInfo.server;
        cc.log("更新远程资源地址:", updateInfo.server);
    }
    const bundleVers = updateInfo.bundles
    if (bundleVers) {
        let changed = false;
        for (let b in bundleVers) {
            if (bundleVers[b] != settings.bundleVers[b]) {
                // 配置中的bundleVer版本不一致,则添加到remote列表中去,以供远程加载.
                if (settings.remoteBundles.indexOf(b) < 0) {
                    settings.remoteBundles.push(b);
                }
                changed = true;
                cc.log("发现更新Bundle:", b);
            }
        }
        settings.bundleVers = bundleVers;
        // 如果首次运行,但检测版本有差异,则标记有更新.
        if (isFirstRun && changed) {
            newVerFlag = true;
            cc.log("标记为新版本.");
        }
    }
    cc.sys.localStorage.setItem('newVerFlag', newVerFlag ? 1 : 0);
    cc.sys.localStorage.setItem('firstRunFlag', isFirstRun ? 1 : 0);
    cc.sys.localStorage.setItem('currentVer', JSON.stringify(updateInfo));
}

// ajax 请求.
function get(url, cb) {
    const ajax = new XMLHttpRequest();
    ajax.open("get", url, true);
    ajax.setRequestHeader("Content-Type", "application/json;charset=utf-8");
    ajax.onreadystatechange = function () {
        if (ajax.readyState == 4) {
            if (ajax.status == 200) {
                var response = JSON.parse(ajax.responseText)
                cb && cb(null, response);
                return;
            } else {
                cb && cb("request error!");
            }
        }
    }
    ajax.send(null);
}