/**
 * The background script to handle url redirection.
 */

var storage = null;
var downloading = false;
var downloadTimer = null;
// 存储MIS的IP
var misHost="121.15.171.92";
// 请求映射表项时兴趣包使用的前缀
var misPrefix="/mis/resolve";
// 兴趣包前缀序号
var misPrefixNum=0;
// 兴趣包过期时间：默认两秒
var interestLifetimeMilliseconds=2000;
// 是否开启mis更新映射表
var misEnableState=true;
// 全局变量，用于设置是否刷新当前active的界面
// var myInterval=null;

// min协议的URI协议头
var minProtocolHeader="min/";
// 适配的其它浏览器默认协议：
// 插件将自动拦截该头部，以做协议转换
var httpProtocolHeader="http://";
var httpsProtocolHeader="https://";
// 适配的搜索引擎
var searchLibs=[
    // 百度
    "https://www.baidu.com",
    "http://www.baidu.com",
    // 谷歌
    "https://www.google.com",
    "http://www.google.com",
    // 搜狗
    "https://www.sogou.com",
    "http://www.sogou.com",
    // 360
    "https://www.so.com",
    "http://www.so.com",
    // bing
    "https://cn.bing.com",
    "http://cn.bing.com",
    // bing
    "https://www.bing.com",
    "http://www.bing.com"
];

// 获取兴趣包前缀
function getInterestPrefix() {
    misPrefixNum++;
    browser.storage.local.set({'misPrefixNum':misPrefixNum});
    return misPrefix+'/'+misPrefixNum;
}

// 加载mis的IP
function loadMisHost() {
    browser.storage.local.get('misHostIP',function (result) {
        if($.isEmptyObject(result)){
            // alert("hostIP: null");
            browser.storage.local.set({'misHostIP':misHost});
        }else{
            // alert("hostIP: "+result.misHostIP);
            misHost=result.misHostIP;
        }
    });
    browser.storage.local.get('misPrefix',function (result) {
        if($.isEmptyObject(result)){
            // alert("misPrefix: null");
            browser.storage.local.set({'misPrefix':misPrefix});
        }else{
            // alert("misPrefix: "+result.misPrefix);
            misPrefix=result.misPrefix;
        }
    });
    browser.storage.local.get('misPrefixNum',function (result) {
        if($.isEmptyObject(result)){
            // alert("misPrefix: null");
            browser.storage.local.set({'misPrefixNum':misPrefixNum});
        }else{
            // alert("misPrefix: "+result.misPrefix);
            misPrefixNum=result.misPrefixNum;
        }
    });
    browser.storage.local.get('misEnableState',function (result) {
        if($.isEmptyObject(result)){
            // alert("misPrefix: null");
            browser.storage.local.set({'misEnableState':misEnableState});
        }else{
            // alert("misPrefix: "+result.misPrefix);
            misEnableState=result.misEnableState;
            // alert("48641");
        }
    });
}

/* Reload callback */
function reload(result) {
    storage = new Storage();
    if (result && result.storage) {
        storage.fromObject(result.storage);
        // resetDownloadTimer();
    }
}

/* Auto reload */
browser.storage.onChanged.addListener(function (changes, area) {
    load("storage", reload);
    loadMisHost();
});


/* The first time of loading storage */
load("storage", reload);
loadMisHost();
// alert("成功加载mis的IP: "+misHost+"; misPrefix: "+misPrefix);

function getJsonString(u_identifier){
    var jsonObj={
        "Type":"user-act",
        "Command":"Resolve",
        "QueryCode":2,
        "U_identifier":u_identifier
    };
    // return jsonObj;
    return JSON.stringify(jsonObj);
}


function onTimeout(interest)
{
    console.log("time out...");
}

// 增加映射表项时，判断该表项是否重复
function addCustomRule(editingRule) {
    var flag=0;
    for (var i=0; i<storage.customRules.length; i++) {
        var rule = storage.customRules[i];
        if ((rule.origin === editingRule.origin)  && (rule.target === editingRule.target)) {
            flag=1;
        }
    }
    if(flag===0){
        storage.customRules.push(editingRule);
    }
}

// 刷新正在浏览的浏览器界面
function refreshActiveTab () {
    chrome.tabs.query({active: true}, function(tabs) {
        var tabIndex = tabs[0].index;
        chrome.tabs.query({}, function(tabs) {
            chrome.tabs.reload(tabs[tabIndex].id);
            // var o;
            // o.url="https://www.csdn.net/";
            // chrome.tabs.create(o,function () {
            //     console.log("test");
            // });
        })
    });
    console.log("refresh########");
}

function express(prefixUri) {
    // alert("成功加载mis的IP: "+misHost+"; misPrefix: "+misPrefix);
    // Connect to the forwarder with a WebSocket.
    var face = new Face({host: misHost});

    var name = new Name(getInterestPrefix());
    var jsonPrefix=getJsonString(prefixUri);

    var interest=new Interest(name);
    interest.setMustBeFresh(true);
    interest.setApplicationParameters(new Blob(jsonPrefix));
    interest.setInterestLifetimeMilliseconds(interestLifetimeMilliseconds);
    // alert("express Interest: "+jsonPrefix+" ; "+interest.name.toString());

    face.expressInterest(interest, function(interest,data){
        var targetJsonString=data.getContent().buf().toString('binary');
        // alert("targetJsonString: "+targetJsonString);
        var targetJson=JSON.parse(targetJsonString);
        // 将targetJson解析成targetUri
        var StatusCode=targetJson.StatusCode;
        var targetUri=targetJson.Message;
        if((StatusCode===200)&&(targetUri!=="")) {
            var editingRule = new Rule();
            editingRule.enable = true;
            editingRule.description = "initial based on MIS";
            editingRule.origin = prefixUri;
            editingRule.target = targetUri;
            editingRule.exclude = "";
            editingRule.example = "";
            editingRule.process = "";
            editingRule.methods = [];
            editingRule.types = [];
            // storage.customRules.push(editingRule);
            addCustomRule(editingRule);
            /* save */
            save({"storage": storage});
            load("storage", reload);
            // setTimeout(refreshActiveTab(),2000);
        }else{
            // mis没有该前缀对应的映射
        }
    }, onTimeout);
}

// /* Download online rules */
// function downloadOnlineURLs() {
//     /* Still downloading */
//     if (!storage.onlineURLs || storage.onlineURLs.length <=0 || downloading) {
//         return;
//     }
//     downloading = true;
//     var toDownload = [];    // URLs that need to be downloaded
//     for (var i = 0; i < storage.onlineURLs.length; i++) {
//         var onlineURL = storage.onlineURLs[i];
//         if (onlineURL.auto && onlineURL.enable && onlineURL.url !== "") {
//             toDownload.push(onlineURL.url);
//         }
//     }
//     if (toDownload.length === 0) {
//         sendMessage("downloaded");
//     }
//     var downloadErrors = [];
//     var parseErrors = [];
//     for (var i = 0; i<toDownload.length; i++) {
//         download(toDownload[i], function (url, content) {
//             toDownload.remove(url);
//             if (content) {
//                 try {
//                     var json;
//                     // content may be a string or json object
//                     if (typeof content === "string") {
//                         json = JSON.parse(content);
//                     } else {
//                         json = content;
//                     }
//                     json.url = url;
//                     json.enable = true;
//                     json.downloadAt = new Date();
//                     /* To compact with gooreplacer */
//                     /* version < 1.0, version >= 1.0 doesn't change */
//                     if (!json.version || json.version < "1.0") {
//                         var rules = [];
//                         for (var key in json.rules) {
//                             var rule = json.rules[key];
//                             rules.push({
//                                 origin: key,
//                                 target: rule.dstURL,
//                                 enable: rule.enable === undefined ? true : rule.enable,
//                                 kind: rule.kind
//                             });
//                         }
//                         json.rules = rules;
//                     }
//                     /* replace the onlineURL */
//                     for (var j = 0; j < storage.onlineURLs.length; j++){
//                         if (storage.onlineURLs[j].url == url){
//                             storage.onlineURLs[j] = new OnlineURL();
//                             storage.onlineURLs[j].fromObject(json);
//                             break;
//                         }
//                     }
//                 } catch (err) {
//                     parseErrors.push(url);
//                     console.error(err);
//                 }
//             }
//             else {
//                 downloadErrors.push(url);
//             }
//             if (toDownload.length <= 0) {
//                 downloading = false;
//                 sendMessage("downloaded");
//                 if (downloadErrors.length > 0) {
//                     sendMessage("downloadError", downloadErrors);
//                 }
//                 if (parseErrors.length > 0) {
//                     sendMessage("parseError", parseErrors);
//                 }
//                 storage.updatedAt = (new Date()).toISOString();
//                 save({"storage": storage});
//             }
//         });
//     }
// }
//
// /* Reset download timer to download online urls */
// /* Setup a listener if alarm api supported */
// if (browser.alarms) {
//     browser.alarms.onAlarm.addListener(function (alarm) {
//         if (alarm.name == "download") {
//             downloadOnlineURLs();
//         }
//     })
// }
//
// /* Reset the download timer */
// function resetDownloadTimer() {
//     var interval = 900;     // Default 15min
//     if (storage.updateInterval) {
//         interval = parseInt(storage.updateInterval);
//     }
//     /* If the browser support alarms api */
//     if (browser.alarms) {
//         browser.alarms.create("download", {
//             periodInMinutes: Math.ceil(interval / 60)
//         });
//     }
//     else {
//         /* With setInterval */
//         if (downloadTimer != null) {
//             clearInterval(downloadTimer);
//         }
//         interval = interval * 1000;     // In milli-seconds
//         downloadTimer = setInterval(function () {
//             if (storage.enable) {
//                 downloadOnlineURLs();
//             }
//         }, interval);
//     }
// }

/* Handle runtime messages */
// browser.runtime.onMessage.addListener(function (message, sender, sendResponse) {
//     if (message.method == "download" && !downloading) {
//         // downloadOnlineURLs();
//     }
//     else if (message.method == "isDownloading") {
//         // sendResponse(downloading);
//     }
//     else {
//         // console.error("Unknown method");
//     }
// });

function redirect(details) {
    if (storage.enable && details.url) {
        var newURL = storage.redirect(details.url, details.method, details.type);
        if (newURL){
            return {
                redirectUrl: newURL
            }
        }
    }
    return {};
}

// var _redirect_promise_supported = false;

// 对小于0的数取0
function getPositiveNum(num) {
    if(num>0){
        return num;
    }else{
        return 0;
    }
}

// 判断某个字符串是否是一个搜索url：搜索某个内容的URI
function isSearchUrl(urlString){
    var flag=0;
    for(var i=0;i<searchLibs.length;i++){
        if(urlString.indexOf(searchLibs[i])>=0){
            flag=1;
            break;
        }
    }
    var haveSearchString=getPositiveNum(urlString.indexOf("?wd="))
        +getPositiveNum(urlString.indexOf("&wd="))
        +getPositiveNum(urlString.indexOf("?q="))
        +getPositiveNum(urlString.indexOf("&q="))
        +getPositiveNum(urlString.indexOf("?query="))
        +getPositiveNum(urlString.indexOf("&query="));
    if((flag>0)&&(haveSearchString>0)){
        // alert("it is a searchUrl: "+urlString);
        return true;
    }else{
        return false;
    }
}

// 传入一个搜索uri，获取其中的搜索数值;
// 传入一个非搜索uri，返回空字符串
function getSearchContent(uriString) {
    if(!isSearchUrl(uriString)){
        return "";
    }
    var content="";
    if(uriString.indexOf("//www.baidu.com")>=0){
        // &wd=   [end] 或 &wd=   &
        var startIndex=getPositiveNum(uriString.indexOf("?wd="))
            +getPositiveNum(uriString.indexOf("&wd="))+4;
        var lastString=uriString.substring(startIndex);
        var endIndex=lastString.indexOf('&');
        if(endIndex>=0){
            content=lastString.substring(0,endIndex);
        }else{
            content=lastString;
        }
    }else if(uriString.indexOf("//www.google.com")>=0){
        //    ?q=   &
        var startIndex=getPositiveNum(uriString.indexOf("?q="))
            +getPositiveNum(uriString.indexOf("&q="))+3;
        var lastString=uriString.substring(startIndex);
        var endIndex=lastString.indexOf('&');
        if(endIndex>=0){
            content=lastString.substring(0,endIndex);
        }else{
            content=lastString;
        }
    }else if(uriString.indexOf("//www.sogou.com")>=0){
        // &query=   [end]
        var startIndex=getPositiveNum(uriString.indexOf("?query="))
            +getPositiveNum(uriString.indexOf("&query="))+7;
        var lastString=uriString.substring(startIndex);
        var endIndex=lastString.indexOf('&');
        if(endIndex>=0){
            content=lastString.substring(0,endIndex);
        }else{
            content=lastString;
        }
    }else if(uriString.indexOf("//www.so.com")>=0){
        // &q=   [end]
        var startIndex=getPositiveNum(uriString.indexOf("?q="))
            +getPositiveNum(uriString.indexOf("&q="))+3;
        var lastString=uriString.substring(startIndex);
        var endIndex=lastString.indexOf('&');
        if(endIndex>=0){
            content=lastString.substring(0,endIndex);
        }else{
            content=lastString;
        }
    }else if(uriString.indexOf("//cn.bing.com")>=0){
        //  ？q=   &
        var startIndex=getPositiveNum(uriString.indexOf("?q="))
            +getPositiveNum(uriString.indexOf("&q="))+3;
        var lastString=uriString.substring(startIndex);
        var endIndex=lastString.indexOf('&');
        if(endIndex>=0){
            content=lastString.substring(0,endIndex);
        }else{
            content=lastString;
        }
    }else if(uriString.indexOf("//www.bing.com")>=0){
        //  ？q=   &
        var startIndex=getPositiveNum(uriString.indexOf("?q="))
            +getPositiveNum(uriString.indexOf("&q="))+3;
        var lastString=uriString.substring(startIndex);
        var endIndex=lastString.indexOf('&');
        if(endIndex>=0){
            content=lastString.substring(0,endIndex);
        }else{
            content=lastString;
        }
    }else{}
    return decodeURIComponent(content);
}

// 模糊判断一个string是否是一个合法前缀/合法标识
function isRightfulPrefix(string){
    // 不能为空
    if(string===''){
        return false;
    }
    // 不能包含.
    if(string.indexOf('.')>=0){
        return false;
    }
    // 第一个字符必须是/
    var stringDecoded=decodeURIComponent(string);
    if(stringDecoded.indexOf('/')!==0){
        return false;
    }
    return true;
}

// 判断一个url是否是一个min协议的合法URI
function isRightfulMinURI(urlString){
    var urlStringDecoded=decodeURIComponent(urlString);
    // 长度要大于min协议头的长度
    if(urlStringDecoded.length<=minProtocolHeader.length){
        return false;
    }
    // 前几个字符必须是min协议头
    if(urlStringDecoded.indexOf(minProtocolHeader)!==0){
        return false;
    }
    // 协议头后面跟的是一个合法前缀/合法标识
    var prefix=urlStringDecoded.substring(minProtocolHeader.length);
    if(!isRightfulPrefix(prefix)){
        return false;
    }
    return true;
}

// 从一个合法minUri提取出前缀
function getPrefixFromMinURI(minURI){
    if(isRightfulMinURI(minURI)){
        var urlStringDecoded=decodeURIComponent(minURI);
        return urlStringDecoded.substring(minProtocolHeader.length);
    }else{
        return "";
    }
}

// 判断某个没使用url编码的string是否是映射表的一个表项
function isCustomRulesItemString(string) {
    // 遍历本地映射表
    var flag=0;
    for (var i=0; i<storage.customRules.length; i++) {
        var rule = storage.customRules[i];
        if (string===rule.origin) {
            flag=1;
            break;
        }
    }
    if(flag===0){
        // alert("it is not rules: "+string);
        return false;
    }else{
        // alert("it is rules: "+string);
        // console.log("it includes rules");
        return true;
    }
}

// 判断某个minUrl中的前缀是否是映射表的一个表项
function isCustomRulesItemMinURI(minURI) {
    // 如果不是min协议URI，返回false
    var prefix=getPrefixFromMinURI(minURI);
    if(prefix===""){
        return false;
    }
    // alert("是minuri");
    return isCustomRulesItemString(prefix);
}

// 根据传入的前缀/标识，更新本地映射表
function updateStorageBasedPrefix(prefix) {
    if(isRightfulPrefix(prefix)){
        express(prefix);
    }
}

// 根据传入的MINuri获取前缀，从而更新本地映射表
function updateStorageBasedMinURI(minURI) {
    // alert("begin upgrate");
    var prefix=getPrefixFromMinURI(minURI);
    if(!(prefix==="")){
        express(prefix);
    }
}

function sleep(numberMillis) {
    // alert("开始卡死cpu");
    var now = new Date();
    var exitTime = now.getTime() + numberMillis;
    while (true) {
        now = new Date();
        if (now.getTime() > exitTime)
            // alert("释放cpu");
            return true;
    }
}

// 将一个http或https请求的协议头去掉
function getCutHttpHeader(urlString){
    var urlString=decodeURIComponent(urlString);
    if(urlString.indexOf(httpProtocolHeader)===0){
        return urlString.substring(httpProtocolHeader.length);
    }else if(urlString.indexOf(httpsProtocolHeader)===0){
        return urlString.substring(httpsProtocolHeader.length);
    }else{
        return "";
    }
}

/* Handle redirect */
function handleRedirect(details) {
    // alert(details.url);
    // 判断url是否是一个搜索url，并根据搜索内容，判断是否直接命中本地映射表
    var searchContent=getSearchContent(details.url); // 已解码
    var minUri=getCutHttpHeader(details.url);  //已解码
    // alert("?s: "+searchContent+" ; ?u: "+minUri);
    // 如果该搜索内容或网址命中了缓存中的映射表前缀，则重定向
    if(isCustomRulesItemMinURI(searchContent)||isCustomRulesItemMinURI(minUri)){
        // alert("s: "+searchContent+" ; u: "+minUri);
        var prefixTemp="";
        if(searchContent!==""){
            prefixTemp=getPrefixFromMinURI(searchContent);
        }else{
            prefixTemp=getPrefixFromMinURI(minUri);
        }
        details.url = httpProtocolHeader+prefixTemp;  //如果映射表中加了http协议头，这里就不要加了
        return redirect(details);
    }
    // 如果没有命中缓存映射表，但是它是一个检索内容的网络请求
    if(searchContent!==""){
        // alert("检索内容了呢："+searchContent);
        if ((misEnableState === true)&&isRightfulMinURI(searchContent)) {
            details.url = httpProtocolHeader + searchContent;
            // 如果检索内容模糊判断是一个前缀，且mis同步是开着的
            // alert("成功加载mis的IP: "+misHost+"; misPrefix: "+misPrefix+", searchContent: "+searchContent);
            updateStorageBasedMinURI(searchContent);
            // alert("重定向url:"+details.url);
            return {
                redirectUrl: details.url
            };
        }else{
            // 如果是搜索了一个内容，该内容没命中缓存，
            // 且mis没开，或该内容不符合前缀标识符表示规则，
            // 则该内容一定是不会命中一个映射表项的
            return {};
        }
    }else{
    // 如果本地没有命中映射表，且没有检索内容，是一个正常的网页
        if((misEnableState===true)&&isRightfulMinURI(minUri)){
            updateStorageBasedMinURI(minUri);
        }
        return redirect(details);
    }
}

/* Since firefox 52, could return a promise to handles asynchronously */
// if (browser.runtime.getBrowserInfo) {
//     function checkRedirectPromise(info) {
//         if (info.name == "Firefox") {
//             if (parseInt(info.version.split('.')[0]) >= 52) {
//                 _redirect_promise_supported = true;
//             }
//         }
//     }
//     var gettingInfo = browser.runtime.getBrowserInfo();
//     gettingInfo.then(checkRedirectPromise)
// }

/* Add listener */
browser.webRequest.onBeforeRequest.addListener(
    handleRedirect,
    {urls: ["<all_urls>"]},
    ["blocking"]
);