// ==UserScript==
// @name         央视网视频下载
// @description  Download videos from cctv.com with one click
// @namespace    https://iteay.top/
// @version      1.1
// @author       BlackTeay
// @match        https://*.cctv.com/*
// @updateURL    https://git.jlntv.work/blackteay/tampermonkey-script/raw/branch/master/Download_CCTV_Video.js
// @downloadURL  https://git.jlntv.work/blackteay/tampermonkey-script/raw/branch/master/Download_CCTV_Video.js
// @require      http://libs.baidu.com/jquery/2.0.0/jquery.min.js
// @require      https://cdn.bootcdn.net/ajax/libs/downloadjs/1.4.8/download.min.js
// @grant        GM_xmlhttpRequest
// @grant        GM_openInTab
// @license      MIT
// ==/UserScript==
(function () {
    function findVideoEle(src) {

        let videoJQ = $("#video");

        // 向视频旁边添加【下载】按钮
        appendDownloadEle(videoJQ, src);

    }

    /**
     * 向视频上边添加【下载】按钮
     */
    function appendDownloadEle(videoJQ, videoSrc) {
        let downloadIdAttrName = videoJQ.attr("id") + "_download";
        console.log(downloadIdAttrName)
        if ($("#" + downloadIdAttrName).length <= 0) {
            // 【下载】按钮
            let downloadJQ = $("<a>下载视频</a>");
            downloadJQ.css({
                'background-color': 'rgba(255,130,0, 1)',
                "color": "#fff",
                'font-size': '15px',
                'cursor': 'pointer',
                "border-radius": "5px",
                "padding": "5px 10px",
                "display":"inline-block",
                "margin-top":"1rem",
                "margin-left":"0.5rem"
            });
            downloadJQ.attr("id", downloadIdAttrName);
            downloadJQ.attr("href", videoSrc);
            downloadJQ.attr("target", "_balnk");
            downloadJQ.attr("download","true")
            videoJQ.parent().after(downloadJQ);
            // console.log(videoJQ.attr("id") +" 添加下载按钮：" + downloadIdAttrName +", src=" + videoJQ.attr("src"));

            // 为下载按钮绑定单击事件下载视频
            downloadJQ.on("click", function (event) {
                // console.log("下载视频：" + $(this).attr("id") + ", href=" +  $(this).attr("href"));
                // 阻止 a 标签默认行为
                event.preventDefault();
                if ($(this).attr("href")) {
                    // 下载视频
                    download($(this).attr("href"));
                    // 打开一个新的标签页面: 新标签页获取页面焦点,新标签页面关闭后，焦点重新回到源页面
                    GM_openInTab($(this).attr("href"), { active: true, setParent: true });

                }
            });
        } else {
            // console.log(videoJQ.attr("id") +" 已存在下载按钮：" + downloadIdAttrName + ", src=" + videoJQ.attr("src"));
        }
    }
    console.log('加载脚本');

    /**
     * 拦截并修改ajax请求
     */
    window.beforeXMLHttpRequestOpen = function (xhr, options) {
        //console.log('before open', xhr);
        // 修改url
        //options.url = options.url.replace('wd=123', 'wd=456');
        // 修改method
        // options.method = 'POST';
    };
    /**
     * 拦截并修改ajax请求
     */
    window.beforeXMLHttpRequestSend = function (xhr, body) {
        //console.log('before send', xhr);

        xhr.onload = () => {
            if (xhr.status < 200 || xhr.status >= 300) {//非2xx区间状态值走失败
                console.log(xhr.statusText)
            }

            var url = new URL(xhr.responseURL)
            if (url.pathname == '/api/getHttpVideoInfo.do') {
                var result=JSON.parse(xhr.response);
                var videoURL=result.video.chapters4[0]["url"];
                console.log(videoURL);
                findVideoEle(videoURL);
            }

        }
        // 修改请求头
        //xhr.setRequestHeader('key1', 'value1');
    };

    /**
     * 重写open方法
     * https://developer.mozilla.org/zh-CN/docs/Web/API/XMLHttpRequest/open
     */
    XMLHttpRequest.prototype.myOpen = XMLHttpRequest.prototype.open;
    XMLHttpRequest.prototype.open = function (method, url, async) {
        // 用对象便于修改参数
        var options = {
            method: method,
            url: url,
            async: async,
        };
        if ('function' === typeof window.beforeXMLHttpRequestOpen) {
            window.beforeXMLHttpRequestOpen(this, options);
        }
        this.myOpen(options.method, options.url, options.async);
    };

    /**
     * 重写send方法
     * https://developer.mozilla.org/zh-CN/docs/Web/API/XMLHttpRequest/send
     */
    XMLHttpRequest.prototype.mySend = XMLHttpRequest.prototype.send;
    XMLHttpRequest.prototype.send = function (body) {
        if ('function' === typeof window.beforeXMLHttpRequestSend) {
            window.beforeXMLHttpRequestSend(this, body);
        }
        this.mySend(body);
    };

})();