// ==UserScript==
// @name         chaoxing-download
// @namespace    http://tampermonkey.net/
// @version      0.4
// @description  超星慕课资源下载提取
// @author       NL
// @match        https://*.chaoxing.com/mycourse/studentstudy?*
// @grant        none
// @downloadURL none
// ==/UserScript==
function setDl(){
    console.log('set dl was called')
var iframes = document.getElementById("iframe").contentWindow.document.querySelectorAll("iframe")
for(let i=0;i<iframes.length;i++){
    if(iframes[i].getAttribute("objectId")==null){
        continue
    }
    var url = "http://d0.ananas.chaoxing.com/download/"+iframes[i].getAttribute("objectId")
    var a = document.createElement('a');
    a.setAttribute('href', url);
    a.setAttribute('class','downloadable-content')
    a.setAttribute('target','_blank')
    var textnode=document.createTextNode("↓下载课件")
    a.appendChild(textnode)
    if(iframes[i].parentElement.getElementsByClassName('downloadable-content').length==0){

        iframes[i].parentNode.insertBefore(a,iframes[i])
        console.log("inserted"+i)
    } else {//console.log('inserted already')
           //console.log(iframes[i].parentElement.getElementsByClassName('downloadable-content'))
    }
}
}
(function() {
    'use strict';
    var old_text = "";
    console.log("downloader script running:");
    setTimeout(function (){
        old_text = document.getElementsByTagName("h1")[0].innerHTML;
        document.getElementsByTagName("h1")[0].innerHTML += "--->Waiting";
    },500);
    setTimeout(function(){

        var parent_node = document.getElementsByClassName("goback")[0]
        var bt = document.createElement("button")
        bt.innerHTML = "刷新下载"
        bt.onclick = function(){setDl()}
        parent_node.appendChild(bt)
    },500);
    setTimeout(function(){
        document.getElementsByTagName("h1")[0].innerHTML = old_text
        //setDl()
        setInterval(setDl,2000)
    },1500);
    // Your code here...
})();