// ==UserScript==
// @name         国家开放大学课程视频后台播放
// @namespace    http://tampermonkey.net/
// @version      1.1
// @description  提升学习效率
// @author       TurbMZ
// @license      MIT
// @match        http://moodle.syxy.ouchn.cn/mod/url/view.php*
// @icon         https://www.google.com/s2/favicons?sz=64&domain=ouchn.cn
// @grant        none
// @downloadURL none
// ==/UserScript==

(function() {
    'use strict';
    //let status = localStorage.getItem('_my_tamermonkey_status_')
    window._my_tamermonkey_status_ = false; //status ||
    let _my_tamermonkey_speed_ = 1;
    const speedMap = [ 1, 1.5, 2, 4 ]
    const container = document.getElementById('page-content')
    let videoDom = document.getElementsByTagName('VIDEO')[0];
    let tryTimes = 0;
    console.log('插件控制状态',status,container)
    const init = function() {
        container.style.position = 'relative';
        let btnText = window._my_tamermonkey_status_?'停用后台播放':'启用后台播放'
        let controlBox = document.createElement('DIV');
        let controlBtn = document.createElement('SPAN');
        let speedBtn = document.createElement('SPAN');
        let jopeToEndBtn = document.createElement('SPAN')
        // 控制开关
        const controlHandler = function(e) {
            window._my_tamermonkey_status_ = !window._my_tamermonkey_status_;
            // localStorage.setItem('_my_tamermonkey_status_',window._my_tamermonkey_status_)
            let btnText = window._my_tamermonkey_status_?'停用后台播放':'启用后台播放'
            e.target.innerText = btnText
        }
        // 调速
        const speedHandler = function(e) {
            let currentSpeedIndex = speedMap.findIndex(v=>_my_tamermonkey_speed_===v);
            if(currentSpeedIndex===speedMap.length-1){
                currentSpeedIndex = 0
            }else{
                ++currentSpeedIndex
            }
            _my_tamermonkey_speed_ = speedMap[currentSpeedIndex]
            videoDom.playbackRate = _my_tamermonkey_speed_
            e.target.innerText = `快进>>${_my_tamermonkey_speed_}倍速`
        }
        // 快进到最后
        const toEndHandler = function(e) {
            console.log('快进到最后')
            let duration = videoDom.duration;
            let toEndTime = Math.floor(duration-1)
            videoDom.currentTime = toEndTime
            console.log(videoDom.currentTime)
        }
        //容器设置样式和id
        controlBox.id = 'myTampermonkeyControl'
        controlBox.style.cssText = 'position:absolute;right:0px;bottom:0px;display:flex;align-items:center;font-size:12px;'
        //控制按钮设置样式和id
        controlBtn.id = 'controlBtn'
        controlBtn.style.cssText = 'display:inline-block;padding: 4px 10px;border-radius:4px;margin-right:10px;cursor:pointer;background:#999;color:#fff;'
        controlBtn.innerText = btnText
        speedBtn.id = 'speedBtn'
        speedBtn.style.cssText = 'display:inline-block;padding: 4px 10px;border-radius:4px;cursor:pointer;background:#999;color:#fff;margin-right:10px;'
        speedBtn.innerText = `快进>>${_my_tamermonkey_speed_}倍速`
        jopeToEndBtn.style.cssText = 'display:inline-block;padding: 4px 10px;border-radius:4px;cursor:pointer;background:#999;color:#fff;'
        jopeToEndBtn.innerText = '跳到最后'
        //添加事件
        controlBtn.onclick= controlHandler
        speedBtn.onclick = speedHandler
        jopeToEndBtn.onclick = toEndHandler
        controlBox.appendChild(controlBtn)
        controlBox.appendChild(speedBtn)
        controlBox.appendChild(jopeToEndBtn)
        container.appendChild(controlBox)
        videoDom.addEventListener('ended', function () { //结束
            console.log("播放结束");
            //controlBtn.click()
        }, false);
        document.addEventListener('visibilitychange', function() {
            if(!videoDom){
                videoDom = document.getElementsByTagName('VIDEO')[0];
            }
            var isHidden = document.hidden;
            console.log(document.visibilityState,isHidden,window._my_tamermonkey_status_)
            if (isHidden && window._my_tamermonkey_status_) {
                console.log(window._my_tamermonkey_status_)
                videoDom.play()
            }else if(isHidden){
                videoDom.pause()
            }
        });
    }
    if(videoDom){ // 有视频
        init()
    }else{
        let timer = null;
            timer = setInterval(()=>{
                console.log('轮询')
                if(tryTimes>=10){
                    clearInterval(timer)
                    timer = null
                    return;
                }
                videoDom = document.getElementsByTagName('VIDEO')[0];
                if(videoDom){
                    try{
                        init()
                        clearInterval(timer)
                        timer = null
                        return;
                    }catch(err){
                        clearInterval(timer)
                        timer = null
                        console.log(err)
                    }
                }
                tryTimes++
            },200)
    }

    // Your code here...
})();