// ==UserScript==
// @name         抖音网页版视频下载
// @namespace    https://bbs.tampermonkey.net.cn/
// @version      0.2.0
// @description  抖音网页版视频添加下载按钮
// @author       昊色居士
// @match        *://www.douyin.com/video/*

// ==/UserScript==

(function () {
    'use strict';

    function getVideoUrl() {
        let video_url = document.querySelector(".xg-video-container video>source").getAttribute("src");
        video_url = video_url.startsWith("//") ? "https:" + video_url : video_url;
        return video_url
    }

    function getVideoName() {
        const filename = document.querySelector("title").innerText;
        return `${filename}.mp4`
    }

    function download(url) {
        return fetch(url, {
            headers: new Headers({
                Origin: location.origin,
            }),
            mode: 'cors',
        }).then(res => {
            return res.blob()
        })
    }

    function main() {
        let videoUrl = getVideoUrl()
        let videoName = getVideoName()
        let douyinHeader = document.querySelector("#douyin-header-menuCt pace-island > div")
        let copyDom = douyinHeader.childNodes[1]
        let dlDom = copyDom.cloneNode(true);
        let dlA = dlDom.querySelector("a")
        let dlBtn = dlA.querySelector("p")

        dlBtn.textContent = "下视频"
        download(videoUrl).then(blob => {
            const blobUrl = URL.createObjectURL(blob)
            dlA.download = videoName
            dlA.href = blobUrl
        })
        douyinHeader.insertBefore(dlDom, copyDom)
    }

    // 等待网页完成加载
    window.addEventListener('load', function () {
        const intervalId = setInterval(() => {
            let dom1 = document.querySelector(".xg-video-container video>source")
            let dom2 = document.querySelectorAll("#douyin-header-menuCt pace-island > div > div")[1].querySelector("p")
            if (dom1 && dom2 && dom2.textContent === "客户端") {
                clearInterval(intervalId)
                main()
            }
        }, 500)

    }, false);

})();