// ==UserScript==
// @name         Bilibili音频下载 
// @namespace    https://bbs.tampermonkey.net.cn/
// @version      0.0.9
// @description  try to take over the world!
// @author       静水流深
// @match        https://www.bilibili.com/video/*
// @grant        unsafeWindow
// @grant        GM_registerMenuCommand
// @grant        GM_notification
// ==/UserScript==

(function() {
    'use strict'
    function getAudioUrl() {
        let audio_list = unsafeWindow.__playinfo__.data.dash.audio;
        if (audio_list.length > 0) {
            return unsafeWindow.__playinfo__.data.dash.audio[0].baseUrl;
        }
        else {
            GM_notification("音频提取失败", "提示");
            return null;
        }
    }

    function fetchDownload({url, download_type}) {
        if (!url) return;

        let download_file_name;
        let title = document.querySelector('li.on > a')
        if (!title) {
            download_file_name = `${document.getElementsByTagName('h1')[0].innerText}.${download_type}`
        } else {
            download_file_name = `${title.getAttribute('title')}.${download_type}`
        }

        fetch(url)
            .then(res => res.blob())
            .then(blob => {
                const link = document.createElement('a')
                link.style.display = 'none'
                document.body.appendChild(link)
                const download_url = window.URL.createObjectURL(blob)
                link.href = download_url;
                link.download = download_file_name
                link.click()
                document.body.removeChild(link)
                window.URL.revokeObjectURL(download_url)
            })
    }

    GM_registerMenuCommand(
        "音频下载",
        function () {
            fetchDownload({
                url: getAudioUrl(),
                download_type: 'mp3'
            });           
        }
    );

    var flag = false;
    function rigister_hot_key({codes, callback}) {

        document.addEventListener('keydown', function(event) {
            if (event.code !== codes && !flag) return;

            flag = true;
            callback();
        });

        document.addEventListener('keyup', function(event) {
            flag = false;
        });
    }

    rigister_hot_key({
        codes: 'KeyH',
        callback: function() {

            fetchDownload({
                url: getAudioUrl(),
                download_type: 'mp3'
            });

        
        }
    })
})();