// ==UserScript==
// @name         SoundCloud Audio Grabber
// @name:zh-CN   SoundCloud 音频抓取器
// @namespace    sc-audio-grabber
// @version      2.0.0
// @description  Grab the original audio of SoundCloud tracks and sets. Direct MP3 when available, otherwise losslessly re-assemble HLS fMP4 segments into .m4a. Streams to disk, cancellable, retryable, SPA aware.
// @description:zh-CN  一键抓取 SoundCloud 曲目/歌单的原始音频：有直链 MP3 就直接下载，没有就把 HLS 的 fMP4 分片（init.mp4 + dataNNN.m4s）无损拼装成 .m4a；支持边下边存盘、进度与速度显示、取消与重试，适配站内无刷新跳转。
// @author       sc-audio-grabber
// @license      MIT
// @icon         https://a-v2.sndcdn.com/assets/images/sc-icons/favicon-2cadd14bdb.ico
// @match        https://soundcloud.com/*
// @match        https://m.soundcloud.com/*
// @run-at       document-idle
// @grant        none
// @noframes
// ==/UserScript==

/*
 * SoundCloud Audio Grabber 2.0.0  (MIT)
 *
 * 工作流程
 *   1. 从页面已发出的请求 / 内联脚本 / sndcdn 资源包里取 client_id，并缓存 6 小时
 *   2. api-v2 /resolve 解析当前页面：单曲返回 track，歌单返回 playlist
 *   3. 挑转码：progressive(直链 mp3) 优先，否则 aac_160k / abr_sq 的 HLS
 *   4. HLS：解析 m3u8 -> init.mp4 + dataNNN.m4s，6 并发下载、按序写盘
 *      fMP4 分片按序拼接即为合法 m4a，无需转码
 *   5. 落盘：支持 File System Access（边下边写、内存占用恒定），否则 Blob 下载
 *
 * 2.0.0
 *   + 歌单 / 曲目集批量下载（目录选择器）
 *   + 边下边存盘、取消下载、分段失败自动退避重试
 *   + Shadow DOM 面板，不受站点样式影响；可拖拽、记忆位置
 *   + 适配 SoundCloud 的 SPA 无刷新跳转
 *   + 中文 / 英文自动切换
 */

(function () {
  'use strict';

  if (window.__SCGRAB_LOADED__) return;
  window.__SCGRAB_LOADED__ = true;

  /* ===================== 常量 / 文案 ===================== */

  var VERSION = '2.0.0';
  var API = 'https://api-v2.soundcloud.com';
  var ZH = /^zh/i.test(navigator.language || navigator.userLanguage || '');
  var STR = ZH ? {
    title: 'SoundCloud 抓取器',
    grab: '抓取本页音频',
    grabSet: '抓取整个歌单',
    working: '处理中…',
    cancel: '取消',
    ready: '就绪，点按钮开始',
    notTrack: '当前页面不是曲目页或歌单页',
    noCid: '拿不到 client_id，请先在页面上播放一次任意曲目',
    noTrans: '该曲目没有可用转码',
    blocked: '该曲目被版权限制，无法抓取',
    resolving: '解析页面…',
    track: '曲目',
    playlist: '歌单',
    transcoding: '转码',
    plan: '分片',
    seg: '分片',
    merging: '写入文件…',
    saved: '已保存',
    copied: '直链已复制到剪贴板',
    copy: '复制直链',
    streamOn: '直接存盘',
    streamHint: '大文件不占内存',
    conc: '并发',
    failed: '失败',
    aborted: '已取消',
    skipped: '跳过',
    speed: '速度',
    chooseDir: '选择保存文件夹…',
    tracks: '首',
    of: '/',
    noPicker: '浏览器不支持目录写入，改为逐首下载',
    doneAll: '全部完成',
    err_net: '网络错误',
    err_http: 'HTTP 错误',
    err_pick: '保存位置未选择，已回退到浏览器下载',
    hint: 'Alt+G 呼出面板'
  } : {
    title: 'SoundCloud Grabber',
    grab: 'Grab this audio',
    grabSet: 'Grab whole set',
    working: 'Working…',
    cancel: 'Cancel',
    ready: 'Ready — press the button',
    notTrack: 'This page is not a track or set page',
    noCid: 'Cannot get client_id — play any track once first',
    noTrans: 'No usable transcoding for this track',
    blocked: 'This track is blocked by rights holder',
    resolving: 'Resolving page…',
    track: 'Track',
    playlist: 'Set',
    transcoding: 'Transcoding',
    plan: 'Segments',
    seg: 'segment',
    merging: 'Writing file…',
    saved: 'Saved',
    copied: 'Direct link copied',
    copy: 'Copy direct link',
    streamOn: 'Stream to disk',
    streamHint: 'constant memory',
    conc: 'Parallel',
    failed: 'Failed',
    aborted: 'Cancelled',
    skipped: 'Skipped',
    speed: 'Speed',
    chooseDir: 'Choose save folder…',
    tracks: 'tracks',
    of: '/',
    noPicker: 'Directory writing unsupported — downloading one by one',
    doneAll: 'All done',
    err_net: 'Network error',
    err_http: 'HTTP error',
    err_pick: 'No location picked — falling back to browser download',
    hint: 'Alt+G for the panel'
  };

  function t(k) { return STR[k] || k; }

  /* ===================== 设置 ===================== */

  var LS = {
    get: function (k, d) {
      try { var v = localStorage.getItem('scgrab.' + k); return v === null ? d : JSON.parse(v); }
      catch (e) { return d; }
    },
    set: function (k, v) {
      try { localStorage.setItem('scgrab.' + k, JSON.stringify(v)); } catch (e) {}
    }
  };

  var cfg = {
    concurrency: LS.get('conc', 6),
    retries: 3,
    stream: LS.get('stream', true)
  };

  /* ===================== 小工具 ===================== */

  function sleep(ms) { return new Promise(function (r) { setTimeout(r, ms); }); }

  function fmtBytes(n) {
    if (!n || n < 0) return '0 B';
    var u = ['B', 'KB', 'MB', 'GB'], i = 0;
    while (n >= 1024 && i < u.length - 1) { n /= 1024; i++; }
    return (n >= 100 || i === 0 ? Math.round(n) : n.toFixed(1)) + ' ' + u[i];
  }

  function absUrl(u, base) {
    try { return new URL(u, base).href; } catch (e) { return u; }
  }

  function safeName(s) {
    return String(s == null ? '' : s)
      .replace(/[\\/:*?"<>|\u0000-\u001f]+/g, '_')
      .replace(/\s+/g, ' ')
      .replace(/^[\s.]+|[\s.]+$/g, '')
      .slice(0, 120) || 'soundcloud';
  }

  function abortError() {
    var e = new Error('aborted');
    e.name = 'AbortError';
    return e;
  }

  function isAbort(e) { return !!e && (e.name === 'AbortError' || e.code === 20); }

  /** 带指数退避的重试；AbortError 直接抛出 */
  async function withRetry(fn, times, base) {
    var last;
    for (var i = 0; i <= times; i++) {
      try { return await fn(i); }
      catch (e) {
        last = e;
        if (isAbort(e)) throw e;
        if (i === times) break;
        await sleep((base || 400) * Math.pow(2, i));
      }
    }
    throw last;
  }

  async function getJson(url, signal) {
    var r = await fetch(url, { signal: signal, credentials: 'include', headers: { accept: 'application/json' } });
    if (!r.ok) { var e = new Error('HTTP ' + r.status); e.status = r.status; throw e; }
    return r.json();
  }

  async function getBuf(url, signal) {
    var r = await fetch(url, { signal: signal, credentials: 'omit' });
    if (!r.ok) { var e = new Error('HTTP ' + r.status); e.status = r.status; throw e; }
    return new Uint8Array(await r.arrayBuffer());
  }

  async function getText(url, signal) {
    var r = await fetch(url, { signal: signal, credentials: 'omit' });
    if (!r.ok) { var e = new Error('HTTP ' + r.status); e.status = r.status; throw e; }
    return r.text();
  }

  /* ===================== client_id ===================== */

  var CID_KEY = 'cid';
  var ctlNoop = undefined;
  var CID_TTL = 6 * 3600 * 1000;

  async function cidValid(cid) {
    if (!cid || !/^[A-Za-z0-9]{32}$/.test(cid)) return false;
    try {
      var r = await fetch(API + '/tracks/13158665?client_id=' + cid, { credentials: 'include' });
      return r.ok;
    } catch (e) { return false; }
  }

  async function getClientId(force) {
    if (!force) {
      var c = LS.get(CID_KEY, null);
      if (c && c.v && c.e > Date.now() && await cidValid(c.v)) return c.v;
    }

    var cands = [];
    function push(v) { if (v && cands.indexOf(v) === -1) cands.push(v); }

    // 1) 页面已经发出去的请求
    try {
      performance.getEntriesByType('resource').forEach(function (e) {
        var m = /[?&]client_id=([A-Za-z0-9]{32})/.exec(e.name || '');
        if (m) push(m[1]);
      });
    } catch (e) {}

    // 2) 内联脚本
    try {
      var html = document.documentElement.innerHTML;
      var mm = html.match(/client_id\s*[:=]\s*"([A-Za-z0-9]{32})"/);
      if (mm) push(mm[1]);
    } catch (e) {}

    for (var i = 0; i < cands.length; i++) {
      if (await cidValid(cands[i])) { remember(cands[i]); return cands[i]; }
    }
    if (cands.length) ui.log('client_id 候选失效 (' + cands.length + ')，扫描资源包…');

    // 3) 扫 sndcdn 资源包
    var srcs = [];
    try {
      Array.prototype.forEach.call(document.querySelectorAll('script[src]'), function (s) {
        if (/sndcdn\.com/.test(s.src) && srcs.indexOf(s.src) === -1) srcs.push(s.src);
      });
    } catch (e) {}

    if (!srcs.length) {
      // 页面还没挂载脚本：直接拉一份首页 HTML 找资源地址
      try {
        var home = await getText('https://soundcloud.com/', ctlNoop);
        var mm2 = home.match(/https:\/\/a-v2\.sndcdn\.com\/assets\/[^"']+\.js/g) || [];
        mm2.forEach(function (u) { if (srcs.indexOf(u) === -1) srcs.push(u); });
      } catch (e) {}
    }

    for (var j = 0; j < srcs.length; j++) {
      try {
        var txt = await getText(srcs[j]);
        var m = txt.match(/client_id\s*[:=]\s*"([A-Za-z0-9]{32})"/) || txt.match(/client_id=([A-Za-z0-9]{32})/);
        if (m && await cidValid(m[1])) {
          ui.log('client_id <- ' + String(srcs[j]).split('/').pop());
          remember(m[1]);
          return m[1];
        }
      } catch (e) {}
    }
    ui.log('client_id 获取失败：已检查 ' + cands.length + ' 个候选 / ' + srcs.length + ' 个资源包');
    return null;
  }

  function remember(cid) {
    LS.set(CID_KEY, { v: cid, e: Date.now() + CID_TTL });
  }

  /* ===================== 解析曲目 / 歌单 ===================== */

  async function resolvePage(url, cid, signal) {
    return getJson(API + '/resolve?url=' + encodeURIComponent(url) + '&client_id=' + cid, signal);
  }

  async function fullTrack(tr, cid, signal) {
    if (tr && tr.media && tr.media.transcodings && tr.media.transcodings.length) return tr;
    if (!tr || !tr.id) return tr;
    return getJson(API + '/tracks/' + tr.id + '?client_id=' + cid, signal);
  }

  async function playlistTracks(pl, cid, signal) {
    var out = (pl.tracks || []).slice();
    var want = pl.track_count || out.length;
    while (out.length < want) {
      var page = await getJson(API + '/playlists/' + pl.id + '/tracks?client_id=' + cid +
        '&limit=50&offset=' + out.length, signal);
      if (!page || !page.length) break;
      out = out.concat(page);
    }
    return out.filter(function (x) { return x && x.kind === 'track'; });
  }

  function pickTranscoding(tr) {
    var list = (tr && tr.media && tr.media.transcodings) || [];
    var i;
    for (i = 0; i < list.length; i++) {
      if (list[i].format && list[i].format.protocol === 'progressive') {
        return { item: list[i], hls: false };
      }
    }
    var order = ['aac_160k', 'abr_sq', 'aac_96k', 'mp3_128', 'mp3_standard'];
    for (var o = 0; o < order.length; o++) {
      for (i = 0; i < list.length; i++) {
        if (list[i].preset === order[o]) return { item: list[i], hls: true };
      }
    }
    if (!list.length) return null;
    return { item: list[0], hls: !(list[0].format && list[0].format.protocol === 'progressive') };
  }

  async function streamUrl(tr, cid, trackAuth, signal) {
    var u = tr.url + (tr.url.indexOf('?') > -1 ? '&' : '?') + 'client_id=' + cid;
    if (trackAuth) u += '&track_authorization=' + encodeURIComponent(trackAuth);
    var j = await getJson(u, signal);
    if (!j || !j.url) throw new Error('no stream url');
    return j.url;
  }

  /* ===================== m3u8 ===================== */

  function parseM3U8(text, base) {
    var lines = String(text).split(/\r?\n/).map(function (l) { return l.trim(); }).filter(Boolean);
    if (!lines.length || lines[0].indexOf('#EXTM3U') !== 0) throw new Error('bad m3u8');

    var variants = [], init = null, segs = [], key = null, dur = 0;

    for (var i = 0; i < lines.length; i++) {
      var l = lines[i];

      if (l.indexOf('#EXT-X-STREAM-INF') === 0) {
        var bw = /BANDWIDTH=(\d+)/.exec(l);
        var nxt = lines[i + 1];
        if (nxt && nxt.charAt(0) !== '#') {
          variants.push({ bw: bw ? parseInt(bw[1], 10) : 0, url: absUrl(nxt, base) });
          i++;
        }
        continue;
      }
      if (l.indexOf('#EXT-X-MAP') === 0) {
        var mu = /URI="([^"]+)"/.exec(l);
        if (mu) init = absUrl(mu[1], base);
        continue;
      }
      if (l.indexOf('#EXT-X-KEY') === 0) {
        var ku = /URI="([^"]+)"/.exec(l);
        if (ku) key = absUrl(ku[1], base);
        continue;
      }
      if (l.indexOf('#EXTINF') === 0) {
        var d = parseFloat(l.slice(8));
        if (!isNaN(d)) dur += d;
        continue;
      }
      if (l.charAt(0) === '#') continue;
      segs.push(absUrl(l, base));
    }
    return { variants: variants, init: init, segs: segs, key: key, duration: dur };
  }

  async function hlsPlan(url, signal) {
    var p = parseM3U8(await getText(url, signal), url);
    if (p.variants.length) {
      p.variants.sort(function (a, b) { return b.bw - a.bw; });
      var best = p.variants[0];
      var p2 = parseM3U8(await getText(best.url, signal), best.url);
      p2.bandwidth = best.bw;
      if (!p2.segs.length) return p;
      return p2;
    }
    return p;
  }

  /* ===================== 输出端（内存 或 直接写盘） ===================== */

  function canPickFile() {
    try {
      return !!(window.showSaveFilePicker && navigator.userActivation &&
        navigator.userActivation.isActive !== false);
    } catch (e) { return false; }
  }

  function canPickDir() {
    try {
      return !!(window.showDirectoryPicker && navigator.userActivation &&
        navigator.userActivation.isActive !== false);
    } catch (e) { return false; }
  }

  function memSink(name, mime) {
    var parts = [], size = 0;
    return {
      write: function (u8) { parts.push(u8); size += u8.byteLength; },
      close: function () {
        var blob = new Blob(parts, { type: mime });
        saveBlob(blob, name);
        parts = null;
        return size;
      },
      abort: function () { parts = null; }
    };
  }

  function makeFsSink(fileHandle, name, mime) {
    var w = null, size = 0;
    return {
      write: async function (u8) {
        if (!w) w = await fileHandle.createWritable();
        size += u8.byteLength;
        await w.write(u8);
      },
      close: async function () { if (w) await w.close(); return size; },
      abort: async function () { try { if (w) await w.abort(); } catch (e) {} }
    };
  }

  function saveBlob(blob, name) {
    var a = document.createElement('a');
    a.href = URL.createObjectURL(blob);
    a.download = name;
    a.style.display = 'none';
    a.rel = 'noopener';
    document.body.appendChild(a);
    a.click();
    setTimeout(function () { URL.revokeObjectURL(a.href); a.remove(); }, 120000);
  }

  async function openSink(name, mime, ext) {
    if (cfg.stream && canPickFile()) {
      try {
        var h = await window.showSaveFilePicker({
          suggestedName: name,
          types: [{ description: 'Audio', accept: (function () { var o = {}; o[mime] = [ext]; return o; })() }]
        });
        return makeFsSink(h, name, mime);
      } catch (e) {
        if (isAbort(e)) throw e;              // 用户自己点了取消
        if (e && (e.name === 'AbortError')) throw abortError();
        // 无用户手势 / 浏览器不支持：静默回退到内存下载
        console.debug('[SCGrab] picker unavailable:', e && e.name);
      }
    }
    return memSink(name, mime);
  }

  /* ===================== 下载 ===================== */

  function abortable(signal) { return signal; }

  async function grabProgressive(url, sink, ctl, onProg) {
    var r = await fetch(url, { signal: ctl.signal, credentials: 'omit' });
    if (!r.ok) { var e = new Error('HTTP ' + r.status); e.status = r.status; throw e; }
    var total = parseInt(r.headers.get('content-length') || '0', 10) || 0;
    var started = Date.now(), bytes = 0;

    if (!r.body || !r.body.getReader) {
      var buf = new Uint8Array(await r.arrayBuffer());
      await sink.write(buf);
      onProg({ bytes: buf.byteLength, totalBytes: buf.byteLength, elapsed: Date.now() - started });
      return;
    }
    var reader = r.body.getReader();
    for (;;) {
      var s = await reader.read();
      if (s.done) break;
      if (ctl.signal.aborted) { try { reader.cancel(); } catch (e2) {} throw abortError(); }
      await sink.write(s.value);
      bytes += s.value.byteLength;
      onProg({ bytes: bytes, totalBytes: total, elapsed: Date.now() - started });
    }
  }

  async function grabHls(plan, sink, ctl, onProg) {
    var total = plan.segs.length;
    var started = Date.now(), bytes = 0, next = 0;

    if (plan.init) {
      var ib = await withRetry(function () { return getBuf(plan.init, ctl.signal); }, cfg.retries, 400);
      await sink.write(ib);
      bytes += ib.byteLength;
    }

    var ready = new Map();
    var flushing = Promise.resolve();
    var report = function () {
      onProg({ done: next, total: total, bytes: bytes, elapsed: Date.now() - started });
    };
    onProg({ done: 0, total: total, bytes: bytes, elapsed: 0 });

    function flush() {
      flushing = flushing.then(async function () {
        while (ready.has(next)) {
          var b = ready.get(next);
          ready.delete(next);
          await sink.write(b);
          bytes += b.byteLength;
          next++;
          report();
        }
      });
      return flushing;
    }

    var cursor = 0;
    async function worker() {
      for (;;) {
        if (ctl.signal.aborted) throw abortError();
        var i = cursor++;
        if (i >= total) return;
        var buf = await withRetry(function () { return getBuf(plan.segs[i], ctl.signal); }, cfg.retries, 400);
        ready.set(i, buf);
        await flush();
      }
    }

    var n = Math.max(1, Math.min(cfg.concurrency, total));
    var workers = [];
    for (var k = 0; k < n; k++) workers.push(worker());
    await Promise.all(workers);
    await flush();
    if (next !== total) throw new Error('incomplete: ' + next + '/' + total);
    report();
  }

  /* ===================== 单曲任务 ===================== */

  async function grabTrack(track, cid, ctl, opts) {
    opts = opts || {};
    var tr = await fullTrack(track, cid, ctl.signal);
    var picked = pickTranscoding(tr);
    if (!picked) throw new Error(t('noTrans'));

    var url = await streamUrl(picked.item, cid, tr.track_authorization, ctl.signal);
    var name = safeName((tr.user && tr.user.username ? tr.user.username + ' - ' : '') + (tr.title || 'track'));

    var ext, mime;
    if (!picked.hls) {
      ext = /\.mp3(\?|$)/i.test(url) ? 'mp3' : (/\.m4a(\?|$)/i.test(url) ? 'm4a' : 'mp3');
      mime = ext === 'mp3' ? 'audio/mpeg' : 'audio/mp4';
    } else {
      ext = 'm4a';
      mime = 'audio/mp4';
    }

    var fileName = name + '.' + ext;

    // 先选保存位置（File System Access 需要用户手势，越早越好）
    var sink = opts.dir
      ? makeFsSink(await opts.dir.getFileHandle(fileName, { create: true }), fileName, mime)
      : await openSink(fileName, mime, ext);

    try {
      if (picked.hls) {
        var plan = await hlsPlan(url, ctl.signal);
        ui.log(t('transcoding') + ': ' + (picked.item.preset || '?') + ' · HLS ' + plan.segs.length + ' seg' +
          (plan.bandwidth ? ' · ' + Math.round(plan.bandwidth / 1000) + 'k' : ''));
        await grabHls(plan, sink, ctl, opts.onProg || function () {});
      } else {
        ui.log(t('transcoding') + ': ' + (picked.item.preset || 'progressive') + ' · direct ' + ext);
        await grabProgressive(url, sink, ctl, opts.onProg || function () {});
      }
      var size = await sink.close();
      return { file: fileName, size: size, url: url };
    } catch (e) {
      await sink.abort();
      throw e;
    }
  }

  /* ===================== 界面 ===================== */

  var ui = {
    host: null, root: null, expanded: false,
    el: {},
    log: function (msg) {
      console.log('[SCGrab] ' + msg);
      if (!ui.el.log) return;
      var line = document.createElement('div');
      line.textContent = msg;
      ui.el.log.appendChild(line);
      while (ui.el.log.childNodes.length > 40) ui.el.log.removeChild(ui.el.log.firstChild);
      ui.el.log.scrollTop = ui.el.log.scrollHeight;
    },
    status: function (msg) { if (ui.el.status) ui.el.status.textContent = msg; },
    progress: function (pct) {
      if (!ui.el.bar) return;
      ui.el.bar.style.width = Math.max(0, Math.min(100, pct)) + '%';
    },
    busy: function (on, label) {
      if (!ui.el.go) return;
      ui.el.go.disabled = !!on;
      ui.el.go.textContent = on ? (label || t('working')) : t('grab');
      ui.el.cancel.style.display = on ? '' : 'none';
    }
  };

  function css() {
    return [
      ':host{all:initial}',
      '*{box-sizing:border-box;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Microsoft YaHei",sans-serif}',
      '.wrap{position:fixed;z-index:2147483000;right:18px;bottom:96px;width:300px;color:#eee;',
      'background:#141414;border:1px solid #2c2c2c;border-radius:12px;box-shadow:0 12px 36px rgba(0,0,0,.5);',
      'overflow:hidden;font-size:12px;line-height:1.5;user-select:none}',
      '.wrap.min{width:auto;border-radius:24px}',
      '.head{display:flex;align-items:center;gap:8px;padding:9px 10px;background:linear-gradient(90deg,#ff5500,#ff7a1a);cursor:move}',
      '.head b{flex:1;font-size:12px;color:#fff;font-weight:700;letter-spacing:.2px}',
      '.head .v{color:rgba(255,255,255,.75);font-size:10px}',
      '.head i{color:#fff;cursor:pointer;font-style:normal;padding:0 3px;opacity:.9}',
      '.head i:hover{opacity:1}',
      '.body{padding:10px}',
      '.wrap.min .body{display:none}',
      '.meta{color:#9a9a9a;margin-bottom:9px;word-break:break-word;display:-webkit-box;-webkit-line-clamp:2;',
      '-webkit-box-orient:vertical;overflow:hidden;min-height:16px}',
      '.row{display:flex;gap:6px}',
      'button{border:0;border-radius:7px;cursor:pointer;font-size:12px;font-family:inherit}',
      '.go{flex:1;padding:8px;background:#ff5500;color:#fff;font-weight:700}',
      '.go:disabled{background:#5a2a10;color:#c9a;cursor:default}',
      '.cancel{padding:8px 10px;background:#333;color:#eee;display:none}',
      '.track{height:4px;background:#2a2a2a;border-radius:3px;margin:9px 0 5px;overflow:hidden}',
      '.bar{height:100%;width:0;background:#ff5500;transition:width .18s}',
      '.status{color:#8fb6d6;min-height:16px;font-size:11px}',
      '.opts{display:flex;flex-direction:column;gap:6px;margin-top:9px;color:#8a8a8a;font-size:11px}',
      '.opts .r{display:flex;align-items:center;gap:6px;min-height:18px}',
      '.opts .grow{flex:1}',
      '.opts label{display:flex;align-items:center;gap:4px;cursor:pointer;white-space:nowrap}',
      '.opts select{background:#222;color:#ddd;border:1px solid #333;border-radius:4px;font-size:11px;padding:1px 2px;outline:none}',
      '.opts input{accent-color:#ff5500;margin:0}',
      '.opts .link{cursor:pointer;color:#8fb6d6;border-bottom:1px dashed #3d5a6b;padding-bottom:1px}',
      '.opts .link:hover{color:#cfe6f5}',
      '.opts .tag{color:#4a4a4a;font-size:10px}',
      '.log{margin-top:8px;max-height:78px;overflow:auto;color:#6f8fa3;font-size:11px;line-height:1.45;',
      'font-family:ui-monospace,Consolas,monospace;word-break:break-all;user-select:text;',
      'scrollbar-width:thin;scrollbar-color:#3a3a3a transparent}',
      '.log::-webkit-scrollbar{width:6px;height:6px}',
      '.log::-webkit-scrollbar-thumb{background:#3a3a3a;border-radius:3px}',
      '.log::-webkit-scrollbar-track{background:transparent}',
      '.pill{position:fixed;right:18px;bottom:96px;z-index:2147483000;padding:9px 14px;border-radius:22px;',
      'background:#ff5500;color:#fff;font-weight:700;font-size:12px;cursor:pointer;border:0;',
      'box-shadow:0 8px 24px rgba(0,0,0,.4)}',
      '.pill:hover{background:#ff6a1f}'
    ].join('');
  }

  function buildUi() {
    if (ui.host) return;
    var host = document.createElement('div');
    host.id = 'scgrab-host';
    host.style.cssText = 'all:initial;position:fixed;z-index:2147483000;right:0;bottom:0;';
    var root;
    try { root = host.attachShadow({ mode: 'open' }); }
    catch (e) { root = host; }
    ui.host = host;
    ui.root = root;

    var style = document.createElement('style');
    style.textContent = css();
    root.appendChild(style);

    var wrap = document.createElement('div');
    wrap.className = 'wrap';
    wrap.innerHTML =
      '<div class="head"><b>' + t('title') + '</b><span class="v">v' + VERSION + '</span>' +
      '<i data-min title="' + t('hint') + '">–</i></div>' +
      '<div class="body">' +
        '<div class="meta" data-meta>' + t('ready') + '</div>' +
        '<div class="row">' +
          '<button class="go" data-go>' + t('grab') + '</button>' +
          '<button class="cancel" data-cancel>' + t('cancel') + '</button>' +
        '</div>' +
        '<div class="track"><div class="bar" data-bar></div></div>' +
        '<div class="status" data-status></div>' +
        '<div class="opts">' +
          '<div class="r">' +
            '<label><input type="checkbox" data-stream ' + (cfg.stream ? 'checked' : '') + '>' + t('streamOn') + '</label>' +
            '<span class="grow"></span>' +
            '<label>' + t('conc') + ' <select data-conc>' +
              [4, 6, 8, 12].map(function (n) {
                return '<option value="' + n + '"' + (n === cfg.concurrency ? ' selected' : '') + '>' + n + '</option>';
              }).join('') +
            '</select></label>' +
          '</div>' +
          '<div class="r">' +
            '<span class="link" data-copy>' + t('copy') + '</span>' +
            '<span class="grow"></span>' +
            '<span class="tag">MIT · Alt+G</span>' +
          '</div>' +
        '</div>' +
        '<div class="log" data-log></div>' +
      '</div>';

    var pill = document.createElement('button');
    pill.className = 'pill';
    pill.textContent = '⬇ ' + (ZH ? '抓取音频' : 'Grab');
    pill.style.display = 'none';
    pill.setAttribute('data-pill', '');
    root.appendChild(wrap);
    root.appendChild(pill);
    document.documentElement.appendChild(host);

    ui.el = {
      wrap: wrap,
      meta: wrap.querySelector('[data-meta]'),
      go: wrap.querySelector('[data-go]'),
      cancel: wrap.querySelector('[data-cancel]'),
      bar: wrap.querySelector('[data-bar]'),
      status: wrap.querySelector('[data-status]'),
      log: wrap.querySelector('[data-log]'),
      copy: wrap.querySelector('[data-copy]'),
      stream: wrap.querySelector('[data-stream]'),
      conc: wrap.querySelector('[data-conc]'),
      pill: pill
    };

    restorePos();

    ui.el.go.addEventListener('click', function () { start(); });
    ui.el.cancel.addEventListener('click', function () { if (ui.ctl) ui.ctl.abort(); });
    ui.el.stream.addEventListener('change', function () {
      cfg.stream = ui.el.stream.checked;
      LS.set('stream', cfg.stream);
    });
    ui.el.conc.addEventListener('change', function () {
      cfg.concurrency = parseInt(ui.el.conc.value, 10) || 6;
      LS.set('conc', cfg.concurrency);
    });
    ui.el.copy.addEventListener('click', function () {
      if (!ui.lastUrl) return ui.log(t('copy') + ': —');
      navigator.clipboard.writeText(ui.lastUrl).then(function () {
        ui.log(t('copied'));
      }, function () { ui.log(ui.lastUrl); });
    });

    wrap.querySelector('[data-min]').addEventListener('click', function () {
      wrap.style.display = 'none';
      pill.style.display = '';
    });
    pill.addEventListener('click', function () {
      wrap.style.display = '';
      pill.style.display = 'none';
    });

    enableDrag(wrap.querySelector('.head'), wrap);
    ui.log(t('hint'));
  }

  function restorePos() {
    var p = LS.get('pos', null);
    if (!p) return;
    var w = ui.el.wrap;
    w.style.left = p.x + 'px';
    w.style.top = p.y + 'px';
    w.style.right = 'auto';
    w.style.bottom = 'auto';
  }

  function enableDrag(handle, el) {
    var sx = 0, sy = 0, ox = 0, oy = 0, dragging = false;
    handle.addEventListener('pointerdown', function (e) {
      if (e.target.tagName === 'I') return;
      dragging = true;
      var r = el.getBoundingClientRect();
      sx = e.clientX; sy = e.clientY; ox = r.left; oy = r.top;
      handle.setPointerCapture(e.pointerId);
      e.preventDefault();
    });
    handle.addEventListener('pointermove', function (e) {
      if (!dragging) return;
      var x = Math.max(0, Math.min(window.innerWidth - 60, ox + e.clientX - sx));
      var y = Math.max(0, Math.min(window.innerHeight - 40, oy + e.clientY - sy));
      el.style.left = x + 'px';
      el.style.top = y + 'px';
      el.style.right = 'auto';
      el.style.bottom = 'auto';
    });
    handle.addEventListener('pointerup', function () {
      if (!dragging) return;
      dragging = false;
      var r = el.getBoundingClientRect();
      LS.set('pos', { x: Math.round(r.left), y: Math.round(r.top) });
    });
  }

  /* ===================== 主流程 ===================== */

  var state = { busy: false };

  function pageUrl() {
    return location.origin + location.pathname;
  }

  async function start() {
    if (state.busy) return;
    state.busy = true;

    var ctl = new AbortController();
    ui.ctl = ctl;
    ui.busy(true, t('resolving'));
    ui.progress(0);
    ui.status(t('resolving'));

    var t0 = Date.now();

    try {
      var cid = await getClientId();
      if (!cid) throw new Error(t('noCid'));

      var obj = await resolvePage(pageUrl(), cid, ctl.signal);
      var tracks, isSet = false;

      if (obj.kind === 'playlist' || obj.kind === 'system-playlists' || obj.tracks) {
        isSet = true;
        ui.status(t('playlist') + ': ' + (obj.title || '') + ' · ' + (obj.track_count || 0) + ' ' + t('tracks'));
        tracks = await playlistTracks(obj, cid, ctl.signal);
      } else if (obj.kind === 'track') {
        tracks = [obj];
      } else {
        throw new Error(t('notTrack'));
      }

      if (!tracks.length) throw new Error(t('notTrack'));

      // 歌单：先选目录（需要用户手势，趁早）
      var dir = null;
      if (isSet && cfg.stream && canPickDir()) {
        ui.status(t('chooseDir'));
        try { dir = await window.showDirectoryPicker({ mode: 'readwrite' }); }
        catch (e) { if (isAbort(e)) throw e; ui.log(t('noPicker')); }
      }

      var okCount = 0, failCount = 0;

      for (var i = 0; i < tracks.length; i++) {
        if (ctl.signal.aborted) throw abortError();
        var tr = tracks[i];
        var label = '(' + (i + 1) + '/' + tracks.length + ') ' + (tr.title || tr.id);
        ui.status(label);
        ui.busy(true, t('working'));
        ui.progress(0);
        ui.log(label);

        try {
          var res = await grabTrack(tr, cid, ctl, {
            dir: dir,
            onProg: function (p) {
              var pct = p.total ? (p.done / p.total * 100)
                : (p.totalBytes ? (p.bytes / p.totalBytes * 100) : 0);
              ui.progress(pct);
              var sp = p.elapsed > 600 ? p.bytes / (p.elapsed / 1000) : 0;
              ui.status(label + ' · ' + Math.round(pct) + '% · ' + fmtBytes(p.bytes) +
                (p.total ? ' · ' + p.done + '/' + p.total + ' ' + t('seg') : '') +
                (sp ? ' · ' + fmtBytes(sp) + '/s' : ''));
            }
          });
          ui.lastUrl = res.url;
          okCount++;
          ui.progress(100);
          ui.log('✓ ' + res.file + '  ' + fmtBytes(res.size));
        } catch (e) {
          if (isAbort(e)) throw e;
          failCount++;
          ui.log('✗ ' + label + ' — ' + (e.message || e));
        }
      }

      ui.status(t('doneAll') + '  ✓ ' + okCount + (failCount ? '  ✗ ' + failCount : '') +
        '  (' + ((Date.now() - t0) / 1000).toFixed(1) + 's)');
    } catch (e) {
      if (isAbort(e)) {
        ui.log(t('aborted'));
        ui.status(t('aborted'));
      } else {
        ui.log('✗ ' + (e.message || e));
        ui.status('✗ ' + (e.message || e));
      }
    } finally {
      state.busy = false;
      ui.ctl = null;
      ui.busy(false);
      ui.el.go.textContent = t('grab');
    }
  }

  /* ===================== 启动 ===================== */

  function mount() {
    buildUi();
    refreshMeta();

    // SPA 路由变化
    var last = location.href;
    setInterval(function () {
      if (location.href === last) return;
      last = location.href;
      refreshMeta();
    }, 800);

    document.addEventListener('keydown', function (e) {
      if (e.altKey && (e.key === 'g' || e.key === 'G')) {
        e.preventDefault();
        if (!ui.el.wrap) return;
        ui.el.wrap.style.display = '';
        ui.el.pill.style.display = 'none';
        start();
      }
    }, true);
  }

  function refreshMeta() {
    if (!ui.el.meta) return;
    var title = String(document.title || '')
      .replace(/\s*\|\s*(Listen online for free|Free Listening)[^|]*$/i, '')
      .replace(/^Stream\s+(.+?)\s+by\s+.+$/, '$1')
      .trim();
    ui.el.meta.textContent = title || t('ready');
  }

  if (document.readyState === 'loading') {
    document.addEventListener('DOMContentLoaded', mount);
  } else {
    mount();
  }

  // 控制台入口
  window.scGrab = function () {
    if (!ui.el.wrap) mount();
    else if (ui.el.wrap.style.display === 'none') { ui.el.wrap.style.display = ''; ui.el.pill.style.display = 'none'; }
    return start();
  };
  window.scGrabInfo = function () { return { version: VERSION, cfg: cfg, busy: state.busy }; };
})();