// ==UserScript==
// @name         WE Learn 课件资源助手
// @namespace    https://cxbank.icu/welearn-tool
// @version      1.0.1
// @description  解析当前课件页的音频/视频/PDF 资源并一键下载，附带学习时长统计。只在主页面工作，不需要进入课件 iframe。
// @author       cx
// @match        *://welearn.sflep.com/*
// @match        *://course.sflep.com/*
// @match        *://wetest.sflep.com/*
// @connect      centercourseware.sflep.com
// @connect      sflep.com
// @grant        GM_xmlhttpRequest
// @grant        unsafeWindow
// @run-at       document-idle
// ==/UserScript==

(function () {
  'use strict';

  var BUILD = '1.0.1';
  var LS = { study: 'wlt_study_', pos: 'wlt_panel_pos' };

  var S = {
    resources: [],
    busy: false,
    log: [],
    timer: null,
    studySec: 0,
  };

  /* ---------------- 工具 ---------------- */
  function sleep(ms) { return new Promise(function (r) { setTimeout(r, ms); }); }
  function qsa(sel, root) { try { return Array.prototype.slice.call((root || document).querySelectorAll(sel)); } catch (e) { return []; } }
  function todayKey() { return LS.study + new Date().toISOString().slice(0, 10); }

  function log(t, kind) {
    var tm = new Date().toLocaleTimeString('zh-CN', { hour12: false });
    S.log.push({ t: t, kind: kind || 'info', tm: tm });
    if (S.log.length > 80) S.log.shift();
    renderLog();
  }

  /* ---------------- 找课件 iframe ---------------- */
  function coursewareFrame() {
    var list = qsa('iframe');
    for (var i = 0; i < list.length; i++) {
      var src = list[i].getAttribute('src') || '';
      if (src.indexOf('centercourseware') >= 0) return src;
    }
    return '';
  }

  function parseFrame(src) {
    try {
      var u = new URL(src, location.href);
      var m = u.pathname.match(/^\/([^/]+)\/([^/]+)\/([^/]+)$/);
      return {
        href: u.href,
        course: m ? decodeURIComponent(m[1]) : '',
        unit: m ? m[2] : '',
        page: m ? m[3] : '',
        origin: u.origin,
        query: u.search,
      };
    } catch (e) { return null; }
  }

  /* ---------------- 拉取课件 HTML（跨域用 GM 请求） ---------------- */
  function gmGet(url, type) {
    return new Promise(function (resolve, reject) {
      try {
        GM_xmlhttpRequest({
          method: 'GET',
          url: url,
          responseType: type || 'text',
          timeout: 30000,
          onload: function (r) {
            if (r.status >= 200 && r.status < 300) resolve(r.response);
            else reject(new Error('HTTP ' + r.status));
          },
          onerror: function () { reject(new Error('网络错误')); },
          ontimeout: function () { reject(new Error('超时')); },
        });
      } catch (e) { reject(e); }
    });
  }

  /* ---------------- 解析资源 ---------------- */
  var EXT_RE = /\.(mp3|mp4|m4a|wav|ogg|pdf|docx?|pptx?|xlsx?|zip|png|jpe?g|gif|svg)$/i;

  function extractResources(html, base) {
    var out = [];
    var seen = {};
    var re = /(?:src|href)\s*=\s*["']([^"']+)["']/gi;
    var m;
    while ((m = re.exec(html))) {
      var raw = m[1];
      if (!EXT_RE.test(raw)) continue;
      var abs;
      try { abs = new URL(raw, base).href; } catch (e) { continue; }
      /* 过滤掉界面音效 / 样式脚本里的图 */
      var low = abs.toLowerCase();
      if (low.indexOf('/resource/') >= 0) continue;
      if (/(^|\/)(t|f|empty|click|correct|wrong)\.mp3$/.test(low)) continue;
      if (seen[abs]) continue;
      seen[abs] = 1;
      out.push({
        url: abs,
        name: decodeURIComponent(abs.split('/').pop().split('?')[0]),
        ext: (abs.match(EXT_RE) || [, ''])[1].toLowerCase(),
      });
    }
    return out;
  }

  async function scan() {
    if (S.busy) return;
    var src = coursewareFrame();
    if (!src) { log('当前页面没有课件，先点「目录」进入具体一节', 'warn'); return; }
    var info = parseFrame(src);
    if (!info) { log('课件地址解析失败', 'warn'); return; }

    S.busy = true;
    render();
    log('正在解析：' + info.unit + ' / ' + info.page);
    try {
      var html = await gmGet(info.href, 'text');
      var list = extractResources(html, info.href);
      /* 同一单元的其它页面也可以顺带扫一下 */
      S.resources = list;
      log('找到 ' + list.length + ' 个资源', 'ok');
      render();
    } catch (e) {
      log('解析失败：' + e.message + '（可尝试直接打开课件地址）', 'warn');
    } finally {
      S.busy = false;
      render();
    }
  }

  /* ---------------- 下载 ---------------- */
  function saveBlob(blob, name) {
    var url = URL.createObjectURL(blob);
    var a = document.createElement('a');
    a.href = url;
    a.download = name || 'download';
    document.body.appendChild(a);
    a.click();
    setTimeout(function () { URL.revokeObjectURL(url); a.remove(); }, 5000);
  }

  async function downloadOne(item) {
    try {
      log('下载中：' + item.name);
      var blob = await gmGet(item.url, 'blob');
      saveBlob(blob instanceof Blob ? blob : new Blob([blob]), item.name);
      log('完成：' + item.name, 'ok');
    } catch (e) {
      log('失败：' + item.name + '（' + e.message + '）', 'warn');
    }
  }

  async function downloadAll() {
    var audio = S.resources.filter(function (r) { return /^(mp3|m4a|wav|ogg|mp4)$/.test(r.ext); });
    if (!audio.length) { log('没有音频/视频可下载', 'warn'); return; }
    log('开始批量下载 ' + audio.length + ' 个文件');
    for (var i = 0; i < audio.length; i++) {
      await downloadOne(audio[i]);
      await sleep(600);
    }
    log('批量下载结束', 'ok');
  }

  /* ---------------- 学习时长 ---------------- */
  function loadStudy() {
    try { return Number(localStorage.getItem(todayKey()) || 0) || 0; } catch (e) { return 0; }
  }
  function saveStudy(v) {
    try { localStorage.setItem(todayKey(), String(v)); } catch (e) {}
  }
  function fmtDur(sec) {
    var h = Math.floor(sec / 3600), m = Math.floor((sec % 3600) / 60), s = sec % 60;
    return (h ? h + ' 时 ' : '') + m + ' 分 ' + s + ' 秒';
  }
  function startTimer() {
    S.studySec = loadStudy();
    S.timer = setInterval(function () {
      if (document.visibilityState === 'hidden') return;
      S.studySec++;
      if (S.studySec % 5 === 0) saveStudy(S.studySec);
      var el = document.getElementById('wlt-study');
      if (el) el.textContent = fmtDur(S.studySec);
    }, 1000);
  }

  /* ---------------- 面板 ---------------- */
  var root = null;

  var CSS = [
    ':host{all:initial}',
    '.wrap{position:fixed;right:14px;top:14px;width:330px;z-index:2147483000;',
    'background:rgba(255,255,255,.94);backdrop-filter:blur(18px);border:.5px solid rgba(60,60,67,.14);',
    'border-radius:14px;box-shadow:0 10px 34px rgba(0,0,0,.2);',
    'font:13px/1.6 -apple-system,"Segoe UI",sans-serif;color:#1c1c1e;overflow:hidden}',
    '.hd{padding:10px 12px;border-bottom:.5px solid rgba(60,60,67,.12);display:flex;align-items:center;gap:7px}',
    '.ttl{flex:1;font-weight:700;font-size:12.5px}',
    '.ver{color:#8e8e93;font-weight:500;font-size:11px}',
    '.bd{padding:10px 12px 12px}',
    '.row{display:flex;justify-content:space-between;font-size:11.5px;color:#8e8e93;margin-bottom:8px}',
    '.row b{color:#1c1c1e}',
    '.btns{display:flex;gap:8px;margin:10px 0}',
    '.btn{flex:1;border:none;border-radius:9px;padding:8px 0;font:600 12.5px inherit;cursor:pointer}',
    '.b1{background:#007aff;color:#fff}',
    '.b2{background:#34c759;color:#fff}',
    '.list{max-height:190px;overflow:auto;border:.5px solid rgba(60,60,67,.12);border-radius:9px}',
    '.item{display:flex;align-items:center;gap:8px;padding:7px 9px;border-bottom:.5px solid rgba(60,60,67,.08)}',
    '.item:last-child{border-bottom:none}',
    '.item .n{flex:1;font-size:11.5px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}',
    '.item .x{border:none;background:#f2f2f7;border-radius:7px;padding:4px 9px;font:600 11px inherit;cursor:pointer}',
    '.log{max-height:120px;overflow:auto;background:#f7f7fa;border-radius:9px;padding:7px 9px;',
    'font:11.5px/1.6 ui-monospace,Consolas,monospace;color:#3a3a3c;margin-top:10px}',
    '.log .ok{color:#248a3d}.log .warn{color:#c77700}',
    '.qq{margin-top:10px;text-align:center;font-size:11.5px;color:#007aff;background:rgba(0,122,255,.08);',
    'border-radius:9px;padding:6px}',
    '.empty{color:#8e8e93;font-size:11.5px;text-align:center;padding:14px}',
  ].join('');

  function el(id) { try { return root ? root.getElementById(id) : null; } catch (e) { return null; } }

  function build() {
    var host = document.createElement('div');
    host.id = 'wlt-host';
    root = host.attachShadow({ mode: 'open' });
    var st = document.createElement('style');
    st.textContent = CSS;
    root.appendChild(st);

    var wrap = document.createElement('div');
    wrap.className = 'wrap';
    wrap.innerHTML =
      '<div class="hd"><div class="ttl">课件资源助手 <span class="ver">' + BUILD + '</span></div></div>' +
      '<div class="bd">' +
      '<div class="row"><span>当前课件</span><b id="cur">-</b></div>' +
      '<div class="row"><span>今日学习</span><b id="wlt-study">-</b></div>' +
      '<div class="btns">' +
      '<button class="btn b1" id="bScan">解析本页资源</button>' +
      '<button class="btn b2" id="bAll">批量下载音频</button>' +
      '</div>' +
      '<div class="list" id="list"><div class="empty">点上面「解析本页资源」</div></div>' +
      '<div class="log" id="log"></div>' +
      '<div class="qq">有问题加 QQ 群：228460464</div>' +
      '</div>';
    root.appendChild(wrap);
    document.body.appendChild(host);

    /* 拖动 */
    var drag = null;
    root.querySelector('.hd').addEventListener('mousedown', function (e) {
      drag = { x: e.clientX, y: e.clientY, r: wrap.getBoundingClientRect() };
      e.preventDefault();
    });
    document.addEventListener('mousemove', function (e) {
      if (!drag) return;
      wrap.style.left = Math.max(0, drag.r.left + e.clientX - drag.x) + 'px';
      wrap.style.top = Math.max(0, drag.r.top + e.clientY - drag.y) + 'px';
      wrap.style.right = 'auto';
    });
    document.addEventListener('mouseup', function () { drag = null; });

    root.getElementById('bScan').onclick = function () { scan(); };
    root.getElementById('bAll').onclick = function () { downloadAll(); };
    render();
  }

  function render() {
    try {
      var src = coursewareFrame();
      var info = src ? parseFrame(src) : null;
      var cur = el('cur');
      if (cur) cur.textContent = info ? (info.unit + ' / ' + info.page) : '未进入课件';
      var st = el('wlt-study');
      if (st) st.textContent = fmtDur(S.studySec);

      var list = el('list');
      if (!list) return;
      if (!S.resources.length) {
        list.innerHTML = '<div class="empty">' + (S.busy ? '解析中…' : '点上面「解析本页资源」') + '</div>';
      } else {
        list.innerHTML = '';
        S.resources.forEach(function (r) {
          var d = document.createElement('div');
          d.className = 'item';
          var n = document.createElement('div');
          n.className = 'n';
          n.textContent = r.name;
          n.title = r.url;
          var b = document.createElement('button');
          b.className = 'x';
          b.textContent = '下载';
          b.onclick = function () { downloadOne(r); };
          d.appendChild(n); d.appendChild(b);
          list.appendChild(d);
        });
      }
    } catch (e) {}
  }

  function renderLog() {
    try {
      var box = el('log');
      if (!box) return;
      box.innerHTML = S.log.slice(-30).map(function (x) {
        return '<div class="' + x.kind + '">' + x.tm + '  ' + String(x.t).replace(/[<>&]/g, function (c) {
          return { '<': '&lt;', '>': '&gt;', '&': '&amp;' }[c];
        }) + '</div>';
      }).join('');
      box.scrollTop = box.scrollHeight;
    } catch (e) {}
  }

  /* ---------------- 启动 ---------------- */
  function boot() {
    if (!document.body) { setTimeout(boot, 300); return; }
    if (document.getElementById('wlt-host')) return;
    try {
      build();
      startTimer();
      log('已加载 v' + BUILD);
      /* 课件切页时刷新显示 */
      setInterval(function () { render(); }, 3000);
      window.addEventListener('hashchange', function () { S.resources = []; render(); });
    } catch (e) { try { console.warn('[课件资源助手]', e); } catch (x) {} }
  }

  if (document.readyState === 'loading') document.addEventListener('DOMContentLoaded', boot);
  else setTimeout(boot, 500);

  window.__wlt = { state: S, scan: scan, downloadAll: downloadAll, resources: function () { return S.resources; } };
})();