// ==UserScript==
// @name         学习视频文字提取助手
// @namespace    https://github.com/local/study-video-text-extractor
// @version      1.0.0
// @icon         data:image/svg+xml;charset=utf-8,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath fill='%232563eb' d='M6 2h9l5 5v15H6z'/%3E%3Cpath fill='%23ffffff' d='M15 2v6h5'/%3E%3Cpath fill='%23ffffff' d='M9 12h6M9 15h6M9 18h4'/%3E%3C/svg%3E
// @description  在看学习类视频时自动收集字幕，提取简介和评论区里的学习链接与重点句子，一键复制，方便粘贴到笔记。
// @author       Codex
// @match        *://*.bilibili.com/video/*
// @match        *://*.bilibili.com/bangumi/play/*
// @match        *://*.bilibili.com/list/*
// @match        *://www.youtube.com/watch*
// @match        *://m.youtube.com/watch*
// @grant        GM_getValue
// @grant        GM_setValue
// @grant        GM_setClipboard
// @grant        GM_registerMenuCommand
// @run-at       document-idle
// @noframes
// @license      MIT
// ==/UserScript==

(function () {
  'use strict';

  const APP_ID = 'study-video-text-extractor';
  const STORE_KEY = APP_ID + ':notes:v1';
  const MAX_SEGMENTS = 800;
  const MAX_HIGHLIGHTS = 300;
  const MAX_LINKS = 200;
  const MAX_STORED_VIDEOS = 30;

  const HIGHLIGHT_KEYWORDS = [
    '重点', '考点', '必考', '注意', '牢记', '记住', '关键', '核心', '总结', '结论',
    '定义', '公式', '定理', '方法', '步骤', '技巧', '误区', '易错', '错误', '常见',
    '典型', '例题', '提示', '提醒', '一定要', '必须', '重要', '切记', '快捷键',
    '命令', '参数', 'note', 'important', 'tip', 'key', 'remember', 'summary',
    'warning', 'error', 'faq'
  ];

  const URL_RE = /\bhttps?:\/\/[^\s<>"'()\[\]）】]+/gi;

  function detectSite() {
    const host = location.hostname.toLowerCase();
    if (host === 'bilibili.com' || host.endsWith('.bilibili.com')) return 'bilibili';
    if (host === 'youtube.com' || host.endsWith('.youtube.com') || host === 'youtu.be' || host.endsWith('.youtu.be')) {
      return 'youtube';
    }
    return null;
  }

  const site = detectSite();
  if (!site) return;

  const gm = {
    getValue: typeof GM_getValue === 'function' ? GM_getValue : null,
    setValue: typeof GM_setValue === 'function' ? GM_setValue : null,
    setClipboard: typeof GM_setClipboard === 'function' ? GM_setClipboard : null,
    registerMenuCommand: typeof GM_registerMenuCommand === 'function' ? GM_registerMenuCommand : null
  };

  const state = {
    videoKey: '',
    title: '',
    segments: [],
    highlights: [],
    links: [],
    autoCapture: true,
    panelOpen: false,
    activeTab: 'subtitles',
    seenAnchors: new WeakSet(),
    tickCount: 0,
    saveTimer: null,
    extractTimers: []
  };

  const lastRendered = { subtitles: -1, highlights: -1, links: -1 };

  let root = null;
  let panelEl = null;
  let fabEl = null;
  let toastEl = null;
  let toastTimer = null;

  function loadNotes() {
    try {
      if (gm.getValue) {
        const val = gm.getValue(STORE_KEY, {});
        if (val && typeof val === 'object') return val;
      }
    } catch (e) {}
    try {
      const raw = window.localStorage.getItem(STORE_KEY);
      if (raw) {
        const val = JSON.parse(raw);
        if (val && typeof val === 'object') return val;
      }
    } catch (e) {}
    return {};
  }

  function writeNotes(notes) {
    try {
      if (gm.setValue) {
        gm.setValue(STORE_KEY, notes);
        return;
      }
    } catch (e) {}
    try {
      window.localStorage.setItem(STORE_KEY, JSON.stringify(notes));
    } catch (e) {}
  }

  function currentVideoKey() {
    const url = new URL(location.href);
    if (site === 'bilibili') {
      const m = url.pathname.match(/^\/(?:video|bangumi\/play|list)\/([^/?#]+)/);
      return 'bilibili:' + (m ? m[1] : url.pathname + url.search);
    }
    if (site === 'youtube') {
      const v = url.searchParams.get('v');
      return 'youtube:' + (v || url.pathname + url.search);
    }
    return url.href;
  }

  function loadVideoState() {
    const key = currentVideoKey();
    const entry = loadNotes()[key] || {};
    state.videoKey = key;
    state.title = entry.title || '';
    state.segments = Array.isArray(entry.segments) ? entry.segments : [];
    state.highlights = Array.isArray(entry.highlights) ? entry.highlights : [];
    state.links = Array.isArray(entry.links) ? entry.links : [];
    state.seenAnchors = new WeakSet();
    state.tickCount = 0;
  }

  function saveNow() {
    const notes = loadNotes();
    const keys = Object.keys(notes);
    if (keys.length >= MAX_STORED_VIDEOS) {
      keys.sort(function (a, b) {
        return (notes[a].updatedAt || 0) - (notes[b].updatedAt || 0);
      });
      while (keys.length >= MAX_STORED_VIDEOS) {
        delete notes[keys.shift()];
      }
    }
    notes[state.videoKey] = {
      title: state.title,
      segments: state.segments.slice(-MAX_SEGMENTS),
      highlights: state.highlights.slice(0, MAX_HIGHLIGHTS),
      links: state.links.slice(0, MAX_LINKS),
      updatedAt: Date.now()
    };
    writeNotes(notes);
  }

  function scheduleSave() {
    if (state.saveTimer) return;
    state.saveTimer = setTimeout(function () {
      state.saveTimer = null;
      saveNow();
    }, 400);
  }

  function normalizeText(s) {
    return String(s || '').replace(/\s+/g, ' ').trim();
  }

  function splitLines(text) {
    return String(text || '').split(/\r?\n/).map(function (line) {
      return line.trim();
    }).filter(Boolean);
  }

  function formatTime(seconds) {
    if (typeof seconds !== 'number' || !Number.isFinite(seconds) || seconds < 0) return '00:00';
    const total = Math.floor(seconds);
    const h = Math.floor(total / 3600);
    const m = Math.floor((total % 3600) / 60);
    const s = total % 60;
    const mm = String(m).padStart(2, '0');
    const ss = String(s).padStart(2, '0');
    return h > 0 ? h + ':' + mm + ':' + ss : mm + ':' + ss;
  }

  function matchKeyword(text) {
    const t = String(text || '').toLowerCase();
    for (let i = 0; i < HIGHLIGHT_KEYWORDS.length; i++) {
      const k = HIGHLIGHT_KEYWORDS[i];
      if (t.indexOf(k.toLowerCase()) !== -1) return k;
    }
    return '';
  }

  function isHighlight(text) {
    return matchKeyword(text) !== '';
  }

  function isChapterLine(line) {
    return /^\s*\d{1,2}:\d{2}(:\d{2})?\s+/.test(line);
  }

  function uniqueLines(lines) {
    const seen = new Set();
    const out = [];
    for (let i = 0; i < lines.length; i++) {
      const key = normalizeText(lines[i]);
      if (!key || seen.has(key)) continue;
      seen.add(key);
      out.push(lines[i].trim());
    }
    return out;
  }

  function readCaptionLines() {
    if (site === 'bilibili') {
      const box = document.querySelector('.bpx-player-subtitle');
      if (!box) return [];
      const spans = Array.prototype.slice.call(box.querySelectorAll('span'));
      let chosen = spans.filter(function (el) {
        return el.classList.contains('bpx-player-subtitle-text');
      });
      if (!chosen.length) {
        chosen = spans.filter(function (el) {
          return !el.querySelector('span');
        });
      }
      if (!chosen.length) chosen = [box];
      return uniqueLines(chosen.map(function (el) {
        return el.textContent;
      }));
    }
    if (site === 'youtube') {
      const container = document.querySelector('.ytp-caption-window-container');
      if (!container) return [];
      const segs = Array.prototype.slice.call(container.querySelectorAll('.ytp-caption-segment'));
      return uniqueLines(segs.map(function (el) {
        return el.textContent;
      }));
    }
    return [];
  }

  function addHighlight(h) {
    const key = normalizeText(h.text);
    if (!key) return;
    const dup = state.highlights.some(function (x) {
      return normalizeText(x.text) === key;
    });
    if (dup) return;
    state.highlights.push(h);
    if (state.highlights.length > MAX_HIGHLIGHTS) {
      state.highlights.splice(0, state.highlights.length - MAX_HIGHLIGHTS);
    }
    scheduleSave();
  }

  function captureTick() {
    if (!state.autoCapture) return;
    const video = document.querySelector('video');
    if (!video) return;
    const lines = readCaptionLines();
    if (!lines.length) return;
    const now = typeof video.currentTime === 'number' ? video.currentTime : 0;
    const recent = state.segments.slice(-8);
    let changed = false;
    for (let i = 0; i < lines.length; i++) {
      const line = lines[i];
      const key = normalizeText(line);
      if (!key) continue;
      const dup = recent.some(function (s) {
        return normalizeText(s.text) === key && Math.abs((s.time || 0) - now) < 5;
      });
      if (dup) continue;
      state.segments.push({ time: now, text: line, source: 'subtitle' });
      changed = true;
      if (isHighlight(line)) {
        addHighlight({ time: now, text: line, source: 'subtitle' });
      }
    }
    if (changed) {
      if (state.segments.length > MAX_SEGMENTS) {
        state.segments.splice(0, state.segments.length - MAX_SEGMENTS);
      }
      scheduleSave();
    }
  }

  function normalizeUrl(url) {
    return String(url || '').replace(/[.,;:!?，。；：！？、]+$/, '').trim();
  }

  function extractUrls(text) {
    if (!text) return [];
    const out = [];
    const re = new RegExp(URL_RE.source, 'gi');
    let m;
    while ((m = re.exec(String(text))) !== null) {
      out.push(m[0]);
    }
    return out;
  }

  function isNoiseUrl(raw) {
    try {
      const u = new URL(raw);
      const host = u.hostname.replace(/^www\./, '').toLowerCase();
      const path = u.pathname.replace(/\/+$/, '').toLowerCase();
      if (/\.(png|jpe?g|gif|webp|svg|ico|css|js)$/i.test(path)) return true;
      if (host === 'youtube.com' || host.endsWith('.youtube.com') || host === 'youtu.be') return true;
      if (host === 'bilibili.com' || host.endsWith('.bilibili.com')) {
        if (/^\/(?:$|login|register|passport|account|search|watchlater|history|fav|following|friends|index|v\d|readlist|blackboard)/.test(path)) {
          return true;
        }
        return false;
      }
      if (!path || path === '/' || path === '/index.html' || path === '/index.php') return true;
    } catch (e) {}
    return false;
  }

  function linkFromAnchor(a, source) {
    if (!a || !a.getAttribute) return null;
    const href = a.getAttribute('href');
    if (!href) return null;
    let url;
    try {
      url = new URL(href, location.href).href;
    } catch (e) {
      return null;
    }
    if (!/^https?:/i.test(url)) return null;
    if (isNoiseUrl(url)) return null;
    const label = normalizeText(a.textContent) || url;
    const context = normalizeText(a.parentElement ? a.parentElement.textContent : '');
    const keyword = matchKeyword(context + ' ' + label);
    return {
      url: url,
      label: label.slice(0, 100),
      source: source || '',
      keyword: keyword || ''
    };
  }

  function addLink(link) {
    if (!link || !link.url) return;
    const clean = function (u) {
      return normalizeUrl(u).replace(/\/+$/, '');
    };
    const u = clean(link.url);
    const dup = state.links.some(function (l) {
      return clean(l.url) === u;
    });
    if (dup) return;
    state.links.push({
      url: u,
      label: link.label || u,
      source: link.source || '',
      keyword: link.keyword || ''
    });
    if (state.links.length > MAX_LINKS) {
      state.links.splice(0, state.links.length - MAX_LINKS);
    }
    scheduleSave();
  }

  function scanPageForLinks() {
    const containers = [];
    if (site === 'bilibili') {
      const desc = document.querySelector('#v_desc, .basic-desc-info, .desc-info-text');
      if (desc) containers.push({ el: desc, source: '简介' });
      const comments = document.querySelectorAll('#commentapp, .reply-wrap, .comment-container');
      for (let i = 0; i < comments.length; i++) {
        containers.push({ el: comments[i], source: '评论区' });
      }
    } else if (site === 'youtube') {
      const desc = document.querySelector('#description, #description-inline-expander, ytd-text-inline-expander#description');
      if (desc) containers.push({ el: desc, source: '简介' });
      const comments = document.querySelectorAll('#comments, ytd-comment-thread-renderer');
      for (let i = 0; i < comments.length; i++) {
        containers.push({ el: comments[i], source: '评论区' });
      }
    }
    for (let c = 0; c < containers.length; c++) {
      const item = containers[c];
      const anchors = item.el.querySelectorAll('a[href]');
      for (let i = 0; i < anchors.length; i++) {
        const a = anchors[i];
        if (state.seenAnchors.has(a)) continue;
        state.seenAnchors.add(a);
        const link = linkFromAnchor(a, item.source);
        if (link) addLink(link);
      }
      const lines = splitLines(item.el.textContent);
      for (let i = 0; i < lines.length; i++) {
        if (isHighlight(lines[i])) {
          addHighlight({ time: null, text: lines[i], source: item.source });
        }
      }
    }
  }

  function descriptionLines() {
    if (site === 'bilibili') {
      try {
        const init = window.__INITIAL_STATE__;
        if (init && init.videoData && init.videoData.desc) {
          return splitLines(init.videoData.desc);
        }
      } catch (e) {}
      const dom = document.querySelector('#v_desc, .basic-desc-info, .desc-info-text');
      if (dom) return splitLines(dom.textContent);
      return [];
    }
    if (site === 'youtube') {
      try {
        const resp = window.ytInitialPlayerResponse;
        if (resp && resp.videoDetails && resp.videoDetails.shortDescription) {
          return splitLines(resp.videoDetails.shortDescription);
        }
      } catch (e) {}
      const dom = document.querySelector('#description, #description-inline-expander, ytd-text-inline-expander#description');
      if (dom) return splitLines(dom.textContent);
      return [];
    }
    return [];
  }

  function readTitle() {
    if (site === 'bilibili') {
      const el = document.querySelector('#viewbox_report h1, .video-title, h1');
      return normalizeText(el ? el.textContent : '');
    }
    if (site === 'youtube') {
      const el = document.querySelector('h1 yt-formatted-string, h1.title');
      return normalizeText(el ? el.textContent : '');
    }
    return '';
  }

  function extractStatic() {
    const t = readTitle();
    if (t) state.title = t;

    const lines = descriptionLines();
    for (let i = 0; i < lines.length; i++) {
      const line = lines[i];
      const urls = extractUrls(line);
      if (urls.length) {
        const label = normalizeText(line.replace(URL_RE, ' ')) || line.slice(0, 60);
        for (let j = 0; j < urls.length; j++) {
          addLink({
            url: normalizeUrl(urls[j]),
            label: label.slice(0, 100),
            source: '简介',
            keyword: matchKeyword(line)
          });
        }
      } else if (isHighlight(line) || isChapterLine(line)) {
        addHighlight({ time: null, text: line, source: '简介' });
      }
    }

    scanPageForLinks();
    scheduleSave();
  }

  function buildSummary() {
    const parts = [];
    parts.push('# ' + (state.title || '学习视频笔记'));
    parts.push('来源: ' + location.href);
    parts.push('');
    if (state.segments.length) {
      parts.push('## 字幕 (' + state.segments.length + ')');
      for (let i = 0; i < state.segments.length; i++) {
        const s = state.segments[i];
        parts.push('[' + formatTime(s.time) + '] ' + s.text);
      }
      parts.push('');
    }
    if (state.highlights.length) {
      parts.push('## 重点句子 (' + state.highlights.length + ')');
      for (let i = 0; i < state.highlights.length; i++) {
        const h = state.highlights[i];
        parts.push('- ' + (typeof h.time === 'number' ? '[' + formatTime(h.time) + '] ' : '') + h.text + (h.source ? '  (' + h.source + ')' : ''));
      }
      parts.push('');
    }
    if (state.links.length) {
      parts.push('## 学习链接 (' + state.links.length + ')');
      for (let i = 0; i < state.links.length; i++) {
        const l = state.links[i];
        let line = '- ';
        if (l.keyword) line += l.keyword + ' | ';
        if (l.label && l.label !== l.url) line += l.label + ': ';
        line += l.url;
        if (l.source) line += '  (' + l.source + ')';
        parts.push(line);
      }
    }
    return parts.join('\n');
  }

  function contentForTab(tab) {
    if (tab === 'subtitles') {
      return state.segments.map(function (s) {
        return '[' + formatTime(s.time) + '] ' + s.text;
      }).join('\n');
    }
    if (tab === 'highlights') {
      return state.highlights.map(function (h) {
        return (typeof h.time === 'number' ? '[' + formatTime(h.time) + '] ' : '') + h.text + (h.source ? ' (' + h.source + ')' : '');
      }).join('\n');
    }
    if (tab === 'links') {
      return state.links.map(function (l) {
        return (l.label && l.label !== l.url ? l.label + ': ' : '') + l.url;
      }).join('\n');
    }
    return buildSummary();
  }

  function textForCopySpec(spec) {
    const parts = String(spec || '').split(':');
    const kind = parts[0];
    const index = Number(parts[1]);
    if (kind === 'segment' && state.segments[index]) {
      return '[' + formatTime(state.segments[index].time) + '] ' + state.segments[index].text;
    }
    if (kind === 'highlight' && state.highlights[index]) {
      const h = state.highlights[index];
      return (typeof h.time === 'number' ? '[' + formatTime(h.time) + '] ' : '') + h.text;
    }
    if (kind === 'link' && state.links[index]) {
      const l = state.links[index];
      return (l.label && l.label !== l.url ? l.label + ': ' : '') + l.url;
    }
    return '';
  }

  function emptyHint(msg) {
    const div = document.createElement('div');
    div.className = 'lte-empty';
    div.textContent = msg;
    return div;
  }

  function segmentItem(s, index) {
    const row = document.createElement('div');
    row.className = 'lte-item';
    row.title = '点击复制';
    row.dataset.copy = 'segment:' + index;
    const time = document.createElement('span');
    time.className = 'lte-time';
    time.textContent = '[' + formatTime(s.time) + ']';
    const text = document.createElement('span');
    text.className = 'lte-text';
    text.textContent = s.text;
    row.appendChild(time);
    row.appendChild(text);
    return row;
  }

  function highlightItem(h, index) {
    const row = document.createElement('div');
    row.className = 'lte-item';
    row.title = '点击复制';
    row.dataset.copy = 'highlight:' + index;
    if (typeof h.time === 'number') {
      const time = document.createElement('span');
      time.className = 'lte-time';
      time.textContent = '[' + formatTime(h.time) + ']';
      row.appendChild(time);
    }
    const text = document.createElement('span');
    text.className = 'lte-text';
    text.textContent = h.text;
    row.appendChild(text);
    const source = document.createElement('span');
    source.className = 'lte-source';
    source.textContent = h.source || '';
    row.appendChild(source);
    return row;
  }

  function linkItem(l, index) {
    const row = document.createElement('div');
    row.className = 'lte-link';
    const label = document.createElement('div');
    label.className = 'lte-link-label';
    label.textContent = l.label && l.label !== l.url ? l.label : '链接';
    row.appendChild(label);
    const url = document.createElement('div');
    url.className = 'lte-link-url';
    url.textContent = l.url;
    row.appendChild(url);
    const meta = document.createElement('div');
    meta.className = 'lte-link-meta';
    if (l.keyword) {
      const badge = document.createElement('span');
      badge.className = 'lte-tag';
      badge.textContent = l.keyword;
      meta.appendChild(badge);
    }
    const source = document.createElement('span');
    source.className = 'lte-source';
    source.textContent = l.source || '';
    meta.appendChild(source);
    const copyBtn = document.createElement('button');
    copyBtn.type = 'button';
    copyBtn.className = 'lte-copy-btn';
    copyBtn.textContent = '复制';
    copyBtn.dataset.copy = 'link:' + index;
    meta.appendChild(copyBtn);
    row.appendChild(meta);
    return row;
  }

  function renderSegments(pane) {
    pane.textContent = '';
    if (!state.segments.length) {
      pane.appendChild(emptyHint('打开视频字幕/CC 后会自动收集字幕'));
      return;
    }
    const frag = document.createDocumentFragment();
    for (let i = 0; i < state.segments.length; i++) {
      frag.appendChild(segmentItem(state.segments[i], i));
    }
    pane.appendChild(frag);
  }

  function renderHighlights(pane) {
    pane.textContent = '';
    if (!state.highlights.length) {
      pane.appendChild(emptyHint('包含重点/注意/公式/总结等关键词的句子会自动收集'));
      return;
    }
    const frag = document.createDocumentFragment();
    for (let i = 0; i < state.highlights.length; i++) {
      frag.appendChild(highlightItem(state.highlights[i], i));
    }
    pane.appendChild(frag);
  }

  function renderLinks(pane) {
    pane.textContent = '';
    if (!state.links.length) {
      pane.appendChild(emptyHint('简介和评论区中的学习链接会自动整理'));
      return;
    }
    const frag = document.createDocumentFragment();
    for (let i = 0; i < state.links.length; i++) {
      frag.appendChild(linkItem(state.links[i], i));
    }
    pane.appendChild(frag);
  }

  function renderSummary(pane) {
    pane.textContent = '';
    const ta = document.createElement('textarea');
    ta.className = 'lte-summary';
    ta.readOnly = true;
    ta.value = buildSummary();
    ta.addEventListener('focus', function () {
      ta.select();
    });
    pane.appendChild(ta);
  }

  function renderCounts() {
    if (!root) return;
    const counts = {
      subtitles: state.segments.length,
      highlights: state.highlights.length,
      links: state.links.length
    };
    const tabs = root.querySelectorAll('.lte-tabs [data-tab]');
    for (let i = 0; i < tabs.length; i++) {
      const countEl = tabs[i].querySelector('.lte-count');
      if (countEl) {
        const n = counts[tabs[i].dataset.tab] || 0;
        countEl.textContent = n ? String(n) : '';
        countEl.style.display = n ? '' : 'none';
      }
    }
  }

  function syncAutoButton() {
    if (!root) return;
    const btn = root.querySelector('[data-action="toggle-auto"]');
    if (!btn) return;
    btn.textContent = state.autoCapture ? '自动采集:开' : '自动采集:关';
    btn.classList.toggle('lte-btn-on', state.autoCapture);
  }

  function renderTab(force) {
    if (!root) return;
    const panes = root.querySelectorAll('.lte-pane');
    for (let i = 0; i < panes.length; i++) {
      panes[i].classList.toggle('lte-hidden', panes[i].dataset.pane !== state.activeTab);
    }
    const tabs = root.querySelectorAll('.lte-tabs [data-tab]');
    for (let i = 0; i < tabs.length; i++) {
      tabs[i].classList.toggle('lte-active', tabs[i].dataset.tab === state.activeTab);
    }
    const countMap = {
      subtitles: state.segments.length,
      highlights: state.highlights.length,
      links: state.links.length
    };
    const changed = force || lastRendered[state.activeTab] !== countMap[state.activeTab];
    if (changed || state.activeTab === 'summary') {
      const pane = root.querySelector('.lte-pane[data-pane="' + state.activeTab + '"]');
      if (pane) {
        if (state.activeTab === 'subtitles') renderSegments(pane);
        else if (state.activeTab === 'highlights') renderHighlights(pane);
        else if (state.activeTab === 'links') renderLinks(pane);
        else renderSummary(pane);
      }
      lastRendered[state.activeTab] = countMap[state.activeTab] || -1;
    }
    renderCounts();
    syncAutoButton();
  }

  function togglePanel() {
    state.panelOpen = !state.panelOpen;
    panelEl.classList.toggle('lte-hidden', !state.panelOpen);
    if (state.panelOpen) renderTab(true);
  }

  function toast(msg) {
    if (!toastEl) return;
    toastEl.textContent = msg;
    toastEl.classList.add('lte-show');
    if (toastTimer) clearTimeout(toastTimer);
    toastTimer = setTimeout(function () {
      toastEl.classList.remove('lte-show');
    }, 1800);
  }

  async function copyText(text) {
    if (!text) {
      toast('还没有可复制的内容');
      return;
    }
    let ok = false;
    try {
      if (gm.setClipboard) {
        gm.setClipboard(text, 'text');
        ok = true;
      }
    } catch (e) {}
    if (!ok) {
      try {
        await navigator.clipboard.writeText(text);
        ok = true;
      } catch (e) {}
    }
    if (!ok) {
      const ta = document.createElement('textarea');
      ta.value = text;
      ta.style.position = 'fixed';
      ta.style.opacity = '0';
      document.body.appendChild(ta);
      ta.select();
      try {
        ok = document.execCommand('copy');
      } catch (e) {}
      ta.remove();
    }
    toast(ok ? '已复制到剪贴板' : '复制失败，请手动选择复制');
  }

  function handleKeydown(e) {
    if (e.altKey && e.shiftKey && (e.key === 'X' || e.key === 'x')) {
      e.preventDefault();
      togglePanel();
    }
  }

  function handleClick(e) {
    const tabBtn = e.target.closest('[data-tab]');
    if (tabBtn) {
      state.activeTab = tabBtn.dataset.tab;
      renderTab(true);
      return;
    }
    const actionBtn = e.target.closest('[data-action]');
    if (actionBtn) {
      const action = actionBtn.dataset.action;
      if (action === 'toggle-auto') {
        state.autoCapture = !state.autoCapture;
        syncAutoButton();
        toast(state.autoCapture ? '自动采集已开启' : '自动采集已关闭');
      } else if (action === 'copy') {
        copyText(contentForTab(state.activeTab));
      } else if (action === 'clear') {
        state.segments = [];
        state.highlights = [];
        state.links = [];
        saveNow();
        renderTab(true);
        toast('已清空当前视频的记录');
      } else if (action === 'close') {
        togglePanel();
      }
      return;
    }
    const copyEl = e.target.closest('[data-copy]');
    if (copyEl) {
      const text = textForCopySpec(copyEl.dataset.copy);
      if (text) copyText(text);
    }
  }

  const STYLE_TEXT = [
    '#lte-root, #lte-root * { box-sizing: border-box; }',
    '#lte-root { all: initial; --lte-panel:#ffffff; --lte-line:#e5e7eb; --lte-muted:#6b7280; --lte-text:#1f2328; --lte-btn:#f2f4f7; --lte-btn-hover:#e8ebf0; --lte-accent:#2563eb; --lte-item:#fcfcfd; --lte-tag:#f3f4f6; --lte-active:#dbeafe; position:fixed; right:16px; bottom:16px; z-index:2147483000; font-family:system-ui,-apple-system,"Segoe UI","Microsoft YaHei",sans-serif; font-size:13px; line-height:1.5; color:var(--lte-text); }',
    '@media (prefers-color-scheme: dark) { #lte-root { --lte-panel:#1f242b; --lte-line:#343b45; --lte-muted:#9aa3af; --lte-text:#e6e9ed; --lte-btn:#2a313a; --lte-btn-hover:#38414c; --lte-accent:#7cb3ff; --lte-item:#232a33; --lte-tag:#2d3540; --lte-active:#1e3a5f; } }',
    '#lte-root button { font:inherit; color:inherit; background:var(--lte-btn); border:1px solid var(--lte-line); border-radius:6px; padding:4px 9px; cursor:pointer; }',
    '#lte-root button:hover { background:var(--lte-btn-hover); }',
    '#lte-fab { position:fixed; right:20px; bottom:20px; width:46px; height:46px; border-radius:50%; background:#2563eb; border:none; color:#fff; font-size:18px; box-shadow:0 4px 14px rgba(0,0,0,.28); display:flex; align-items:center; justify-content:center; padding:0; }',
    '#lte-fab:hover { background:#1d4ed8; }',
    '#lte-panel { position:fixed; right:20px; bottom:78px; width:min(400px, calc(100vw - 40px)); max-height:min(76vh, 620px); display:flex; flex-direction:column; background:var(--lte-panel); border:1px solid var(--lte-line); border-radius:10px; box-shadow:0 12px 36px rgba(0,0,0,.22); overflow:hidden; }',
    '#lte-panel.lte-hidden { display:none; }',
    '.lte-head { display:flex; align-items:center; justify-content:space-between; gap:8px; padding:10px 12px; border-bottom:1px solid var(--lte-line); }',
    '.lte-title { font-weight:600; font-size:14px; white-space:nowrap; }',
    '.lte-actions { display:flex; gap:6px; }',
    '.lte-actions button { white-space:nowrap; }',
    '.lte-btn-on { background:var(--lte-active) !important; border-color:var(--lte-accent) !important; }',
    '.lte-tabs { display:flex; gap:2px; padding:6px 10px 0; border-bottom:1px solid var(--lte-line); }',
    '.lte-tabs button { flex:1; border:none; border-bottom:2px solid transparent; background:transparent; padding:6px 2px; border-radius:0; color:var(--lte-muted); }',
    '.lte-tabs button:hover { background:transparent; color:var(--lte-text); }',
    '.lte-tabs button.lte-active { color:var(--lte-accent); border-bottom-color:var(--lte-accent); font-weight:600; }',
    '.lte-count { display:inline-block; min-width:16px; margin-left:3px; padding:0 4px; border-radius:8px; background:var(--lte-tag); font-size:11px; line-height:16px; font-weight:400; }',
    '.lte-body { flex:1; overflow:auto; padding:8px 10px; min-height:140px; }',
    '.lte-pane { display:flex; flex-direction:column; gap:6px; }',
    '.lte-pane.lte-hidden { display:none; }',
    '.lte-empty { color:var(--lte-muted); padding:20px 8px; text-align:center; }',
    '.lte-item { display:flex; gap:8px; align-items:flex-start; padding:7px 8px; border:1px solid var(--lte-line); border-radius:6px; background:var(--lte-item); cursor:pointer; }',
    '.lte-item:hover { border-color:var(--lte-accent); }',
    '.lte-time { flex:none; color:var(--lte-muted); font-variant-numeric:tabular-nums; font-size:12px; white-space:nowrap; }',
    '.lte-text { flex:1; min-width:0; word-break:break-word; }',
    '.lte-source { flex:none; font-size:11px; color:var(--lte-muted); background:var(--lte-tag); border-radius:4px; padding:0 5px; line-height:18px; white-space:nowrap; }',
    '.lte-link { border:1px solid var(--lte-line); border-radius:6px; padding:8px; background:var(--lte-item); display:flex; flex-direction:column; gap:4px; }',
    '.lte-link-label { font-weight:600; word-break:break-word; }',
    '.lte-link-url { color:var(--lte-accent); word-break:break-all; font-size:12px; }',
    '.lte-link-meta { display:flex; align-items:center; gap:6px; }',
    '.lte-link-meta .lte-source { margin-right:auto; }',
    '.lte-tag { font-size:11px; color:var(--lte-accent); background:var(--lte-active); border-radius:4px; padding:0 5px; line-height:18px; white-space:nowrap; }',
    '.lte-copy-btn { margin-left:auto; }',
    '.lte-summary { width:100%; min-height:260px; resize:vertical; border:1px solid var(--lte-line); border-radius:6px; padding:8px; font:12px/1.6 ui-monospace,Consolas,"Courier New",monospace; color:var(--lte-text); background:var(--lte-item); }',
    '.lte-foot { padding:8px 12px; border-top:1px solid var(--lte-line); color:var(--lte-muted); font-size:12px; }',
    '#lte-toast { position:fixed; left:50%; bottom:90px; transform:translateX(-50%) translateY(8px); background:rgba(17,24,39,.92); color:#fff; padding:7px 14px; border-radius:6px; opacity:0; pointer-events:none; transition:opacity .18s, transform .18s; font-size:13px; }',
    '#lte-toast.lte-show { opacity:1; transform:translateX(-50%) translateY(0); }'
  ].join('\n');

  function buildUI() {
    if (document.getElementById('lte-root')) return;

    const style = document.createElement('style');
    style.id = 'lte-style';
    style.textContent = STYLE_TEXT;
    document.head.appendChild(style);

    root = document.createElement('div');
    root.id = 'lte-root';

    fabEl = document.createElement('button');
    fabEl.id = 'lte-fab';
    fabEl.type = 'button';
    fabEl.title = '学习文字提取 (Alt+Shift+X)';
    fabEl.textContent = '摘';
    root.appendChild(fabEl);

    panelEl = document.createElement('div');
    panelEl.id = 'lte-panel';
    panelEl.className = 'lte-hidden';
    panelEl.innerHTML = `
      <div class="lte-head">
        <div class="lte-title">学习文字提取</div>
        <div class="lte-actions">
          <button type="button" data-action="toggle-auto" class="lte-btn-on">自动采集:开</button>
          <button type="button" data-action="copy">复制</button>
          <button type="button" data-action="clear">清空</button>
          <button type="button" data-action="close" title="收起">收起</button>
        </div>
      </div>
      <div class="lte-tabs">
        <button type="button" data-tab="subtitles" class="lte-active">字幕<span class="lte-count"></span></button>
        <button type="button" data-tab="highlights">重点<span class="lte-count"></span></button>
        <button type="button" data-tab="links">链接<span class="lte-count"></span></button>
        <button type="button" data-tab="summary">汇总</button>
      </div>
      <div class="lte-body">
        <div class="lte-pane" data-pane="subtitles"></div>
        <div class="lte-pane lte-hidden" data-pane="highlights"></div>
        <div class="lte-pane lte-hidden" data-pane="links"></div>
        <div class="lte-pane lte-hidden" data-pane="summary"></div>
      </div>
      <div class="lte-foot">开启字幕/CC 后自动采集，简介与评论中的链接会自动整理。</div>
    `;
    root.appendChild(panelEl);

    toastEl = document.createElement('div');
    toastEl.id = 'lte-toast';
    root.appendChild(toastEl);

    document.body.appendChild(root);

    fabEl.addEventListener('click', togglePanel);
    root.addEventListener('click', handleClick);
    root.addEventListener('mousedown', function (e) {
      e.stopPropagation();
    });
    document.addEventListener('keydown', handleKeydown);
  }

  function scheduleExtract() {
    state.extractTimers.forEach(clearTimeout);
    state.extractTimers = [];
    [1200, 4000, 8000].forEach(function (delay) {
      const id = setTimeout(extractStatic, delay);
      state.extractTimers.push(id);
    });
  }

  function tick() {
    const key = currentVideoKey();
    if (key !== state.videoKey) {
      saveNow();
      loadVideoState();
      scheduleExtract();
      if (state.panelOpen) renderTab(true);
    }
    const t = readTitle();
    if (t && t !== state.title) {
      state.title = t;
      scheduleSave();
    }
    captureTick();
    state.tickCount += 1;
    if (state.tickCount % 3 === 0) {
      scanPageForLinks();
      if (state.panelOpen && state.activeTab !== 'summary') renderTab(false);
    }
  }

  function registerMenuCommand() {
    const label = '学习文字提取: 打开/收起面板';
    let registered = false;
    try {
      if (gm.registerMenuCommand) {
        gm.registerMenuCommand(label, togglePanel);
        registered = true;
      }
    } catch (e) {}
    if (!registered) {
      try {
        if (typeof GM !== 'undefined' && typeof GM.registerMenuCommand === 'function') {
          GM.registerMenuCommand(label, togglePanel);
        }
      } catch (e) {}
    }
  }

  function init() {
    loadVideoState();
    buildUI();
    scheduleExtract();
    setInterval(tick, 1000);
    registerMenuCommand();
  }

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