/**
 * LLM 论文图书馆 — 前端 JS
 * 打开时 ping 所有论文源 → 底部状态条 → 点击论文直用缓存结果
 */

const API = '/api';

let modules = {};
let moduleData = {};
let currentPdf = null;
let pdfTimeout = null;
let networkStatus = {}; // { arxiv: bool, huggingface: bool, hk: bool }

const $ = (sel) => document.querySelector(sel);
const $$ = (sel) => document.querySelectorAll(sel);
const TAG_CLASS = { '起点':'tag-start','关键节点':'tag-milestone','前沿':'tag-frontier','前瞻':'tag-forward','支线':'tag-branch' };

// ═══════════════ INIT ═══════════════════════════════════
async function init() {
  // Build network status bar
  buildStatusBar();
  // Load modules
  try {
    const resp = await fetch(`${API}/modules`);
    const mods = await resp.json();
    modules = {};
    for (const m of mods) modules[m.id] = m;
    renderCards(mods);
    attachGlowTracking();
  } catch (e) { console.error(e); }

  // Ping sources
  checkSources();

  document.addEventListener('keydown', e => {
    if (e.key === 'Escape') {
      if ($('#pdfOverlay')?.classList.contains('open')) closePdf();
      else if ($('#overlay').classList.contains('open')) closeModal();
    }
  });
}

// ═══════════════ STATUS BAR ════════════════════════════
function buildStatusBar() {
  const bar = document.createElement('div');
  bar.id = 'statusBar';
  bar.className = 'status-bar';
  bar.innerHTML = `
    <span class="status-label">连通性检测</span>
    <span class="status-item" id="status-arxiv"><span class="status-dot"></span> arXiv <span class="status-ms" id="ms-arxiv">—</span></span>
    <span class="status-item" id="status-hf"><span class="status-dot"></span> HuggingFace <span class="status-ms" id="ms-hf">—</span></span>
    <span style="flex:1"></span>
    <a href="https://spdis.space" style="color:var(--blue);text-decoration:none;font-size:0.85em;margin-right:12px">spdis.space</a>
    <span style="color:var(--text-dim);font-size:0.75em">由 <strong style="color:var(--cyan)">DeepSeek-V4-Pro</strong> 每周维护</span>
  `;
  document.body.appendChild(bar);
}

function setStatus(id, ok, ms, aborted) {
  networkStatus[id.replace('status-','')] = ok;
  const el = document.getElementById(id);
  if (!el) return;
  const dot = el.querySelector('.status-dot');
  dot.className = 'status-dot ' + (ok ? 'status-ok' : 'status-fail');
  const msEl = document.getElementById('ms-' + id.replace('status-',''));
  if (msEl) {
    if (aborted) msEl.textContent = '超时 (4s)';
    else if (ok) msEl.textContent = ms + 'ms';
    else           msEl.textContent = '—';
  }
}

async function checkSource(name, url, statusId) {
  const start = performance.now();
  let aborted = false;
  // Add cache-buster and force no-store to avoid browser caching
  const probeUrl = url + '?_=' + Date.now();
  try {
    const ctrl = new AbortController();
    setTimeout(() => { aborted = true; ctrl.abort(); }, 4000);
    await fetch(probeUrl, { mode: 'no-cors', signal: ctrl.signal, cache: 'no-store' });
    const ms = Math.round(performance.now() - start);
    setStatus(statusId, true, ms, false);
  } catch {
    const ms = Math.round(performance.now() - start);
    setStatus(statusId, false, ms, aborted);
  }
}

async function checkSources() {
  checkSource('arxiv', 'https://arxiv.org/favicon.ico', 'status-arxiv');
  checkSource('hf', 'https://huggingface.co/favicon.ico', 'status-hf');
}

// ═══════════════ GLOW ══════════════════════════════════
function attachGlowTracking() {
  $$('.card').forEach(card => {
    card.addEventListener('mousemove', e => {
      const rect = card.getBoundingClientRect();
      card.style.setProperty('--mx', ((e.clientX - rect.left) / rect.width * 100) + '%');
      card.style.setProperty('--my', ((e.clientY - rect.top) / rect.height * 100) + '%');
    });
  });
}

// ═══════════════ CARDS -> MODAL -> PAPERS ═══════════════
function renderCards(mods) {
  $('#moduleGrid').innerHTML = mods.map(m => `
    <div class="card card-${m.id}" onclick="openModule('${m.id}')">
      <div class="card-header"><span class="card-icon">${m.icon}</span> ${m.name}</div>
      <div class="card-desc">${m.desc}</div>
      <div class="card-badge">${m.area_count} 子领域 · ${m.paper_count} 篇</div>
    </div>`).join('');
}

async function openModule(modId) {
  let data = moduleData[modId];
  if (!data) {
    try { data = await (await fetch(`${API}/modules/${modId}`)).json(); moduleData[modId] = data; }
    catch (e) { return; }
  }
  const mod = modules[modId];
  $('#modalTitle').innerHTML = `<span class="card-icon">${mod?.icon||''}</span> ${data.name}`;
  $('#modalSubtitle').textContent = data.desc || '';
  const areas = data.areas || [];
  $('#modalTabs').innerHTML = areas.map((a,i) =>
    `<button class="tab ${i===0?'active':''}" onclick="switchArea(${i})">${a.name}</button>`).join('');
  if (areas.length > 0) { $('#modalTabs').dataset.areaIdx = '0'; renderPapers(areas[0]); }
  $('#overlay').classList.add('open');
}

function switchArea(idx) {
  const data = Object.values(moduleData).find(d => d.areas && d.areas[idx]);
  if (!data) return;
  $$('#modalTabs .tab').forEach((t,i) => t.classList.toggle('active', i===idx));
  renderPapers(data.areas[idx]);
}

function closeModal() { $('#overlay').classList.remove('open'); }

function renderPapers(area) {
  let h = '';
  function s(l, ps, c) { return ps.length ? `<div class="section-label ${c}">${l}</div>`+ps.map(renderPaper).join('') : ''; }
  h += s('📌 主线论文', area.mainline||[], 'mainline');
  h += s('🌿 支线论文', area.branches||[], 'branch');
  h += s('🔮 前瞻探索', area.forward||[], 'forward');
  $('#modalContent').innerHTML = h || '<p style="color:var(--text-dim);padding:20px;">暂无论文数据</p>';
}

function renderPaper(p) {
  const pdfUrl = getPdfLink(p);
  const id = 'p'+Math.random().toString(36).slice(2,8);
  const tags = (p.tags||[]).map(t => `<span class="paper-tag ${TAG_CLASS[t]||'tag-branch'}">${t}</span>`).join(' ');
  const links = [];
  if (pdfUrl) links.push(`<button class="paper-link" data-pdf="${encodeURIComponent(pdfUrl)}" data-title="${encodeURIComponent(p.title)}" onclick="openPdfBtn(this)">📄 阅读</button>`);
  else if (p.arxiv) links.push(`<a class="paper-link" href="https://arxiv.org/abs/${p.arxiv}" target="_blank">📋 arXiv</a>`);
  // Show translation button for ALL papers with arxiv or pdf
  const paperId = p.arxiv || (p.pdf ? p.pdf.split('/').pop().replace('.pdf','') : null);
  if (paperId) {
    links.push('<button class="paper-link trans-btn" data-pdf="/papers/translated/' + paperId + '.pdf" data-title="' + p.title + ' [译文]" onclick="openTrans(this)">📖 译文</button>');
  }
  return `<div class="paper-item"><div class="paper-year">${p.year||'—'}</div><div class="paper-body" id="${id}">
    <div class="paper-title">${p.title}</div>
    <div class="paper-meta"><span>${p.authors||''}</span>${p.venue?`<span class="paper-venue">${p.venue}</span>`:''}${tags}</div>
    <div class="paper-links">${links.join('')}</div>
  </div></div>`;
}

function getPdfLink(p) {
  if (p.pdf) return p.pdf;
  if (p.arxiv) return `https://arxiv.org/pdf/${p.arxiv}.pdf`;
  return null;
}

function openPdfBtn(btn) { openPdf(btn.dataset.pdf, btn.dataset.title); }

function openTrans(btn) {
  const url = btn.dataset.pdf;
  const title = btn.dataset.title;
  openPdf(url, title);
  // If translation doesn't exist, the iframe will show error - user can see it
}

// ═══════════════ PDF VIEWER (状态条驱动) ═══════════════
function getLocalPdfUrl(extUrl) {
  const am = extUrl.match(/arxiv\.org\/pdf\/(\d+\.\d+)/);
  if (am) return `/papers/arxiv/${am[1]}.pdf`;
  if (extUrl.includes('huggingface.co')) return `/papers/hf/${extUrl.split('/').pop().replace('.pdf','')}.pdf`;
  return null;
}

async function openPdf(url, title) {
  const decodedUrl = decodeURIComponent(url);
  const decodedTitle = decodeURIComponent(title);
  currentPdf = decodedUrl;
  const hkFallback = getLocalPdfUrl(decodedUrl);

  if (!$('#pdfOverlay')) {
    const div = document.createElement('div'); div.id='pdfOverlay'; div.className='pdf-overlay';
    div.innerHTML = `<div class="pdf-container" id="pdfContainer">
      <div class="pdf-toolbar"><span id="pdfTitle">PDF</span><span id="pdfStatus" style="color:var(--orange);font-size:0.8em;margin-left:8px;display:none"></span>
        <button onclick="window.open(currentPdf,'_blank')">🔗 新窗口</button>
        <button class="pdf-close" onclick="closePdf()">&times;</button></div>
      <iframe class="pdf-frame" id="pdfFrame" src=""></iframe></div>`;
    document.body.appendChild(div);
    div.addEventListener('click', e => { if (e.target===div) closePdf(); });
  }

  if (pdfTimeout) { clearTimeout(pdfTimeout); pdfTimeout = null; }
  $('#pdfTitle').textContent = decodedTitle;
  $('#pdfStatus').style.display = 'none';
  const frame = $('#pdfFrame');
  let loaded = false;
  let abortCtrl = null;
  frame.src = 'about:blank';

  frame.onload = () => {
    loaded = true;
    if (pdfTimeout) { clearTimeout(pdfTimeout); pdfTimeout = null; }
    $('#pdfStatus').style.display = 'none';
  };

  const isArxiv = decodedUrl.includes('arxiv.org');
  const remoteOk = (isArxiv && networkStatus['arxiv'] !== false);

  // arXiv: iframe 直连（跨域，IDM 只能认了）
  if (remoteOk) {
    loaded = false;
    $('#pdfStatus').textContent = '🌐 arXiv 加载中...';
    $('#pdfStatus').style.display = '';
    frame.onload = () => { loaded=true; $('#pdfStatus').style.display='none'; };
    frame.src = decodedUrl;

    pdfTimeout = setTimeout(async () => {
      if (loaded) return;
      if (!hkFallback) { $('#pdfStatus').textContent='⚠️ arXiv 超时'; return; }
      // fallback to HK, use fetch→blob to beat IDM
      $('#pdfStatus').textContent = '⏳ arXiv 超时，走 HK 服务器...';
      try {
        const resp = await fetch(hkFallback, { cache:'default' });
        const blobUrl = URL.createObjectURL(await resp.blob());
        $('#pdfStatus').textContent = '';
        frame.src = blobUrl;
      } catch(e) { $('#pdfStatus').textContent = '⚠️ HK 加载失败'; }
    }, 5000);
  } else {
    // arXiv down / local / HF → use HK with fetch→blob
    const src = hkFallback || decodedUrl;
    $('#pdfStatus').textContent = hkFallback ? '📂 HK 服务器加载中...' : '⏳ 加载中...';
    $('#pdfStatus').style.display = '';
    try {
      const resp = await fetch(src, { cache:'default' });
      const blobUrl = URL.createObjectURL(await resp.blob());
      $('#pdfStatus').textContent = '';
      frame.src = blobUrl;
    } catch(e) { $('#pdfStatus').textContent = '⚠️ 加载失败'; }
  }

  $('#pdfOverlay').classList.add('open');
}

function closePdf() {
  if (pdfTimeout) { clearTimeout(pdfTimeout); pdfTimeout = null; }
  $('#pdfOverlay').classList.remove('open');
  $('#pdfFrame').src = '';
  currentPdf = null;
}

// ═══════════════ SEARCH ═══════════════════════════════
function searchPapers(q) {
  q = (q||'').toLowerCase().trim();
  if (q.length<2) { $$('.card').forEach(c=>c.style.outline=''); return; }
  fetch(`${API}/papers?q=${encodeURIComponent(q)}&limit=10`).then(r=>r.json()).then(ps=>{
    const matched = new Set(ps.map(p=>p.module_id));
    $$('.card').forEach(c=>{
      const m=[...c.classList].find(x=>x.startsWith('card-'))?.replace('card-','');
      c.style.outline=matched.has(m)?'2px solid var(--green)':'';
    });
  });
}

// ═══════════════ EVENTS ═══════════════════════════════
if (typeof document !== 'undefined') {
  document.addEventListener('DOMContentLoaded', () => {
    init();
    $('.search-input').addEventListener('input', e => searchPapers(e.target.value));
    $('#modalClose').addEventListener('click', closeModal);
    $('#overlay').addEventListener('click', e => { if (e.target===$('#overlay')) closeModal(); });
  });
}