const API = '/api';
const USER = 'default';           // 2.0 无鉴权：这里自报身份
let sessionId = null;
let controller = null;
let streaming = false;
let resuming = false;
let loadingHistory = false;
let sessions = [];
let pendingApproval = false;

const el = (id) => document.getElementById(id);
const log = el('log');

function setStatus(text, state) {
  el('statusPill').textContent = text;
  el('statusPill').title = text;
  el('statusDot').className = 'status-dot ' + (state || (streaming ? 'busy' : 'ready'));
}

function scrollDown() { const area = el('conversationScroll'); area.scrollTop = area.scrollHeight; }

function addNode(cls, html) {
  const wrap = document.createElement('div');
  wrap.className = 'msg ' + cls;
  wrap.innerHTML = html;
  el('welcome').hidden = true;
  log.appendChild(wrap);
  scrollDown();
  return wrap;
}

function addUserBubble(text) {
  const node = addNode('user', '');
  const b = document.createElement('div');
  b.className = 'bubble';
  b.textContent = text;
  node.appendChild(b);
  return node;
}

function newAssistant() {
  const node = addNode('assistant', '');
  const b = document.createElement('div');
  b.className = 'bubble';
  node.appendChild(b);
  return { node, bubble: b, tools: {}, thinking: null, segment: null };
}

// Keep Markdown source separate from the rendered DOM. Each text segment owns
// its timer, so a tool card cannot steal a pending update from the previous one.
const markdownSegments = new WeakMap();

function renderMarkdownSegment(segment) {
  const state = markdownSegments.get(segment);
  if (!state) return;
  clearTimeout(state.timer);
  state.timer = null;
  if (!window.marked || !window.DOMPurify) {
    segment.classList.add('plain-text');
    segment.textContent = state.source;
    return;
  }
  segment.classList.remove('plain-text');
  const html = marked.parse(state.source, { gfm: true, breaks: true, async: false });
  // Model output and stored history are untrusted. Sanitize before insertion.
  const fragment = DOMPurify.sanitize(html, {
    RETURN_DOM_FRAGMENT: true,
    ALLOWED_TAGS: ['p', 'br', 'h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'strong',
      'em', 'del', 's', 'blockquote', 'ul', 'ol', 'li', 'pre', 'code', 'hr',
      'a', 'img', 'table', 'thead', 'tbody', 'tr', 'th', 'td', 'input'],
    ALLOWED_ATTR: ['href', 'title', 'src', 'alt', 'start', 'align', 'type', 'checked', 'disabled'],
    ALLOW_DATA_ATTR: false,
    ALLOW_ARIA_ATTR: false,
  });
  fragment.querySelectorAll('a').forEach((link) => {
    link.target = '_blank';
    link.rel = 'noopener noreferrer';
  });
  fragment.querySelectorAll('input').forEach((checkbox) => {
    checkbox.type = 'checkbox';
    checkbox.disabled = true;
  });
  fragment.querySelectorAll('table').forEach((table) => {
    const wrapper = document.createElement('div');
    wrapper.className = 'markdown-table';
    wrapper.tabIndex = 0;
    wrapper.setAttribute('role', 'region');
    wrapper.setAttribute('aria-label', '表格，可横向滚动');
    table.replaceWith(wrapper);
    wrapper.appendChild(table);
  });
  segment.replaceChildren(fragment);
}

function appendToken(ui, text) {
  if (!ui.segment) {
    ui.segment = document.createElement('div');
    ui.segment.className = 'segment';
    ui.bubble.appendChild(ui.segment);
    markdownSegments.set(ui.segment, { source: '', timer: null });
  }
  const segment = ui.segment;
  const state = markdownSegments.get(segment);
  state.source += text;
  // Batch bursts of tokens rather than parsing the entire reply per token.
  if (state.timer === null) {
    state.timer = setTimeout(() => {
      renderMarkdownSegment(segment);
      if (segment.isConnected) scrollDown();
    }, 50);
  }
}

// Flush before adding tool/status cards to preserve chronological ordering.
function breakSegment(ui) {
  if (ui.segment) renderMarkdownSegment(ui.segment);
  ui.segment = null;
}

function addCard(bubble, cls, title, body) {
  const card = document.createElement('div');
  card.className = 'card ' + cls;
  const t = document.createElement('div');
  t.className = 'title';
  t.textContent = title;
  card.appendChild(t);
  if (body) {
    const pre = document.createElement('pre');
    pre.textContent = body;
    card.appendChild(pre);
  }
  bubble.appendChild(card);
  scrollDown();
  return card;
}

function addCardFor(ui, cls, title, body) {
  breakSegment(ui);
  return addCard(ui.bubble, cls, title, body);
}

// ---------- 发送 ----------
async function send() {
  const input = el('input');
  const text = input.value.trim();
  if (!text || streaming || loadingHistory || pendingApproval) return;
  const form = buildForm(text);
  if (!sessionId) el('chatTitle').textContent = text.slice(0, 30);
  const attachmentName = el('file').files[0]?.name;
  input.value = '';
  input.style.height = 'auto';
  addUserBubble(text + (attachmentName ? '\n📎 ' + attachmentName : ''));
  clearAttachment();
  await stream(`${API}/chat`, 'POST', form);
}

function buildForm(text) {
  const fd = new FormData();
  fd.append('message', text);
  if (sessionId) fd.append('session_id', sessionId);
  fd.append('mode', el('mode').value);
  fd.append('user_name', USER);
  const f = el('file').files[0];
  if (f) fd.append('file', f);
  return fd;
}

function buildResumeBody(extra) {
  return JSON.stringify(Object.assign({
    session_id: sessionId, thread_id: sessionId, user_name: USER,
  }, extra));
}

// ---------- 流式 ----------
async function stream(url, method, body, isJson) {
  const ui = newAssistant();
  controller = new AbortController();
  streaming = true;
  updateControls();
  setStatus('连接中...');

  let citations = [];

  try {
    const headers = {};
    if (isJson) headers['Content-Type'] = 'application/json';
    const res = await fetch(url, { method, body, headers, signal: controller.signal });

    if (!res.ok) {
      let detail = '';
      const raw = await res.text();
      try { const parsed = JSON.parse(raw); detail = parsed.detail?.message || JSON.stringify(parsed.detail || parsed); } catch (e) { detail = raw; }
      addCard(ui.bubble, 'error', `HTTP ${res.status}`, detail);
      setStatus('请求失败', 'error');
      return;
    }
    if (isJson) {
      pendingApproval = false;
      log.querySelectorAll('.approval .actions').forEach((row) => {
        row.closest('.msg').dataset.resolved = 'true';
        row.replaceWith(document.createTextNode('已提交确认'));
      });
    }
    const sid = res.headers.get('X-Session-Id');
    if (sid) { sessionId = sid; el('sessionPill').textContent = '会话：' + sid.slice(0, 8); }

    const reader = res.body.getReader();
    const decoder = new TextDecoder();
    let buffer = '';

    while (true) {
      const { done, value } = await reader.read();
      if (done) break;
      buffer += decoder.decode(value, { stream: true });
      const lines = buffer.split('\n');
      buffer = lines.pop() || '';
      for (const line of lines) {
        if (!line.startsWith('data: ')) continue;
        try { handle(JSON.parse(line.slice(6)), ui, citations); }
        catch (e) { /* 半截 JSON，忽略 */ }
      }
    }
    if (!ui.failed) setStatus(pendingApproval ? '等待你的确认' : '回复已完成', pendingApproval ? 'busy' : 'ready');
  } catch (e) {
    if (e.name === 'AbortError') {
      addCard(ui.bubble, '', '已停止生成', '');
      setStatus('已停止', 'ready');
    } else {
      addCard(ui.bubble, 'error', '连接中断，请重试', String(e));
      setStatus('连接失败', 'error');
    }
  } finally {
    breakSegment(ui);
    scrollDown();
    streaming = false;
    controller = null;
    updateControls();
    loadSessions();
  }
}

function handle(ev, ui, citations) {
  switch (ev.type) {
    case 'agent_start':
      setStatus(`${ev.cn_agent || ev.agent} 已启动`);
      break;
    case 'thinking':
      setStatus(ev.cn_agent ? `${ev.cn_agent}：${ev.message}` : ev.message);
      break;
    case 'thinking_token':
      if (!ui.thinking) {
        breakSegment(ui);
        ui.thinking = document.createElement('details');
        const s = document.createElement('summary');
        s.textContent = '思考过程';
        s.style.color = 'var(--fg-dim)';
        ui.thinking.appendChild(s);
        const p = document.createElement('pre');
        p.style.fontSize = '12px';
        p.style.color = 'var(--fg-dim)';
        ui.thinking.appendChild(p);
        ui.bubble.appendChild(ui.thinking);
      }
      ui.thinking.querySelector('pre').textContent += ev.content || '';
      break;
    case 'executing':
      setStatus(ev.message || '执行中...');
      if (ev.tools && ev.tools.length) {
        const i = ev.tools.length - 1;
        ui.tools[ev.tools[i]] = addCardFor(ui, 'pending', `调用 ${ev.cn_tools ? ev.cn_tools[i] : ev.tools[i]}`, '');
      }
      break;
    case 'tool_call':
      // 按 tool_call_id 索引：同一工具被调多次时按名字索引会把结果挂错卡
      ui.tools[ev.tool_call_id || ev.tool] = addCardFor(ui, 'pending', `工具 ${ev.cn_tool || ev.tool}`, JSON.stringify(ev.args, null, 1));
      break;
    case 'tool_result': {
      const key = ev.tool_call_id || ev.tool;
      const card = ui.tools[key] || ui.tools[ev.tool];
      const body = typeof ev.content === 'string' ? ev.content : JSON.stringify(ev.content, null, 1);
      if (card) {
        card.className = 'card ' + (ev.error ? 'error' : 'done');
        const pre = document.createElement('pre'); pre.textContent = body; card.appendChild(pre);
      } else {
        addCardFor(ui, ev.error ? 'error' : 'done', `结果 ${ev.cn_tool || ev.tool}`, body);
      }
      break;
    }
    case 'updated_todo_list':
      renderTodos(ui, ev.todos || []);
      break;
    case 'token':
      appendToken(ui, ev.content || '');
      break;
    case 'citations':
      citations.length = 0;
      (ev.items || []).forEach((it) => citations.push(it));
      renderCitations(ui, citations, ev.model_only);
      break;
    case 'interrupt':
      pendingApproval = !!ev.tool_approval;
      setStatus('等待你的确认', 'busy');
      renderInterrupt(ui, ev);
      break;
    case 'agent_done':
      setStatus(`完成 ${ev.duration_ms ? ev.duration_ms + 'ms' : ''} 上下文 ${ev.context_tokens || 0}/${ev.context_window || 0}`);
      break;
    case 'agent_error':
    case 'error':
      ui.failed = true;
      setStatus('回复出错', 'error');
      addCardFor(ui, 'error', `错误 [${ev.code || '-'}]`, ev.message || '');
      break;
    case 'done':
      if (ev.usage) {
        addCardFor(ui, '', '用量',
          `输入 ${ev.usage.input_tokens} / 输出 ${ev.usage.output_tokens} / 合计 ${ev.usage.total_tokens}（${ev.usage.usage_source}）`);
      }
      break;
  }
}

function renderTodos(ui, todos) {
  breakSegment(ui);
  let card = ui.node.querySelector('.todos');
  if (!card) {
    card = document.createElement('div');
    card.className = 'card todos';
    ui.bubble.appendChild(card);
  }
  const mark = { completed: '[x]', in_progress: '[~]', pending: '[ ]' };
  card.innerHTML = '<div class="title">待办</div>' +
    todos.map((t) => `${mark[t.status] || '[ ]'} ${escapeHtml(t.content || '')}`).join('<br>');
}

function renderCitations(ui, items, modelOnly) {
  breakSegment(ui);
  const box = document.createElement('div');
  box.className = 'card cite';
  if (!items.length) {
    box.textContent = modelOnly ? '本回答未引用外部数据源' : '无来源';
  } else {
    box.innerHTML = '<div class="title">来源（' + items.length + '）</div>' +
      items.map((it, i) => {
        const label = escapeHtml(it.title || it.url || '未命名');
        const link = /^https?:\/\//i.test(it.url || '') ? ` <a href="${escapeAttr(it.url)}" target="_blank" rel="noreferrer">链接</a>` : '';
        const score = (it.score !== undefined) ? ` <span style="color:var(--fg-dim)">score=${it.score}</span>` : '';
        return `${i + 1}. ${label}${link}${score}`;
      }).join('<br>');
  }
  ui.bubble.appendChild(box);
  scrollDown();
}

function renderInterrupt(ui, ev) {
  const ta = ev.tool_approval;
  if (!ta) {
    addCardFor(ui, 'approval', '智能体暂停', ev.message || '等待输入');
    return;
  }
  const card = addCardFor(ui, 'approval',
    `需确认：${ta.tool}`,
    `${ta.reason || ''}\n${ta.side_effect || ''}\n\n参数：${JSON.stringify(ta.args, null, 1)}`);
  const row = document.createElement('div');
  row.className = 'actions';
  const ok = document.createElement('button'); ok.className = 'ok'; ok.textContent = '批准';
  const no = document.createElement('button'); no.className = 'no'; no.textContent = '拒绝';
  const decide = async (extra) => {
    if (streaming || resuming || ui.node.parentNode !== log) return;
    ok.disabled = no.disabled = true;
    await resume(extra, ui);
    // Failed requests keep their original approval controls available for retry.
    if (pendingApproval && !ui.node.dataset.resolved) ok.disabled = no.disabled = false;
  };
  ok.onclick = () => decide({ approved: true });
  no.onclick = () => decide({ approved: false, status: 'cancelled' });
  row.appendChild(ok); row.appendChild(no);
  card.appendChild(row);
}

async function resume(extra, ui) {
  // 双重保险：按钮点击后已经被 row.remove() 摘掉，这里再挡一次重复调用。
  // 恢复请求重复发出会让图在同一 thread 上被 resume 两次，第二次必然失败。
  if (streaming || resuming) return;
  resuming = true;
  setStatus('恢复中...');
  try {
    await stream(`${API}/chat/resume`, 'POST', buildResumeBody(extra), true);
  } finally {
    resuming = false;
  }
}

function escapeHtml(s) {
  return String(s).replace(/[&<>"']/g, (c) =>
    ({ '&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;', "'": '&#39;' }[c]));
}
function escapeAttr(s) { return escapeHtml(s).replace(/`/g, '&#96;'); }

// ---------- 工作台交互 ----------
function updateControls() {
  const busy = streaming || loadingHistory;
  el('sendBtn').disabled = busy || pendingApproval || !el('input').value.trim();
  el('sendBtn').hidden = streaming;
  el('stopBtn').disabled = !streaming;
  el('stopBtn').hidden = !streaming;
  el('newBtn').disabled = busy;
  el('mode').disabled = busy || pendingApproval;
  el('attachBtn').disabled = busy || pendingApproval;
  el('removeFileBtn').disabled = busy;
  document.querySelectorAll('.session-button').forEach((button) => { button.disabled = busy; });
}

function resizeInput() {
  const input = el('input');
  input.style.height = 'auto';
  input.style.height = Math.min(input.scrollHeight, 160) + 'px';
  updateControls();
}

function clearAttachment() {
  el('file').value = '';
  el('attachment').hidden = true;
  el('fileName').textContent = '';
}

function toggleSidebar(open) {
  el('sidebar').classList.toggle('open', open);
  el('sidebarBackdrop').hidden = !open;
  el('sidebarToggle').setAttribute('aria-expanded', String(open));
  el('sidebarToggle').setAttribute('aria-label', open ? '收起会话列表' : '展开会话列表');
}

function renderSessions() {
  const list = el('sessionList');
  list.replaceChildren();
  if (!sessions.length) {
    const empty = document.createElement('p');
    empty.className = 'list-empty';
    empty.textContent = '还没有对话。开启新对话，记录你的每一个想法。';
    list.appendChild(empty);
  }
  for (const session of sessions) {
    const button = document.createElement('button');
    button.className = 'session-button' + (session.id === sessionId ? ' active' : '');
    button.setAttribute('aria-current', session.id === sessionId ? 'page' : 'false');
    button.title = session.title || '未命名对话';
    button.innerHTML = '<svg aria-hidden="true"><use href="#i-chat"/></svg><span></span>';
    button.querySelector('span').textContent = (session.pinned ? '⌁ ' : '') + button.title;
    button.onclick = () => openSession(session);
    list.appendChild(button);
  }
  updateControls();
}

async function loadSessions() {
  el('refreshBtn').disabled = true;
  try {
    const response = await fetch(`${API}/sessions?user_name=${encodeURIComponent(USER)}`);
    if (!response.ok) throw new Error('会话列表加载失败');
    const data = await response.json();
    sessions = data.items || [];
    renderSessions();
  } catch (error) {
    if (!sessions.length) {
      const message = document.createElement('p');
      message.className = 'list-empty';
      message.textContent = '暂时无法加载对话，请点击刷新重试。';
      el('sessionList').replaceChildren(message);
    }
  } finally { el('refreshBtn').disabled = false; }
}

async function openSession(session) {
  if (streaming || loadingHistory || sessionId === session.id) return;
  loadingHistory = true;
  updateControls();
  setStatus('正在加载对话', 'busy');
  try {
    const response = await fetch(`${API}/chat/history/${encodeURIComponent(session.id)}?user_name=${encodeURIComponent(USER)}&limit=500`);
    if (!response.ok) throw new Error('无法加载这段对话，请重试');
    const data = await response.json();
    sessionId = session.id;
    pendingApproval = false;
    el('sessionPill').textContent = '会话：' + session.id.slice(0, 8);
    el('chatTitle').textContent = session.title || '未命名对话';
    el('mode').value = session.mode === 'plan' ? 'plan' : 'full';
    el('input').value = '';
    clearAttachment();
    log.replaceChildren();
    el('welcome').hidden = !!data.items.length;
    for (const message of data.items) {
      if (message.msg_role === 'user') addUserBubble(message.content);
      else if (message.msg_role === 'assistant') {
        const ui = newAssistant();
        appendToken(ui, message.content || '');
        breakSegment(ui);
        if (Array.isArray(message.citations) && message.citations.length) renderCitations(ui, message.citations, false);
      }
    }
    renderSessions();
    toggleSidebar(false);
    setStatus('对话已加载', 'ready');
    try {
      const response = await fetch(`${API}/chat/interrupt?session_id=${encodeURIComponent(sessionId)}&user_name=${encodeURIComponent(USER)}`);
      if (!response.ok) throw new Error('确认状态读取失败');
      if (response.status !== 204) {
        const data = await response.json();
        for (const event of data.interrupts || []) handle(event, newAssistant(), []);
      }
    } catch (error) { setStatus('对话已加载，确认状态获取失败', 'error'); }
  } catch (error) {
    setStatus(error.message, 'error');
  } finally {
    loadingHistory = false;
    resizeInput();
    scrollDown();
  }
}

el('sendBtn').onclick = send;
el('stopBtn').onclick = () => { if (controller) controller.abort(); };
el('newBtn').onclick = () => {
  if (streaming || loadingHistory) return;
  sessionId = null;
  pendingApproval = false;
  el('sessionPill').textContent = '新会话';
  el('chatTitle').textContent = '新对话';
  el('input').value = '';
  clearAttachment();
  log.replaceChildren();
  el('welcome').hidden = false;
  setStatus('就绪', 'ready');
  renderSessions();
  resizeInput();
  toggleSidebar(false);
  el('input').focus();
};
el('input').addEventListener('keydown', (event) => {
  if (event.key === 'Enter' && !event.shiftKey && !event.isComposing && event.keyCode !== 229) {
    event.preventDefault();
    send();
  }
});
el('input').addEventListener('input', resizeInput);
el('attachBtn').onclick = () => el('file').click();
el('removeFileBtn').onclick = clearAttachment;
el('file').addEventListener('change', () => {
  const file = el('file').files[0];
  el('attachment').hidden = !file;
  el('fileName').textContent = file?.name || '';
});
el('refreshBtn').onclick = loadSessions;
el('sidebarToggle').onclick = () => toggleSidebar(!el('sidebar').classList.contains('open'));
el('sidebarBackdrop').onclick = () => { toggleSidebar(false); el('sidebarToggle').focus(); };
document.addEventListener('keydown', (event) => {
  if (event.key === 'Escape' && el('sidebar').classList.contains('open')) {
    toggleSidebar(false); el('sidebarToggle').focus();
  }
});

fetch(`${API}/model`).then((response) => {
  if (!response.ok) throw new Error('服务不可达');
  return response.json();
}).then((data) => {
  el('modelName').textContent = data.model || 'Deep Agent';
  if (!streaming && !loadingHistory) setStatus('服务已就绪', 'ready');
}).catch(() => {
  el('modelName').textContent = '暂未连接模型';
  if (!streaming && !loadingHistory) setStatus('服务不可达', 'error');
});
loadSessions();