const chatLog = document.getElementById('chatLog');
const userInput = document.getElementById('userInput');
const sendBtn = document.getElementById('sendBtn');
const statusIndicator = document.getElementById('statusIndicator');
const conversationList = document.getElementById('conversationList');
const newChatBtn = document.getElementById('newChat');
const toggleSidebarBtn = document.getElementById('toggleSidebar');

let currentConversationId = null;
let isStreaming = false;

function setStatus(text) { statusIndicator.textContent = text; }
function clearChat() { chatLog.innerHTML = ''; }

const loaderHTML = `
  <span class="loader-wrapper">
    <span class="letter-wrapper">
      <span class="loader-letter">搜</span>
      <span class="loader-letter">索</span>
      <span class="loader-letter">中</span>
      <span class="loader-letter">.</span>
      <span class="loader-letter">.</span>
      <span class="loader-letter">.</span>
    </span>
  </span>`;
const doneHTML = `<span class="search-done">搜索完成</span>`;
const escapeHTML = (s) => s.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;');
const withBr = (s) => escapeHTML(s).replace(/\n/g, '<br>');

function normalizeText(text) {
  if (!text) return '';
  // 去掉首尾空白，压缩多余空行
  let t = text.replace(/^\s+/, '').replace(/\s+$/, '');
  t = t.replace(/\n{3,}/g, '\n\n'); // 连续3行以上压缩为1个空行
  return t;
}

function setAssistantText(bubble, text, position = 'before') {
  const cls = position === 'after' ? '.assistant-after' : '.assistant-before';
  const el = bubble.querySelector(cls);
  if (el) el.innerHTML = withBr(normalizeText(text || ''));
}

function setToolState(bubble, state) {
  const el = bubble.querySelector('.assistant-tool');
  if (!el) return;
  if (state === 'searching') {
    el.innerHTML = `<div class="search-state loading">${loaderHTML}</div>`;
  } else if (state === 'done') {
    el.innerHTML = `<div class="search-state done">${doneHTML}</div>`;
  } else {
    el.innerHTML = '';
  }
}

function createBubble(role, content = '') {
  const div = document.createElement('div');
  div.className = `message ${role}`;
  if (role === 'assistant') {
    div.innerHTML = '<div class="assistant-before"></div><div class="assistant-tool"></div><div class="assistant-after"></div>';
    setAssistantText(div, content, 'before');
  } else {
    div.textContent = content;
  }
  chatLog.appendChild(div);
  chatLog.scrollTop = chatLog.scrollHeight;
  return div;
}

async function loadConversations() {
  const res = await fetch('/api/conversations');
  const data = await res.json();
  conversationList.innerHTML = '';
  data.forEach(item => {
    const li = document.createElement('li');
    li.textContent = item.title;
    li.dataset.id = item.id;
    if (item.id === currentConversationId) li.classList.add('active');
    li.onclick = () => loadConversation(item.id);
    conversationList.appendChild(li);
  });
}

async function loadConversation(id) {
  const res = await fetch(`/api/conversations/${id}`);
  if (!res.ok) return;
  const data = await res.json();
  currentConversationId = data.id;
  clearChat();
  const msgs = data.messages || [];
  for (let i = 0; i < msgs.length; i++) {
    const msg = msgs[i];
    if (msg.role === 'tool') continue;

    // 处理带 tool_calls 的助手消息：组合“前置文字 + 搜索状态 + 完成后文字”
    if (msg.role === 'assistant' && Array.isArray(msg.tool_calls) && msg.tool_calls.length) {
      let beforeText = msg.content || '';
      let afterText = '';
      // 查找后续的 tool 结果和下一条 assistant 回复
      let j = i + 1;
      while (j < msgs.length && msgs[j].role === 'tool') j++;
      if (j < msgs.length && msgs[j].role === 'assistant' && !msgs[j].tool_calls) {
        afterText = msgs[j].content || '';
        // 跳过已消费的助手消息
        i = j;
      }
      const bubble = createBubble('assistant', beforeText);
      setToolState(bubble, 'done');
      setAssistantText(bubble, afterText, 'after');
      continue;
    }

    createBubble(msg.role, msg.content || '');
  }
  await loadConversations();
}

async function sendMessage() {
  const text = userInput.value.trim();
  if (!text || isStreaming) return;
  isStreaming = true;
  sendBtn.disabled = true;
  userInput.value = '';

  createBubble('user', text);
  const assistantBubble = createBubble('assistant', '');
  setStatus('生成中');

  try {
    const response = await fetch('/api/chat', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ conversation_id: currentConversationId, message: text })
    });

    if (!response.ok || !response.body) throw new Error('请求失败');

    const newId = response.headers.get('X-Conversation-Id');
    if (newId) currentConversationId = newId;

    const reader = response.body.getReader();
    const decoder = new TextDecoder();
    let beforeText = '';
    let afterText = '';
    let lineBuffer = '';
    let toolStarted = false;
    let toolFinished = false;

    while (true) {
      const { value, done } = await reader.read();
      if (done) break;
      const chunk = decoder.decode(value, { stream: true });
      lineBuffer += chunk;

      while (true) {
        const nl = lineBuffer.indexOf('\n');
        if (nl === -1) break;
        const line = lineBuffer.slice(0, nl);
        lineBuffer = lineBuffer.slice(nl + 1);
        if (!line.trim()) continue;

        let evt;
        try { evt = JSON.parse(line); } catch { continue; }
        if (evt.type === 'assistant_delta') {
          if (!toolStarted || !toolFinished) {
            beforeText += evt.delta || '';
            setAssistantText(assistantBubble, beforeText, 'before');
          } else {
            afterText += evt.delta || '';
            setAssistantText(assistantBubble, afterText, 'after');
          }
        } else if (evt.type === 'tool_call_start') {
          toolStarted = true;
          setToolState(assistantBubble, 'searching');
        } else if (evt.type === 'tool_result') {
          toolFinished = true;
          setToolState(assistantBubble, 'done');
        }
      }
      chatLog.scrollTop = chatLog.scrollHeight;
    }
  } catch (err) {
    setAssistantText(assistantBubble, '出错了，请重试');
    setToolState(assistantBubble, null);
    console.error(err);
  } finally {
    isStreaming = false;
    sendBtn.disabled = false;
    setStatus('空闲');
    await loadConversations();
  }
}

sendBtn.addEventListener('click', sendMessage);
userInput.addEventListener('keydown', (e) => {
  if (e.key === 'Enter' && !e.shiftKey) {
    e.preventDefault();
    sendMessage();
  }
});

newChatBtn.addEventListener('click', () => {
  currentConversationId = null;
  clearChat();
  setStatus('空闲');
  userInput.focus();
  Array.from(conversationList.children).forEach(li => li.classList.remove('active'));
});

toggleSidebarBtn.addEventListener('click', () => {
  document.querySelector('.sidebar').classList.toggle('open');
});

// 初始加载
loadConversations();