// pages/wiki/chat/index.js

Page({
  data: {
    messages: [],
    inputValue: '',
    isTyping: false,
    scrollAnchor: '',
    _counter: 0,
  },

  onLoad(options) {
    if (options && options.fromHistory === '1') {
      const channel = this.getOpenerEventChannel();
      channel.on('historyData', (data) => {
        const msgs = [
          { id: 'h1', role: 'user', content: data.question },
          { id: 'h2', role: 'ai', content: this._cleanMd(data.answer) },
        ];
        this.setData({ messages: msgs, _counter: 2 }, () => this.scrollToBottom());
      });
    } else if (options && options.prefillQuestion) {
      const q = decodeURIComponent(options.prefillQuestion);
      this.setData({ inputValue: q }, () => this.onSend());
    }
  },

  goToHistory() {
    wx.navigateTo({ url: '/pages/wiki/chat/history/index' });
  },

  onQuickAsk(e) {
    const query = e.currentTarget.dataset.q;
    this.setData({ inputValue: query }, () => this.onSend());
  },

  onInput(e) {
    this.setData({ inputValue: e.detail.value });
  },

  onSend() {
    const query = this.data.inputValue.trim();
    if (!query || this.data.isTyping) return;

    const uid = 'u' + (++this.data._counter);
    const aid = 'a' + (++this.data._counter);
    const len = this.data.messages.length;

    // Push user msg + empty AI msg at once
    this.setData({
      [`messages[${len}]`]: { id: uid, role: 'user', content: query },
      [`messages[${len + 1}]`]: { id: aid, role: 'ai', content: '' },
      inputValue: '',
      isTyping: true,
    }, () => {
      this.scrollToBottom();
      this._streamRequest(query, aid);
    });
  },

  _streamRequest(query, aiMsgId) {
    const token = wx.getStorageSync('token');
    const baseUrl = 'http://192.168.0.184:8889';
    const url = `${baseUrl}/plant/chat/stream?query=${encodeURIComponent(query)}`;
    let fullText = '';

    const task = wx.request({
      url,
      method: 'GET',
      enableChunked: true,
      header: {
        'Authorization': `Bearer ${token}`,
        'Accept': 'text/event-stream',
      },
      success: () => {
        this.setData({ isTyping: false });
        this.scrollToBottom();
      },
      fail: () => {
        this._updateAiMsg(aiMsgId, '网络连接失败，请稍后重试');
        this.setData({ isTyping: false });
      },
    });

    task.onChunkReceived((res) => {
      const text = this._decode(res.data);
      const lines = text.split('\n');

      for (const line of lines) {
        if (!line.startsWith('data: ')) continue;
        const chunk = line.substring(6);

        if (chunk === '[DONE]') {
          this.setData({ isTyping: false });
          return;
        }
        if (chunk.startsWith('[ERROR]')) {
          fullText += '\n⚠️ ' + (chunk.substring(7) || '服务异常');
          this._updateAiMsg(aiMsgId, fullText);
          this.setData({ isTyping: false });
          return;
        }

        fullText += chunk;
        this._updateAiMsg(aiMsgId, fullText);
      }
      this.scrollToBottom();
    });
  },

  _updateAiMsg(id, content) {
    const idx = this.data.messages.findIndex(m => m.id === id);
    if (idx !== -1) {
      this.setData({ [`messages[${idx}].content`]: this._cleanMd(content) });
    }
  },

  // Strip residual markdown symbols for clean display
  _cleanMd(text) {
    return text
      .replace(/^#{1,6}\s*/gm, '')          // ### headers
      .replace(/\*\*(.+?)\*\*/g, '【$1】')   // **bold** → 【bold】
      .replace(/\*(.+?)\*/g, '$1')           // *italic*
      .replace(/^[\-\*]\s+/gm, '· ')         // - list → · list
      .replace(/^\d+\.\s+/gm, (m) => m)      // keep numbered lists
      .replace(/`([^`]+)`/g, '$1')            // `code`
      .replace(/^---+$/gm, '————')            // --- → ————
      .replace(/\n{3,}/g, '\n\n');            // collapse blank lines
  },

  _decode(buffer) {
    try {
      return new TextDecoder('utf-8').decode(new Uint8Array(buffer));
    } catch (e) {
      const bytes = new Uint8Array(buffer);
      let s = '';
      for (let i = 0; i < bytes.length; i++) s += String.fromCharCode(bytes[i]);
      try { return decodeURIComponent(escape(s)); } catch (_) { return s; }
    }
  },

  scrollToBottom() {
    this.setData({ scrollAnchor: 'scroll-bottom' });
  },
});