/**
 * 聊天详情页 U24（重构：用 messageStore + message-bubble）
 *
 * 不变量（AGENTS.md）：
 *   - 第 3 条：Mutual Match 后才能聊天——sendMessage 若后端返回 MATCH_REQUIRED，
 *     UI 给出引导文案；不在客户端做硬阻断，由后端守门。
 *   - 第 4 条：Block/Unmatch 后会话 canSendMessage=false，输入栏禁用并显示"已停用"。
 *   - 第 6 条：单向活动意向不泄露——本页只展示已建立的 Mutual 会话消息。
 *   - 第 7 条：普通工作人员不能查看私人聊天——本页仅服务用户端。
 *   - 第 9 条：PostgreSQL 是 Source of Truth——本地仅缓存最近活跃会话消息，冷启动从服务端拉取。
 */
const { messageStore, appStore, blockUser } = require('../../stores');
const { messageService } = require('../../services');
const { to, ROUTE, DANGER_ACTION, BUSINESS_ERROR_CODE } = require('../../constants');

/** 超过该间隔则显示时间分隔（5 分钟） */
const TIME_GAP_MS = 5 * 60 * 1000;

Page({
  data: {
    conversationId: '',
    otherDisplayName: '',
    otherUserId: '',
    otherAvatarUrl: '',
    canSend: true,
    messages: [],
    hasMore: true,
    loading: false,
    loadingMore: false,
    sending: false,
    inputText: '',
    scrollIntoView: '',
    statusBarHeight: 20,
    navBarHeight: 44,
    showDangerDialog: false,
    dangerAction: DANGER_ACTION.BLOCK,
    connectionState: 'disconnected',
  },

  onLoad(options) {
    const conversationId = options.id || '';
    if (!conversationId) {
      appStore.toast('会话不存在');
      wx.navigateBack();
      return;
    }

    // 注入状态栏高度供 ui-nav-bar 使用
    try {
      const info = (wx.getWindowInfo && wx.getWindowInfo()) || wx.getSystemInfoSync();
      this.setData({
        statusBarHeight: info.statusBarHeight || 20,
        navBarHeight: info.platform === 'android' ? 48 : 44,
      });
    } catch (e) { /* 使用默认值 */ }

    this.setData({ conversationId });

    // 绑定 messageStore.connectionState 到页面
    this._unsubConn = messageStore.bindToPage(this, {
      connectionState: 'connectionState',
    });
    // 订阅消息列表 / 分页 / loading 变化
    this._unsubList = messageStore.subscribe((state) => this._syncFromStore(state));
    // 注册实时消息监听：收到对方消息立即标记已读（会话已处于前台）
    this._unsubRealtime = messageStore.onMessage(conversationId, (msg) => {
      if (msg.bubbleType === 'other') {
        messageStore.markConversationRead(conversationId).catch(() => {});
      }
    });

    // 打开会话：拉取最近消息 + 清未读（AGENTS 第 9 条，DB 为准）
    messageStore.openConversation(conversationId).catch((err) => appStore.toastError(err));
    // 拉取会话元数据（displayName / canSend / targetUserId / 头像）
    this.loadConversationMeta();
  },

  onUnload() {
    this._unsubConn && this._unsubConn();
    this._unsubList && this._unsubList();
    this._unsubRealtime && this._unsubRealtime();
    if (this.data.conversationId) {
      // 关闭会话：activeConversationId 置空，后续收到对方消息将累计未读
      messageStore.closeConversation();
    }
  },

  /** 拉取会话元数据（canSend 以服务端为准） */
  async loadConversationMeta() {
    try {
      const conv = await messageService.getConversation(this.data.conversationId);
      if (conv) {
        this.setData({
          otherDisplayName: conv.targetDisplayName || conv.otherDisplayName || '用户',
          otherUserId: conv.targetUserId || '',
          otherAvatarUrl: conv.targetAvatarUrl || '',
          canSend: conv.canSendMessage !== false,
        });
      }
    } catch (err) {
      // 兜底：从 store 会话列表查找
      const local = messageStore.state.conversations.find(
        (c) => c.conversationId === this.data.conversationId,
      );
      if (local) {
        this.setData({
          otherDisplayName: local.targetDisplayName || '用户',
          otherUserId: local.targetUserId || '',
          otherAvatarUrl: local.targetAvatarUrl || '',
          canSend: local.canSendMessage !== false,
        });
      } else {
        appStore.toastError(err);
      }
    }
  },

  /** 把 store 状态同步到页面 */
  _syncFromStore(state) {
    const cid = this.data.conversationId;
    const rawList = state.messagesByConversation[cid] || [];
    const hasMore = state.hasMoreByConversation[cid] !== false;
    const loading = state.conversationsLoading;
    const messages = this._formatMessageList(rawList);
    const patch = { messages, hasMore };
    if (loading !== this.data.loading) patch.loading = loading;
    this.setData(patch);

    // 加载更早消息时，保持滚动位置（定位到加载前的第一条）
    if (this._loadingMore && this._preserveMsgId) {
      const idx = messages.findIndex((m) => m.messageId === this._preserveMsgId);
      if (idx >= 0) this.setData({ scrollIntoView: `msg-${idx}` });
      this._loadingMore = false;
      this._preserveMsgId = null;
    } else {
      this._scrollToLast(messages);
    }
  },

  /** 派生时间分隔 / 头像 / 是否显示头像 */
  _formatMessageList(list) {
    const otherAvatar = this.data.otherAvatarUrl;
    const result = [];
    let lastTs = 0;
    for (let i = 0; i < list.length; i++) {
      const m = list[i];
      const ts = m.sentAt || 0;
      const showTime = i === 0 || (ts && ts - lastTs > TIME_GAP_MS);
      result.push({
        ...m,
        showTime,
        sentAtText: showTime ? this._formatTime(ts) : '',
        showAvatar: m.bubbleType === 'other',
        avatarUrl: m.bubbleType === 'other' ? otherAvatar : '',
      });
      lastTs = ts;
    }
    return result;
  },

  _formatTime(ts) {
    if (!ts) return '';
    const d = new Date(ts);
    const now = new Date();
    const hm = d.toLocaleTimeString('zh-CN', { hour: '2-digit', minute: '2-digit' });
    if (d.toDateString() === now.toDateString()) return hm;
    return `${d.getMonth() + 1}/${d.getDate()} ${hm}`;
  },

  _scrollToLast(list) {
    if (!list.length) return;
    const id = `msg-${list.length - 1}`;
    if (id !== this.data.scrollIntoView) {
      this.setData({ scrollIntoView: id });
    }
  },

  onBack() {
    const pages = getCurrentPages();
    if (pages.length > 1) {
      wx.navigateBack();
    } else {
      wx.switchTab({ url: ROUTE.TAB.MESSAGES });
    }
  },

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

  async onSend() {
    const { inputText, conversationId, sending, canSend } = this.data;
    if (!canSend || !inputText.trim() || sending) return;
    this.setData({ sending: true, inputText: '' });
    try {
      await messageStore.sendMessage(conversationId, inputText.trim());
    } catch (err) {
      // MATCH_REQUIRED：双方互相喜欢后才能聊天（AGENTS 第 3 条，后端守门）
      if (err && err.code === BUSINESS_ERROR_CODE.MATCH_REQUIRED) {
        appStore.toast('双方互相喜欢后才能开始聊天');
      } else {
        appStore.toastError(err, '发送失败');
      }
    } finally {
      this.setData({ sending: false });
    }
  },

  /** 重发失败消息 */
  onRetrySend(e) {
    const messageId = e.currentTarget.dataset.msgId;
    if (!messageId) return;
    messageStore
      .retrySend(this.data.conversationId, messageId)
      .catch((err) => appStore.toastError(err, '重发失败'));
  },

  /** 滚动到顶部：加载更早消息（保持滚动位置） */
  async onScrollToUpper() {
    const { conversationId, hasMore, loadingMore } = this.data;
    if (!hasMore || loadingMore) return;
    const first = this.data.messages[0];
    this._loadingMore = true;
    this._preserveMsgId = first ? first.messageId : null;
    this.setData({ loadingMore: true });
    try {
      await messageStore.loadMoreMessages(conversationId);
    } catch (err) {
      appStore.toastError(err);
      this._loadingMore = false;
      this._preserveMsgId = null;
    } finally {
      this.setData({ loadingMore: false });
    }
  },

  /** 右上角更多：查看资料 / 举报 / 拉黑 */
  onMore() {
    const { otherUserId } = this.data;
    if (!otherUserId) {
      appStore.toast('暂无更多信息');
      return;
    }
    wx.showActionSheet({
      itemList: ['查看 Ta 的资料', '举报 Ta', '拉黑 Ta'],
      success: (res) => {
        if (res.tapIndex === 0) {
          wx.navigateTo({ url: to.detail(otherUserId) });
        } else if (res.tapIndex === 1) {
          wx.navigateTo({ url: to.report(otherUserId) });
        } else if (res.tapIndex === 2) {
          this.setData({ showDangerDialog: true, dangerAction: DANGER_ACTION.BLOCK });
        }
      },
    });
  },

  /** 危险动作确认（拉黑） */
  async onConfirmDanger(e) {
    const action = e.detail.action;
    const { otherUserId, conversationId } = this.data;
    this.setData({ showDangerDialog: false });
    if (action !== DANGER_ACTION.BLOCK) return;
    try {
      appStore.showLoading('处理中…');
      // 拉黑：触发 MatchStore + MessageStore 同步副作用（AGENTS 第 4 条即时停用）
      await blockUser(otherUserId, '用户主动拉黑');
      appStore.hideLoading();
      this.setData({ canSend: false });
      appStore.toastSuccess('已拉黑');
    } catch (err) {
      appStore.hideLoading();
      appStore.toastError(err);
    }
  },

  onCancelDanger() {
    this.setData({ showDangerDialog: false });
  },
});