/**
 * 公益活动列表页 U31
 *
 * 重构要点（遵循 AGENTS.md 不变量）：
 *   - 数据：ActivityStore.fetchActivities / loadMoreActivities（游标分页）
 *   - 列表项：ui-activity-card 组件，"公益免费"为主视觉标识（AGENTS 第 1 条：用户永久免费）
 *   - 跳转：点击卡片 → activity-detail，不在列表页处理报名
 *   - 单向意向保密：本页不接入互选意向提交（仅在 activity-matches 页由用户主动操作，AGENTS 第 6 条）
 *   - 下拉刷新 + onReachBottom 加载更多
 */
const { activityStore, appStore, authStore } = require('../../stores');
const { to } = require('../../constants');

Page({
  data: {
    activities: [],
    loading: false,
    loadingMore: false,
    hasMore: true,
    firstLoaded: false,
    /** @type {{title:string, description:string, illustration:string, actions:Array}} */
    emptyConfig: {
      title: '暂无进行中的活动',
      description: '近期暂无报名中的公益活动，请稍后再来',
      illustration: 'activity',
      actions: [
        { text: '我的活动', event: 'my', variant: 'secondary' },
      ],
    },
  },

  onLoad() {
    if (!authStore.state.isLoggedIn) return;
    this._unsub = activityStore.bindToPage(this, {
      activities: 'activities',
      activitiesHasMore: 'activitiesHasMore',
    });
    this.fetchActivities(true);
  },

  onShow() {
    if (!authStore.state.isLoggedIn) return;
    // 从活动详情返回后，若列表为空则刷新（避免详情页报名后列表不同步）
    if (this.data.firstLoaded && this.data.activities.length === 0) {
      this.fetchActivities(true);
    }
  },

  onUnload() {
    if (this._unsub) this._unsub();
  },

  /** 首次或下拉刷新拉取活动列表 */
  async fetchActivities(first = false) {
    if (this.data.loading) return;
    this.setData({ loading: true });
    try {
      await activityStore.fetchActivities();
      this.setData({
        loading: false,
        firstLoaded: true,
        hasMore: activityStore.state.activitiesHasMore,
      });
    } catch (err) {
      this.setData({ loading: false, firstLoaded: true });
      appStore.toastError(err, '加载活动失败');
    }
  },

  /** 加载更多（onReachBottom 触发） */
  async loadMore() {
    if (this.data.loadingMore || !this.data.hasMore) return;
    this.setData({ loadingMore: true });
    try {
      await activityStore.loadMoreActivities();
      this.setData({
        loadingMore: false,
        hasMore: activityStore.state.activitiesHasMore,
      });
    } catch (err) {
      this.setData({ loadingMore: false });
      appStore.toastError(err, '加载更多失败');
    }
  },

  onPullDownRefresh() {
    this.fetchActivities(true).then(() => {
      wx.stopPullDownRefresh();
    });
  },

  onReachBottom() {
    this.loadMore();
  },

  /** 点击活动卡片 → 跳转详情 */
  onActivityTap(e) {
    const activityId = e.detail.activityId;
    if (!activityId) return;
    wx.navigateTo({ url: to.activityDetail(activityId) });
  },

  /** 空状态：去我的活动 */
  onEmptyAction(e) {
    const { event } = e.detail;
    if (event === 'my') {
      wx.navigateTo({ url: '/pages/my-activities/my-activities' });
    }
  },

  /** 顶部"我的活动"入口 */
  onMyActivities() {
    wx.navigateTo({ url: '/pages/my-activities/my-activities' });
  },
});