fetchData() {

  const user = getApp().globalData.currentUser;

  if (!user) return Promise.resolve({ categoryTotals: {}, categoryDailyData: {} });

  const db = wx.cloud.database();

  const collectionName = this.data.statsType === '采购统计' ? 'purchases' : 'consumes';

  // 构建基础查询条件，使用数组直接构造 $in

  let condition = {

    userId: user.nickName,

    category: { $in: this.data.selectedCategories }

  };

  // 根据时间范围添加日期条件（年除外，即查询所有数据）

  if (this.data.timeRange !== '年') {

    const now = new Date();

    let startDate;

    switch (this.data.timeRange) {

      case '周':

        startDate = new Date(now.getFullYear(), now.getMonth(), now.getDate() - 7);

        break;

      case '月':

        startDate = new Date(now.getFullYear(), now.getMonth() - 1, now.getDate());

        break;

      case '季':

        startDate = new Date(now.getFullYear(), now.getMonth() - 3, now.getDate());

        break;

      default:

        startDate = new Date(now.getFullYear(), now.getMonth(), now.getDate() - 365);

    }

    const startDateStr = `${startDate.getFullYear()}-${(startDate.getMonth()+1).toString().padStart(2,'0')}-${startDate.getDate().toString().padStart(2,'0')}`;

    condition.date = { $gte: startDateStr };

  }

  if (this.data.statsType === '消费统计' && this.data.target === '成员') {

    condition.consumer = this.data.member;

  }

  console.log('查询条件：', condition);

  wx.showLoading({ title: '加载数据中' });

  // 一次性获取最多1000条记录（110条足够）

  return db.collection(collectionName)

    .where(condition)

    .field({ date: true, category: true, quantity: true, value: true })

    .limit(1000)

    .get()

    .then(res => {

      wx.hideLoading();

      console.log('查询返回记录数：', res.data.length);

      const records = res.data;

      const categoryTotals = {};

      const categoryDailyData = {};

      this.data.selectedCategories.forEach(cat => {

        categoryTotals[cat] = { quantity: 0, value: 0 };

        categoryDailyData[cat] = new Map();

      });

      records.forEach(r => {

        const cat = r.category;

        if (!categoryTotals[cat]) return;

        const qty = parseFloat(r.quantity || 0);

        const val = parseFloat(r.value || 0);

        categoryTotals[cat].quantity += qty;

        categoryTotals[cat].value += val;

        const date = r.date;

        const map = categoryDailyData[cat];

        if (!map.has(date)) {

          map.set(date, { quantity: 0, value: 0 });

        }

        const day = map.get(date);

        day.quantity += qty;

        day.value += val;

      });

      const finalCategoryDailyData = {};

      for (const cat in categoryDailyData) {

        const map = categoryDailyData[cat];

        const arr = Array.from(map.entries())

          .map(([date, totals]) => ({ date, ...totals }))

          .sort((a, b) => a.date.localeCompare(b.date));

        finalCategoryDailyData[cat] = arr;

      }

      return { categoryTotals, categoryDailyData: finalCategoryDailyData };

    })

    .catch(err => {

      wx.hideLoading();

      console.error('查询失败', err);

      wx.showToast({ title: '数据加载失败', icon: 'none' });

      return { categoryTotals: {}, categoryDailyData: {} };

    });

}