如何触发Firebase云函数每天按条件更新一次字段，并向Android客户端发送推送通知

const functions = require('firebase-functions');
const admin = require('firebase-admin');

admin.initializeApp();

exports.updateFieldAndSendNotification = functions.pubsub
  .schedule('every day 00:00')
  .timeZone('Asia/Shanghai')
  .onRun(async (context) => {
    try {
      const db = admin.firestore();
      const collectionRef = db.collection('your_collection');
      
      // 查询满足条件的文档
      const querySnapshot = await collectionRef.where('your_condition', '==', 'your_value').get();
      
      // 更新字段
      const batch = db.batch();
      querySnapshot.forEach((doc) => {
        const docRef = collectionRef.doc(doc.id);
        batch.update(docRef, { your_field: 'new_value' });
      });
      await batch.commit();
      
      // 发送推送通知给Android客户端
      const message = {
        notification: {
          title: 'Notification Title',
          body: 'Notification Body',
        },
        topic: 'your_topic',
      };
      await admin.messaging().send(message);
      
      return null;
    } catch (error) {
      console.error('Error:', error);
      throw new functions.https.HttpsError('internal', 'An error occurred.');
    }
  });