feat(schedules): add next invocation logging for event-watch job

- Import 'dayjs' to format timestamps for better readability.
- Store the scheduled job instance in a private field to access next execution time.
- Update the 'start' method to log the job name and the precise next run time.
- Update 'watchEvents' method with a debug log for the next invocation.

This improves observability by showing exactly when the scheduled task is expected to run next, rather than just the schedule definition.

src/schedules/EventWatchSchedule.ts

@@ -6,11 +6,16 @@ import { diffArrays } from '../utils/common';
 import { sendNotification } from '../utils/firebase-admin';
 import { prisma } from '../prisma/db';
 import type { Schedule } from './schedule';
+import dayjs from 'dayjs';
 
 export class EventWatchSchedule implements Schedule {
+
+  #job?: nodeSchedule.Job;
+
   constructor() {}
 
   async watchEvents() {
+    console.debug('nextStartTime: %s', dayjs(this.#job?.nextInvocation()).format('YYYY-MM-DD HH:mm:ss'));
     const events = await EventSubscribeService.getAllEvents();
     events.forEach((e) => this.diffEvent(e));
   }
@@ -56,10 +61,11 @@ export class EventWatchSchedule implements Schedule {
     await Promise.all(tokens.map(token => sendNotification(token, { title, body, url })));
   }
   start() {
-    const schedule = nodeSchedule.scheduleJob('event-watch', {
+    const job = nodeSchedule.scheduleJob('event-watch', {
       minute: [0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55],
       hour: new nodeSchedule.Range(7, 23),
     }, () => this.watchEvents());
-    console.debug('Start schedule:', schedule.name);
+    this.#job = job;
+    console.debug('Start schedule: %s, next run at %s', job.name, dayjs(job.nextInvocation()).format('YYYY-MM-DD HH:mm:ss'));
   }
 }