feat: add cron job for allowance and implement cron lock

src/allowance/entities/allowance.entity.ts

@@ -1,3 +1,4 @@
+import moment from 'moment';
 import {
   Column,
   CreateDateColumn,
@@ -13,7 +14,6 @@ import { Guardian } from '~/guardian/entities/guradian.entity';
 import { Junior } from '~/junior/entities';
 import { AllowanceFrequency, AllowanceType } from '../enums';
 import { AllowanceChangeRequest } from './allowance-change-request.entity';
-
 @Entity('allowances')
 export class Allowance {
   @PrimaryGeneratedColumn('uuid')
@@ -71,4 +71,31 @@ export class Allowance {
 
   @DeleteDateColumn({ name: 'deleted_at', type: 'timestamp with time zone', nullable: true })
   deletedAt?: Date;
+
+  get nextPaymentDate(): Date | null {
+    const startDate = moment(this.startDate).clone().startOf('day');
+    const endDate = this.endDate ? moment(this.endDate).endOf('day') : null;
+    const now = moment().startOf('day');
+
+    if (endDate && moment().isAfter(endDate)) {
+      return null;
+    }
+
+    const calculateNextDate = (unit: moment.unitOfTime.Diff) => {
+      const diff = now.diff(startDate, unit);
+      const nextDate = startDate.clone().add(diff, unit);
+      return nextDate.isSameOrAfter(now) ? nextDate.toDate() : nextDate.add('1', unit).toDate();
+    };
+
+    switch (this.frequency) {
+      case AllowanceFrequency.DAILY:
+        return calculateNextDate('days');
+      case AllowanceFrequency.WEEKLY:
+        return calculateNextDate('weeks');
+      case AllowanceFrequency.MONTHLY:
+        return calculateNextDate('months');
+      default:
+        return null;
+    }
+  }
 }