zod-backend/src/common/modules/notification/dtos/response/notifications.response.dto.ts

import { ApiProperty } from '@nestjs/swagger';
import { Notification } from '../../entities';
import { NotificationStatus } from '../../enums';

export class NotificationsResponseDto {
  @ApiProperty({ example: 'f1b1b9b1-1b1b-1b1b-1b1b-1b1b1b1b1b1b' })
  id!: string;

  @ApiProperty({ example: 'Test' })
  title: string;

  @ApiProperty({ example: 'TestBody' })
  body: string;

  @ApiProperty({ example: NotificationStatus.UNREAD })
  status!: NotificationStatus;

  @ApiProperty({ example: '2021-09-01T00:00:00.000Z' })
  createdAt!: Date;

  constructor(notification: Notification) {
    this.id = notification.id;
    this.title = notification.title;
    this.body = notification.message;
    this.status = notification.status!;
    
    // Use event timestamp from data if available, otherwise use notification creation time
    // This ensures notifications show when the event occurred, not when notification was saved
    // Note: Timestamps are stored in UTC. The client should convert to the user's local timezone.
    if (notification.data?.timestamp) {
      // Parse the ISO string timestamp (which is in UTC)
      // The client should convert this to the user's local timezone based on their device settings
      this.createdAt = new Date(notification.data.timestamp);
    } else {
      // Use notification creation time (also in UTC)
      this.createdAt = notification.createdAt;
    }
  }
}