import { Injectable, signal, OnDestroy } from '@angular/core';
import { ApiService } from './api';

export interface Notification {
  event_type: 'deadline' | 'expense';
  event_id: number;
  title: string;
  date: string;
}

@Injectable({ providedIn: 'root' })
export class NotificationService implements OnDestroy {
  notifications = signal<Notification[]>([]);
  private intervalId: any;

  constructor(private api: ApiService) {}

  start() {
    this.load();
    this.intervalId = setInterval(() => this.load(), 60_000);
  }

  stop() {
    clearInterval(this.intervalId);
  }

  ngOnDestroy() {
    this.stop();
  }

  private load() {
    this.api.getNotifications().subscribe({
      next: (data) => this.notifications.set(data),
      error: () => {},
    });
  }

  markRead(notification: Notification) {
    this.api.markNotificationRead(notification.event_type, notification.event_id).subscribe({
      next: () => {
        this.notifications.update(list =>
          list.filter(n => !(n.event_type === notification.event_type && n.event_id === notification.event_id))
        );
      },
    });
  }

  markAllRead() {
    const current = this.notifications();
    current.forEach(n =>
      this.api.markNotificationRead(n.event_type, n.event_id).subscribe()
    );
    this.notifications.set([]);
  }
}