import { Injectable } from '@angular/core';
import { BehaviorSubject, Observable } from 'rxjs';
import { Task } from '../entity/task';
import { TaskPersistenceService } from './task-persistence.service';

@Injectable({
  providedIn: 'root'
})
export class TaskService {
  private _tasks: BehaviorSubject<Task[]> = new BehaviorSubject<Task[]>([]);

  constructor(
    private _taskPersistenceService: TaskPersistenceService
  ) {
    const tasks = this._taskPersistenceService.getAll() || [];
    this._tasks.next(tasks);
  }

  get tasks(): Observable<Task[]> {
    return this._tasks.asObservable();
  }

  add(task: Task): void {
    const tasks = this._tasks.value;
    tasks.push(task);
    this._tasks.next(tasks);
    this._saveTasks();
  }

  private _saveTasks(): void {
    this._taskPersistenceService.save(this._tasks.value);
  }

  refresh() {
    const tasks = this._taskPersistenceService.getAll();
    this._tasks.next(tasks);
  }
}