import { Injectable } from '@angular/core';
import {
  NavigationCancel,
  NavigationEnd,
  NavigationError,
  NavigationStart,
  Router,
} from '@angular/router';
import { BehaviorSubject, Observable } from 'rxjs';
import { filter } from 'rxjs/operators';

@Injectable({
  providedIn: 'root',
})
export class MwProgressBarService {
  private localBufferValue: BehaviorSubject<number>;
  private localMode: BehaviorSubject<string>;
  private localValue: BehaviorSubject<number>;
  private localVisible: BehaviorSubject<boolean>;

  constructor(private router: Router) {
    this.localBufferValue = new BehaviorSubject(0);
    this.localMode = new BehaviorSubject('indeterminate');
    this.localValue = new BehaviorSubject(0);
    this.localVisible = new BehaviorSubject<boolean>(false);

    this._init();
  }

  get bufferValue(): Observable<any> {
    return this.localBufferValue.asObservable();
  }

  setBufferValue(value: number): void {
    this.localBufferValue.next(value);
  }

  get mode(): Observable<any> {
    return this.localMode.asObservable();
  }

  setMode(value: 'determinate' | 'indeterminate' | 'buffer' | 'query'): void {
    this.localMode.next(value);
  }

  get value(): Observable<any> {
    return this.localValue.asObservable();
  }

  setValue(value: number): void {
    this.localValue.next(value);
  }

  get visible(): Observable<any> {
    return this.localVisible.asObservable();
  }

  private _init(): void {
    // Subscribe to the router events to show/hide the loading bar
    this.router.events
      .pipe(filter((event) => event instanceof NavigationStart))
      .subscribe(() => {
        this.show();
      });

    this.router.events
      .pipe(
        filter(
          (event) =>
            event instanceof NavigationEnd ||
            event instanceof NavigationError ||
            event instanceof NavigationCancel
        )
      )
      .subscribe(() => {
        this.hide();
      });
  }

  show(): void {
    this.localVisible.next(true);
  }

  hide(): void {
    this.localVisible.next(false);
  }
}