graycoreio/daffodil

import { BreakpointObserver } from '@angular/cdk/layout';
import {
  Overlay,
  OverlayRef,
} from '@angular/cdk/overlay';
import { ComponentPortal } from '@angular/cdk/portal';
import {
  ComponentRef,
  EventEmitter,
  Inject,
  Injectable,
  Injector,
  OnDestroy,
  Optional,
  SkipSelf,
} from '@angular/core';
import {
  EMPTY,
  merge,
  of,
  Subscription,
} from 'rxjs';
import {
  delay,
  filter,
  map,
  take,
  tap,
} from 'rxjs/operators';

import {
  DaffBreakpoints,
  DaffFocusStackService,
} from '@daffodil/design';

import { daffToastChangesFocus } from './changes-focus';
import { createPositionStrategy } from './position-strategy';
import { DaffToastPositionService } from './position.service';
import {
  DaffToast,
  DaffToastData,
} from '../interfaces/toast';
import {
  DAFF_TOAST_OPTIONS,
  DaffToastOptions,
} from '../options/daff-toast-options';
import {
  daffDefaultToastConfiguration,
  DaffToastConfiguration,
} from '../toast/toast-config';
import { DaffToastTemplateComponent } from '../toast/toast-template.component';

@Injectable()
export class DaffToastService implements OnDestroy {

  private _sub: Subscription;

  private _toasts: DaffToast[] = [];

  private _overlayRef?: OverlayRef;

  private _template?: ComponentRef<DaffToastTemplateComponent>;

  constructor(
    private overlay: Overlay,
    @Inject(DAFF_TOAST_OPTIONS) private options: DaffToastOptions,
    @Optional() @SkipSelf() private _parentToast: DaffToastService,
    private mediaQuery: BreakpointObserver,
    private toastPosition: DaffToastPositionService,
    private focusStack: DaffFocusStackService,
    private injector: Injector,
  ) {
    this._sub = this.mediaQuery.observe(DaffBreakpoints.MOBILE).pipe(
      filter(() => this._overlayRef !== undefined),
      map((position) => createPositionStrategy(this.toastPosition.config)),
      tap((strategy) => this._overlayRef.updatePositionStrategy(strategy)),
    ).subscribe();
  }

  ngOnDestroy(): void {
    this._sub.unsubscribe();
  }

  private _attachToastTemplate(
    overlayRef: OverlayRef,
  ): ComponentRef<DaffToastTemplateComponent> {
    const template = overlayRef.attach(new ComponentPortal(DaffToastTemplateComponent, null, this.injector));
    return template;
  }

  private _createOverlayRef(): OverlayRef {
    return this.overlay.create({
      hasBackdrop: false,
      scrollStrategy: this.overlay.scrollStrategies.noop(),
      positionStrategy: createPositionStrategy(this.toastPosition.config),
    });
  }

  open(
    toast: DaffToastData,
    configuration?: Partial<DaffToastConfiguration>,
  ): DaffToast {
    if(this._parentToast && this.options.useParent) {
      return this._parentToast.open(toast, configuration);
    }

    const config: DaffToastConfiguration = {
      ...daffDefaultToastConfiguration,
      // sets the default duration to 5000ms if a toast does not have actions
      duration: toast.actions?.length > 0 ? undefined : 5000,
      ...configuration,
    };
    if(this._toasts.length === 0) {
      this._overlayRef = this._createOverlayRef();
      this._template = this._attachToastTemplate(this._overlayRef);
    }
    const dismissEvent = new EventEmitter<void>();
    const _toastPlus: DaffToast = {
      dismissible: true,
      ...toast,
      dismiss: () => {
        dismissEvent.emit();
      },
      dismissalStream: merge(
        config.duration ? of(undefined).pipe(delay(config.duration)) : EMPTY,
        dismissEvent,
      ).pipe(
        take(1),
      ),
    };

    _toastPlus.dismissalStream.subscribe(() => {
      this.close(_toastPlus);
    });

    this._toasts = [
      _toastPlus,
      ...this._toasts,
    ];

    this._template.instance.items = this._toasts;

    return _toastPlus;
  }

  close(toast: DaffToast): void {
    if(this._parentToast && this.options.useParent) {
      this._parentToast.close(toast);
      return;
    }

    if(daffToastChangesFocus(toast)) {
      this.focusStack.pop();
    }

    const index = this._toasts.indexOf(toast);
    if (index === -1) {
      throw new Error(
        'The Toast that you are trying to remove does not exist.',
      );
    }

    this._toasts = this._toasts.filter(m => m !== toast);
    this._template.instance.items = [...this._toasts];

    // This currently overrides the ":leave" animation as we currently
    // remove the animating element immediately after there are no more toasts,
    // without waiting for the animation to complete.
    if(this._toasts.length === 0) {
      this._overlayRef.dispose();
      this._template.destroy();
      this._overlayRef = undefined;
      this._template = undefined;
    }
  }
}