import {Injectable, NgZone, TemplateRef} from '@angular/core';
import {Observable, Subject} from 'rxjs';
import {MatDialog, MatDialogConfig, MatDialogRef} from '@angular/material/dialog';
import {ComponentType} from '@angular/cdk/portal';

type Dialog<T> = {subject: Subject<T|undefined>, dialog_service_identifier: string};

@Injectable({
  providedIn: 'root'
})
export class DialogService {
  private dialogs: Record<string, MatDialogRef<Dialog<any>>> = {};

  constructor(public materialDialog: MatDialog, private zone: NgZone) {}

  public show<T>(dialogType: ComponentType<any> | TemplateRef<any>, configuration?: MatDialogConfig): Observable<T> {
    // Now using NgZone to avoid weird bug where ngOnInit would only be called after dialog was closed,
    // thus rendering an empty unusable dialog
    return this.zone.run(() => {
      const dialog = this.materialDialog.open(dialogType, Object.assign({width: '400'}, configuration || {} ) );
      dialog.componentInstance.dialog_service_identifier = `dialog_${new Date().getTime()}`;
      this.dialogs[(dialog.componentInstance as any).dialog_service_identifier] = dialog;
      return dialog.afterClosed();
    });
  }

  public close<T>(dialog: any, value?: T): void {
    if (dialog) {
      this.getDialog(dialog).close(value);
    }
  }

  private getDialog(dialog: any): MatDialogRef<any> {
    const result =  this.dialogs[dialog.dialog_service_identifier];
    if (result) {
      return result;
    }
    throw new Error('Could not close dialog - did you try to close it without opening it?');
  }

  public getDialogs(): Record<string, MatDialogRef<Dialog<any>>> {
    return this.dialogs;
  }
}