import { AppDataService, AppNotificationService } from '../services';
import { AppError } from '../entities';
import { Injectable, Injector, ErrorHandler } from '@angular/core';


@Injectable()
export class AppErrorHandler implements ErrorHandler {

  constructor(private injector: Injector) { }


  handleError(error) {

    //As AppErrorHandler would be loaded before AppDataService, hence we cannot insantiate AppDataService in constructor
    //so get AppDataService using injector
    const dataService = this.injector.get(AppDataService);

    const errorMessage = error.message || 'Unknown error thrown. Please see stack';

    // post the error to the server logs
    dataService.addToLog({ title: errorMessage, description: error.stack });

    // when throwing errors anywhere in app in try/catch blocks, we cast the error as AppError.
    // AppError is a type to store error details
    if (error instanceof AppError){
      if (error.notifyUser){ //if user needs to be informed
         const appNotificationService = this.injector.get(AppNotificationService);
         appNotificationService.set({ type: error.type, message: error.message });
      }
    }

    throw appError;
  }

}