import {EventEmitter, Injectable} from '@angular/core';
import {Observable, of} from 'rxjs';
import {GameActionsService} from './game-actions.service';
import {MicroLessonMetricsService} from './metrics/micro-lesson-metrics.service';
import {PartCorrectness, UserAnswer} from 'ox-types';

@Injectable({
  providedIn: 'root'
})
export abstract class AnswerService {

  private _currentAnswer: UserAnswer;

  get currentAnswer(): UserAnswer {
    return this._currentAnswer;
  }

  set currentAnswer(value: UserAnswer) {
    this._currentAnswer = value;
    this.validAnswer.emit(this.isValidAnswer(this.currentAnswer));
  }

  public tryAnswer = new EventEmitter<UserAnswer>();
  public validAnswer = new EventEmitter<boolean>();

  protected constructor(private gameActions: GameActionsService<any>,
                        private metricsService: MicroLessonMetricsService<any>) {
  }

  protected checkAnswer(answer: UserAnswer): Observable<PartCorrectness> {
    return of(answer.parts.length > 0
    && answer.parts.every(z => z.correctness === 'correct') ? 'correct' : 'wrong');
  }

  public onTryAnswer(): void {
    this.tryAnswer.emit(this.currentAnswer);
    if (this.metricsService.currentMetrics.metricsType === 'results-without-correction') {
      this.gameActions.checkedAnswer.emit({answer: this.currentAnswer, correctness: 'unknown'});
    } else {
      this.checkAnswer(this.currentAnswer).subscribe(value => {
        this.gameActions.checkedAnswer.emit({answer: this.currentAnswer, correctness: value});
      });
    }
  }

  // protected abstract isValidAnswer(answer: UserAnswer): boolean;
  protected isValidAnswer(answer: UserAnswer): boolean {
    return answer !== undefined;
  }

}