import { Question } from '@/modules/questions/entities/question.entity';
import { AnswerSubmissionDTO } from '../dtos/answer-submission.dto';
import { QuestionTransitionType } from '@/modules/questions/enums/question-transition-type.enum';
import { QuestionType } from '@/modules/questions/enums/question-type.enum';
import { SingleChoiceCondition } from '@/modules/questions/interfaces/single-choice-condition.interface';
import { NumericCondition } from '@/modules/questions/interfaces/numeric-condition.interface';
import { AppException } from '@/common/exceptions/app.exception';
import { HttpStatus } from '@nestjs/common';

export const getNextTransition = (
  question: Question,
  answerSubmissionDto: AnswerSubmissionDTO,
) => {
  const transitions = question.outgoingTransitions ?? [];

  const endTransition = transitions.find(
    (t) => t.type === QuestionTransitionType.END,
  );

  if (
    question.type === QuestionType.SINGLE_CHOICE &&
    answerSubmissionDto.choiceId !== undefined
  ) {
    const transition = transitions.find(
      (t) =>
        t.type === QuestionTransitionType.CHOICE &&
        (t.condition as SingleChoiceCondition).choiceId ===
          answerSubmissionDto.choiceId,
    );

    if (transition) return transition;
  }

  if (
    question.type === QuestionType.NUMERIC &&
    answerSubmissionDto.numericValue !== undefined
  ) {
    const value = answerSubmissionDto.numericValue;

    const transition = transitions.find((t) => {
      if (t.type !== QuestionTransitionType.NUMBER_RANGE) return false;

      const condition = t.condition as NumericCondition;

      return value >= condition.min && value <= condition.max;
    });

    if (transition) return transition;
  }

  const defaultTransition = transitions.find(
    (t) => t.type === QuestionTransitionType.DEFAULT,
  );

  if (defaultTransition) return defaultTransition;

  if (endTransition) return endTransition;

  throw new AppException(
    'submissions.errors.nextQuestionNotFound',
    HttpStatus.BAD_REQUEST,
  );
};