survey-webapp/SurveyBackend/SurveyBackend.API/Mappers/QuestionMapper.cs

using SurveyBackend.DTOs.Question;
using SurveyBackend.Services.Exceptions;
using SurveyLib.Core.Models;
using SurveyLib.Core.Models.QuestionVariants;

namespace SurveyBackend.Mappers;

public static class QuestionMapper
{
    public static QuestionBase QuestionCreationToModel(CreateQuestionDto dto, int surveyId)
    {
        return dto.QuestionType.ToLower() switch
        {
            "textquestion" => new TextQuestion
            {
                Title = dto.Title,
                SurveyId = surveyId,
            },
            "singleanswerquestion" => new SingleAnswerQuestion
            {
                Title = dto.Title,
                SurveyId = surveyId,
                AnswerVariants = dto.AnswerVariants?.Select(v => new AnswerVariant { Text = v }).ToList() ?? [],
            },
            "multipleanswerquestion" => new MultipleAnswerQuestion
            {
                Title = dto.Title,
                SurveyId = surveyId,
                AnswerVariants = dto.AnswerVariants?.Select(v => new AnswerVariant { Text = v }).ToList() ?? []
            },
            _ => throw new BadRequestException("Unknown question type")
        };
    }

    public static OutputQuestionDto ModelToQuestionDto(QuestionBase question)
    {
        var withAnswerVariants = question.GetType() != typeof(TextQuestion);
        return new OutputQuestionDto
        {
            Id = question.Id,
            SurveyId = question.SurveyId,
            Title = question.Title,
            QuestionType = question.Discriminator,
            AnswerVariants = withAnswerVariants ? AnswerVariantsToDto(question.AnswerVariants) : null,
        };
    }

    private static List<OutputAnswerVariantDto> AnswerVariantsToDto(IEnumerable<AnswerVariant> answerVariants)
    {
        return answerVariants.Select(av => new OutputAnswerVariantDto
        {
            Id = av.Id,
            QuestionId = av.QuestionId,
            Text = av.Text,
        }).ToList();
    }
}