move services to separate project

+ add GetByUserId methods to Survey

SurveyLib.Services/Services/QuestionService.cs

@@ -0,0 +1,43 @@
+using SurveyLib.Core.Models;
+using SurveyLib.Core.Repositories;
+using SurveyLib.Core.Services;
+
+namespace SurveyLib.Services.Services;
+
+public class QuestionService : IQuestionService
+{
+    private readonly IQuestionRepository _questionRepository;
+
+    public QuestionService(IQuestionRepository questionRepository)
+    {
+        _questionRepository = questionRepository;
+    }
+
+    public async Task AddQuestionAsync(QuestionBase question)
+    {
+        await _questionRepository.AddAsync(question);
+    }
+
+    public async Task UpdateQuestionAsync(QuestionBase question)
+    {
+        await _questionRepository.UpdateAsync(question);
+    }
+
+    public async Task DeleteQuestionAsync(int id)
+    {
+        var question = await GetQuestionByIdAsync(id);
+
+        await _questionRepository.DeleteAsync(question);
+    }
+
+    public async Task<QuestionBase> GetQuestionByIdAsync(int id)
+    {
+        var question = await _questionRepository.GetByIdAsync(id) ?? throw new NullReferenceException();
+        return question;
+    }
+
+    public async Task<IEnumerable<QuestionBase>> GetQuestionsBySurveyIdAsync(int surveyId)
+    {
+        return await _questionRepository.GetQuestionsBySurveyId(surveyId);
+    }
+}