i'm sorry guys it's stupid commit...

SurveyBackend/SurveyBackend.API/Controllers/CompletionController.cs

@@ -0,0 +1,48 @@
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using SurveyBackend.Contexts;
+using SurveyBackend.Core.Contexts;
+using SurveyBackend.DTOs.Completion;
+using SurveyBackend.Mappers;
+using SurveyLib.Core.Models;
+using SurveyLib.Core.Services;
+
+namespace SurveyBackend.Controllers;
+
+[ApiController]
+[Route("api/surveys/{surveyId:int}/completions")]
+public class CompletionController : ControllerBase
+{
+    private readonly ICompletionService _completionService;
+    private readonly IUserContext _userContext;
+
+    public CompletionController(ICompletionService completionService, IUserContext userContext)
+    {
+        _completionService = completionService;
+        _userContext = userContext;
+    }
+
+    [HttpGet]
+    [Authorize]
+    public async Task<IActionResult> GetCompletionsAsync(int surveyId)
+    {
+        return NotFound();
+    }
+
+    [HttpGet("{id:int}")]
+    [Authorize]
+    public async Task<IActionResult> GetCompletionAsync(int id)
+    {
+        return NotFound();
+    }
+
+    [HttpPost]
+    [AllowAnonymous]
+    public async Task<IActionResult> PostCompletionAsync([FromBody] CompletionCreateDto dto, [FromRoute] int surveyId)
+    {
+        var userId = _userContext.NullableUserId;
+        var model = CompletionMapper.CreateDtoToModel(dto, surveyId, userId);
+        await _completionService.AddCompletionAsync(model);
+        return Ok();
+    }
+}

SurveyBackend/SurveyBackend.API/DTOs/Answer/AnswerCreateDto.cs

@@ -0,0 +1,7 @@
+namespace SurveyBackend.DTOs.Answer;
+
+public class AnswerCreateDto
+{
+    public int QuestionId { get; set; }
+    public required string AnswerText { get; set; }
+}

SurveyBackend/SurveyBackend.API/DTOs/Answer/AnswerOutputDto.cs

@@ -0,0 +1,8 @@
+namespace SurveyBackend.DTOs.Answer;
+
+public class AnswerOutputDto
+{
+    public int QuestionId { get; set; }
+    public int CompletionId { get; set; }
+    public required string AnswerText { get; set; }
+}

SurveyBackend/SurveyBackend.API/DTOs/Completion/CompletionCreateDto.cs

@@ -0,0 +1,8 @@
+using SurveyBackend.DTOs.Answer;
+
+namespace SurveyBackend.DTOs.Completion;
+
+public class CompletionCreateDto
+{
+    public List<AnswerCreateDto> Answers { get; set; }
+}

SurveyBackend/SurveyBackend.API/DTOs/Completion/CompletionOutputDto.cs

@@ -0,0 +1,10 @@
+using SurveyBackend.DTOs.Answer;
+
+namespace SurveyBackend.DTOs.Completion;
+
+public class CompletionOutputDto
+{
+    public int? CompletedBy { get; set; }
+    public DateTime FinishedAt { get; set; }
+    public List<AnswerOutputDto> Answers { get; set; }
+}

SurveyBackend/SurveyBackend.API/Mappers/AnswerMapper.cs

@@ -0,0 +1,20 @@
+using SurveyBackend.DTOs.Answer;
+using SurveyLib.Core.Models;
+
+namespace SurveyBackend.Mappers;
+
+public static class AnswerMapper
+{
+    public static Answer CreateDtoToModel(AnswerCreateDto dto) => new Answer
+    {
+        QuestionId = dto.QuestionId,
+        AnswerText = dto.AnswerText,
+    };
+
+    public static AnswerOutputDto ModelToOutputDto(Answer model) => new AnswerOutputDto
+    {
+        QuestionId = model.QuestionId,
+        AnswerText = model.AnswerText,
+        CompletionId = model.CompletionId,
+    };
+}

SurveyBackend/SurveyBackend.API/Mappers/CompletionMapper.cs

@@ -0,0 +1,21 @@
+using SurveyBackend.DTOs.Completion;
+using SurveyLib.Core.Models;
+
+namespace SurveyBackend.Mappers;
+
+public static class CompletionMapper
+{
+    public static Completion CreateDtoToModel(CompletionCreateDto dto, int surveyId, int? performerId) => new Completion
+    {
+        SurveyId = surveyId,
+        CompletedBy = performerId,
+        Answers = dto.Answers.Select(AnswerMapper.CreateDtoToModel).ToList(),
+    };
+
+    public static CompletionOutputDto ModelToOutputDto(Completion model) => new CompletionOutputDto
+    {
+        CompletedBy = model.CompletedBy,
+        FinishedAt = model.FinishedAt,
+        Answers = model.Answers.Select(AnswerMapper.ModelToOutputDto).ToList(),
+    };
+}

SurveyBackend/SurveyBackend.API/Program.cs

@@ -12,6 +12,7 @@ using SurveyBackend.Infrastructure.Data;
 using SurveyBackend.Infrastructure.Repositories;
 using SurveyBackend.Middlewares;
 using SurveyBackend.Services;
+using SurveyBackend.Services.Helpers;
 using SurveyBackend.Services.Services;
 using SurveyLib.Core.Repositories;
 using SurveyLib.Core.Services;
@@ -49,10 +50,12 @@ public class Program
         builder.Services.AddScoped<ISurveyRepository, SurveyRepository>();
         builder.Services.AddScoped<IQuestionRepository, QuestionRepository>();
         builder.Services.AddScoped<IAnswerVariantsRepository, AnswerVariantsRepository>();
+        builder.Services.AddScoped<ICompletionRepository, CompletionRepository>();
 
         builder.Services.AddScoped<ISurveyService, SurveyService>();
         builder.Services.AddScoped<IQuestionService, QuestionService>();
         builder.Services.AddScoped<IAnswerVariantsService, AnswerVariantsService>();
+        builder.Services.AddScoped<ICompletionService, CompletionService>();
 
 
         builder.Services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)