(B) Add get doctor user by id

Clinics.Backend/Application/Users/Queries/GetDoctorUserById/GetDoctorUserByIdHandler.cs

+using Application.Abstractions.CQRS.Queries;
+using Domain.Repositories;
+using Domain.Shared;
+
+namespace Application.Users.Queries.GetDoctorUserById;
+
+public class GetDoctorUserByIdHandler : IQueryHandler<GetDoctorUserByIdQuery, GetDoctorUserByIdResponse>
+{
+    #region CTOD DI
+    private readonly IUserRepository _userRepository;
+
+    public GetDoctorUserByIdHandler(IUserRepository userRepository)
+    {
+        _userRepository = userRepository;
+    }
+    #endregion
+    public async Task<Result<GetDoctorUserByIdResponse>> Handle(GetDoctorUserByIdQuery request, CancellationToken cancellationToken)
+    {
+        #region 1. Fetch doctor user from DB
+        var doctorUserFromDbResult = await _userRepository.GetDoctorUserByIdAsync(request.Id);
+        if (doctorUserFromDbResult.IsFailure)
+            return Result.Failure<GetDoctorUserByIdResponse>(doctorUserFromDbResult.Error);
+        #endregion
+
+        #region 2. Generate response
+        var response = GetDoctorUserByIdResponse.GetResponse(doctorUserFromDbResult.Value);
+        if (response.IsFailure)
+            return Result.Failure<GetDoctorUserByIdResponse>(response.Error);
+        #endregion
+    
+        return Result.Success<GetDoctorUserByIdResponse>(response.Value);
+
+    }
+}

Clinics.Backend/Application/Users/Queries/GetDoctorUserById/GetDoctorUserByIdQuery.cs

+using Application.Abstractions.CQRS.Queries;
+
+namespace Application.Users.Queries.GetDoctorUserById;
+
+public class GetDoctorUserByIdQuery : IQuery<GetDoctorUserByIdResponse>
+{
+    public int Id { get; set; }
+}

Clinics.Backend/Application/Users/Queries/GetDoctorUserById/GetDoctorUserByIdResponse.cs

+using Domain.Entities.Identity.Users;
+using Domain.Errors;
+using Domain.Shared;
+
+namespace Application.Users.Queries.GetDoctorUserById;
+
+public class GetDoctorUserByIdResponse
+{
+    public int Id { get; set; }
+    public string UserName { get; set; } = null!;
+    public string FirstName { get; set; } = null!;
+    public string MiddleName { get; set; } = null!;
+    public string LastName { get; set; } = null!;
+
+    public static Result<GetDoctorUserByIdResponse> GetResponse (DoctorUser doctorUser)
+    {
+        if (doctorUser.Id <= 0 || doctorUser.User is null || doctorUser.Doctor is null)
+            return Result.Failure<GetDoctorUserByIdResponse>(PersistenceErrors.NotFound);
+        if (doctorUser.Doctor.PersonalInfo is null)
+            return Result.Failure<GetDoctorUserByIdResponse>(PersistenceErrors.NotFound);
+
+        return new GetDoctorUserByIdResponse
+        {
+            Id = doctorUser.Id,
+            UserName = doctorUser.User.UserName,
+            FirstName = doctorUser.Doctor.PersonalInfo.FirstName,
+            MiddleName = doctorUser.Doctor.PersonalInfo.MiddleName,
+            LastName = doctorUser.Doctor.PersonalInfo.LastName,
+        };
+    }
+}

Clinics.Backend/Domain/Repositories/IUserRepository.cs

@@ -28,6 +28,10 @@ public interface IUserRepository : IRepository<User>
     public Task<Result<ICollection<DoctorUser>>> GetAllDoctorUsersAsync();
     #endregion
 
+    #region Get doctor user by id
+    public Task<Result<DoctorUser>> GetDoctorUserByIdAsync(int id);
+    #endregion
+
     #region Register doctor
     public Task<Result<DoctorUser>> RegisterDoctorAsync(DoctorUser doctorUser);
     #endregion

Clinics.Backend/Persistence/Repositories/Users/UserRepository.cs

@@ -116,6 +116,26 @@ public class UserRepository : Repositroy<User>, IUserRepository
     }
     #endregion
 
+    #region Get doctor user by id
+    public async Task<Result<DoctorUser>> GetDoctorUserByIdAsync(int id)
+    {
+        try
+        {
+            var query = _context.Set<DoctorUser>()
+                .Where(doctorUser => doctorUser.Id == id)
+                .Include(doctorUser => doctorUser.User)
+                .Include(doctorUser => doctorUser.Doctor)
+                    .ThenInclude(doctor => doctor.PersonalInfo);
+            return await query.FirstAsync();
+
+        }
+        catch (Exception)
+        {
+            return Result.Failure<DoctorUser>(PersistenceErrors.NotFound);
+        }
+    }
+    #endregion
+
     #region Register doctor
     public async Task<Result<DoctorUser>> RegisterDoctorAsync(DoctorUser doctorUser)
     {

Clinics.Backend/Presentation/Controllers/UsersController.cs

@@ -3,6 +3,7 @@ using Application.Users.Commands.RegisterDoctor;
 using Application.Users.Commands.RegisterReceptionist;
 using Application.Users.Queries.GetAllDoctorUsers;
 using Application.Users.Queries.GetAllReceptionistsUsers;
+using Application.Users.Queries.GetDoctorUserById;
 using Domain.Entities.Identity.UserRoles;
 using MediatR;
 using Microsoft.AspNetCore.Authorization;
@@ -58,6 +59,17 @@ public class UsersController : ApiController
             return HandleFailure(result);
         return Ok(result.Value);
     }
+
+    [Authorize(Roles = Roles.AdminName)]
+    [HttpGet("Doctors/{id:int}")]
+    public async Task<IActionResult> GetDoctorUserById([FromRoute(Name ="id")] int id )
+    {
+        var query = new GetDoctorUserByIdQuery { Id = id };
+        var result = await _sender.Send(query);
+        if (result.IsFailure)
+            return HandleFailure(result);
+        return Ok(result.Value);
+    }
     #endregion
 
     #region Receptionist