Update

MBS_COMMAND.Application/UserCases/Commands/Groups/AddMentorToGroupCommandHandler.cs

@@ -0,0 +1,42 @@
+using MBS_COMMAND.Contract.Abstractions.Messages;
+using MBS_COMMAND.Contract.Abstractions.Shared;
+using MBS_COMMAND.Contract.Services.Groups;
+using MBS_COMMAND.Domain.Abstractions;
+using MBS_COMMAND.Domain.Abstractions.Repositories;
+using MBS_COMMAND.Domain.Entities;
+
+namespace MBS_COMMAND.Application.UserCases.Commands.Groups;
+
+public class AddMentorToGroupCommandHandler(
+    IRepositoryBase<User, Guid> userRepository,
+    IRepositoryBase<Group, Guid> groupRepository,
+    IUnitOfWork unitOfWork)
+    : ICommandHandler<Command.AddMentorToGroup>
+{
+    public async Task<Result> Handle(Command.AddMentorToGroup request, CancellationToken cancellationToken)
+    {
+        var user = await userRepository.FindByIdAsync(request.MentorId, cancellationToken);
+        if (user == null)
+        {
+            return Result.Failure(new Error("404", "User not found"));
+        }
+        if(user.Role!=2)
+        {
+            return Result.Failure(new Error("403", "User is not a mentor"));
+        }
+        var group = await groupRepository.FindByIdAsync(request.GroupId, cancellationToken);
+        if (group == null)
+        {
+            return Result.Failure(new Error("404", "Group not found"));
+        }
+
+        if (group.MentorId is not null)
+        {
+            return Result.Failure(new Error("400", "Group already has a mentor"));
+        }
+        group.MentorId = request.MentorId;
+        groupRepository.Update(group);
+        await unitOfWork.SaveChangesAsync(cancellationToken);
+        return Result.Success();
+    }
+}

MBS_COMMAND.Contract/Services/Groups/Command.cs

@@ -10,4 +10,5 @@ public record RemoveMemberFromGroup(Guid GroupId, Guid MemberId) : ICommand;
     public record ChangeLeader(Guid GroupId, Guid NewLeaderId) : ICommand;
     public record UpdateGroup(Guid GroupId, string Name, string Stacks) : ICommand;
     public record AcceptGroupInvitation(Guid GroupId, Guid MemberId) : ICommand;
+    public record AddMentorToGroup(Guid GroupId, Guid MentorId) : ICommand;
 }

MBS_COMMAND.Presentation/APIs/Groups/GroupApi.cs

@@ -15,9 +15,14 @@ public void AddRoutes(IEndpointRouteBuilder app)
         gr1.MapPut("change-leader", ChangeLeader).WithSummary("must login in order to use this api");
         gr1.MapPut(string.Empty, UpdateGroup);
         gr1.MapGet("accept-invitation/{groupId}/{memberId}", AcceptGroupInvitation);
+        gr1.MapPost("mentor", AddMentorToGroup);
     }
 
-
+    private static async Task<IResult> AddMentorToGroup(ISender sender, [FromBody] Command.AddMentorToGroup request)
+    {
+        var result = await sender.Send(request);
+        return result.IsFailure ? HandlerFailure(result) : Results.Ok(result);
+    }
     private static async Task<IResult> AcceptGroupInvitation(ISender sender, string groupId,string memberId)
     {
         var result = await sender.Send(new Command.AcceptGroupInvitation(Guid.Parse(groupId), Guid.Parse(memberId)));