public async Task <IActionResult> AddToGroup(AddStudentToGroupInputModel model)
        {
            int studentId = await CheckStudentId(this.TempData["studentId"]);

            int groupId = model.IdIsSelected;

            if (this.TempData["studentStatus"].ToString() == "Active") // TODO magic string
            {
                await this.groupsService.RemoveStudentFromGroup(studentId);
            }

            await this.groupsService.AddStudentToGroup(studentId, groupId);

            return(await Task.Run(() => this.RedirectToAction("Details", new { studentId = studentId })));
        }
        public async Task <IActionResult> AddToGroup()
        {
            int studentId = await CheckStudentId(this.TempData["studentId"]);

            var groupsList = await this.groupsService.GetVacantGroupsWithProperAge(studentId);

            var model = new AddStudentToGroupInputModel()
            {
                GroupsForSelection = groupsList.ToList()
            };

            this.TempData.Keep("studentId");
            this.TempData.Keep("studentStatus");

            return(await Task.Run(() => View(model)));
        }