public async Task <IEnumerable <Attendance> > GetAttendancesAtWorkshopAsync(int workshopId)
{
if (workshopId <= 0)
{
throw new ArgumentException($"Argument {nameof(workshopId)} can't be less or equal zero!");
}
int groupId = (await workshopRepository.GetWorkshopAsync(workshopId)).GroupId;
var students = await groupRepository.GetStudentsAsync(groupId);
var attendances = new List <Attendance>();
foreach (var student in students)
{
var attendance = (await workshopRepository.GetStudentAttendanceAsync(workshopId, student.Id)).ToAttendance();
attendances.Add(attendance);
}
return(attendances);
}