public async Task <int> Add(Lecturer lecturer)
{
var l = new Lecturer
{
Name = lecturer.Name
};
_context.Lecturers.Add(l);
await SaveChangesAsync();
var newStudents = lecturer.LecturerStudents.Select(ls => ls.Student).Where(s => s.Id == 0).ToList();
var existingStudents = lecturer.LecturerStudents.Select(ls => ls.Student).Where(s => s.Id != 0).ToList();
var newStudentIds = await _studentService.AddMany(newStudents);
var existingStudentIds = await _studentService.UpdateMany(existingStudents);
foreach (var studentId in newStudentIds.Union(existingStudentIds))
{
_context.LecturerStudents.Add(new LecturerStudent
{
LecturerId = l.Id,
StudentId = studentId
});
}
await SaveChangesAsync();
return(l.Id);
}