/// <summary>
/// Method that adds a student to a course with a given ID.
/// The attributes needed to add a student to a course are given with
/// a view model class.
/// </summary>
/// <param name="id">ID of the course</param>
/// <param name="model">Add student view model (ViewModel class)</param>
/// <returns>The student that was added to the course (DTO class)</returns>
public StudentDTO AddStudentToCourse(int id, AddStudentViewModel model)
{
var course = _db.Courses.SingleOrDefault(x => x.ID == id);
var student = _db.Students.SingleOrDefault(x => x.SSN == model.SSN);
if (course == null || student == null)
{
throw new AppObjectNotFoundException();
}
var studentInCourse = _db.CourseStudents.SingleOrDefault(x => x.CourseID == id && x.StudentID == student.ID && x.IsActive == true);
if(studentInCourse != null)
{
throw new AppObjectIllegalAddException();
}
if (course.MaxStudents <= GetStudentsInCourse(id).Count)
{
throw new AppMaxReachedException();
}
var studentInWaitingList = _db.WaitingLists.SingleOrDefault(x => x.CourseID == id && x.StudentID == student.ID);
if(studentInWaitingList != null)
{
_db.WaitingLists.Remove(studentInWaitingList);
}
var courseStudent = _db.CourseStudents.SingleOrDefault(x => x.CourseID == id && x.StudentID == student.ID && x.IsActive == false);
if(courseStudent != null)
{
courseStudent.IsActive = true;
}
else
{
var newCourseStudent = new CourseStudent
{
CourseID = course.ID,
StudentID = student.ID,
IsActive = true
};
_db.CourseStudents.Add(newCourseStudent);
}
_db.SaveChanges();
var result = new StudentDTO
{
Name = student.Name,
SSN = student.SSN
};
return result;
}
/// <summary>
/// Adds a student to a given course
/// </summary>
/// <param name="id"></param>
/// <param name="model"></param>
/// <returns></returns>
public StudentDTO AddStudentToCourse(int id, AddStudentViewModel model)
{
var course = _db.Courses.SingleOrDefault(x => x.ID == id);
//if course doesn't exist an error will be thrown. Not possible to add student to non existing courses
if (course == null)
{
throw new AppObjectNotFoundException();
}
//verify that the person exists!
var person = _db.Persons.SingleOrDefault(x => x.SSN == model.SSN);
if(person == null)
{
throw new AppObjectNotFoundException();
}
//count students in the course
var countStudents = _db.CourseStudents.Count(x => x.CourseID == course.ID);
//stop adding new students if course is full
if(countStudents >= course.MaxStudents)
{
throw new MaxStudentException();
}
//check if student already in course
var studentAlreadyInCourse = (from cs in _db.CourseStudents
where cs.CourseID == id
&& person.ID == cs.PersonID
select cs).SingleOrDefault();
if (studentAlreadyInCourse != null)
{
throw new DuplicateEntryException();
}
//check if person is on the waitinglist
var isOnWaitList = (from cwl in _db.CourseWaitingList
//join p in _db.Persons on cwl.PersonID equals p.ID
where cwl.CourseID == id
&& person.ID == cwl.PersonID
select cwl).SingleOrDefault();
//person is on the waitinglist
if(isOnWaitList != null)
{
_db.CourseWaitingList.Remove(isOnWaitList);
_db.SaveChanges();
}
//Actually add the record
var courseStudent = new CourseStudent
{
PersonID = person.ID,
CourseID = course.ID
};
_db.CourseStudents.Add(courseStudent);
_db.SaveChanges();
//3.Figure out what to return.
var returnValue = new StudentDTO
{
Name = person.Name,
SSN = person.SSN
};
return returnValue;
}