/// <summary>
/// Adds student to a waitinglist in the course with the given ID.
/// If there is no course with the given ID, exception is thrown,
/// </summary>
/// <param name="id">ID of the course's waitinglist</param>
/// <param name="student">AddStudentViewModel object containing the students information</param>
public void AddStudentToWaitingList(int id, AddStudentViewModel student)
{
// Check if course exists
var courseExistance = _db.Courses.SingleOrDefault(x => x.ID == id);
if (courseExistance == null)
{
throw new AppObjectNotFoundException();
}
// Check if students exists
var studentExistance = _db.Students.SingleOrDefault(x => x.SSN == student.SSN);
if (studentExistance == null)
{
throw new AppObjectNotFoundException();
}
// Check if student is already enrolled in course
var studentAlreadyInCourse = (from cr in _db.CourseRegistrations
where cr.CourseID == id
where studentExistance.ID == cr.StudentID
where cr.Active
select cr).SingleOrDefault();
if (studentAlreadyInCourse != null)
{
throw new AppConflictException();
}
// Check if student is already on the waitinglist in the course
var studentWaitingListExistance = (from wl in _db.WaitingListEntries
where wl.CourseID == id
where studentExistance.ID == wl.StudentID
select wl).SingleOrDefault();
if (studentWaitingListExistance != null)
{
throw new AppConflictException();
}
// Create a new WaitingListEntry
var waitingListEntry = new WaitingListEntry
{
CourseID = id,
StudentID = studentExistance.ID
};
// Add the entry to the database
_db.WaitingListEntries.Add(waitingListEntry);
_db.SaveChanges();
}
public IHttpActionResult AddStudentToCourse(int id, AddStudentViewModel student)
{
if (ModelState.IsValid)
{
try
{
var result = _service.AddStudentToCourse(id, student);
return Content(HttpStatusCode.Created, result);
}
catch (AppObjectNotFoundException)
{
//return 404
return NotFound();
}
catch (AppPreconditionFailedException)
{
//return 409
return StatusCode(HttpStatusCode.PreconditionFailed);
}
}
else
{
return StatusCode(HttpStatusCode.PreconditionFailed);
}
}
/// <summary>
/// Adds a pre existing student to a pre existing course.
/// </summary>
/// <param name="id">The ID of the course to add the student to</param>
/// <param name="model">A AddStudentViewModel containing the student that is to be added</param>
public StudentDTO AddStudentToCourse(int id, AddStudentViewModel model)
{
// Checking if student exists in the database
var student = _db.Students.SingleOrDefault(x => x.SSN == model.SSN);
if (student == null)
{
// If the student cannot be found:
throw new AppObjectNotFoundException();
}
// Checking if the course exists in the database
var course = _db.Courses.SingleOrDefault(x => x.ID == id);
if (course == null)
{
// If the course cannot be found:
throw new AppObjectNotFoundException();
}
var studentCount = (from cr in _db.CourseRegistrations
where id == cr.CourseID
where cr.Active
select cr.StudentID).ToList().Count();
// If the max count of student has been reached for this class,
// return 412
if (studentCount == course.MaxStudents)
{
throw new AppPreconditionFailedException();
}
// Check if the student is on the waiting list for the course
var studentOnWaitingList = (from wl in _db.WaitingListEntries
where wl.CourseID == id
where student.ID == wl.StudentID
select wl).SingleOrDefault();
// Checking if the student is already enrolled in the course
var studentAlreadyInCourse = (from cr in _db.CourseRegistrations
where cr.CourseID == id
where student.ID == cr.StudentID
where cr.Active
select cr).SingleOrDefault();
// If he is not enrolled, we enroll him in the course
if (studentAlreadyInCourse == null)
{
//remove the student from waitinglist if he was on it
if (studentOnWaitingList != null)
{
_db.WaitingListEntries.Remove(studentOnWaitingList);
_db.SaveChanges();
}
//Create a new CourseRegistration
var newRegistration = new CourseRegistration
{
CourseID = id,
StudentID = student.ID,
Active = true
};
//Add it to the database
_db.CourseRegistrations.Add(newRegistration);
_db.SaveChanges();
//Make a new StudentDTO to return to the client
var studentDto = new StudentDTO
{
Name = student.Name,
SSN = student.SSN
};
return studentDto;
}
else
{
throw new AppPreconditionFailedException();
}
}
public IHttpActionResult AddStudentToWaitingList(int id, AddStudentViewModel student)
{
if (ModelState.IsValid)
{
try
{
_service.AddStudentToWaitingList(id, student);
return StatusCode(HttpStatusCode.OK);
}
catch (AppObjectNotFoundException)
{
//return 404
return NotFound();
}
catch (AppConflictException)
{
//return 409
return StatusCode(HttpStatusCode.PreconditionFailed);
}
}
else
{
return StatusCode(HttpStatusCode.PreconditionFailed);
}
}
