public async Task <Result <Unit> > Handle(CreateClassroomCommand request, CancellationToken cancellationToken)
{
var user = await _context.Users.SingleOrDefaultAsync(x =>
x.UserName == _userAccessor.GetCurrentUsername());
// Create the classroom.
var classroom = new Classroom {
Id = request.Id,
Name = request.Name,
DiscussionsCount = 0,
CreatedBy = user
};
_context.Classrooms.Add(classroom);
var student = new ApplicationUserClassroom(user.Id, classroom.Id, true, user, classroom);
_context.ApplicationUserClassrooms.Add(student);
var success = await _context.SaveChangesAsync() > 0;
if (!success)
{
return(Result <Unit> .Failure("There was a problem saving changes."));
}
return(Result <Unit> .Success(Unit.Value));
}
// TODO: Need to check for expired tokens/invite links.
// TODO: Need to update the 'Hits' column in the InviteLinks table whenever a token gets used successfully.
public async Task <Result <Unit> > Handle(JoinClassroomCommand request, CancellationToken cancellationToken)
{
// Get the invite link and the related classroom id.
var inviteLink = await _context.InviteLinks.SingleOrDefaultAsync(x =>
x.Token == request.Token);
// Get the classroom.
var classroom = await _context.Classrooms.FindAsync(inviteLink.Classroom.Id);
// No classroom was found with the given id.
if (classroom is null)
{
Result <Unit> .Failure("Unable to find classroom.");
}
// Get the currently authorized user.
var user = await _context.Users.SingleOrDefaultAsync(x =>
x.UserName == _userAccessor.GetCurrentUsername());
var student = await _context.ApplicationUserClassrooms
.SingleOrDefaultAsync(x => x.ClassroomId == classroom.Id &&
x.ApplicationUserId == user.Id);
// User is already attending this classroom.
if (student != null)
{
return(Result <Unit> .Failure("User is already participating in this classroom."));
}
// Create a new entry in the UserClassroom table.
student = new ApplicationUserClassroom(user.Id, classroom.Id, true, user, classroom);
_context.ApplicationUserClassrooms.Add(student);
// Save changes to the database.
var success = await _context.SaveChangesAsync() > 0;
// Return the final response.
if (success)
{
return(Result <Unit> .Success(Unit.Value));
}
return(Result <Unit> .Failure("There was a problem saving changes."));
}