/// <summary>
/// Creates an excercise for the supplied session
/// </summary>
/// <param name="session"></param>
/// <returns></returns>
public Exercise CreateExercise(Session session, int attempt = 1)
{
if (attempt > 100) // 100 can be changed to required value to prevent looping and StackOverflowException.
{
throw new UniqueExerciseNotAvailableException("Maximum number of attempts to create an exercises have reached. Please retry after sometime.");
}
var randomNumbers = _randomNumberGenerator.GenerateNumbers();
var expression1 = randomNumbers.Item1;
var expression2 = randomNumbers.Item2;
var currentExerciseWithTheSameExpressions = State.Exercises.FirstOrDefault(e =>
((e.Expression1 == expression1 && e.Expression2 == expression2) ||
(e.Expression1 == expression2 && e.Expression2 == expression1)) &&
e.CreatedDateTime >= DateTime.Now.AddSeconds(-30));
if (currentExerciseWithTheSameExpressions != null)
{
return(CreateExercise(session, ++attempt));
}
else
{
var exercise = new Exercise();
exercise.Id = Guid.NewGuid();
exercise.Expression1 = expression1;
exercise.Expression2 = expression2;
exercise.TimeLimit = State.RankTimeLimit[session.Rank];
exercise.AssignedSession = session.Id;
exercise.CreatedDateTime = DateTime.Now;
State.Exercises.Add(exercise);
return(exercise);
}
}