private Train AddAttemptsToExamTrain(ExamTrain train, IEnumerable <TaskAnswerBindingModel> answers)
{
//get pairs attempt - answer and add answer value to attempt
//attempts in exam train defined already
train.TaskAttempts
.Join(
answers,
attempt => attempt.ExamTask.Id,
ans => ans.id,
((ta, ua) => new
{
bindingModel = ua,
attempt = ta
})
)
.ForEach(
x =>
{
var attemptFromTrain = x.attempt;
attemptFromTrain.UserAnswer = x.bindingModel.answer;
attemptFromTrain = addExtraInfoForType(attemptFromTrain, x.bindingModel);
}
);
return(train);
}
public IEnumerable <ExamTaskViewModel> GenerateNewExamTrain(int userId)
{
var user = _dbContext.Users.FirstOrDefault(x => x.Id == userId);
if (user != null)
{
var unfinishedTrain =
user.Trains.OfType <ExamTrain>()
.TrainsOfUsersCurrentExamType()?.FirstOrDefault(x => x.FinishTime == null);
if (unfinishedTrain != null)
{
unfinishedTrain.FinishTime = DateTime.Now;
}
ExamTrain train = new ExamTrain();
train.Exam = user.CurrentExam;
train.User = user;
train.StartTime = DateTime.Now;
Random rnd = new Random();
//get one task from each topic at fixed random examNumber position
var lastIndexOfTasksList = _dbContext
.TaskTopics
.FirstOrDefault(x => x.Exam.Id == user.CurrentExam.Id)?
.ExamTasks
.Count() ?? 0;
if (lastIndexOfTasksList == 0)
{
return(new List <ExamTaskViewModel>());
}
var examNumber = rnd.Next(
0,
lastIndexOfTasksList - 1
);
train.TaskAttempts = _dbContext
.TaskTopics
.Where(x => x.Exam.Id == user.CurrentExam.Id)
.ToList()
.Select(x => GenerateNewEmptyAttempt(x.ExamTasks.ElementAt(examNumber)))
.ToList();
//save to db
_dbContext.Trains.Add(train);
_dbContext.SaveChanges();
return(train
.TaskAttempts
.ToList()
.Select(x => new ExamTaskViewModel(x.ExamTask)));
}
else
{
return(null);
}
}
