public ChallengeSolveResult Solve(Challenge challenge, Guid userId, string answer)
{
var solveResult = ValidateAnswer(challenge, answer);
if (solveResult.IsSolved)
{
var solver = challenge.Solvers.Single(x => x.UserId == userId);
solver.HasSolved = true;
challenge.TimesSolved++;
var rating = (double)((int)challenge.Difficulty + 1) / challenge.TimesSolved;
solveResult.RatingObtained = rating;
identityService.AddRatingToUser(userId, rating);
unitOfWork.InsertOrUpdate(challenge);
unitOfWork.InsertOrUpdate(solver);
unitOfWork.Commit();
}
return(solveResult);
}