public SaveInDbStrategy(MovieReviewEntities movieReviewEntities)
{
_movieReviewEntities = movieReviewEntities;
}
static void Main(string[] args)
{
//parse input
int movieId;
int criticId;
int stars;
try
{
movieId = Int32.Parse(args[0]);
criticId = Int32.Parse(args[1]);
stars = Int32.Parse(args[2]);
}
catch(Exception ex)
{
Console.WriteLine(ex.Message);
return;
}
//process rating
MovieReviewEntities db = null;
try
{
db = new MovieReviewEntities();
//insert or update new rating
var existingRating = db.Ratings.SingleOrDefault(r => r.MovieId == movieId && r.CriticId == criticId);
if (existingRating == null)
{
existingRating = new Rating {MovieId = movieId, CriticId = criticId};
db.Ratings.Add(existingRating);
}
existingRating.Stars = stars;
//update critic rating weight according to how closely their ratings match the average rating
var criticsHavingRated = db.Critics.Where(c => c.Ratings.Count > 0);
foreach (var critic in criticsHavingRated)
{
var ratingsWithAverages = critic.Ratings.Where(r => r.Movie.AverageRating.HasValue).ToList();
var totalDisparity = ratingsWithAverages.Sum(r => Math.Abs(r.Stars - r.Movie.AverageRating.Value));
var relativeDisparity = totalDisparity / ratingsWithAverages.Count;
critic.RatingWeight = relativeDisparity > 2 ? 0.15 : relativeDisparity > 1 ? 0.33 : 1.0;
}
//re-calculate weighted average of all movie ratings
foreach (var movie in db.Movies)
{
var weightTotal = movie.Ratings.Select(r => r.Critic.RatingWeight).Sum();
var ratingTotal = movie.Ratings.Select(r => r.Stars * r.Critic.RatingWeight).Sum();
movie.AverageRating = ratingTotal / weightTotal;
}
db.SaveChanges();
//output summary
var newCriticRatingWeight = db.Critics.Single(c => c.Id == criticId).RatingWeight;
var newMovieRating = db.Movies.Single(m => m.Id == movieId).AverageRating.Value;
Console.WriteLine("New critic rating weight: {0:N1}", newCriticRatingWeight);
Console.WriteLine("New movie rating: {0:N1}", newMovieRating);
}
catch(Exception ex)
{
Console.WriteLine(ex.Message);
}
finally
{
if (db != null) db.Dispose();
}
Console.ReadKey();
}
