Initial commit — AllMusicGuide scraper and music metadata tagger

Client.AllMusicGuide/Services/TrackRater.cs

@@ -0,0 +1,57 @@
+using System;
+using System.Linq;
+using MusicMetaTagger.Core.Model;
+using MusicMetaTagger.Core.Services;
+
+namespace MusicMetaTagger.Client.AllMusicGuide.Services
+{
+	public class TrackRater : ITrackRater
+	{
+		private readonly IMusicGuide _musicGuide;
+
+		public TrackRater(IMusicGuide musicGuide)
+		{
+			_musicGuide = musicGuide;
+		}
+
+		public int? RateTrack(Track track)
+		{
+			if (track == null)
+				throw new ArgumentNullException("track");
+
+			if (track.PerformerIds == null || track.PerformerIds.Count == 0)
+				return null;
+
+			// get the track pick statistics for this album
+			var albumInfo = _musicGuide.GetAlbum(track.AlbumId);
+			
+			if (!albumInfo.Rating.HasValue)
+				return null;
+			
+			// get the album rating statistics for this artist
+			double artistAlbumRatingMean = 0;
+			var artistInfo = _musicGuide.GetArtist(albumInfo.ArtistId);
+
+			if (artistInfo != null)
+			{
+				var currentDi =
+					artistInfo.Discography.Find(di => di.AlbumId == albumInfo.AlbumId);
+
+				artistAlbumRatingMean =
+					(from di in artistInfo.Discography
+					 where currentDi == null || di.ReleaseType == currentDi.ReleaseType
+					 where di.Rating.HasValue
+					 select di.Rating.Value).Average();
+			}
+
+			// calculate the track rating
+			var trackRating = albumInfo.Rating.Value;
+			if (albumInfo.Rating.Value >= 9 && albumInfo.Tracks.Any(t => t.Pick)) trackRating -= 1;
+			if (artistAlbumRatingMean >= 8 && albumInfo.Tracks.Any(t => t.Pick)) trackRating -= 1;
+			if (albumInfo.Pick) trackRating += 1;
+			if (track.Pick) trackRating += 2;
+		
+			return Math.Min(Math.Max(0, trackRating), 10);
+		}
+	}
+}