Fuzzy matching (#508)

* Fixed: correctly match albums whose title is all special characters

* New: fuzzy matching on album and track names

src/NzbDrone.Common/Extensions/StringExtensions.cs

@@ -141,5 +141,42 @@ namespace NzbDrone.Common.Extensions
             return CamelCaseRegex.Replace(input, match => " " + match.Value);
         }
 
+        public static double FuzzyMatch(this string a, string b)
+        {
+            if (a.Contains(" ") && b.Contains(" "))
+            {
+                var partsA = a.Split(' ');
+                var partsB = b.Split(' ');
+                var weightedHighCoefficients = new double[partsA.Length];
+                var distanceRatios = new double[partsA.Length];
+                for (int i = 0; i < partsA.Length; i++)
+                {
+                    double high = 0.0;
+                    int indexDistance = 0;
+                    for (int x = 0; x < partsB.Length; x++)
+                    {
+                        var coef = LevenshteinCoefficient(partsA[i], partsB[x]);
+                        if (coef > high)
+                        {
+                            high = coef;
+                            indexDistance = Math.Abs(i - x);
+                        }
+                    }
+                    double distanceWeight = 1.0 - (double)indexDistance / (double)partsA.Length;
+                    weightedHighCoefficients[i] = high * distanceWeight;
+                }
+                return weightedHighCoefficients.Sum() / (double)partsA.Length;
+            }
+            else
+            {
+                return LevenshteinCoefficient(a, b);
+            }
+        }
+
+        public static double LevenshteinCoefficient(this string a, string b)
+        {
+            return 1.0 - (double)a.LevenshteinDistance(b) / Math.Max(a.Length, b.Length);
+        }
+
     }
 }

src/NzbDrone.Core.Test/MusicTests/AlbumRepositoryTests/AlbumRepositoryFixture.cs

@@ -8,6 +8,7 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
+using NLog;
 
 namespace NzbDrone.Core.Test.MusicTests.AlbumRepositoryTests
 {
@@ -16,6 +17,8 @@ namespace NzbDrone.Core.Test.MusicTests.AlbumRepositoryTests
     {
         private Artist _artist;
         private Album _album;
+        private Album _albumSpecial;
+        private Album _albumSimilar;
         private AlbumRepository _albumRepo;
 
         [SetUp]
@@ -29,12 +32,15 @@ namespace NzbDrone.Core.Test.MusicTests.AlbumRepositoryTests
                 Id = 1
             };
 
+            _albumRepo = Mocker.Resolve<AlbumRepository>();
+
             _album = new Album
             {
                 Title = "ANThology",
                 ForeignAlbumId = "1",
                 CleanTitle = "anthology",
                 Artist = _artist,
+                ArtistId = _artist.Id,
                 AlbumType = "",
                 Releases = new List<AlbumRelease>
                 {
@@ -46,9 +52,46 @@ namespace NzbDrone.Core.Test.MusicTests.AlbumRepositoryTests
                 
             };
 
-            _albumRepo = Mocker.Resolve<AlbumRepository>();
-
             _albumRepo.Insert(_album);
+
+            _albumSpecial = new Album
+            {
+                Title = "+",
+                ForeignAlbumId = "2",
+                CleanTitle = "",
+                Artist = _artist,
+                ArtistId = _artist.Id,
+                AlbumType = "",
+                Releases = new List<AlbumRelease>
+                {
+                    new AlbumRelease
+                    {
+                        Id = "fake id"
+                    }
+                }
+                
+            };
+
+            _albumRepo.Insert(_albumSpecial);
+
+            _albumSimilar = new Album
+            {
+                Title = "ANThology2",
+                ForeignAlbumId = "3",
+                CleanTitle = "anthology2",
+                Artist = _artist,
+                ArtistId = _artist.Id,
+                AlbumType = "",
+                Releases = new List<AlbumRelease>
+                {
+                    new AlbumRelease
+                    {
+                        Id = "fake id 2"
+                    }
+                }
+                
+            };
+
         }
 
 
@@ -59,9 +102,62 @@ namespace NzbDrone.Core.Test.MusicTests.AlbumRepositoryTests
 
             var album = _albumRepo.FindAlbumByRelease(id);
 
+            album.Should().NotBeNull();
+            album.Title.Should().Be(_album.Title);
+        }
+
+        [TestCase("ANThology")]
+        [TestCase("anthology")]
+        [TestCase("anthology!")]
+        public void should_find_album_in_db_by_title(string title)
+        {
+            var album = _albumRepo.FindByTitle(_artist.Id, title);
+
+            album.Should().NotBeNull();
             album.Title.Should().Be(_album.Title);
         }
 
+        [Test]
+        public void should_find_album_in_db_by_title_all_special_characters()
+        {
+            var album = _albumRepo.FindByTitle(_artist.Id, "+");
+
+            album.Should().NotBeNull();
+            album.Title.Should().Be(_albumSpecial.Title);
+        }
+
+        [TestCase("ANTholog")]
+        [TestCase("nthology")]
+        [TestCase("antholoyg")]
+        public void should_not_find_album_in_db_by_incorrect_title(string title)
+        {
+            var album = _albumRepo.FindByTitle(_artist.Id, title);
+
+            album.Should().BeNull();
+        }
+
+        [TestCase("ANTholog")]
+        [TestCase("antholoyg")]
+        [TestCase("ANThology CD")]
+        public void should_find_album_in_db_by_inexact_title(string title)
+        {
+            var album = _albumRepo.FindByTitleInexact(_artist.Id, title);
+
+            album.Should().NotBeNull();
+            album.Title.Should().Be(_album.Title);
+        }
+
+        [TestCase("ANTholog")]
+        [TestCase("antholoyg")]
+        [TestCase("ANThology CD")]
+        public void should_not_find_album_in_db_by_inexact_title_when_two_similar_matches(string title)
+        {
+            _albumRepo.Insert(_albumSimilar);
+            var album = _albumRepo.FindByTitleInexact(_artist.Id, title);
+
+            album.Should().BeNull();
+        }
+
         [Test]
         public void should_not_find_album_in_db_by_partial_releaseid()
         {

src/NzbDrone.Core.Test/MusicTests/TitleMatchingTests/TitleMatchingFixture.cs

@@ -5,6 +5,7 @@ using NUnit.Framework;
 using NzbDrone.Core.Configuration;
 using NzbDrone.Core.Music;
 using NzbDrone.Core.Test.Framework;
+using System.Collections.Generic;
 
 namespace NzbDrone.Core.Test.MusicTests.TitleMatchingTests
 {
@@ -21,49 +22,82 @@ namespace NzbDrone.Core.Test.MusicTests.TitleMatchingTests
             _trackService =
                 new TrackService(_trackRepository, Mocker.Resolve<ConfigService>(), Mocker.Resolve<Logger>());
 
-            _trackRepository.Insert(new Track
+            var trackNames = new List<string> {
-            {
+                "Courage",
-                Title = "This is the short test title",
+                "Movies",
-                ForeignTrackId = "this is a fake id2",
+                "Flesh and Bone",
-                AlbumId = 4321,
+                "Whisper",
-                AbsoluteTrackNumber = 1,
+                "Summer",
-                MediumNumber = 1,
+                "Sticks and Stones",
-                TrackFileId = 1
+                "Attitude",
-            });
+                "Stranded",
+                "Wish",
+                "Calico",
+                "(Happy) Death Day",
+                "Smooth Criminal",
+                "Universe / Orange Appeal"
+            };
 
+            for (int i = 0; i < trackNames.Count; i++) {
                 _trackRepository.Insert(new Track
                         {
-                Title = "This is the long test title",
+                            Title = trackNames[i],
-                ForeignTrackId = "this is a fake id",
+                            ForeignTrackId = (i+1).ToString(),
                             AlbumId = 4321,
-                AbsoluteTrackNumber = 2,
+                            AbsoluteTrackNumber = i+1,
                             MediumNumber = 1,
-                TrackFileId = 2
+                            TrackFileId = i+1
                         });
             }
+        }
 
         [Test]
-        public void should_find_track_in_db_by_tracktitle_longer_then_relaeasetitle()
+        public void should_find_track_in_db_by_tracktitle_longer_then_releasetitle()
         {
-            var track = _trackService.FindTrackByTitle(1234, 4321, 1, 1, "This is the short test title with some bla");
+            var track = _trackService.FindTrackByTitle(1234, 4321, 1, 1, "Courage with some bla");
 
+            track.Should().NotBeNull();
             track.Title.Should().Be(_trackRepository.GetTracksByFileId(1).First().Title);
         }
 
         [Test]
-        public void should_find_track_in_db_by_tracktitle_shorter_then_relaeasetitle()
+        public void should_find_track_in_db_by_tracktitle_shorter_then_releasetitle()
         {
-            var track = _trackService.FindTrackByTitle(1234, 4321, 1, 2, "test title");
+            var track = _trackService.FindTrackByTitle(1234, 4321, 1, 3, "and Bone");
 
-            track.Title.Should().Be(_trackRepository.GetTracksByFileId(2).First().Title);
+            track.Should().NotBeNull();
+            track.Title.Should().Be(_trackRepository.GetTracksByFileId(3).First().Title);
         }
 
         [Test]
         public void should_not_find_track_in_db_by_wrong_title()
         {
-            var track = _trackService.FindTrackByTitle(1234, 4321, 1, 1, "the short title");
+            var track = _trackService.FindTrackByTitle(1234, 4321, 1, 1, "Not a track");
 
             track.Should().BeNull();
         }
+
+        [TestCase("Fesh and Bone", 3)]
+        [TestCase("Atitude", 7)]
+        [TestCase("Smoth cRimnal", 12)]
+        [TestCase("Sticks and Stones (live)", 6)]
+        public void should_find_track_in_db_by_inexact_title(string title, int trackNumber)
+        {
+            var track = _trackService.FindTrackByTitleInexact(1234, 4321, 1, trackNumber, title);
+
+            track.Should().NotBeNull();
+            track.Title.Should().Be(_trackRepository.GetTracksByFileId(trackNumber).First().Title);
+        }
+
+        [TestCase("A random title", 1)]
+        [TestCase("Stones and Sticks", 6)]
+        public void should_not_find_track_in_db_by_different_inexact_title(string title, int trackId)
+        {
+            var track = _trackService.FindTrackByTitleInexact(1234, 4321, 1, trackId, title);
+
+            track.Should().BeNull();
+        }
+
+
     }
 }

src/NzbDrone.Core/Music/AlbumRepository.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Linq;
+using NLog;
 using Marr.Data.QGen;
 using NzbDrone.Core.Datastore;
 using NzbDrone.Core.Datastore.Extensions;
@@ -16,6 +17,7 @@ namespace NzbDrone.Core.Music
         List<Album> GetAlbums(int artistId);
         Album FindByName(string cleanTitle);
         Album FindByTitle(int artistId, string title);
+        Album FindByTitleInexact(int artistId, string title);
         Album FindByArtistAndName(string artistName, string cleanTitle);
         Album FindById(string spotifyId);
         PagingSpec<Album> AlbumsWithoutFiles(PagingSpec<Album> pagingSpec);
@@ -31,14 +33,15 @@ namespace NzbDrone.Core.Music
     public class AlbumRepository : BasicRepository<Album>, IAlbumRepository
     {
         private readonly IMainDatabase _database;
+        private readonly Logger _logger;
 
-        public AlbumRepository(IMainDatabase database, IEventAggregator eventAggregator)
+        public AlbumRepository(IMainDatabase database, IEventAggregator eventAggregator, Logger logger)
             : base(database, eventAggregator)
         {
             _database = database;
+            _logger = logger;
         }
 
-
         public List<Album> GetAlbums(int artistId)
         {
             return Query.Where(s => s.ArtistId == artistId).ToList();
@@ -287,13 +290,49 @@ namespace NzbDrone.Core.Music
 
         public Album FindByTitle(int artistId, string title)
         {
-            title = Parser.Parser.CleanArtistName(title);
+            var cleanTitle = Parser.Parser.CleanArtistName(title);
+            
+            if (string.IsNullOrEmpty(cleanTitle))
+                cleanTitle = title;
             
-            return Query.Where(s => s.CleanTitle == title)
+            return Query.Where(s => s.CleanTitle == cleanTitle || s.Title == title)
                         .AndWhere(s => s.ArtistId == artistId)
                         .FirstOrDefault();
         }
 
+        public Album FindByTitleInexact(int artistId, string title)
+        {
+            double fuzzThreshold = 0.7;
+            double fuzzGap = 0.4;
+            var cleanTitle = Parser.Parser.CleanArtistName(title);
+
+            if (string.IsNullOrEmpty(cleanTitle))
+                cleanTitle = title;
+
+            var sortedAlbums = Query.Where(s => s.ArtistId == artistId)
+                .Select(s => new
+                    {
+                        MatchProb = s.CleanTitle.FuzzyMatch(cleanTitle),
+                        Album = s
+                    })
+                .ToList()
+                .OrderByDescending(s => s.MatchProb)
+                .ToList();
+
+            if (!sortedAlbums.Any())
+                return null;
+
+            _logger.Trace("\nFuzzy album match on '{0}':\n{1}",
+                          cleanTitle,
+                          string.Join("\n", sortedAlbums.Select(x => $"{x.Album.CleanTitle}: {x.MatchProb}")));
+
+            if (sortedAlbums[0].MatchProb > fuzzThreshold
+                && (sortedAlbums.Count == 1 || sortedAlbums[0].MatchProb - sortedAlbums[1].MatchProb > fuzzGap))
+                return sortedAlbums[0].Album;
+
+            return null;
+        }
+
         public Album FindByArtistAndName(string artistName, string cleanTitle)
         {
             var cleanArtistName = Parser.Parser.CleanArtistName(artistName);

src/NzbDrone.Core/Music/AlbumService.cs

@@ -17,7 +17,7 @@ namespace NzbDrone.Core.Music
         List<Album> AddAlbums(List<Album> newAlbums);
         Album FindById(string spotifyId);
         Album FindByTitle(int artistId, string title);
-        Album FindByTitleInexact(string title);
+        Album FindByTitleInexact(int artistId, string title);
         void DeleteAlbum(int albumId, bool deleteFiles);
         List<Album> GetAllAlbums();
         Album UpdateAlbum(Album album);
@@ -87,9 +87,9 @@ namespace NzbDrone.Core.Music
             return _albumRepository.FindByTitle(artistId, title);
         }
 
-        public Album FindByTitleInexact(string title)
+        public Album FindByTitleInexact(int artistId, string title)
         {
-            throw new NotImplementedException();
+            return _albumRepository.FindByTitleInexact(artistId, title);
         }
 
         public List<Album> GetAllAlbums()

src/NzbDrone.Core/Music/TrackService.cs

@@ -5,6 +5,7 @@ using NzbDrone.Core.MediaFiles;
 using NzbDrone.Core.MediaFiles.Events;
 using NzbDrone.Core.Messaging.Events;
 using NzbDrone.Core.Music.Events;
+using NzbDrone.Common.Extensions;
 using System;
 using System.Collections.Generic;
 using System.Linq;
@@ -18,6 +19,7 @@ namespace NzbDrone.Core.Music
         List<Track> GetTracks(IEnumerable<int> ids);
         Track FindTrack(int artistId, int albumId, int mediumNumber, int trackNumber);
         Track FindTrackByTitle(int artistId, int albumId, int mediumNumber, int trackNumber, string releaseTitle);
+        Track FindTrackByTitleInexact(int artistId, int albumId, int mediumNumber, int trackNumber, string releaseTitle);
         List<Track> GetTracksByArtist(int artistId);
         List<Track> GetTracksByAlbum(int albumId);
         //List<Track> GetTracksByAlbumTitle(string artistId, string albumTitle);
@@ -100,6 +102,43 @@ namespace NzbDrone.Core.Music
             return matches.OrderByDescending(e => e.NormalizedLength).FirstOrDefault()?.Track;
         }
 
+        public Track FindTrackByTitleInexact(int artistId, int albumId, int mediumNumber, int trackNumber, string releaseTitle)
+        {
+            double fuzzThreshold = 0.6;
+            double fuzzGap = 0.2;
+
+            var normalizedReleaseTitle = Parser.Parser.NormalizeTrackTitle(releaseTitle).Replace(".", " ");
+            var tracks = _trackRepository.GetTracksByMedium(albumId, mediumNumber);
+
+            var matches = from track in tracks
+                let normalizedTitle = Parser.Parser.NormalizeTrackTitle(track.Title).Replace(".", " ")
+                let matchProb = normalizedTitle.FuzzyMatch(normalizedReleaseTitle)
+                where track.Title.Length > 0
+                orderby matchProb descending
+                select new
+                {
+                    MatchProb = matchProb,
+                    NormalizedTitle = normalizedTitle,
+                    Track = track
+                };
+
+            var matchList = matches.ToList();
+
+            if (!matchList.Any())
+                return null;
+
+            _logger.Trace("\nFuzzy track match on '{0}':\n{1}",
+                          normalizedReleaseTitle,
+                          string.Join("\n", matchList.Select(x => $"{x.NormalizedTitle}: {x.MatchProb}")));
+
+            if (matchList[0].MatchProb > fuzzThreshold
+                && (matchList.Count == 1 || matchList[0].MatchProb - matchList[1].MatchProb > fuzzGap)
+                && (trackNumber == 0 || matchList[0].Track.AbsoluteTrackNumber == trackNumber))
+                return matchList[0].Track;
+
+            return null;
+        }
+
         public List<Track> TracksWithFiles(int artistId)
         {
             return _trackRepository.TracksWithFiles(artistId);

src/NzbDrone.Core/Parser/ParsingService.cs

@@ -290,6 +290,12 @@ namespace NzbDrone.Core.Parser
                 album = _albumService.FindByTitle(artist.Id, cleanAlbumTitle);
             }
 
+            if (album == null)
+            {
+                _logger.Debug("Trying inexact album match for {0}", parsedTrackInfo);
+                album = _albumService.FindByTitleInexact(artist.Id, cleanAlbumTitle);
+            }
+
             if (album == null)
             {
                 _logger.Debug("Parsed album title not found in Db for {0}", parsedTrackInfo);
@@ -318,6 +324,12 @@ namespace NzbDrone.Core.Parser
                     trackInfo = _trackService.FindTrackByTitle(artist.Id, album.Id, parsedTrackInfo.DiscNumber, parsedTrackInfo.TrackNumbers.FirstOrDefault(), parsedTrackInfo.Title);
                 }
 
+                if (trackInfo == null)
+                {
+                    _logger.Debug("Trying inexact track match for {0}", parsedTrackInfo);
+                    trackInfo = _trackService.FindTrackByTitleInexact(artist.Id, album.Id, parsedTrackInfo.DiscNumber, parsedTrackInfo.TrackNumbers.FirstOrDefault(), cleanTrackTitle);
+                }
+
                 if (trackInfo != null)
                 {
                     _logger.Debug("Track {0} selected for {1}", trackInfo, parsedTrackInfo);