Improve the fuzzy matching (#522)

* Fixed: improve track matching

* Deal with tracks sequentially numbered across discs

src/NzbDrone.Common.Test/ExtensionTests/FuzzyContainsFixture.cs

@@ -0,0 +1,61 @@
+using FluentAssertions;
+using NUnit.Framework;
+using NzbDrone.Common.Extensions;
+using NzbDrone.Test.Common;
+
+namespace NzbDrone.Common.Test
+{
+    [TestFixture]
+    public class FuzzyContainsFixture : TestBase
+    {
+        [TestCase("abcdef", "abcdef", 0.5, 0)]
+        [TestCase("", "abcdef", 0.5, -1)]
+        [TestCase("abcdef", "", 0.5, -1)]
+        [TestCase("", "", 0.5, -1)]
+        [TestCase("abcdef", "de", 0.5, 3)]
+        [TestCase("abcdef", "defy", 0.5, 3)]
+        [TestCase("abcdef", "abcdefy", 0.5, 0)]
+        [TestCase("I am the very model of a modern major general.", " that berry ", 0.3, 4)]
+        [TestCase("abcdefghijk", "fgh", 0.5, 5)]
+        [TestCase("abcdefghijk", "fgh", 0.5, 5)]
+        [TestCase("abcdefghijk", "efxhi", 0.5, 4)]
+        [TestCase("abcdefghijk", "cdefxyhijk", 0.5, 2)]
+        [TestCase("abcdefghijk", "bxy", 0.5, -1)]
+        [TestCase("123456789xx0", "3456789x0", 0.5, 2)]
+        [TestCase("abcdef", "xxabc", 0.5, 0)]
+        [TestCase("abcdef", "defyy", 0.5, 3)]
+        [TestCase("abcdef", "xabcdefy", 0.5, 0)]
+        [TestCase("abcdefghijk", "efxyhi", 0.6, 4)]
+        [TestCase("abcdefghijk", "efxyhi", 0.7, -1)]
+        [TestCase("abcdefghijk", "bcdef", 0.0, 1)]
+        [TestCase("abcdexyzabcde", "abccde", 0.5, 0)]
+        [TestCase("abcdefghijklmnopqrstuvwxyz", "abcdxxefg", 0.5, 0)]
+        [TestCase("abcdefghijklmnopqrstuvwxyz", "abcdefg", 0.5, 0)]
+        [TestCase("The quick brown fox jumps over the lazy dog", "The quick brown fox jumps over the lazy d", 0.5, 0)]
+        [TestCase("The quick brown fox jumps over the lazy dog", "The quick brown fox jumps over the lazy g", 0.5, 0)]
+        [TestCase("The quick brown fox jumps over the lazy dog", "quikc brown fox jumps over the lazy dog", 0.5, 4)]
+        [TestCase("The quick brown fox jumps over the lazy dog", "qui jumps over the lazy dog", 0.5, 16)]
+        [TestCase("The quick brown fox jumps over the lazy dog", "quikc brown fox jumps over the lazy dog", 0.5, 4)]
+        [TestCase("u6IEytQiYpzAccsbjQ5ISuE4smDQ1ZiU42cFBrTeKB2XrVLEqAvgIiKlDP75iApy07jzmK", "xEytQiYpzAccsbjQ5ISuE4smDQ1ZiU42cFBrTeKB2XrVLEqAvgIiKlDP75iApy07jzmK", 0.5, 2)]
+        [TestCase("plusifeelneedforredundantinformationintitlefield", "anthology", 0.5, -1)]
+        public void FuzzyFind(string text, string pattern, double threshold, int expected)
+        {
+            text.FuzzyFind(pattern, threshold).Should().Be(expected);
+        }
+
+        [TestCase("abcdef", "abcdef", 1)]
+        [TestCase("", "abcdef", 0)]
+        [TestCase("abcdef", "", 0)]
+        [TestCase("", "", 0)]
+        [TestCase("abcdef", "de", 1)]
+        [TestCase("abcdef", "defy", 0.75)]
+        [TestCase("abcdef", "abcdefghk", 6.0/9)]
+        [TestCase("abcdef", "zabcdefz", 6.0/8)]
+        [TestCase("plusifeelneedforredundantinformationintitlefield", "anthology", 4.0/9)]
+        [TestCase("+ (Plus) - I feel the need for redundant information in the title field", "+", 1)]
+        public void FuzzyContains(string text, string pattern, double expectedScore)
+        {
+            text.FuzzyContains(pattern).Should().BeApproximately(expectedScore, 1e-9);
+        }
+    }
+}

src/NzbDrone.Common.Test/LevenshteinDistanceFixture.cs

@@ -42,5 +42,21 @@ namespace NzbDrone.Common.Test
         {
             text.ToLower().LevenshteinDistanceClean(other.ToLower()).Should().Be(expected);
         }
+
+        [TestCase("hello", "hello")]
+        [TestCase("hello", "bye")]
+        [TestCase("a longer string", "a different long string")]
+        public void FuzzyMatchSymmetric(string a, string b)
+        {
+            a.FuzzyMatch(b).Should().Be(b.FuzzyMatch(a));
+        }
+
+        [TestCase("", "", 0)]
+        [TestCase("a", "", 0)]
+        [TestCase("", "a", 0)]
+        public void FuzzyMatchEmptyValuesReturnZero(string a, string b, double expected)
+        {
+            a.FuzzyMatch(b).Should().Be(expected);
+        }
     }
 }

src/NzbDrone.Common.Test/NzbDrone.Common.Test.csproj

@@ -84,6 +84,7 @@
     <Compile Include="ExtensionTests\IEnumerableExtensionTests\IntersectByFixture.cs" />
     <Compile Include="ExtensionTests\Int64ExtensionFixture.cs" />
     <Compile Include="ExtensionTests\UrlExtensionsFixture.cs" />
+    <Compile Include="ExtensionTests\FuzzyContainsFixture.cs" />
     <Compile Include="HashUtilFixture.cs" />
     <Compile Include="Http\HttpClientFixture.cs" />
     <Compile Include="Http\HttpHeaderFixture.cs" />

src/NzbDrone.Common/Extensions/FuzzyContains.cs

@@ -0,0 +1,167 @@
+/*
+ * This file incorporates work covered by the following copyright and  
+ * permission notice:  
+ *
+ * Diff Match and Patch
+ * Copyright 2018 The diff-match-patch Authors.
+ * https://github.com/google/diff-match-patch
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+using System;
+using System.Collections.Generic;
+using System.Numerics;
+
+namespace NzbDrone.Common.Extensions
+{
+
+    public static class FuzzyContainsExtension {
+
+        public static int FuzzyFind(this string text, string pattern, double matchProb)
+        {
+            return match(text, pattern, matchProb).Item1;
+        }
+
+        // return the accuracy of the best match of pattern within text
+        public static double FuzzyContains(this string text, string pattern)
+        {
+            return match(text, pattern, 0.25).Item2;
+        }
+        
+        /**
+         * Locate the best instance of 'pattern' in 'text'.
+         * Returns (-1, 1) if no match found.
+         * @param text The text to search.
+         * @param pattern The pattern to search for.
+         * @return Best match index or -1.
+         */
+        private static Tuple<int, double> match(string text, string pattern, double matchThreshold = 0.5) {
+            // Check for null inputs not needed since null can't be passed in C#.
+            if (text.Length == 0 || pattern.Length == 0) {
+                // Nothing to match.
+                return new Tuple<int, double> (-1, 0);
+            }
+
+            if (pattern.Length <= text.Length)
+            {
+                var loc = text.IndexOf(pattern, StringComparison.Ordinal);
+                if (loc != -1)
+                {
+                    // Perfect match!
+                    return new Tuple<int, double> (loc, 1);
+                }
+            }
+
+            // Do a fuzzy compare.
+            return match_bitap(text, pattern, matchThreshold);
+        }
+
+        /**
+         * Locate the best instance of 'pattern' in 'text' near 'loc' using the
+         * Bitap algorithm.  Returns -1 if no match found.
+         * @param text The text to search.
+         * @param pattern The pattern to search for.
+         * @return Best match index or -1.
+         */
+        private static Tuple<int, double> match_bitap(string text, string pattern, double matchThreshold) {
+
+            // Initialise the alphabet.
+            Dictionary<char, BigInteger> s = alphabet(pattern);
+            // don't keep creating new BigInteger(1)
+            var big1 = new BigInteger(1);
+
+            // Lowest score belowe which we give up.
+            var score_threshold = matchThreshold;
+           
+            // Initialise the bit arrays.
+            var matchmask = big1 << (pattern.Length - 1);
+            int best_loc = -1;
+
+            // Empty initialization added to appease C# compiler.
+            var last_rd = new BigInteger[0];
+            for (int d = 0; d < pattern.Length; d++) {
+                // Scan for the best match; each iteration allows for one more error.
+                int start = 1;
+                int finish = text.Length + pattern.Length;
+
+                var rd = new BigInteger[finish + 2];
+                rd[finish + 1] = (big1 << d) - big1;
+                for (int j = finish; j >= start; j--) {
+                    BigInteger charMatch;
+                    if (text.Length <= j - 1 || !s.ContainsKey(text[j - 1])) {
+                        // Out of range.
+                        charMatch = 0;
+                    } else {
+                        charMatch = s[text[j - 1]];
+                    }
+                    if (d == 0) {
+                        // First pass: exact match.
+                        rd[j] = ((rd[j + 1] << 1) | big1) & charMatch;
+                    } else {
+                        // Subsequent passes: fuzzy match.
+                        rd[j] = ((rd[j + 1] << 1) | big1) & charMatch
+                            | (((last_rd[j + 1] | last_rd[j]) << 1) | big1) | last_rd[j + 1];
+                    }
+                    if ((rd[j] & matchmask) != 0) {
+                        var score = bitapScore(d, pattern);
+                        // This match will almost certainly be better than any existing
+                        // match.  But check anyway.
+                        if (score >= score_threshold) {
+                            // Told you so.
+                            score_threshold = score;
+                            best_loc = j - 1;
+                        }
+                    }
+                }
+                if (bitapScore(d + 1, pattern) < score_threshold) {
+                    // No hope for a (better) match at greater error levels.
+                    break;
+                }
+                last_rd = rd;
+            }
+            return new Tuple<int, double> (best_loc, score_threshold);
+        }
+
+        /**
+         * Compute and return the score for a match with e errors and x location.
+         * @param e Number of errors in match.
+         * @param pattern Pattern being sought.
+         * @return Overall score for match (1.0 = good, 0.0 = bad).
+         */
+        private static double bitapScore(int e, string pattern) {
+            return 1.0 - (double)e / pattern.Length;
+        }
+
+        /**
+         * Initialise the alphabet for the Bitap algorithm.
+         * @param pattern The text to encode.
+         * @return Hash of character locations.
+         */
+        private static Dictionary<char, BigInteger> alphabet(string pattern) {
+            var s = new Dictionary<char, BigInteger>();
+            char[] char_pattern = pattern.ToCharArray();
+            foreach (char c in char_pattern) {
+                if (!s.ContainsKey(c)) {
+                    s.Add(c, 0);
+                }
+            }
+            int i = 0;
+            foreach (char c in char_pattern) {
+                s[c] = s[c] | (new BigInteger(1) << (pattern.Length - i - 1));
+                i++;
+            }
+            return s;
+        }
+    }
+}

src/NzbDrone.Common/Extensions/StringExtensions.cs

@@ -143,29 +143,17 @@ namespace NzbDrone.Common.Extensions
 
         public static double FuzzyMatch(this string a, string b)
         {
-            if (a.Contains(" ") && b.Contains(" "))
+            if (a.IsNullOrWhiteSpace() || b.IsNullOrWhiteSpace())
+            {
+                return 0;
+            }
+            else 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];
+                var coef = (FuzzyMatchComponents(partsA, partsB) + FuzzyMatchComponents(partsB, partsA)) / (partsA.Length + partsB.Length);
-                for (int i = 0; i < partsA.Length; i++)
+                return Math.Max(coef, LevenshteinCoefficient(a, b));
-                {
-                    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
             {
@@ -173,6 +161,28 @@ namespace NzbDrone.Common.Extensions
             }
         }
 
+        private static double FuzzyMatchComponents(string[] a, string[] b)
+        {
+            double weightDenom = Math.Max(a.Length, b.Length);
+            double sum = 0;
+            for (int i = 0; i < a.Length; i++)
+            {
+                double high = 0.0;
+                int indexDistance = 0;
+                for (int x = 0; x < b.Length; x++)
+                {
+                    var coef = LevenshteinCoefficient(a[i], b[x]);
+                    if (coef > high)
+                    {
+                        high = coef;
+                        indexDistance = Math.Abs(i - x);
+                    }
+                }
+                sum += (1.0 - (double)indexDistance / weightDenom) * high;
+            }
+            return sum;
+        }
+
         public static double LevenshteinCoefficient(this string a, string b)
         {
             return 1.0 - (double)a.LevenshteinDistance(b) / Math.Max(a.Length, b.Length);

src/NzbDrone.Common/NzbDrone.Common.csproj

@@ -71,6 +71,7 @@
     <Reference Include="Microsoft.CSharp" />
     <Reference Include="System.Xml" />
     <Reference Include="System.Xml.Linq" />
+    <Reference Include="System.Numerics" />
   </ItemGroup>
   <ItemGroup>
     <Compile Include="ArchiveService.cs" />
@@ -198,6 +199,7 @@
     <Compile Include="Instrumentation\Sentry\LidarrSentryPacket.cs" />
     <Compile Include="Instrumentation\VersionLayoutRenderer.cs" />
     <Compile Include="Extensions\LevenstheinExtensions.cs" />
+    <Compile Include="Extensions\FuzzyContains.cs" />
     <Compile Include="Messaging\IEvent.cs" />
     <Compile Include="Messaging\IMessage.cs" />
     <Compile Include="Model\ProcessInfo.cs" />

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

@@ -94,7 +94,6 @@ namespace NzbDrone.Core.Test.MusicTests.AlbumRepositoryTests
 
         }
 
-
         [Test]
         public void should_find_album_in_db_by_releaseid()
         {
@@ -129,6 +128,7 @@ namespace NzbDrone.Core.Test.MusicTests.AlbumRepositoryTests
         [TestCase("ANTholog")]
         [TestCase("nthology")]
         [TestCase("antholoyg")]
+        [TestCase("÷")]
         public void should_not_find_album_in_db_by_incorrect_title(string title)
         {
             var album = _albumRepo.FindByTitle(_artist.Id, title);
@@ -136,28 +136,6 @@ namespace NzbDrone.Core.Test.MusicTests.AlbumRepositoryTests
             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/AlbumServiceFixture.cs

@@ -0,0 +1,77 @@
+using FizzWare.NBuilder;
+using FluentAssertions;
+using NUnit.Framework;
+using NzbDrone.Core.Music;
+using NzbDrone.Core.Test.Framework;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using NLog;
+using Moq;
+
+namespace NzbDrone.Core.Test.MusicTests.AlbumRepositoryTests
+{
+    [TestFixture]
+    public class AlbumServiceFixture : CoreTest<AlbumService>
+    {
+        private List<Album> _albums;
+
+        [SetUp]
+        public void Setup()
+        {
+            _albums = new List<Album>();
+            _albums.Add(new Album
+                {
+                    Title = "ANThology",
+                    CleanTitle = "anthology",
+                });
+
+            _albums.Add(new Album
+                {
+                    Title = "+",
+                    CleanTitle = "",
+                });
+
+            Mocker.GetMock<IAlbumRepository>()
+                .Setup(s => s.GetAlbums(It.IsAny<int>()))
+                .Returns(_albums);
+        }
+
+        private void GivenSimilarAlbum()
+        {
+            _albums.Add(new Album
+                {
+                    Title = "ANThology2",
+                    CleanTitle = "anthology2",
+                });
+        }
+
+        [TestCase("ANTholog", "ANThology")]
+        [TestCase("antholoyg", "ANThology")]
+        [TestCase("ANThology CD", "ANThology")]
+        [TestCase("ANThology CD xxxx (Remastered) - [Oh please why do they do this?]", "ANThology")]
+        [TestCase("+ (Plus) - I feel the need for redundant information in the title field", "+")]
+        public void should_find_album_in_db_by_inexact_title(string title, string expected)
+        {
+            var album = Subject.FindByTitleInexact(0, title);
+
+            album.Should().NotBeNull();
+            album.Title.Should().Be(expected);
+        }
+
+        [TestCase("ANTholog")]
+        [TestCase("antholoyg")]
+        [TestCase("ANThology CD")]
+        [TestCase("÷")]
+        [TestCase("÷ (Divide)")]
+        public void should_not_find_album_in_db_by_inexact_title_when_two_similar_matches(string title)
+        {
+            GivenSimilarAlbum();
+            var album = Subject.FindByTitleInexact(0, title);
+
+            album.Should().BeNull();
+        }
+    }
+}

src/NzbDrone.Core.Test/MusicTests/ArtistRepositoryTests/ArtistRepositoryFixture.cs

@@ -17,6 +17,24 @@ namespace NzbDrone.Core.Test.MusicTests.ArtistRepositoryTests
 
     public class ArtistRepositoryFixture : DbTest<ArtistRepository, Artist>
     {
+        private ArtistRepository _artistRepo;
+
+        private Artist CreateArtist(string name)
+        {
+            return Builder<Artist>.CreateNew()
+                .With(a => a.Name = name)
+                .With(a => a.CleanName = Parser.Parser.CleanArtistName(name))
+                .With(a => a.ForeignArtistId = name)
+                .BuildNew();
+        }
+
+        private void GivenArtists()
+        {
+            _artistRepo = Mocker.Resolve<ArtistRepository>();
+            _artistRepo.Insert(CreateArtist("The Black Eyed Peas"));
+            _artistRepo.Insert(CreateArtist("The Black Keys"));
+        }
+
         [Test]
         public void should_lazyload_profiles()
         {
@@ -61,5 +79,16 @@ namespace NzbDrone.Core.Test.MusicTests.ArtistRepositoryTests
             StoredModel.MetadataProfile.Should().NotBeNull();
 
         }
+
+        [TestCase("The Black Eyed Peas")]
+        [TestCase("The Black Keys")]
+        public void should_find_artist_in_db_by_name(string name)
+        {
+            GivenArtists();
+            var artist = _artistRepo.FindByName(Parser.Parser.CleanArtistName(name));
+
+            artist.Should().NotBeNull();
+            artist.Name.Should().Be(name);
+        }
     }
 }

src/NzbDrone.Core.Test/MusicTests/ArtistServiceTests/FindByNameInexactFixture.cs

@@ -0,0 +1,58 @@
+using System.Collections.Generic;
+using FizzWare.NBuilder;
+using FluentAssertions;
+using NUnit.Framework;
+using NzbDrone.Core.Test.Framework;
+using NzbDrone.Core.Music;
+
+namespace NzbDrone.Core.Test.MusicTests.ArtistServiceTests
+{
+    [TestFixture]
+
+    public class FindByNameInexactFixture : CoreTest<ArtistService>
+    {
+        private List<Artist> _artists;
+        
+        private Artist CreateArtist(string name)
+        {
+            return Builder<Artist>.CreateNew()
+                .With(a => a.Name = name)
+                .With(a => a.CleanName = Parser.Parser.CleanArtistName(name))
+                .With(a => a.ForeignArtistId = name)
+                .BuildNew();
+        }
+
+        [SetUp]
+        public void Setup()
+        {
+            _artists = new List<Artist>();
+            _artists.Add(CreateArtist("The Black Eyed Peas"));
+            _artists.Add(CreateArtist("The Black Keys"));
+
+            Mocker.GetMock<IArtistRepository>()
+                .Setup(s => s.All())
+                .Returns(_artists);
+        }
+
+        [TestCase("The Black Eyde Peas", "The Black Eyed Peas")]
+        [TestCase("Black Eyed Peas", "The Black Eyed Peas")]
+        [TestCase("The Black eys", "The Black Keys")]
+        public void should_find_artist_in_db_by_name_inexact(string name, string expected)
+        {
+            var artist = Subject.FindByNameInexact(name);
+
+            artist.Should().NotBeNull();
+            artist.Name.Should().Be(expected);
+        }
+
+        [TestCase("The Black Peas")]
+        public void should_not_find_artist_in_db_by_ambiguous_name(string name)
+        {
+
+            var artist = Subject.FindByNameInexact(name);
+
+            artist.Should().BeNull();
+        }
+
+    }
+}

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

@@ -1,27 +1,21 @@
 using System.Linq;
 using FluentAssertions;
-using NLog;
 using NUnit.Framework;
-using NzbDrone.Core.Configuration;
 using NzbDrone.Core.Music;
 using NzbDrone.Core.Test.Framework;
 using System.Collections.Generic;
+using Moq;
 
 namespace NzbDrone.Core.Test.MusicTests.TitleMatchingTests
 {
     [TestFixture]
-    public class TitleMatchingFixture : DbTest<TrackService, Track>
+    public class TitleMatchingFixture : CoreTest<TrackService>
     {
-        private TrackRepository _trackRepository;
+        private List<Track> _tracks;
-        private TrackService _trackService;
+        
-
         [SetUp]
         public void Setup()
         {
-            _trackRepository = Mocker.Resolve<TrackRepository>();
-            _trackService =
-                new TrackService(_trackRepository, Mocker.Resolve<ConfigService>(), Mocker.Resolve<Logger>());
-
             var trackNames = new List<string> {
                 "Courage",
                 "Movies",
@@ -35,65 +29,148 @@ namespace NzbDrone.Core.Test.MusicTests.TitleMatchingTests
                 "Calico",
                 "(Happy) Death Day",
                 "Smooth Criminal",
-                "Universe / Orange Appeal"
+                "Universe / Orange Appeal",
+                "Christian's Inferno"
+            };
+
+            _tracks = new List<Track>();
+            for (int i = 0; i < trackNames.Count; i++) {
+                _tracks.Add(new Track
+                    {
+                        Title = trackNames[i],
+                        ForeignTrackId = (i+1).ToString(),
+                        AbsoluteTrackNumber = i+1,
+                        MediumNumber = 1
+                    });
+            }
+
+            Mocker.GetMock<ITrackRepository>()
+                .Setup(s => s.GetTracksByMedium(It.IsAny<int>(), It.IsAny<int>()))
+                .Returns(_tracks);
+
+            Mocker.GetMock<ITrackRepository>()
+                .Setup(s => s.Find(1234, 4321, It.IsAny<int>(), It.IsAny<int>()))
+                .Returns((int artistid, int albumid, int medium, int track) => _tracks.Where(t => t.AbsoluteTrackNumber == track && t.MediumNumber == medium).Single());
+        }
+
+        private void GivenSecondDisc()
+        {
+            var trackNames = new List<string> {
+                "Courage",
+                "another entry",
+                "random name"
             };
 
             for (int i = 0; i < trackNames.Count; i++) {
-                _trackRepository.Insert(new Track
+                _tracks.Add(new Track
-                        {
+                    {
-                            Title = trackNames[i],
+                        Title = trackNames[i],
-                            ForeignTrackId = (i+1).ToString(),
+                        ForeignTrackId = (100+i+1).ToString(),
-                            AlbumId = 4321,
+                        AbsoluteTrackNumber = i+1,
-                            AbsoluteTrackNumber = i+1,
+                        MediumNumber = 2
-                            MediumNumber = 1,
+                    });
-                            TrackFileId = i+1
-                        });
             }
         }
 
         [Test]
         public void should_find_track_in_db_by_tracktitle_longer_then_releasetitle()
         {
-            var track = _trackService.FindTrackByTitle(1234, 4321, 1, 1, "Courage with some bla");
+            var track = Subject.FindTrackByTitle(1234, 4321, 1, 1, "Courage with some bla");
 
             track.Should().NotBeNull();
-            track.Title.Should().Be(_trackRepository.GetTracksByFileId(1).First().Title);
+            track.Title.Should().Be(Subject.FindTrack(1234, 4321, 1, 1).Title);
         }
 
         [Test]
         public void should_find_track_in_db_by_tracktitle_shorter_then_releasetitle()
         {
-            var track = _trackService.FindTrackByTitle(1234, 4321, 1, 3, "and Bone");
+            var track = Subject.FindTrackByTitle(1234, 4321, 1, 3, "and Bone");
 
             track.Should().NotBeNull();
-            track.Title.Should().Be(_trackRepository.GetTracksByFileId(3).First().Title);
+            track.Title.Should().Be(Subject.FindTrack(1234, 4321, 1, 3).Title);
         }
 
         [Test]
         public void should_not_find_track_in_db_by_wrong_title()
         {
-            var track = _trackService.FindTrackByTitle(1234, 4321, 1, 1, "Not a track");
+            var track = Subject.FindTrackByTitle(1234, 4321, 1, 1, "Not a track");
 
             track.Should().BeNull();
         }
 
+        [TestCase("another entry", 2, 2)]
+        [TestCase("random name", 2, 3)]
+        public void should_find_track_on_second_disc_when_disc_tag_missing(string title, int discNumber, int trackNumber)
+        {
+            GivenSecondDisc();
+            var track = Subject.FindTrackByTitle(1234, 4321, 0, trackNumber, title);
+            var expected = Subject.FindTrack(1234, 4321, discNumber, trackNumber);
+
+            track.Should().NotBeNull();
+            expected.Should().NotBeNull();
+
+            track.Title.Should().Be(expected.Title);
+        }
+
+        [Test]
+        public void should_return_null_if_tracks_with_same_name_and_number_on_different_discs()
+        {
+            GivenSecondDisc();
+            var track = Subject.FindTrackByTitle(1234, 4321, 0, 1, "Courage");
+            track.Should().BeNull();
+        }
+
         [TestCase("Fesh and Bone", 3)]
         [TestCase("Atitude", 7)]
         [TestCase("Smoth cRimnal", 12)]
         [TestCase("Sticks and Stones (live)", 6)]
+        [TestCase("Sticks and Stones (live) - there's a lot of rubbish here", 6)]
+        [TestCase("Smoth cRimnal feat. someone I don't care about", 12)]
+        [TestCase("Christians Inferno", 14)]
+        [TestCase("xxxyyy some random prefix Christians Infurno", 14)]
         public void should_find_track_in_db_by_inexact_title(string title, int trackNumber)
         {
-            var track = _trackService.FindTrackByTitleInexact(1234, 4321, 1, trackNumber, title);
+            var track = Subject.FindTrackByTitleInexact(1234, 4321, 1, trackNumber, title);
+            var expected = Subject.FindTrack(1234, 4321, 1, trackNumber);
 
             track.Should().NotBeNull();
-            track.Title.Should().Be(_trackRepository.GetTracksByFileId(trackNumber).First().Title);
+            expected.Should().NotBeNull();
+
+            track.Title.Should().Be(expected.Title);
+        }
+
+        [TestCase("Fesh and Bone", 1)]
+        [TestCase("Atitude", 1)]
+        [TestCase("Smoth cRimnal", 1)]
+        [TestCase("Sticks and Stones (live)", 1)]
+        [TestCase("Christians Inferno", 1)]
+        public void should_not_find_track_in_db_by_inexact_title_with_wrong_tracknumber(string title, int trackNumber)
+        {
+            var track = Subject.FindTrackByTitleInexact(1234, 4321, 1, trackNumber, title);
+
+            track.Should().BeNull();
+        }
+
+        [TestCase("Movis", 1, 2)]
+        [TestCase("anoth entry", 2, 2)]
+        [TestCase("random.name", 2, 3)]
+        public void should_find_track_in_db_by_inexact_title_when_disc_tag_missing(string title, int discNumber, int trackNumber)
+        {
+            GivenSecondDisc();
+            var track = Subject.FindTrackByTitleInexact(1234, 4321, 0, trackNumber, title);
+            var expected = Subject.FindTrack(1234, 4321, discNumber, trackNumber);
+
+            track.Should().NotBeNull();
+            expected.Should().NotBeNull();
+
+            track.Title.Should().Be(expected.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);
+            var track = Subject.FindTrackByTitleInexact(1234, 4321, 1, trackId, title);
 
             track.Should().BeNull();
         }

src/NzbDrone.Core.Test/NzbDrone.Core.Test.csproj

@@ -299,12 +299,14 @@
     <Compile Include="MetadataSource\SearchArtistComparerFixture.cs" />
     <Compile Include="MetadataSource\SkyHook\SkyHookProxyFixture.cs" />
     <Compile Include="MusicTests\AddAlbumFixture.cs" />
+    <Compile Include="MusicTests\AlbumServiceFixture.cs" />
     <Compile Include="MusicTests\AddArtistFixture.cs" />
     <Compile Include="MusicTests\AlbumMonitoredServiceTests\AlbumMonitoredServiceFixture.cs" />
     <Compile Include="MusicTests\AlbumRepositoryTests\AlbumRepositoryFixture.cs" />
     <Compile Include="MusicTests\ArtistRepositoryTests\ArtistRepositoryFixture.cs" />
     <Compile Include="MusicTests\ArtistServiceTests\AddArtistFixture.cs" />
     <Compile Include="MusicTests\ArtistServiceTests\UpdateMultipleArtistFixture.cs" />
+    <Compile Include="MusicTests\ArtistServiceTests\FindByNameInexactFixture.cs" />
     <Compile Include="MusicTests\RefreshAlbumServiceFixture.cs" />
     <Compile Include="MusicTests\ShouldRefreshAlbumFixture.cs" />
     <Compile Include="MusicTests\TitleMatchingTests\TitleMatchingFixture.cs" />

src/NzbDrone.Core/Music/AlbumRepository.cs

@@ -8,7 +8,6 @@ using System.Collections.Generic;
 using NzbDrone.Core.Messaging.Events;
 using NzbDrone.Core.Languages;
 using NzbDrone.Core.Qualities;
-using NzbDrone.Common.Extensions;
 
 namespace NzbDrone.Core.Music
 {
@@ -17,7 +16,6 @@ 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);
@@ -49,7 +47,7 @@ namespace NzbDrone.Core.Music
 
         public Album FindById(string foreignAlbumId)
         {
-            return Query.SingleOrDefault(s => s.ForeignAlbumId == foreignAlbumId);
+            return Query.Where(s => s.ForeignAlbumId == foreignAlbumId).SingleOrDefault();
         }
 
         public PagingSpec<Album> AlbumsWithoutFiles(PagingSpec<Album> pagingSpec)
@@ -285,7 +283,7 @@ namespace NzbDrone.Core.Music
         {
             cleanTitle = cleanTitle.ToLowerInvariant();
 
-            return Query.SingleOrDefault(s => s.CleanTitle == cleanTitle);
+            return Query.Where(s => s.CleanTitle == cleanTitle).SingleOrDefault();
         }
 
         public Album FindByTitle(int artistId, string title)
@@ -300,39 +298,6 @@ namespace NzbDrone.Core.Music
                         .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);
@@ -340,7 +305,8 @@ namespace NzbDrone.Core.Music
 
             return Query.Join<Album, Artist>(JoinType.Inner, album => album.Artist, (album, artist) => album.ArtistId == artist.Id)
                         .Where<Artist>(artist => artist.CleanName == cleanArtistName)
-                        .SingleOrDefault(album => album.CleanTitle == cleanTitle);
+                        .Where<Album>(album => album.CleanTitle == cleanTitle)
+                        .SingleOrDefault();
         }
 
         public Album FindAlbumByRelease(string releaseId)

src/NzbDrone.Core/Music/AlbumService.cs

@@ -5,6 +5,8 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using NzbDrone.Core.Datastore;
+using NzbDrone.Core.Parser;
+using NzbDrone.Common.Extensions;
 
 namespace NzbDrone.Core.Music
 {
@@ -89,7 +91,63 @@ namespace NzbDrone.Core.Music
 
         public Album FindByTitleInexact(int artistId, string title)
         {
-            return _albumRepository.FindByTitleInexact(artistId, title);
+            var cleanTitle = title.CleanArtistName();
+
+            var albums = GetAlbumsByArtist(artistId);
+
+            Func< Func<Album, string, double>, string, Tuple<Func<Album, string, double>, string>> tc = Tuple.Create;
+            var scoringFunctions = new List<Tuple<Func<Album, string, double>, string>> {
+                tc((a, t) => a.CleanTitle.FuzzyMatch(t), cleanTitle),
+                tc((a, t) => a.Title.FuzzyMatch(t), title),
+                tc((a, t) => a.CleanTitle.FuzzyMatch(t), title.RemoveBracketsAndContents().CleanArtistName()),
+                tc((a, t) => a.CleanTitle.FuzzyMatch(t), title.RemoveAfterDash().CleanArtistName()),
+                tc((a, t) => a.CleanTitle.FuzzyMatch(t), title.RemoveBracketsAndContents().RemoveAfterDash().CleanArtistName()),
+                tc((a, t) => t.FuzzyContains(a.CleanTitle), cleanTitle),
+                tc((a, t) => t.FuzzyContains(a.Title), title)
+            };
+
+            foreach (var func in scoringFunctions)
+            {
+                var album = FindByStringInexact(albums, func.Item1, func.Item2);
+                if (album != null)
+                {
+                    return album;
+                }
+            }
+
+            return null;
+        }
+
+        private Album FindByStringInexact(List<Album> albums, Func<Album, string, double> scoreFunction, string title)
+        {
+            const double fuzzThreshold = 0.7;
+            const double fuzzGap = 0.4;
+
+            var sortedAlbums = albums.Select(s => new
+                {
+                    MatchProb = scoreFunction(s, title),
+                    Album = s
+                })
+                .ToList()
+                .OrderByDescending(s => s.MatchProb)
+                .ToList();
+
+            if (!sortedAlbums.Any())
+            {
+                return null;
+            }
+
+            _logger.Trace("\nFuzzy album match on '{0}':\n{1}",
+                          title,
+                          string.Join("\n", sortedAlbums.Select(x => $"[{x.Album.Title}] {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 List<Album> GetAllAlbums()

src/NzbDrone.Core/Music/ArtistService.cs

@@ -20,7 +20,7 @@ namespace NzbDrone.Core.Music
         List<Artist> AddArtists(List<Artist> newArtists);
         Artist FindById(string spotifyId);
         Artist FindByName(string title);
-        Artist FindByTitleInexact(string title);
+        Artist FindByNameInexact(string title);
         void DeleteArtist(int artistId, bool deleteFiles);
         List<Artist> GetAllArtists();
         List<Artist> AllForTag(int tagId);
@@ -89,9 +89,43 @@ namespace NzbDrone.Core.Music
             return _artistRepository.FindByName(title.CleanArtistName());
         }
 
-        public Artist FindByTitleInexact(string title)
+        public Artist FindByNameInexact(string title)
         {
-            throw new NotImplementedException();
+            const double fuzzThreshold = 0.8;
+            const double fuzzGap = 0.2;
+            var cleanTitle = Parser.Parser.CleanArtistName(title);
+
+            if (string.IsNullOrEmpty(cleanTitle))
+            {
+                cleanTitle = title;
+            }
+
+            var sortedArtists = GetAllArtists()
+                .Select(s => new
+                    {
+                        MatchProb = s.CleanName.FuzzyMatch(cleanTitle),
+                        Artist = s
+                    })
+                .ToList()
+                .OrderByDescending(s => s.MatchProb)
+                .ToList();
+
+            if (!sortedArtists.Any())
+            {
+                return null;
+            }
+
+            _logger.Trace("\nFuzzy artist match on '{0}':\n{1}",
+                          cleanTitle,
+                          string.Join("\n", sortedArtists.Select(x => $"{x.Artist.CleanName}: {x.MatchProb}")));
+
+            if (sortedArtists[0].MatchProb > fuzzThreshold
+                && (sortedArtists.Count == 1 || sortedArtists[0].MatchProb - sortedArtists[1].MatchProb > fuzzGap))
+            {
+                return sortedArtists[0].Artist;
+            }
+
+            return null;
         }
 
         public List<Artist> GetAllArtists()
@@ -110,7 +144,6 @@ namespace NzbDrone.Core.Music
             return _artistRepository.Get(artistDBId);
         }
 
-
         public List<Artist> GetArtists(IEnumerable<int> artistIds)
         {
             return _artistRepository.Get(artistIds).ToList();

src/NzbDrone.Core/Music/TrackRepository.cs

@@ -61,6 +61,11 @@ namespace NzbDrone.Core.Music
 
         public List<Track> GetTracksByMedium(int albumId, int mediumNumber)
         {
+            if (mediumNumber < 1)
+            {
+                return GetTracksByAlbum(albumId);
+            }
+
             return Query.Where(s => s.AlbumId == albumId)
                         .AndWhere(s => s.MediumNumber == mediumNumber)
                         .ToList();

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.Core.Parser;
 using NzbDrone.Common.Extensions;
 using System;
 using System.Collections.Generic;
@@ -81,60 +82,73 @@ namespace NzbDrone.Core.Music
         public Track FindTrackByTitle(int artistId, int albumId, int mediumNumber, int trackNumber, string releaseTitle)
         {
             // TODO: can replace this search mechanism with something smarter/faster/better
-            var normalizedReleaseTitle = Parser.Parser.NormalizeTrackTitle(releaseTitle).Replace(".", " ");
+            var normalizedReleaseTitle = releaseTitle.NormalizeTrackTitle().Replace(".", " ");
             var tracks = _trackRepository.GetTracksByMedium(albumId, mediumNumber);
 
-            var matches = from track in tracks
+            var matches = tracks.Where(t => (trackNumber == 0 || t.AbsoluteTrackNumber == trackNumber)
-                //if we have a trackNumber use it
+                                       && t.Title.Length > 0
-                let trackNumCheck = (trackNumber == 0 || track.AbsoluteTrackNumber == trackNumber)
+                                       && (normalizedReleaseTitle.Contains(t.Title.NormalizeTrackTitle())
-                //if release title is longer than track title
+                                           || t.Title.NormalizeTrackTitle().Contains(normalizedReleaseTitle)));
-                let posReleaseTitle = normalizedReleaseTitle.IndexOf(Parser.Parser.NormalizeTrackTitle(track.Title), StringComparison.CurrentCultureIgnoreCase)
-                //if track title is longer than release title 
-                let posTrackTitle = Parser.Parser.NormalizeTrackTitle(track.Title).IndexOf(normalizedReleaseTitle, StringComparison.CurrentCultureIgnoreCase)
-                where track.Title.Length > 0 && trackNumCheck && (posReleaseTitle >= 0 || posTrackTitle >= 0)
-                orderby posReleaseTitle, posTrackTitle
-                select new
-                {
-                    NormalizedLength = Parser.Parser.NormalizeTrackTitle(track.Title).Length,
-                    Track = track
-                };
 
-            return matches.OrderByDescending(e => e.NormalizedLength).FirstOrDefault()?.Track;
+            return matches.Count() > 1 ? null : matches.SingleOrDefault();
         }
 
-        public Track FindTrackByTitleInexact(int artistId, int albumId, int mediumNumber, int trackNumber, string releaseTitle)
+        public Track FindTrackByTitleInexact(int artistId, int albumId, int mediumNumber, int trackNumber, string title)
         {
-            double fuzzThreshold = 0.6;
+            var normalizedTitle = title.NormalizeTrackTitle().Replace(".", " ");
-            double fuzzGap = 0.2;
-
-            var normalizedReleaseTitle = Parser.Parser.NormalizeTrackTitle(releaseTitle).Replace(".", " ");
             var tracks = _trackRepository.GetTracksByMedium(albumId, mediumNumber);
 
-            var matches = from track in tracks
+            Func< Func<Track, string, double>, string, Tuple<Func<Track, string, double>, string>> tc = Tuple.Create;
-                let normalizedTitle = Parser.Parser.NormalizeTrackTitle(track.Title).Replace(".", " ")
+            var scoringFunctions = new List<Tuple<Func<Track, string, double>, string>> {
-                let matchProb = normalizedTitle.FuzzyMatch(normalizedReleaseTitle)
+                tc((a, t) => a.Title.NormalizeTrackTitle().FuzzyMatch(t), normalizedTitle),
-                where track.Title.Length > 0
+                tc((a, t) => a.Title.NormalizeTrackTitle().FuzzyContains(t), normalizedTitle),
-                orderby matchProb descending
+                tc((a, t) => t.FuzzyContains(a.Title.NormalizeTrackTitle()), normalizedTitle)
-                select new
+            };
+
+            foreach (var func in scoringFunctions)
+            {
+                var track = FindByStringInexact(tracks, func.Item1, func.Item2, trackNumber);
+                if (track != null)
                 {
-                    MatchProb = matchProb,
+                    return track;
-                    NormalizedTitle = normalizedTitle,
+                }
-                    Track = track
+            }
-                };
 
-            var matchList = matches.ToList();
+            return null;
+        }
 
-            if (!matchList.Any())
+        private Track FindByStringInexact(List<Track> tracks, Func<Track, string, double> scoreFunction, string title, int trackNumber)
+        {
+            const double fuzzThreshold = 0.7;
+            const double fuzzGap = 0.2;
+
+            var sortedTracks = tracks.Select(s => new
+                {
+                    MatchProb = scoreFunction(s, title),
+                    Track = s
+                })
+                .ToList()
+                .OrderByDescending(s => s.MatchProb)
+                .ToList();
+
+            if (!sortedTracks.Any())
+            {
                 return null;
+            }
 
-            _logger.Trace("\nFuzzy track match on '{0}':\n{1}",
+            _logger.Trace("\nFuzzy track match on '{0:D2} - {1}':\n{2}",
-                          normalizedReleaseTitle,
+                          trackNumber,
-                          string.Join("\n", matchList.Select(x => $"{x.NormalizedTitle}: {x.MatchProb}")));
+                          title,
+                          string.Join("\n", sortedTracks.Select(x => $"{x.Track.AbsoluteTrackNumber:D2} - {x.Track.Title}: {x.MatchProb}")));
 
-            if (matchList[0].MatchProb > fuzzThreshold
+            if (sortedTracks[0].MatchProb > fuzzThreshold
-                && (matchList.Count == 1 || matchList[0].MatchProb - matchList[1].MatchProb > fuzzGap)
+                && (sortedTracks.Count == 1 || sortedTracks[0].MatchProb - sortedTracks[1].MatchProb > fuzzGap)
-                && (trackNumber == 0 || matchList[0].Track.AbsoluteTrackNumber == trackNumber))
+                && (trackNumber == 0
-                return matchList[0].Track;
+                    || sortedTracks[0].Track.AbsoluteTrackNumber == trackNumber
+                    || sortedTracks[0].Track.AbsoluteTrackNumber + tracks.Count(t => t.MediumNumber < sortedTracks[0].Track.MediumNumber) == trackNumber))
+            {
+                return sortedTracks[0].Track;
+            }
 
             return null;
         }

src/NzbDrone.Core/Parser/Parser.cs

@@ -208,6 +208,14 @@ namespace NzbDrone.Core.Parser
             new Regex(@"(\[|\()*\b((featuring|feat.|feat|ft|ft.)\s{1}){1}\s*.*(\]|\))*", RegexOptions.IgnoreCase | RegexOptions.Compiled),
             new Regex(@"(?:\(|\[)(?:[^\(\[]*)(?:version|limited|deluxe|single|clean|album|special|bonus|promo|remastered)(?:[^\)\]]*)(?:\)|\])", RegexOptions.IgnoreCase | RegexOptions.Compiled)
         };
+
+        private static readonly Regex[] BracketRegex = new Regex[]
+        {
+            new Regex(@"\(.*\)", RegexOptions.Compiled),
+            new Regex(@"\[.*\]", RegexOptions.Compiled)
+        };
+
+        private static readonly Regex AfterDashRegex = new Regex(@"[-:].*", RegexOptions.Compiled);
         
         public static ParsedTrackInfo ParseMusicPath(string path)
         {
@@ -528,14 +536,13 @@ namespace NzbDrone.Core.Parser
             return NormalizeRegex.Replace(name, string.Empty).ToLower().RemoveAccent();
         }
 
-        public static string NormalizeTrackTitle(string title)
+        public static string NormalizeTrackTitle(this string title)
         {
             title = SpecialEpisodeWordRegex.Replace(title, string.Empty);
             title = PunctuationRegex.Replace(title, " ");
             title = DuplicateSpacesRegex.Replace(title, " ");
 
-            return title.Trim()
+            return title.Trim().ToLower();
-                        .ToLower();
         }
 
         public static string NormalizeTitle(string title)
@@ -601,6 +608,22 @@ namespace NzbDrone.Core.Parser
             return CommonTagRegex[1].Replace(album, string.Empty).Trim();
         }
 
+        public static string RemoveBracketsAndContents(this string album)
+        {
+            var intermediate = album;
+            foreach (var regex in BracketRegex)
+            {
+                intermediate = regex.Replace(intermediate, string.Empty).Trim();
+            }
+            
+            return intermediate;
+        }
+
+        public static string RemoveAfterDash(this string text)
+        {
+            return AfterDashRegex.Replace(text, string.Empty).Trim();
+        }
+
         public static string CleanTrackTitle(string title)
         {
             var intermediateTitle = title;
@@ -619,7 +642,7 @@ namespace NzbDrone.Core.Parser
 
             var trackNumber = file.Tag.Track;
             var trackTitle = file.Tag.Title;
-            var discNumber = (file.Tag.Disc > 0) ? Convert.ToInt32(file.Tag.Disc) : 1;
+            var discNumber = (int)file.Tag.Disc;
 
             var artist = file.Tag.FirstAlbumArtist;
 

src/NzbDrone.Core/Parser/ParsingService.cs

@@ -50,14 +50,21 @@ namespace NzbDrone.Core.Parser
         public Artist GetArtist(string title)
         {
             var parsedAlbumInfo = Parser.ParseAlbumTitle(title);
-            
+
-            if (parsedAlbumInfo == null || parsedAlbumInfo.ArtistName.IsNullOrWhiteSpace())
+            if (parsedAlbumInfo != null && !parsedAlbumInfo.ArtistName.IsNullOrWhiteSpace())
             {
-                return _artistService.FindByName(title);
+                title = parsedAlbumInfo.ArtistName;
+            }
+            
+            var artistInfo = _artistService.FindByName(title);
+
+            if (artistInfo == null)
+            {
+                _logger.Debug("Trying inexact artist match for {0}", title);
+                artistInfo = _artistService.FindByNameInexact(title);
             }
 
-            return _artistService.FindByName(parsedAlbumInfo.ArtistName);
+            return artistInfo;
-            
         }
 
         public Artist GetArtistFromTag(string file)
@@ -81,8 +88,15 @@ namespace NzbDrone.Core.Parser
                 return null;
             }
 
-            return _artistService.FindByName(parsedTrackInfo.ArtistTitle);
+            artist = _artistService.FindByName(parsedTrackInfo.ArtistTitle);
 
+            if (artist == null)
+            {
+                _logger.Debug("Trying inexact artist match for {0}", parsedTrackInfo.ArtistTitle);
+                artist = _artistService.FindByNameInexact(parsedTrackInfo.ArtistTitle);
+            }
+
+            return artist;
         }
 
         public RemoteAlbum Map(ParsedAlbumInfo parsedAlbumInfo, SearchCriteriaBase searchCriteria = null)
@@ -147,6 +161,12 @@ namespace NzbDrone.Core.Parser
                 albumInfo = _albumService.FindByTitle(artist.Id, parsedAlbumInfo.AlbumTitle);
             }
 
+            if (albumInfo == null)
+            {
+                _logger.Debug("Trying inexact album match for {0}", parsedAlbumInfo.AlbumTitle);
+                albumInfo = _albumService.FindByTitleInexact(artist.Id, parsedAlbumInfo.AlbumTitle);
+            }
+
             if (albumInfo != null)
             {
                 result.Add(albumInfo);
@@ -186,6 +206,12 @@ namespace NzbDrone.Core.Parser
 
             artist = _artistService.FindByName(parsedAlbumInfo.ArtistName);
 
+            if (artist == null)
+            {
+                _logger.Debug("Trying inexact artist match for {0}", parsedAlbumInfo.ArtistName);
+                artist = _artistService.FindByNameInexact(parsedAlbumInfo.ArtistName);
+            }
+
             if (artist == null)
             {
                 _logger.Debug("No matching artist {0}", parsedAlbumInfo.ArtistName);