New similarity module to help with comparing track titles

go.mod

@@ -28,6 +28,7 @@ require (
 require (
 	github.com/VividCortex/ewma v1.2.0 // indirect
 	github.com/acarl005/stripansi v0.0.0-20180116102854-5a71ef0e047d // indirect
+	github.com/agnivade/levenshtein v1.1.1 // indirect
 	github.com/chzyer/readline v0.0.0-20180603132655-2972be24d48e // indirect
 	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
 	github.com/dustin/go-humanize v1.0.1 // indirect

go.sum

@@ -44,6 +44,9 @@ github.com/Xuanwo/go-locale v1.1.0 h1:51gUxhxl66oXAjI9uPGb2O0qwPECpriKQb2hl35mQk
 github.com/Xuanwo/go-locale v1.1.0/go.mod h1:UKrHoZB3FPIk9wIG2/tVSobnHgNnceGSH3Y8DY5cASs=
 github.com/acarl005/stripansi v0.0.0-20180116102854-5a71ef0e047d h1:licZJFw2RwpHMqeKTCYkitsPqHNxTmd4SNR5r94FGM8=
 github.com/acarl005/stripansi v0.0.0-20180116102854-5a71ef0e047d/go.mod h1:asat636LX7Bqt5lYEZ27JNDcqxfjdBQuJ/MM4CN/Lzo=
+github.com/agnivade/levenshtein v1.1.1 h1:QY8M92nrzkmr798gCo3kmMyqXFzdQVpxLlGPRBij0P8=
+github.com/agnivade/levenshtein v1.1.1/go.mod h1:veldBMzWxcCG2ZvUTKD2kJNRdCk5hVbJomOvKkmgYbo=
+github.com/arbovm/levenshtein v0.0.0-20160628152529-48b4e1c0c4d0/go.mod h1:t2tdKJDJF9BV14lnkjHmOQgcvEKgtqs5a1N3LNdJhGE=
 github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
 github.com/chzyer/logex v1.1.10 h1:Swpa1K6QvQznwJRcfTfQJmTE72DqScAa40E+fbHEXEE=
 github.com/chzyer/logex v1.1.10/go.mod h1:+Ywpsq7O8HXn0nuIou7OrIPyXbp3wmkHB+jjWRnGsAI=
@@ -64,6 +67,7 @@ github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1
 github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/delucks/go-subsonic v0.0.0-20220915164742-2744002c4be5 h1:RuuxidatioSKGOiBzL1mTY4X22DQD8weEbS3iRLHnAg=
 github.com/delucks/go-subsonic v0.0.0-20220915164742-2744002c4be5/go.mod h1:vnbEuj6Z20PLcHB4rrLQAOXGMjtULfMGhRVSFPcSdUo=
+github.com/dgryski/trifles v0.0.0-20200323201526-dd97f9abfb48/go.mod h1:if7Fbed8SFyPtHLHbg49SI7NAdJiC5WIA09pe59rfAA=
 github.com/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkpeCY=
 github.com/dustin/go-humanize v1.0.1/go.mod h1:Mu1zIs6XwVuF/gI1OepvI0qD18qycQx+mFykh5fBlto=
 github.com/envoyproxy/go-control-plane v0.9.0/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=

internal/similarity/similarity.go

@@ -0,0 +1,55 @@
+/*
+Copyright © 2024 Philipp Wolfer <phw@uploadedlobster.com>
+
+Scotty is free software: you can redistribute it and/or modify it under the
+terms of the GNU General Public License as published by the Free Software
+Foundation, either version 3 of the License, or (at your option) any later version.
+
+Scotty is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along with
+Scotty. If not, see <https://www.gnu.org/licenses/>.
+*/
+
+package similarity
+
+import (
+	"regexp"
+	"strings"
+
+	"github.com/agnivade/levenshtein"
+	"go.uploadedlobster.com/scotty/internal/util"
+	"golang.org/x/text/unicode/norm"
+)
+
+// Returns the Levensthein distance between s1 and s2 relative to the length of
+// the longer string.
+// Unicode normalization on the strings is performed.
+func Similarity(s1 string, s2 string) float64 {
+	s1 = norm.NFKC.String(s1)
+	s2 = norm.NFKC.String(s2)
+	l1 := len([]rune(s1))
+	l2 := len([]rune(s2))
+	maxLen := util.Max(l1, l2)
+	// Empty strings always compare full equal
+	if maxLen == 0 {
+		return 1.0
+	}
+	dist := levenshtein.ComputeDistance(s1, s2)
+	// fmt.Printf("%v (%v) ~ %v (%v) = %v\n", s1, l1, s2, l2, dist)
+	return 1.0 - (float64(dist) / float64(maxLen))
+}
+
+var reExtraTitleInfo = regexp.MustCompile(`\([^)]+\)$`)
+var reMultiSpace = regexp.MustCompile(`\s+`)
+
+// Normalizes a track or release title.
+func NormalizeTitle(s string) string {
+	s = strings.TrimSpace(s)
+	s = strings.ToLower(s)
+	s = reExtraTitleInfo.ReplaceAllString(s, "")
+	s = reMultiSpace.ReplaceAllString(s, " ")
+	return s
+}

internal/similarity/similarity_test.go

@@ -0,0 +1,51 @@
+/*
+Copyright © 2024 Philipp Wolfer <phw@uploadedlobster.com>
+
+Scotty is free software: you can redistribute it and/or modify it under the
+terms of the GNU General Public License as published by the Free Software
+Foundation, either version 3 of the License, or (at your option) any later version.
+
+Scotty is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along with
+Scotty. If not, see <https://www.gnu.org/licenses/>.
+*/
+
+package similarity_test
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"go.uploadedlobster.com/scotty/internal/similarity"
+)
+
+func ExampleSimilarity() {
+	s := similarity.Similarity("bar1", "bär1")
+	fmt.Println(s)
+	// Output: 0.75
+}
+
+func TestSimilarity(t *testing.T) {
+	assert := assert.New(t)
+	assert.Equal(1.0, similarity.Similarity("", ""))
+	assert.Equal(0.0, similarity.Similarity("foo", ""))
+	assert.Equal(0.0, similarity.Similarity("foo", "bar"))
+	assert.Equal(0.5, similarity.Similarity("foobar", "bar"))
+	assert.Equal(1.0, similarity.Similarity("foo", "foo"))
+}
+
+func ExampleNormalizeTitle() {
+	s := similarity.NormalizeTitle(" Forever \tFailure (video edit) ")
+	fmt.Println(s)
+	// Output: forever failure
+}
+
+func TestNormalizeTitle(t *testing.T) {
+	assert := assert.New(t)
+	assert.Equal("forever failure", similarity.NormalizeTitle("Forever Failure"))
+	assert.Equal("foo", similarity.NormalizeTitle(" \tfoo\t \t"))
+}