scotty/internal/similarity/similarity.go
2025-04-03 15:00:45 +02:00

82 lines
2.5 KiB
Go

/*
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/models"
"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 := 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 reMultiSpace = regexp.MustCompile(`\s+`)
var reIgnoredPatterns = []*regexp.Regexp{
regexp.MustCompile(`\s+\([^)]+\)$`),
regexp.MustCompile(`\s+- (\d{4} )?remaster(ed)?$`),
}
// Normalizes a track or release title.
func NormalizeTitle(s string) string {
s = strings.TrimSpace(s)
s = strings.ToLower(s)
s = reMultiSpace.ReplaceAllString(s, " ")
for _, re := range reIgnoredPatterns {
s = re.ReplaceAllString(s, "")
}
return s
}
// Compare two tracks for similarity.
func CompareTracks(t1 models.Track, t2 models.Track) float64 {
// Identical recording MBID always compares 100%
if t1.RecordingMBID == t2.RecordingMBID && t1.RecordingMBID != "" {
return 1.0
}
// Compare track name and artist
sims := []float64{
Similarity(NormalizeTitle(t1.TrackName), NormalizeTitle(t2.TrackName)),
Similarity(NormalizeTitle(t1.ArtistName()), NormalizeTitle(t2.ArtistName())),
}
// Compare release names only if they are set for both tracks
if t1.ReleaseName != "" && t2.ReleaseName != "" {
sims = append(sims, Similarity(NormalizeTitle(t1.ReleaseName), NormalizeTitle(t2.ReleaseName)))
}
return util.Average(sims...)
}