Files
NaviWatcher/internal/scanner/diff.go
Vladimir Zagainov a4f0460664 feat: implement scanner diff engine (missing-release detection)
Add FindMissingReleases and MissingRelease to internal/scanner: skips
IsIgnored external releases, scopes matches per ArtistID, and reports
external releases with no local album above the fuzzy threshold.
2026-07-19 18:16:58 +03:00

64 lines
1.8 KiB
Go

package scanner
import (
"naviwatcher/internal/database"
)
// MissingRelease describes an external release that has no sufficiently similar
// local album. It is a flattened, consumer-friendly projection of a
// database.ExternalRelease.
type MissingRelease struct {
RGID string `json:"rgid"`
ArtistID string `json:"artist_id"`
Title string `json:"title"`
Type string `json:"type"`
ReleaseDate string `json:"release_date"`
}
// FindMissingReleases compares an artist's external discography against the
// user's local albums and returns the releases that are present externally but
// have no sufficiently similar local album.
//
// Rules:
// - External releases flagged IsIgnored are never reported.
// - A local album only matches an external release for the same ArtistID.
// - An external release is "missing" when none of the local albums (same
// ArtistID) IsMatch at the given threshold.
func FindMissingReleases(local []database.LocalAlbum, external []database.ExternalRelease, threshold float64) []MissingRelease {
// Group local albums by artist for O(1) lookup per external release.
localByArtist := make(map[string][]database.LocalAlbum)
for _, a := range local {
localByArtist[a.ArtistID] = append(localByArtist[a.ArtistID], a)
}
var missing []MissingRelease
for _, ext := range external {
if ext.IsIgnored {
continue
}
albums := localByArtist[ext.ArtistID]
matched := false
for _, a := range albums {
if IsMatch(a.Title, ext.Title, threshold) {
matched = true
break
}
}
if matched {
continue
}
missing = append(missing, MissingRelease{
RGID: ext.RGID,
ArtistID: ext.ArtistID,
Title: ext.Title,
Type: ext.Type,
ReleaseDate: ext.ReleaseDate,
})
}
return missing
}