update

model/artwork_id.go

@@ -0,0 +1,123 @@
+package model
+
+import (
+	"errors"
+	"fmt"
+	"strconv"
+	"strings"
+	"time"
+)
+
+type Kind struct {
+	prefix string
+	name   string
+}
+
+func (k Kind) String() string {
+	return k.name
+}
+
+var (
+	KindMediaFileArtwork = Kind{"mf", "media_file"}
+	KindArtistArtwork    = Kind{"ar", "artist"}
+	KindAlbumArtwork     = Kind{"al", "album"}
+	KindPlaylistArtwork  = Kind{"pl", "playlist"}
+)
+
+var artworkKindMap = map[string]Kind{
+	KindMediaFileArtwork.prefix: KindMediaFileArtwork,
+	KindArtistArtwork.prefix:    KindArtistArtwork,
+	KindAlbumArtwork.prefix:     KindAlbumArtwork,
+	KindPlaylistArtwork.prefix:  KindPlaylistArtwork,
+}
+
+type ArtworkID struct {
+	Kind       Kind
+	ID         string
+	LastUpdate time.Time
+}
+
+func (id ArtworkID) String() string {
+	if id.ID == "" {
+		return ""
+	}
+	s := fmt.Sprintf("%s-%s", id.Kind.prefix, id.ID)
+	if lu := id.LastUpdate.Unix(); lu > 0 {
+		return fmt.Sprintf("%s_%x", s, lu)
+	}
+	return s + "_0"
+}
+
+func NewArtworkID(kind Kind, id string, lastUpdate *time.Time) ArtworkID {
+	artID := ArtworkID{kind, id, time.Time{}}
+	if lastUpdate != nil {
+		artID.LastUpdate = *lastUpdate
+	}
+	return artID
+}
+
+func ParseArtworkID(id string) (ArtworkID, error) {
+	parts := strings.SplitN(id, "-", 2)
+	if len(parts) != 2 {
+		return ArtworkID{}, errors.New("invalid artwork id")
+	}
+	kind, ok := artworkKindMap[parts[0]]
+	if !ok {
+		return ArtworkID{}, errors.New("invalid artwork kind")
+	}
+	parsedID := ArtworkID{
+		Kind: kind,
+		ID:   parts[1],
+	}
+	parts = strings.SplitN(parts[1], "_", 2)
+	if len(parts) == 2 {
+		if parts[1] != "0" {
+			lastUpdate, err := strconv.ParseInt(parts[1], 16, 64)
+			if err != nil {
+				return ArtworkID{}, err
+			}
+			parsedID.LastUpdate = time.Unix(lastUpdate, 0)
+		}
+		parsedID.ID = parts[0]
+	}
+	return parsedID, nil
+}
+
+func MustParseArtworkID(id string) ArtworkID {
+	artID, err := ParseArtworkID(id)
+	if err != nil {
+		panic(artID)
+	}
+	return artID
+}
+
+func artworkIDFromAlbum(al Album) ArtworkID {
+	return ArtworkID{
+		Kind:       KindAlbumArtwork,
+		ID:         al.ID,
+		LastUpdate: al.UpdatedAt,
+	}
+}
+
+func artworkIDFromMediaFile(mf MediaFile) ArtworkID {
+	return ArtworkID{
+		Kind:       KindMediaFileArtwork,
+		ID:         mf.ID,
+		LastUpdate: mf.UpdatedAt,
+	}
+}
+
+func artworkIDFromPlaylist(pls Playlist) ArtworkID {
+	return ArtworkID{
+		Kind:       KindPlaylistArtwork,
+		ID:         pls.ID,
+		LastUpdate: pls.UpdatedAt,
+	}
+}
+
+func artworkIDFromArtist(ar Artist) ArtworkID {
+	return ArtworkID{
+		Kind: KindArtistArtwork,
+		ID:   ar.ID,
+	}
+}