Import missing artist portraits from uploaded album folders

services/api/internal/library/artist_images.go

@@ -0,0 +1,74 @@
+package library
+
+import (
+	"context"
+	"crypto/sha256"
+	"encoding/hex"
+	"errors"
+	"os"
+
+	"github.com/google/uuid"
+	"github.com/jackc/pgx/v5"
+)
+
+type artistImageStore interface {
+	ArtistWithoutImageForFile(context.Context, uuid.UUID) (uuid.UUID, error)
+	SetArtistImageIfMissing(context.Context, uuid.UUID, string) error
+}
+
+type imageRenderer interface {
+	StoreImage(context.Context, []byte) (string, error)
+}
+
+// ArtistImages applies approved portraits to the album artist, never guests.
+type ArtistImages struct {
+	store  artistImageStore
+	images imageRenderer
+}
+
+func NewArtistImages(store *Store, covers *Covers) *ArtistImages {
+	return &ArtistImages{store: store, images: covers}
+}
+
+func (a *ArtistImages) ApplyArtistImage(ctx context.Context, file uuid.UUID, data []byte) error {
+	id, err := a.store.ArtistWithoutImageForFile(ctx, file)
+	if errors.Is(err, ErrNotFound) {
+		return nil
+	}
+	if err != nil {
+		return err
+	}
+	key, err := a.images.StoreImage(ctx, data)
+	if err != nil {
+		return err
+	}
+	return a.store.SetArtistImageIfMissing(ctx, id, key)
+}
+
+func (c *Covers) StoreImage(ctx context.Context, data []byte) (string, error) {
+	if err := os.MkdirAll(c.Dir, 0o755); err != nil {
+		return "", err
+	}
+	sum := sha256.Sum256(data)
+	key := hex.EncodeToString(sum[:8])
+	_, err := c.render(ctx, data, key)
+	return key, err
+}
+
+func (st *Store) ArtistWithoutImageForFile(ctx context.Context, file uuid.UUID) (uuid.UUID, error) {
+	var id uuid.UUID
+	err := st.pool.QueryRow(ctx, `SELECT a.id FROM media_files f JOIN tracks t ON t.id=f.track_id
+		JOIN albums al ON al.id=t.album_id JOIN artists a ON a.id=al.album_artist_id
+		WHERE f.id=$1 AND a.image_path IS NULL AND a.genius_image_url IS NULL`, file).Scan(&id)
+	if errors.Is(err, pgx.ErrNoRows) {
+		return id, ErrNotFound
+	}
+	return id, err
+}
+
+func (st *Store) SetArtistImageIfMissing(ctx context.Context, id uuid.UUID, key string) error {
+	// Another import or Genius may have supplied a portrait during rendering.
+	_, err := st.pool.Exec(ctx, `UPDATE artists SET image_path=$2 WHERE id=$1
+		AND image_path IS NULL AND genius_image_url IS NULL`, id, key)
+	return err
+}