1 files changed, 80 insertions, 0 deletions
diff --git a/player-server/internal/thumb/resolver.go b/player-server/internal/thumb/resolver.go
new file mode 100644
index 0000000..a6614d6
--- /dev/null
+++ b/player-server/internal/thumb/resolver.go
@@ -0,0 +1,80 @@
+package thumb
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"codeberg.org/snonux/player/internal/model"
+)
+
+// ErrNotFound is returned by a Resolver when a media item has no thumbnail
+// (and no acceptable fallback) available. Callers translate this sentinel
+// to their domain-specific not-found error (e.g. service.ErrNotFound).
+var ErrNotFound = errors.New("thumbnail not found")
+
+// ResolvedFile describes a thumbnail file that has been located on (or
+// abstractly resolved from) some backing store. It contains everything a
+// caller needs to construct a HTTP file response without itself touching
+// the filesystem.
+type ResolvedFile struct {
+	Path     string
+	FileName string
+	FileSize int64
+}
+
+// Resolver abstracts the "given a media item, return a thumbnail file" step.
+// Pulling this out of browseService lets the service layer avoid direct
+// os.Stat calls and lets tests inject a fake resolver instead of writing
+// temporary files.
+type Resolver interface {
+	// Resolve returns a ResolvedFile for the media's thumbnail. If the
+	// media has no thumbnail and no fallback is available, it returns
+	// ErrNotFound. Any other error indicates a real I/O problem.
+	Resolve(media *model.Media) (*ResolvedFile, error)
+}
+
+// FSResolver is the production Resolver that stats files on the local
+// filesystem. It encapsulates the original logic that lived in
+// browseService.GetThumbnail: prefer the generated thumbnail, fall back to
+// the original file for images so that cover.jpg-style assets still render.
+type FSResolver struct{}
+
+// NewFSResolver returns a Resolver backed by os.Stat against real paths.
+func NewFSResolver() *FSResolver {
+	return &FSResolver{}
+}
+
+// Resolve looks up the thumbnail file on disk for media, falling back to
+// the original AbsPath for image media when the generated thumbnail is
+// missing. A missing or empty thumbnail path with no fallback yields
+// ErrNotFound so callers can map it to a 404 cleanly.
+func (FSResolver) Resolve(media *model.Media) (*ResolvedFile, error) {
+	if media == nil {
+		return nil, ErrNotFound
+	}
+	if media.ThumbnailPath == "" {
+		return nil, ErrNotFound
+	}
+	if info, err := os.Stat(media.ThumbnailPath); err == nil {
+		return &ResolvedFile{
+			Path:     media.ThumbnailPath,
+			FileName: filepath.Base(media.ThumbnailPath),
+			FileSize: info.Size(),
+		}, nil
+	} else if media.Type == model.MediaTypeImage {
+		// Generated thumbnail missing: for images, fall back to the
+		// original file so cover.jpg / folder.jpg etc. still render.
+		if info, statErr := os.Stat(media.AbsPath); statErr == nil {
+			return &ResolvedFile{
+				Path:     media.AbsPath,
+				FileName: filepath.Base(media.AbsPath),
+				FileSize: info.Size(),
+			}, nil
+		}
+		return nil, fmt.Errorf("stat thumbnail: %w", err)
+	} else {
+		return nil, fmt.Errorf("stat thumbnail: %w", err)
+	}
+}