1 files changed, 38 insertions, 0 deletions
diff --git a/player-server/internal/thumb/path.go b/player-server/internal/thumb/path.go
new file mode 100644
index 0000000..66f3145
--- /dev/null
+++ b/player-server/internal/thumb/path.go
@@ -0,0 +1,38 @@
+package thumb
+
+import (
+	"path/filepath"
+	"strings"
+)
+
+// DirName is the on-disk directory name used to store generated thumbnails.
+// It is a hidden subdirectory placed alongside the source media files.
+const DirName = ".thumbnails"
+
+// thumbExt is the canonical extension used for all generated thumbnails.
+// Thumbnails are always JPEGs regardless of the source media type.
+const thumbExt = ".jpg"
+
+// ThumbnailDir returns the conventional thumbnail directory inside parent.
+// The directory is a hidden ".thumbnails" subfolder sitting next to the
+// source media. filepath.Join handles any trailing slashes on parent.
+func ThumbnailDir(parent string) string {
+	return filepath.Join(parent, DirName)
+}
+
+// ThumbnailNameFor returns the canonical thumbnail filename for the given
+// source file (basename without extension + ".jpg"). For dotfiles (e.g.
+// ".bashrc") filepath.Ext returns the leading-dot name itself; TrimSuffix
+// then yields an empty base, producing just ".jpg" — matching the historical
+// behaviour of the inlined helpers being replaced.
+func ThumbnailNameFor(srcPath string) string {
+	base := filepath.Base(srcPath)
+	return strings.TrimSuffix(base, filepath.Ext(base)) + thumbExt
+}
+
+// ThumbnailPathFor returns the full path to the thumbnail for srcPath stored
+// under parent/.thumbnails/. parent is the directory that should contain the
+// thumbnail folder (typically the set directory or the source's parent dir).
+func ThumbnailPathFor(srcPath, parent string) string {
+	return filepath.Join(ThumbnailDir(parent), ThumbnailNameFor(srcPath))
+}