skip already existing files

internal/sorter.go

@@ -1,6 +1,7 @@
 package ripsort
 
 import (
+	"errors"
 	"fmt"
 	"io"
 	"log/slog"
@@ -30,8 +31,17 @@ func sortSong(src, dst string, updateMeta bool) error {
 	dstPath := pathForFile(src, *m)
 	finalPath := filepath.Join(dst, dstPath)
 
-	if updateMeta {
+	exists, err := fileExists(finalPath)
+	if err != nil {
+		return err
+	}
 
+	if exists {
+		slog.Info("File already exists", "file", src, "dst", dst)
+		return nil
+	}
+
+	if updateMeta {
 		slog.Info("Copying song with updated metadata", "file", src, "dst", dstPath)
 		err = copyFileUpdateMetadata(src, finalPath, *m)
 		if err != nil {
@@ -191,3 +201,17 @@ func checkForExtraFiles(originalPath string) []string {
 
 	return extraFiles
 }
+
+func fileExists(file string) (bool, error) {
+	_, err := os.Stat(file)
+
+	if errors.Is(err, os.ErrNotExist) {
+		return false, nil
+	}
+
+	if err != nil {
+		return false, err
+	}
+
+	return true, nil
+}