fix: prevent overwrite when document has multiple files

main.go

@@ -323,10 +323,16 @@ func handleExistingFile(ctx context.Context, client *DocspellClient, cfg config,
 		return fmt.Errorf("create directory: %w", err)
 	}
 
-	subfolder := fmt.Sprintf("%s %s - %s.%s", date.Format("20060102"), corr, itemName, extension)
-	newPath := filepath.Join(curDir, subfolder)
-
-	if err := MoveFile(fileExistsResponse.File, newPath); err != nil {
+	baseName := fmt.Sprintf("%s %s - %s", date.Format("20060102"), corr, itemName)
+	newPath, alreadyArchived, err := archiveDestination(curDir, baseName, extension, len(itemDetails.Attachments), fileExistsResponse.File)
+	if err != nil {
+		return err
+	}
+	if alreadyArchived {
+		if err := os.Remove(fileExistsResponse.File); err != nil {
+			return fmt.Errorf("remove duplicate source file: %w", err)
+		}
+	} else if err := MoveFile(fileExistsResponse.File, newPath); err != nil {
 		return fmt.Errorf("move file: %w", err)
 	}
 
@@ -334,6 +340,37 @@ func handleExistingFile(ctx context.Context, client *DocspellClient, cfg config,
 	return nil
 }
 
+func archiveDestination(directory, baseName, extension string, attachmentCount int, sourcePath string) (string, bool, error) {
+	if attachmentCount < 1 {
+		attachmentCount = 1
+	}
+	for index := 1; ; index++ {
+		suffix := ""
+		if attachmentCount > 1 || index > 1 {
+			suffix = fmt.Sprintf(".%d", index)
+		}
+		destination := filepath.Join(directory, baseName+suffix+"."+extension)
+		_, err := os.Stat(destination)
+		if os.IsNotExist(err) {
+			return destination, false, nil
+		}
+		if err != nil {
+			return "", false, fmt.Errorf("inspect archive destination: %w", err)
+		}
+		sourceHash, err := fileSHA256(sourcePath)
+		if err != nil {
+			return "", false, fmt.Errorf("hash source file: %w", err)
+		}
+		destinationHash, err := fileSHA256(destination)
+		if err != nil {
+			return "", false, fmt.Errorf("hash archive destination: %w", err)
+		}
+		if sourceHash == destinationHash {
+			return destination, true, nil
+		}
+	}
+}
+
 func validateConfig(cfg config) {
 	if len(cfg.ImportDirectories) == 0 || cfg.ArchiveDirectory == "" {
 		fmt.Println("FATAL  Parameter missing")