improved game scanning

internal/gamefile.go

@@ -23,23 +23,39 @@ func scanGameFileForID(filename string) (string, error) {
 		return "", fmt.Errorf("failed to read file: %w", err)
 	}
 
-	pattern := regexp.MustCompile(`(SLUS|SLES|SLPS|SCUS|SCES|SCPS)[_-]?\d{3}[\._]\d{2}`)
-
-	match := pattern.Find(buffer[:n])
-	if match != nil {
-		gameID := string(match)
-		return normalizeGameID(gameID), nil
+	id, found := scanBufferForID(buffer[:n])
+	if !found {
+		return "", fmt.Errorf("no PS2 game ID found in file")
 	}
 
-	return "", fmt.Errorf("no PS2 game ID found in file")
+	return id, nil
+}
+
+func scanBufferForID(buffer []byte) (string, bool) {
+	pattern := regexp.MustCompile(`(SLUS|SLES|SLPS|SCUS|SCES|SCPS)[_\-\s]?\d{3}[\._\-\s]?\d{2}`)
+
+	match := pattern.Find(buffer)
+	if match != nil {
+		gameID := string(match)
+		return normalizeGameID(gameID), true
+	}
+
+	return "", false
 }
 
 func normalizeGameID(id string) string {
-	s := strings.ReplaceAll(id, "_", "-")
-	s = strings.ReplaceAll(s, ".", "")
-	s = strings.ToUpper(s)
+	re := regexp.MustCompile(`(?i)^([A-Z]{4})[^0-9]*([0-9]{3})[^0-9]*([0-9]{2})$`)
+	id = strings.TrimSpace(id)
 
-	return s
+	matches := re.FindStringSubmatch(id)
+	if len(matches) != 4 {
+		return ""
+	}
+
+	prefix := strings.ToUpper(matches[1])
+	number := matches[2] + matches[3]
+
+	return prefix + "-" + number
 }
 
 func renameGameFile(filePath, gameName string) (string, error) {
@@ -67,4 +83,3 @@ func renameGameFile(filePath, gameName string) (string, error) {
 
 	return newPath, nil
 }
-