规范化代码结构

lib/features/recording/utils/recording_display_name.dart

@@ -0,0 +1,53 @@
+import 'dart:io';
+
+/// 非法文件名字符（路径分隔符等）。
+final _invalidNameChars = RegExp(r'[/\\:*?"<>|]');
+
+const _maxBaseNameLength = 120;
+
+/// 清洗小程序复制的文件名基底（不含扩展名）。
+String? sanitizeRecordingBaseName(String raw) {
+  var name = raw.replaceAll(_invalidNameChars, '_').trim();
+  if (name.isEmpty) return null;
+  if (name.length > _maxBaseNameLength) {
+    name = name.substring(0, _maxBaseNameLength);
+  }
+  return name;
+}
+
+/// 解析录制展示名：优先剪切板 filename，否则 REC_时间戳。
+String resolveRecordingDisplayName(String? clipboardFilename) {
+  final sanitized = clipboardFilename == null
+      ? null
+      : sanitizeRecordingBaseName(clipboardFilename);
+  if (sanitized != null) return sanitized;
+  final now = DateTime.now();
+  final stamp =
+      '${now.year}'
+      '${now.month.toString().padLeft(2, '0')}'
+      '${now.day.toString().padLeft(2, '0')}_'
+      '${now.hour.toString().padLeft(2, '0')}'
+      '${now.minute.toString().padLeft(2, '0')}'
+      '${now.second.toString().padLeft(2, '0')}';
+  return 'REC_$stamp';
+}
+
+/// 为展示名补全视频扩展名（已有 .mp4/.mov 则保留）。
+String withVideoExtension(String baseName, {bool? isIOS}) {
+  final ios = isIOS ?? Platform.isIOS;
+  final ext = ios ? '.mov' : '.mp4';
+  final lower = baseName.toLowerCase();
+  if (lower.endsWith('.mp4') || lower.endsWith('.mov')) {
+    return baseName;
+  }
+  return '$baseName$ext';
+}
+
+/// 传给原生的完整文件名（含扩展名）。
+String recordingFileNameForPlatform(
+  String? clipboardFilename, {
+  bool? isIOS,
+}) {
+  final base = resolveRecordingDisplayName(clipboardFilename);
+  return withVideoExtension(base, isIOS: isIOS);
+}