tweaks (#1142)

* opt: unused layout

* mod: semantics

* opt: DanmakuMsg type

* opt: avoid cast

* opt: unnecessary_lambdas

* opt: use isEven

* opt: logger

* opt: invalid common page

* tweak

* opt: unify DynController

lib/services/logger.dart

@@ -0,0 +1,57 @@
+import 'dart:io';
+
+import 'package:logger/logger.dart';
+import 'package:path/path.dart' as p;
+import 'package:path_provider/path_provider.dart';
+
+final logger = PiliLogger();
+
+class PiliLogger extends Logger {
+  PiliLogger() : super();
+
+  @override
+  Future<void> log(
+    Level level,
+    dynamic message, {
+    Object? error,
+    StackTrace? stackTrace,
+    DateTime? time,
+  }) async {
+    if (level == Level.error || level == Level.fatal) {
+      // 添加至文件末尾
+      File logFile = await LoggerUtils.getLogsPath();
+      logFile.writeAsString(
+        "**${DateTime.now()}** \n $message \n $stackTrace",
+        mode: FileMode.writeOnlyAppend,
+      );
+    }
+    super.log(level, "$message", error: error, stackTrace: stackTrace);
+  }
+}
+
+class LoggerUtils {
+  static File? _logFile;
+
+  static Future<File> getLogsPath() async {
+    if (_logFile != null) return _logFile!;
+
+    String dir = (await getApplicationDocumentsDirectory()).path;
+    final String filename = p.join(dir, ".pili_logs");
+    final File file = File(filename);
+    if (!file.existsSync()) {
+      await file.create(recursive: true);
+    }
+    return _logFile = file;
+  }
+
+  static Future<bool> clearLogs() async {
+    final file = await getLogsPath();
+    try {
+      await file.writeAsBytes(const [], flush: true);
+    } catch (e) {
+      // if (kDebugMode) debugPrint('Error clearing file: $e');
+      return false;
+    }
+    return true;
+  }
+}