networking and error handling

lib/core/utils/app_exceptions.dart

@@ -1,8 +1,15 @@
 class AppException implements Exception {
   final String message;
   final String prefix;
+  final int? statusCode;
+  final dynamic originalError;
 
-  AppException([this.message = 'An unknown error occurred.', this.prefix = '']);
+  AppException([
+    this.message = 'An unknown error occurred.',
+    this.prefix = '',
+    this.statusCode,
+    this.originalError,
+  ]);
 
   @override
   String toString() {
@@ -11,11 +18,91 @@ class AppException implements Exception {
 }
 
 class FetchDataException extends AppException {
-  FetchDataException([String? message])
-    : super(message ?? 'Error During Communication: ', 'Network Error');
+  FetchDataException([String? message, int? statusCode, originalError])
+    : super(
+        message ?? 'Error During Communication: ',
+        'Network Error',
+        statusCode,
+        originalError,
+      );
 }
 
 class AuthenticationException extends AppException {
-  AuthenticationException([String? message])
-    : super(message ?? 'Authentication Failed.', 'Auth Error');
+  AuthenticationException([String? message, int? statusCode, originalError])
+    : super(
+        message ?? 'Authentication Failed.',
+        'Auth Error: ',
+        statusCode,
+        originalError,
+      );
+}
+
+class NetworkConnectionException extends AppException {
+  NetworkConnectionException([String? message, originalError])
+    : super(
+        message ?? 'No internet connection available.',
+        'Connection Error: ',
+        null,
+        originalError,
+      );
+}
+
+class TimeoutException extends AppException {
+  TimeoutException([String? message, originalError])
+    : super(
+        message ?? 'Request timed out.',
+        'Timeout Error: ',
+        null,
+        originalError,
+      );
+}
+
+class ServerException extends AppException {
+  ServerException([String? message, int? statusCode, originalError])
+    : super(
+        message ?? 'Server error occurred.',
+        'Server Error: ',
+        statusCode,
+        originalError,
+      );
+}
+
+class BadRequestException extends AppException {
+  BadRequestException([String? message, int? statusCode, originalError])
+    : super(
+        message ?? 'Bad request.',
+        'Bad Request Error: ',
+        statusCode,
+        originalError,
+      );
+}
+
+class NotFoundException extends AppException {
+  NotFoundException([String? message, int? statusCode, originalError])
+    : super(
+        message ?? 'Resource not found.',
+        'Not Found Error: ',
+        statusCode,
+        originalError,
+      );
+}
+
+class ForbiddenException extends AppException {
+  ForbiddenException([String? message, int? statusCode, originalError])
+    : super(
+        message ?? 'Access forbidden.',
+        'Forbidden Error: ',
+        statusCode,
+        originalError,
+      );
+}
+
+class RateLimitException extends AppException {
+  RateLimitException([String? message, int? statusCode, originalError])
+    : super(
+        message ?? 'Rate limit exceeded.',
+        'Rate Limit Error: ',
+        statusCode,
+        originalError,
+      );
 }

lib/core/utils/network_connectivity.dart

@@ -0,0 +1,21 @@
+import 'dart:io';
+
+class NetworkConnectivity {
+  static final NetworkConnectivity _instance = NetworkConnectivity._internal();
+  factory NetworkConnectivity() => _instance;
+  NetworkConnectivity._internal();
+
+  /// Check if device has internet connectivity
+  Future<bool> hasInternetConnection() async {
+    try {
+      // Try to reach a reliable host to check internet connectivity
+      final result = await InternetAddress.lookup('google.com');
+      return result.isNotEmpty && result[0].rawAddress.isNotEmpty;
+    } on SocketException catch (_) {
+      return false;
+    } on Exception catch (_) {
+      // If connectivity check fails, assume no connection
+      return false;
+    }
+  }
+}