Initial push to my private server

lib/controller/functions/network/connection_check.dart

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+import 'dart:async';
+import 'dart:io';
+import 'package:http/http.dart' as http;
+
+import 'net_guard.dart';
+
+typedef BodyEncoder = Future<http.Response> Function();
+
+class HttpRetry {
+  /// ريتراي لـ network/transient errors فقط.
+  static Future<http.Response> sendWithRetry(
+    BodyEncoder send, {
+    int maxRetries = 3,
+    Duration baseDelay = const Duration(milliseconds: 400),
+    Duration timeout = const Duration(seconds: 12),
+  }) async {
+    // ✅ Pre-flight check for internet connection
+    if (!await NetGuard().hasInternet()) {
+      // Immediately throw a specific exception if there's no internet.
+      // This avoids pointless retries.
+      throw const SocketException("No internet connection");
+    }
+    int attempt = 0;
+    while (true) {
+      attempt++;
+      try {
+        final res = await send().timeout(timeout);
+        return res;
+      } on TimeoutException catch (_) {
+        if (attempt >= maxRetries) rethrow;
+      } on SocketException catch (_) {
+        if (attempt >= maxRetries) rethrow;
+      } on HandshakeException catch (_) {
+        if (attempt >= maxRetries) rethrow;
+      } on http.ClientException catch (e) {
+        // مثال: Connection reset by peer
+        final msg = e.message.toLowerCase();
+        final transient = msg.contains('connection reset') ||
+            msg.contains('broken pipe') ||
+            msg.contains('timed out');
+        if (!transient || attempt >= maxRetries) rethrow;
+      }
+      // backoff: 0.4s, 0.8s, 1.6s
+      final delay = baseDelay * (1 << (attempt - 1));
+      await Future.delayed(delay);
+    }
+  }
+}

lib/controller/functions/network/net_guard.dart

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+import 'dart:async';
+import 'dart:io';
+import 'package:connectivity_plus/connectivity_plus.dart';
+import 'package:internet_connection_checker/internet_connection_checker.dart';
+
+class NetGuard {
+  static final NetGuard _i = NetGuard._();
+  NetGuard._();
+  factory NetGuard() => _i;
+
+  bool _notified = false;
+
+  /// فحص: (أ) فيه شبكة؟ (ب) فيه انترنت؟ (ج) السيرفر نفسه reachable؟
+  Future<bool> hasInternet({Uri? mustReach}) async {
+    final connectivity = await Connectivity().checkConnectivity();
+    if (connectivity == ConnectivityResult.none) return false;
+
+    final hasNet =
+        await InternetConnectionChecker.createInstance().hasConnection;
+    if (!hasNet) return false;
+
+    if (mustReach != null) {
+      try {
+        final host = mustReach.host;
+        final result = await InternetAddress.lookup(host);
+        if (result.isEmpty || result.first.rawAddress.isEmpty) return false;
+
+        // اختباري خفيف عبر TCP (80/443) — 400ms timeout
+        final port = mustReach.scheme == 'http' ? 80 : 443;
+        final socket = await Socket.connect(host, port,
+            timeout: const Duration(milliseconds: 400));
+        socket.destroy();
+      } catch (_) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  /// إظهار إشعار مرة واحدة ثم إسكات التكرارات
+  void notifyOnce(void Function(String title, String msg) show) {
+    if (_notified) return;
+    _notified = true;
+    show('لا يوجد اتصال بالإنترنت', 'تحقق من الشبكة ثم حاول مجددًا.');
+    // إعادة السماح بعد 15 ثانية
+    Future.delayed(const Duration(seconds: 15), () => _notified = false);
+  }
+}