diff --git a/lib/data/api/api_client.dart b/lib/data/api/api_client.dart
index 21fda9a3..71192923 100644
--- a/lib/data/api/api_client.dart
+++ b/lib/data/api/api_client.dart
@@ -4,7 +4,6 @@ import 'package:http/http.dart' as http;
 import 'package:test_sa/core/enums.dart';
 
 class ApiClient {
-
   final String baseUrl, endPoint;
   final RequestMethod requestMethod;
 
@@ -15,7 +14,6 @@ class ApiClient {
   });
 
   Future<Map<String, dynamic>> execute({
-    String? token,
     Map<String, String>? headers,
     Map<String, dynamic>? queryParameters,
     Object? body,
diff --git a/old_lib/controllers/http_status_manger/http_status_manger.dart b/old_lib/controllers/http_status_manger/http_status_manger.dart
index 012a9a23..e5eb40ad 100644
--- a/old_lib/controllers/http_status_manger/http_status_manger.dart
+++ b/old_lib/controllers/http_status_manger/http_status_manger.dart
@@ -1,40 +1,38 @@
-import 'package:test_sa/models/subtitle.dart';
-import 'package:meta/meta.dart';
+import '../../models/subtitle.dart';
 
-class HttpStatusManger{
+class HttpStatusManger {
   static String getStatusMessage({
-    @required int status,
-    @required Subtitle subtitle,
-    String messageFor400,
-    String messageFor200,
-  }){
-    if(status == null)
-      // no status code - code error no need for subtitle
+    required int? status,
+    required Subtitle subtitle,
+    String? messageFor400,
+    String? messageFor200,
+  }) {
+    if (status == null) {
       return "careful null status";
-    if(status == -1)
-      // client's request in process
+    }
+    if (status == -1) {
       return subtitle.currentlyServiceNotAvailable;
-    if(status == -2){
+    }
+    if (status == -2) {
       // client's request in process
       return subtitle.waitUntilYourRequestComplete;
-    }else if(status >= 200 && status < 300){
+    } else if (status >= 200 && status < 300) {
       // client's request was successfully received
       return messageFor200 ?? subtitle.requestCompleteSuccessfully;
-    } else if(status >= 400 && status < 500){
+    } else if (status >= 400 && status < 500) {
       // client's request have error
-      switch(status){
+      switch (status) {
         case 400:
           return messageFor400 ?? subtitle.failedToCompleteRequest;
         default:
           return subtitle.failedToCompleteRequest;
       }
-    } else if(status >= 500){
+    } else if (status >= 500) {
       // server error
       return subtitle.currentlyServiceNotAvailable;
     } else {
       // no error match so return default error
       return subtitle.failedToCompleteRequest;
     }
-
   }
-}
\ No newline at end of file
+}
diff --git a/old_lib/controllers/localization/localization.dart b/old_lib/controllers/localization/localization.dart
index a6e7fe82..fa866174 100644
--- a/old_lib/controllers/localization/localization.dart
+++ b/old_lib/controllers/localization/localization.dart
@@ -2,29 +2,31 @@ import 'dart:convert';
 
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
-import 'package:test_sa/models/subtitle.dart';
 
+import '../../models/subtitle.dart';
 
 class AppLocalization {
   AppLocalization(this.locale);
 
   final Locale locale;
-  static AppLocalization of(BuildContext context) {
+
+  static AppLocalization? of(BuildContext context) {
     return Localizations.of<AppLocalization>(context, AppLocalization);
   }
 
-  Subtitle _subtitle;
-  Subtitle get subtitle => _subtitle;
+  Subtitle? _subtitle;
+
+  Subtitle? get subtitle => _subtitle;
 
   Future<void> load() async {
-    String jsonStringValues =
-    await rootBundle.loadString('assets/subtitles/${locale.languageCode}_subtitle.json');
+    String jsonStringValues = await rootBundle
+        .loadString('assets/subtitles/${locale.languageCode}_subtitle.json');
     _subtitle = Subtitle.fromJson(json.decode(jsonStringValues));
   }
 
   // static member to have simple access to the delegate from Material App
   static const LocalizationsDelegate<AppLocalization> delegate =
-  _DemoLocalizationsDelegate();
+      _DemoLocalizationsDelegate();
 }
 
 class _DemoLocalizationsDelegate
@@ -33,16 +35,16 @@ class _DemoLocalizationsDelegate
 
   @override
   bool isSupported(Locale locale) {
-    return ['en','ar'].contains(locale.languageCode);
+    return ['en', 'ar'].contains(locale.languageCode);
   }
 
   @override
   Future<AppLocalization> load(Locale locale) async {
-    AppLocalization localization = new AppLocalization(locale);
+    AppLocalization localization = AppLocalization(locale);
     await localization.load();
     return localization;
   }
 
   @override
   bool shouldReload(LocalizationsDelegate<AppLocalization> old) => false;
-}
\ No newline at end of file
+}
diff --git a/old_lib/controllers/notification/firebase_notification_manger.dart b/old_lib/controllers/notification/firebase_notification_manger.dart
index 153d28fa..f92e68e7 100644
--- a/old_lib/controllers/notification/firebase_notification_manger.dart
+++ b/old_lib/controllers/notification/firebase_notification_manger.dart
@@ -3,16 +3,15 @@ import 'dart:convert';
 import 'package:firebase_core/firebase_core.dart';
 import 'package:firebase_messaging/firebase_messaging.dart';
 import 'package:flutter/material.dart';
-import 'package:test_sa/models/app_notification.dart';
 
+import '../../models/app_notification.dart';
 import 'notification_manger.dart';
 
-class FirebaseNotificationManger{
-
+class FirebaseNotificationManger {
   static FirebaseMessaging messaging = FirebaseMessaging.instance;
-  static String token;
+  static String? token;
 
-  static Future<String> getToken() async {
+  static Future<String?> getToken() async {
     NotificationSettings settings = await messaging.requestPermission(
       alert: true,
       announcement: false,
@@ -23,7 +22,7 @@ class FirebaseNotificationManger{
       sound: true,
     );
 
-    if(settings.authorizationStatus == AuthorizationStatus.authorized){
+    if (settings.authorizationStatus == AuthorizationStatus.authorized) {
       token = await messaging.getToken();
     }
     return token;
@@ -32,7 +31,7 @@ class FirebaseNotificationManger{
   static initialized(BuildContext context) async {
     await Firebase.initializeApp();
     NotificationSettings settings;
-    try{
+    try {
       settings = await messaging.requestPermission(
         alert: true,
         announcement: false,
@@ -42,11 +41,11 @@ class FirebaseNotificationManger{
         provisional: false,
         sound: true,
       );
-    }catch(error){
+    } catch (error) {
       return;
     }
 
-    if(settings.authorizationStatus != AuthorizationStatus.authorized){
+    if (settings.authorizationStatus != AuthorizationStatus.authorized) {
       return;
     }
 
@@ -56,28 +55,24 @@ class FirebaseNotificationManger{
 
     FirebaseMessaging.onMessageOpenedApp.listen((RemoteMessage message) {
       AppNotification notification = AppNotification.fromJson(message.data);
-      if(notification.path == null
-          || notification.path.isEmpty)
-        return;
       Navigator.pushNamed(
-          context,
-          notification.path,
-          arguments: notification.requestId
+        context,
+        notification.path,
+        arguments: notification.requestId,
       );
     });
 
     FirebaseMessaging.onMessage.listen((RemoteMessage message) {
       AppNotification notification = AppNotification.fromJson(message.data);
       NotificationManger.showNotification(
-        title: message.notification.title,
-        subtext: message.notification.body,
-        hashcode: int.tryParse(notification.requestId ?? "") ?? 1,
-        payload: json.encode(message.data)
+        title: message.notification?.title,
+        subtext: message.notification?.body,
+        hashcode: int.tryParse(notification.requestId) ?? 1,
+        payload: json.encode(message.data),
       );
       return;
     });
   }
 }
 
-Future<void> firebaseMessagingBackgroundHandler(RemoteMessage message) async {
-}
\ No newline at end of file
+Future<void> firebaseMessagingBackgroundHandler(RemoteMessage message) async {}
diff --git a/old_lib/controllers/notification/notification_manger.dart b/old_lib/controllers/notification/notification_manger.dart
index a568d5d3..8892f17c 100644
--- a/old_lib/controllers/notification/notification_manger.dart
+++ b/old_lib/controllers/notification/notification_manger.dart
@@ -1,54 +1,54 @@
-import 'package:flutter/foundation.dart';
 import 'package:flutter_local_notifications/flutter_local_notifications.dart';
-import 'package:test_sa/views/app_style/colors.dart';
 
-class NotificationManger{
+import '../../views/app_style/colors.dart';
+
+class NotificationManger {
   // private constructor to avoid create object
   NotificationManger._();
 
-  static FlutterLocalNotificationsPlugin localNotificationsPlugin = FlutterLocalNotificationsPlugin();
+  static FlutterLocalNotificationsPlugin localNotificationsPlugin =
+      FlutterLocalNotificationsPlugin();
 
   /// initialisation setting for all platform
   /// onNotificationPressed action when notification pressed to open tap
   /// onIOSNotificationPressed action when notification pressed
   /// to open tap in iOS versions older than 10
-  static initialisation(
-      Function(NotificationResponse) onNotificationPressed,
-      DidReceiveLocalNotificationCallback onIOSNotificationPressed
-    ) async {
+  static initialisation(Function(NotificationResponse) onNotificationPressed,
+      DidReceiveLocalNotificationCallback onIOSNotificationPressed) async {
     FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin =
-    FlutterLocalNotificationsPlugin();
+        FlutterLocalNotificationsPlugin();
     // initialise the plugin. app_icon needs to be a added as a drawable resource to the Android head project
     const AndroidInitializationSettings initializationSettingsAndroid =
-    AndroidInitializationSettings('app_icon',);
+        AndroidInitializationSettings(
+      'app_icon',
+    );
 
     final DarwinInitializationSettings initializationSettingsDarwin =
-    DarwinInitializationSettings(
-        onDidReceiveLocalNotification: onIOSNotificationPressed);
+        DarwinInitializationSettings(
+            onDidReceiveLocalNotification: onIOSNotificationPressed);
 
-    final InitializationSettings initializationSettings = InitializationSettings(
-        android: initializationSettingsAndroid,
-        iOS: initializationSettingsDarwin,
-        macOS: initializationSettingsDarwin);
+    final InitializationSettings initializationSettings =
+        InitializationSettings(
+            android: initializationSettingsAndroid,
+            iOS: initializationSettingsDarwin,
+            macOS: initializationSettingsDarwin);
 
-    await flutterLocalNotificationsPlugin.initialize(
-        initializationSettings,
+    await flutterLocalNotificationsPlugin.initialize(initializationSettings,
         onDidReceiveNotificationResponse: onNotificationPressed);
   }
 
   // push new notification
-  static Future showNotification(
-      {
-        @required String title,
-        @required String subtext,
-        @required int hashcode,
-        String payload
-      }) async {
-
-    const AndroidNotificationDetails androidChannel = AndroidNotificationDetails(
+  static Future showNotification({
+    required String? title,
+    required String? subtext,
+    required int hashcode,
+    String? payload,
+  }) async {
+    const AndroidNotificationDetails androidChannel =
+        AndroidNotificationDetails(
       'com.newtrack.testsa',
       'Test SA',
-      channelDescription:'Push notification service for Test SA',
+      channelDescription: 'Push notification service for Test SA',
       importance: Importance.max,
       priority: Priority.max,
       playSound: true,
@@ -63,7 +63,7 @@ class NotificationManger{
     );
 
     const DarwinNotificationDetails iosNotificationDetails =
-    DarwinNotificationDetails(
+        DarwinNotificationDetails(
       categoryIdentifier: "testSA",
     );
 
@@ -81,5 +81,4 @@ class NotificationManger{
       payload: payload,
     );
   }
-
-}
\ No newline at end of file
+}
diff --git a/old_lib/controllers/providers/api/departments_provider.dart b/old_lib/controllers/providers/api/departments_provider.dart
index 0bcd0f02..ed29c683 100644
--- a/old_lib/controllers/providers/api/departments_provider.dart
+++ b/old_lib/controllers/providers/api/departments_provider.dart
@@ -2,13 +2,13 @@ import 'dart:convert';
 
 import 'package:flutter/cupertino.dart';
 import 'package:http/http.dart';
-import 'package:test_sa/controllers/api_routes/urls.dart';
-import 'package:test_sa/models/department.dart';
 
-class DepartmentsProvider extends ChangeNotifier{
+import '../../../models/department.dart';
+import '../../api_routes/urls.dart';
 
+class DepartmentsProvider extends ChangeNotifier {
   //reset provider data
-  void reset(){
+  void reset() {
     departments = null;
     stateCode = null;
   }
@@ -16,52 +16,51 @@ class DepartmentsProvider extends ChangeNotifier{
   // state code of current request to defied error message
   // like 400 customer request failed
   // 500 service not available
-  int stateCode;
-
+  int? stateCode;
 
   // contain user data
   // when user not login or register _user = null
-  List<Department> departments;
+  List<Department>? departments;
 
   // when categories in-process _loading = true
   // done _loading = true
   // failed _loading = false
-  bool isLoading;
-
+  bool? isLoading;
 
   /// return -2 if request in progress
   /// return -1 if error happen when sending request
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<int> getDepartment (String host) async {
-    if(isLoading == true)
+  Future<int> getDepartment(String host) async {
+    if (isLoading == true) {
       return -2;
+    }
     isLoading = true;
     notifyListeners();
     Response response;
-    try{
+    try {
       response = await get(
-          Uri.parse(host + URLs.getDepartments),
-        headers: {
-            "Content-Type":"application/json; charset=utf-8"
-        }
+        Uri.parse(host + URLs.getDepartments),
+        headers: {"Content-Type": "application/json; charset=utf-8"},
       );
-    } catch(error) {
+    } catch (error) {
       isLoading = false;
       stateCode = -1;
       notifyListeners();
       return -1;
     }
     stateCode = response.statusCode;
-    if(response.statusCode >= 200 && response.statusCode < 300) {
+    if (response.statusCode >= 200 && response.statusCode < 300) {
       // client's request was successfully received
-      List listJson = json.decode(utf8.decode(response.bodyBytes).replaceAll("\\", ""));
-      departments = listJson.map((department) => Department.fromJson(department)).toList();
+      List listJson =
+          json.decode(utf8.decode(response.bodyBytes).replaceAll("\\", ""));
+      departments = listJson
+          .map((department) => Department.fromJson(department))
+          .toList();
     }
     isLoading = false;
     notifyListeners();
     return response.statusCode;
   }
-
-}
\ No newline at end of file
+}
diff --git a/old_lib/controllers/providers/api/device_transfer_provider.dart b/old_lib/controllers/providers/api/device_transfer_provider.dart
index 1d433c11..f76fde18 100644
--- a/old_lib/controllers/providers/api/device_transfer_provider.dart
+++ b/old_lib/controllers/providers/api/device_transfer_provider.dart
@@ -2,18 +2,18 @@ import 'dart:convert';
 
 import 'package:flutter/cupertino.dart';
 import 'package:http/http.dart';
-import 'package:test_sa/controllers/api_routes/urls.dart';
-import 'package:test_sa/models/device/device_transfer.dart';
-import 'package:test_sa/models/device/device_transfer_info.dart';
-import 'package:test_sa/models/user.dart';
 
-class DeviceTransferProvider extends ChangeNotifier{
+import '../../../models/device/device_transfer.dart';
+import '../../../models/device/device_transfer_info.dart';
+import '../../../models/user.dart';
+import '../../api_routes/urls.dart';
 
+class DeviceTransferProvider extends ChangeNotifier {
   // number of items call in each request
   final pageItemNumber = 50;
 
   //reset provider data
-  void reset(){
+  void reset() {
     items = null;
     nextPage = true;
     stateCode = null;
@@ -22,30 +22,31 @@ class DeviceTransferProvider extends ChangeNotifier{
   // state code of current request to defied error message
   // like 400 customer request failed
   // 500 service not available
-  int stateCode;
+  int? stateCode;
 
   // true if there is next page in product list and false if not
-  bool nextPage = true;
+  bool? nextPage = true;
 
   // list of user requests
-  List<DeviceTransfer> items;
+  List<DeviceTransfer>? items;
 
   // when requests in-process _loading = true
   // done _loading = true
   // failed _loading = false
-  bool isLoading;
+  bool? isLoading;
 
   /// return -2 if request in progress
   /// return -1 if error happen when sending request
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<int> getRequests ({
-    @required String host,
-    @required User user,
+  Future<int> getRequests({
+    required String host,
+    required User user,
   }) async {
-    if(isLoading == true)
+    if (isLoading == true) {
       return -2;
+    }
     isLoading = true;
 
     // isLoading = false;
@@ -63,108 +64,97 @@ class DeviceTransferProvider extends ChangeNotifier{
     // notifyListeners();
     // return 200;
     Response response;
-    try{
+    try {
       response = await get(
-          Uri.parse(
-              "$host${URLs.getDeviceTransfer}?uid=${user.id}"
-              "&token=${user.token}&page=${(items?.length ?? 0) ~/pageItemNumber}"
-          ),
-        headers: {
-            "Content-Type":"application/json; charset=utf-8"
-        }
-      );
+          Uri.parse("$host${URLs.getDeviceTransfer}?uid=${user.id}"
+              "&token=${user.token}&page=${(items?.length ?? 0) ~/ pageItemNumber}"),
+          headers: {"Content-Type": "application/json; charset=utf-8"});
       stateCode = response.statusCode;
-      if(stateCode >= 200 && stateCode < 300) {
+      if (stateCode != null && stateCode! >= 200 && stateCode! < 300) {
         // client's request was successfully received
-        List listJson = json.decode(utf8.decode(response.bodyBytes).replaceAll("\\", ""));
-        List<DeviceTransfer> itemsPage = listJson.map(
-                (request) => DeviceTransfer.fromJson(request)).toList();
+        List listJson =
+            json.decode(utf8.decode(response.bodyBytes).replaceAll("\\", ""));
+        List<DeviceTransfer> itemsPage = listJson
+            .map((request) => DeviceTransfer.fromJson(request))
+            .toList();
         items ??= [];
-        items.addAll(itemsPage);
-        if(itemsPage.length == pageItemNumber){
+        items?.addAll(itemsPage);
+        if (itemsPage.length == pageItemNumber) {
           nextPage = true;
-        }else{
+        } else {
           nextPage = false;
         }
       }
       isLoading = false;
       notifyListeners();
       return response.statusCode;
-
-    } catch(error) {
+    } catch (error) {
       isLoading = false;
       stateCode = -1;
       notifyListeners();
       return -1;
     }
-
   }
 
-  Future<int> createRequest ({
-    @required String host,
-    @required User user,
-    @required DeviceTransfer model,
+  Future<int> createRequest({
+    required String host,
+    required User user,
+    required DeviceTransfer model,
   }) async {
-    Map<String,dynamic> body = {
+    Map<String, dynamic> body = {
       "uid": user.id.toString(),
       "token": user.token ?? "",
-      "serial_id": model.device.id ?? "",
-      "destination_client": model.receiver.client.id ?? "",
-      "destination_department": model.receiver.department.id ?? "",
+      "serial_id": model.device?.id ?? "",
+      "destination_client": model.receiver?.client?.id ?? "",
+      "destination_department": model.receiver?.department?.id ?? "",
     };
 
-
     Response response;
-    try{
+    try {
       response = await post(
-          Uri.parse(
-          host+URLs.requestDeviceTransfer),
-          body: body,
+        Uri.parse(host + URLs.requestDeviceTransfer),
+        body: body,
       );
       stateCode = response.statusCode;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
-        if(items != null) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
+        final items = this.items;
+        if (items != null) {
           items.insert(
               0,
               DeviceTransfer.fromJson(
-                json.decode(utf8.decode(response.bodyBytes))[0]
-              )
-          );
+                  json.decode(utf8.decode(response.bodyBytes))[0]));
           notifyListeners();
         }
       }
       return response.statusCode;
-
-    } catch(error) {
+    } catch (error) {
       return -1;
     }
-
   }
 
-  Future<int> updateRequest ({
-    @required String host,
-    @required User user,
-    @required bool isSender,
-    @required String requestId,
-    @required DeviceTransfer oldModel,
-    @required DeviceTransferInfo newModel,
+  Future<int> updateRequest({
+    required String host,
+    required User user,
+    required bool isSender,
+    required String requestId,
+    required DeviceTransfer oldModel,
+    required DeviceTransferInfo newModel,
   }) async {
-
-    Map<String,dynamic> body = {
+    Map<String, dynamic> body = {
       "uid": user.id.toString(),
       "token": user.token ?? "",
       "current_user": user.id ?? "",
     };
-    
+
     body.addAll(newModel.toJson(isSender));
     Response response;
-    try{
+    try {
       response = await post(
         Uri.parse("$host${URLs.updateDeviceTransfer}/$requestId"),
         body: body,
       );
       stateCode = response.statusCode;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         reset();
         // oldModel.fromDeviceTransfer(
         //   DeviceTransfer.fromJson(
@@ -174,10 +164,8 @@ class DeviceTransferProvider extends ChangeNotifier{
         notifyListeners();
       }
       return response.statusCode;
-
-    } catch(error) {
+    } catch (error) {
       return -1;
     }
-
   }
-}
\ No newline at end of file
+}
diff --git a/old_lib/controllers/providers/api/devices_provider.dart b/old_lib/controllers/providers/api/devices_provider.dart
index b55d1733..150acfdc 100644
--- a/old_lib/controllers/providers/api/devices_provider.dart
+++ b/old_lib/controllers/providers/api/devices_provider.dart
@@ -2,14 +2,14 @@ import 'dart:convert';
 
 import 'package:flutter/cupertino.dart';
 import 'package:http/http.dart';
-import 'package:test_sa/controllers/api_routes/urls.dart';
-import 'package:test_sa/models/device/device.dart';
-import 'package:test_sa/models/user.dart';
 
-class DevicesProvider extends ChangeNotifier{
+import '../../../models/device/device.dart';
+import '../../../models/user.dart';
+import '../../api_routes/urls.dart';
 
+class DevicesProvider extends ChangeNotifier {
   //reset provider data
-  void reset(){
+  void reset() {
     _devices = null;
     _stateCode = null;
   }
@@ -17,18 +17,22 @@ class DevicesProvider extends ChangeNotifier{
   // state code of current request to defied error message
   // like 400 customer request failed
   // 500 service not available
-  int _stateCode;
-  int get stateCode => _stateCode;
+  int? _stateCode;
 
-  List<Device> _devices;
-  List<Device> get devices => _devices;
+  int? get stateCode => _stateCode;
+
+  List<Device>? _devices;
+
+  List<Device>? get devices => _devices;
 
   // when categories in-process _loading = true
   // done _loading = true
   // failed _loading = false
-  bool _loading;
-  bool get isLoading => _loading;
-  set isLoading(bool isLoading){
+  bool? _loading;
+
+  bool? get isLoading => _loading;
+
+  set isLoading(bool? isLoading) {
     _loading = isLoading;
     notifyListeners();
   }
@@ -38,34 +42,33 @@ class DevicesProvider extends ChangeNotifier{
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<int> getEquipment ({
-    @required String host,
-    @required User user,
-    @required String hospitalId
-  }) async {
-    if(_loading == true)
+  Future<int> getEquipment(
+      {required String host,
+      required User user,
+      required String hospitalId}) async {
+    if (_loading == true) {
       return -2;
+    }
     _loading = true;
     notifyListeners();
     Response response;
-    try{
+    try {
       response = await get(
-          Uri.parse(host + URLs.getEquipment+"?client=$hospitalId"),
-        headers: {
-            "Content-Type":"application/json; charset=utf-8"
-        }
+        Uri.parse("${host + URLs.getEquipment}?client=$hospitalId"),
+        headers: {"Content-Type": "application/json; charset=utf-8"},
       );
-    } catch(error) {
+    } catch (error) {
       _loading = false;
       _stateCode = -1;
       notifyListeners();
       return -1;
     }
     _stateCode = response.statusCode;
-    if(response.statusCode >= 200 && response.statusCode < 300) {
+    if (response.statusCode >= 200 && response.statusCode < 300) {
       // client's request was successfully received
       List equipmentListJson = json.decode(utf8.decode(response.bodyBytes));
-      _devices = equipmentListJson.map((device) => Device.fromJson(device)).toList();
+      _devices =
+          equipmentListJson.map((device) => Device.fromJson(device)).toList();
     }
     _loading = false;
     notifyListeners();
@@ -77,32 +80,32 @@ class DevicesProvider extends ChangeNotifier{
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<List<Device>> getDevicesList ({
-    @required String host,
-    @required User user,
-    @required String hospitalId,
-    String serialNumber,
-    String number,
+  Future<List<Device>> getDevicesList({
+    required String host,
+    required User user,
+    required String hospitalId,
+    String? serialNumber,
+    String? number,
   }) async {
     Response response;
-    try{
+    try {
       response = await get(
-          Uri.parse("$host${URLs.getEquipment}?client=$hospitalId"
-              "${serialNumber?.isEmpty == false ? "&name=$serialNumber" :""}"
-              "${number?.isEmpty == false ? "&number=$number" : ""}"
-          ),
+        Uri.parse("$host${URLs.getEquipment}?client=$hospitalId"
+            "${serialNumber?.isEmpty == false ? "&name=$serialNumber" : ""}"
+            "${number?.isEmpty == false ? "&number=$number" : ""}"),
       );
-      List<Device>  page = [];
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      List<Device> page = [];
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         // client's request was successfully received
         List categoriesListJson = json.decode(utf8.decode(response.bodyBytes));
-        page = categoriesListJson.map((device) => Device.fromJson(device)).toList();
+        page = categoriesListJson
+            .map((device) => Device.fromJson(device))
+            .toList();
       }
       return page;
-    } catch(error) {
+    } catch (error) {
       return [];
     }
-
   }
 
   /// return -2 if request in progress
@@ -110,33 +113,34 @@ class DevicesProvider extends ChangeNotifier{
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<List<Device>> getDevicesListBySN ({
-    @required String host,
-    @required User user,
-    @required String hospitalId,
-    @required String sn
+  Future<List<Device>> getDevicesListBySN({
+    required String host,
+    required User user,
+    required String hospitalId,
+    required String sn,
   }) async {
     Response response;
-    try{
+    try {
       response = await get(
-        Uri.parse(host + URLs.getEquipment+"?client=$hospitalId"
-            + ( sn == null || sn.isEmpty ? "" : "&serial_qr=$sn" )),
+        Uri.parse(
+            "$host${URLs.getEquipment}?client=$hospitalId${sn.isEmpty ? "" : "&serial_qr=$sn"}"),
       );
 
       _stateCode = response.statusCode;
-      List<Device>  _page = [];
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      List<Device> page = [];
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         // client's request was successfully received
         List categoriesListJson = json.decode(utf8.decode(response.bodyBytes));
-        _page = categoriesListJson.map((device) => Device.fromJson(device)).toList();
+        page = categoriesListJson
+            .map((device) => Device.fromJson(device))
+            .toList();
       }
-      return _page;
-    } catch(error) {
+      return page;
+    } catch (error) {
       _loading = false;
       _stateCode = -1;
       notifyListeners();
       return [];
     }
-
   }
-}
\ No newline at end of file
+}
diff --git a/old_lib/controllers/providers/api/gas_refill_provider.dart b/old_lib/controllers/providers/api/gas_refill_provider.dart
index 7dba6a8c..532819a7 100644
--- a/old_lib/controllers/providers/api/gas_refill_provider.dart
+++ b/old_lib/controllers/providers/api/gas_refill_provider.dart
@@ -2,17 +2,17 @@ import 'dart:convert';
 
 import 'package:flutter/cupertino.dart';
 import 'package:http/http.dart';
-import 'package:test_sa/controllers/api_routes/urls.dart';
-import 'package:test_sa/models/gas_refill/gas_refill_model.dart';
-import 'package:test_sa/models/user.dart';
 
-class GasRefillProvider extends ChangeNotifier{
+import '../../../models/gas_refill/gas_refill_model.dart';
+import '../../../models/user.dart';
+import '../../api_routes/urls.dart';
 
+class GasRefillProvider extends ChangeNotifier {
   // number of items call in each request
   final pageItemNumber = 50;
 
   //reset provider data
-  void reset(){
+  void reset() {
     items = null;
     nextPage = true;
     stateCode = null;
@@ -21,152 +21,145 @@ class GasRefillProvider extends ChangeNotifier{
   // state code of current request to defied error message
   // like 400 customer request failed
   // 500 service not available
-  int stateCode;
+  int? stateCode;
 
   // true if there is next page in product list and false if not
   bool nextPage = true;
 
   // list of user requests
-  List<GasRefillModel> items;
+  List<GasRefillModel>? items;
 
   // when requests in-process _loading = true
   // done _loading = true
   // failed _loading = false
-  bool isLoading;
+  bool? isLoading;
 
   /// return -2 if request in progress
   /// return -1 if error happen when sending request
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<int> getRequests ({
-    @required String host,
-    @required User user,
+  Future<int> getRequests({
+    required String host,
+    required User user,
   }) async {
-    if(isLoading == true)
+    if (isLoading == true) {
       return -2;
+    }
     isLoading = true;
     Response response;
-    try{
+    try {
       response = await get(
-          Uri.parse(
-              "$host${URLs.getGasRefill}?uid=${user.id}"
-              "&token=${user.token}&page=${(items?.length ?? 0) ~/pageItemNumber}"
-          ),
-        headers: {
-            "Content-Type":"application/json; charset=utf-8"
-        }
-      );
+          Uri.parse("$host${URLs.getGasRefill}?uid=${user.id}"
+              "&token=${user.token}&page=${(items?.length ?? 0) ~/ pageItemNumber}"),
+          headers: {"Content-Type": "application/json; charset=utf-8"});
       stateCode = response.statusCode;
-      if(stateCode >= 200 && stateCode < 300) {
+      if (stateCode != null && stateCode! >= 200 && stateCode! < 300) {
         // client's request was successfully received
         List requestsListJson = json.decode(utf8.decode(response.bodyBytes));
-        List<GasRefillModel> itemsPage = requestsListJson.map(
-                (request) => GasRefillModel.fromJson(request)).toList();
+        List<GasRefillModel> itemsPage = requestsListJson
+            .map((request) => GasRefillModel.fromJson(request))
+            .toList();
         items ??= [];
-        items.addAll(itemsPage);
-        if(itemsPage.length == pageItemNumber){
+        items?.addAll(itemsPage);
+        if (itemsPage.length == pageItemNumber) {
           nextPage = true;
-        }else{
+        } else {
           nextPage = false;
         }
       }
       isLoading = false;
       notifyListeners();
       return response.statusCode;
-
-    } catch(error) {
+    } catch (error) {
       isLoading = false;
       stateCode = -1;
       notifyListeners();
       return -1;
     }
-
   }
 
-  Future<int> createModel ({
-    @required String host,
-    @required User user,
-    @required GasRefillModel model,
+  Future<int> createModel({
+    required String host,
+    required User user,
+    required GasRefillModel model,
   }) async {
-    Map<String,dynamic> body = {
+    Map<String, dynamic> body = {
       "uid": user.id.toString(),
       "token": user.token ?? "",
       "title": model.title ?? "",
-      "status": "0",//model.status.value.toString(),
+      "status": "0", //model.status.value.toString(),
     };
 
-    body["details"] = jsonEncode(model.details.map((model) => {
-      "type": model.type.id?.toString(),
-      "size": model.cylinderSize?.id.toString(),
-      "requsted_qty": model.requestedQuantity.toString(),
-    }).toList());
+    body["details"] = jsonEncode(model.details
+        ?.map((model) => {
+              "type": model.type?.id.toString(),
+              "size": model.cylinderSize?.id.toString(),
+              "requsted_qty": model.requestedQuantity.toString(),
+            })
+        .toList());
 
     Response response;
-    try{
+    try {
       response = await post(
-          Uri.parse(
-          host+URLs.requestGasRefill),
-          body: body,
+        Uri.parse(host + URLs.requestGasRefill),
+        body: body,
       );
 
       stateCode = response.statusCode;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
-        if(items != null) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
+        final items = this.items;
+        if (items != null) {
           items.insert(
               0,
               GasRefillModel.fromJson(
-                  json.decode(utf8.decode(response.bodyBytes))[0]
-              )
-          );
+                  json.decode(utf8.decode(response.bodyBytes))[0]));
           notifyListeners();
         }
       }
       return response.statusCode;
-
-    } catch(error) {
+    } catch (error) {
       return -1;
     }
-
   }
 
-  Future<int> updateModel ({
-    @required String host,
-    @required User user,
-    @required GasRefillModel oldModel,
-    @required GasRefillModel newModel,
+  Future<int> updateModel({
+    required String host,
+    required User user,
+    required GasRefillModel oldModel,
+    required GasRefillModel newModel,
   }) async {
-    Map<String,dynamic> body = {
+    Map<String, dynamic> body = {
       "uid": user.id.toString(),
-      "token": user.token ?? "",
+      "token": user.token,
       "title": newModel.title ?? "",
-      "status": newModel.status.id.toString(),
+      "status": newModel.status?.id.toString(),
     };
 
-    body["details"] = jsonEncode(newModel.details.map((model) => {
-      "type": model.type.id.toString(),
-      "size": model.cylinderSize.id.toString(),
-      "requsted_qty": model.requestedQuantity.toString(),
-      "deliverd_qty": model.deliveredQuantity.toString(),
-    }).toList());
+    body["details"] = jsonEncode(newModel.details
+        ?.map((model) => {
+              "type": model.type?.id.toString(),
+              "size": model.cylinderSize?.id.toString(),
+              "requsted_qty": model.requestedQuantity.toString(),
+              "deliverd_qty": model.deliveredQuantity.toString(),
+            })
+        .toList());
 
     Response response;
-    try{
+    try {
       response = await post(
         Uri.parse("$host${URLs.updateGasRefill}/${newModel.id}"),
         body: body,
       );
 
       stateCode = response.statusCode;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         oldModel.fromGasRefillModel(newModel);
         notifyListeners();
       }
       return response.statusCode;
-
-    } catch(error) {
+    } catch (error) {
       return -1;
     }
-
   }
-}
\ No newline at end of file
+}
diff --git a/old_lib/controllers/providers/api/hospitals_provider.dart b/old_lib/controllers/providers/api/hospitals_provider.dart
index df70994f..54c687b4 100644
--- a/old_lib/controllers/providers/api/hospitals_provider.dart
+++ b/old_lib/controllers/providers/api/hospitals_provider.dart
@@ -3,17 +3,17 @@ import 'dart:convert';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:http/http.dart';
-import 'package:test_sa/controllers/api_routes/urls.dart';
-import 'package:test_sa/models/hospital.dart';
-import 'package:test_sa/models/user.dart';
 
-class HospitalsProvider extends ChangeNotifier{
+import '../../../models/hospital.dart';
+import '../../../models/user.dart';
+import '../../api_routes/urls.dart';
 
+class HospitalsProvider extends ChangeNotifier {
   // number of items call in each request
   final pageItemNumber = 50;
 
   //reset provider data
-  void reset(){
+  void reset() {
     _hospitals = null;
     _stateCode = null;
   }
@@ -21,24 +21,29 @@ class HospitalsProvider extends ChangeNotifier{
   // state code of current request to defied error message
   // like 400 customer request failed
   // 500 service not available
-  int _stateCode;
-  int get stateCode => _stateCode;
+  int? _stateCode;
+
+  int? get stateCode => _stateCode;
 
   // true if there is next page in product list and false if not
   bool _nextPage = true;
+
   bool get nextPage => _nextPage;
 
   // contain user data
   // when user not login or register _user = null
-  List<Hospital> _hospitals;
-  List<Hospital> get hospitals => _hospitals;
+  List<Hospital>? _hospitals;
+
+  List<Hospital>? get hospitals => _hospitals;
 
   // when categories in-process _loading = true
   // done _loading = true
   // failed _loading = false
-  bool _loading;
-  bool get isLoading => _loading;
-  set isLoading(bool isLoading){
+  bool? _loading;
+
+  bool? get isLoading => _loading;
+
+  set isLoading(bool? isLoading) {
     _loading = isLoading;
     notifyListeners();
   }
@@ -48,77 +53,80 @@ class HospitalsProvider extends ChangeNotifier{
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<int> getHospitals ({String host,User user,String title}) async {
-    if(_loading == true)
+  Future<int> getHospitals({
+    required String host,
+    required User user,
+    required String? title,
+  }) async {
+    if (_loading == true) {
       return -2;
+    }
     _loading = true;
     notifyListeners();
     Response response;
-    try{
-     response = await get(
-          Uri.parse(
-              host + URLs.getHospitals
-          + "?page=${(_hospitals?.length ?? 0) ~/pageItemNumber}"
-          + ( title == null || title.isEmpty ? "" : "&name=$title" )
-          ),
-        headers: {
-          "Content-Type":"application/json; charset=utf-8"
-        }
+    try {
+      response = await get(
+        Uri.parse(
+          "${host + URLs.getHospitals}?page=${(_hospitals?.length ?? 0) ~/ pageItemNumber}${title == null || title.isEmpty ? "" : "&name=$title"}",
+        ),
+        headers: {"Content-Type": "application/json; charset=utf-8"},
       );
       _stateCode = response.statusCode;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         // client's request was successfully received
         List categoriesListJson = json.decode(utf8.decode(response.bodyBytes));
-        List<Hospital>  _page = categoriesListJson.map((category) => Hospital.fromJson(category)).toList();
-        if(hospitals == null)
-          _hospitals = [];
+        List<Hospital> page = categoriesListJson
+            .map((category) => Hospital.fromJson(category))
+            .toList();
+        if (hospitals == null) _hospitals = [];
 
-        _hospitals.addAll(_page);
-        if(_page.length >= pageItemNumber){
+        _hospitals?.addAll(page);
+        if (page.length >= pageItemNumber) {
           _nextPage = true;
-        }else{
+        } else {
           _nextPage = false;
         }
       }
       _loading = false;
       notifyListeners();
       return response.statusCode;
-    } catch(error) {
+    } catch (error) {
       _loading = false;
       _stateCode = -1;
       notifyListeners();
       return -1;
     }
-
   }
 
-  Future<List<Hospital>> getHospitalsList ({String host,User user,String title}) async {
+  Future<List<Hospital>> getHospitalsList({
+    required String host,
+    required User user,
+    required String title,
+  }) async {
     Response response;
-    try{
-
+    try {
       response = await get(
-          Uri.parse(host + URLs.getHospitals
-              + ( title == null || title.isEmpty ? "" : "?name=$title" )),
-          headers: {
-            "Content-Type":"application/json; charset=utf-8"
-          }
+        Uri.parse(
+          host + URLs.getHospitals + (title.isEmpty ? "" : "?name=$title"),
+        ),
+        headers: {"Content-Type": "application/json; charset=utf-8"},
       );
       _stateCode = response.statusCode;
 
-      List<Hospital>  _page = [];
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      List<Hospital> page = [];
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         // client's request was successfully received
         List categoriesListJson = json.decode(utf8.decode(response.bodyBytes));
-        _page = categoriesListJson.map((category) => Hospital.fromJson(category)).toList();
+        page = categoriesListJson
+            .map((category) => Hospital.fromJson(category))
+            .toList();
       }
-      return _page;
-    } catch(error) {
+      return page;
+    } catch (error) {
       _loading = false;
       _stateCode = -1;
       notifyListeners();
       return [];
     }
-
   }
-
-}
\ No newline at end of file
+}
diff --git a/old_lib/controllers/providers/api/notifications_provider.dart b/old_lib/controllers/providers/api/notifications_provider.dart
index d21ec77b..15c8bf64 100644
--- a/old_lib/controllers/providers/api/notifications_provider.dart
+++ b/old_lib/controllers/providers/api/notifications_provider.dart
@@ -2,17 +2,17 @@ import 'dart:convert';
 
 import 'package:flutter/cupertino.dart';
 import 'package:http/http.dart';
-import 'package:test_sa/controllers/api_routes/urls.dart';
-import 'package:test_sa/models/app_notification.dart';
-import 'package:test_sa/models/user.dart';
 
-class NotificationsProvider extends ChangeNotifier{
+import '../../../models/app_notification.dart';
+import '../../../models/user.dart';
+import '../../api_routes/urls.dart';
 
+class NotificationsProvider extends ChangeNotifier {
   // number of items call in each request
   final pageItemNumber = 20;
 
   //reset provider data
-  void reset(){
+  void reset() {
     notifications = null;
     nextPage = true;
     stateCode = null;
@@ -21,71 +21,66 @@ class NotificationsProvider extends ChangeNotifier{
   // state code of current request to defied error message
   // like 400 customer request failed
   // 500 service not available
-  int stateCode;
+  int? stateCode;
 
   // true if there is next page in product list and false if not
-  bool nextPage = true;
+  bool? nextPage = true;
 
   // list of user requests
-  List<AppNotification> notifications;
+  List<AppNotification>? notifications;
 
   // when requests in-process _loading = true
   // done _loading = true
   // failed _loading = false
-  bool isLoading;
-
+  bool? isLoading;
 
   /// return -2 if request in progress
   /// return -1 if error happen when sending request
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<int> getNotifications ({
-    @required String host,
-    @required User user,
-    @required String hospitalId,
+  Future<int> getNotifications({
+    required String host,
+    required User user,
+    required String hospitalId,
   }) async {
-    if(isLoading == true)
+    if (isLoading == true) {
       return -2;
+    }
     isLoading = true;
     notifyListeners();
     Response response;
-   // userId = 397.toString(); // testing id to view data
-    try{
+    // userId = 397.toString(); // testing id to view data
+    try {
       response = await get(
-          Uri.parse(host+URLs.getNotifications
-          +"?uid=${user.id}"
-          "&token=${user.token}"
-          "&page=${(notifications?.length ?? 0) ~/pageItemNumber}"),
-        headers: {
-            "Content-Type":"application/json; charset=utf-8"
-        }
-      );
+          Uri.parse(
+            "${host + URLs.getNotifications}?uid=${user.id}&token=${user.token}&page=${(notifications?.length ?? 0) ~/ pageItemNumber}",
+          ),
+          headers: {"Content-Type": "application/json; charset=utf-8"});
       stateCode = response.statusCode;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         // client's request was successfully received
         List requestsListJson = json.decode(utf8.decode(response.bodyBytes));
-        List<AppNotification> _serviceRequestsPage = requestsListJson.map(
-                (request) => AppNotification.fromJson(request)).toList();
-        if(notifications == null)
-          notifications = [];
-        notifications.addAll(_serviceRequestsPage);
-        if(_serviceRequestsPage.length == pageItemNumber){
+        List<AppNotification> serviceRequestsPage = requestsListJson
+            .map((request) => AppNotification.fromJson(request))
+            .toList();
+        notifications ??= [];
+        notifications?.addAll(serviceRequestsPage);
+        if (serviceRequestsPage.length == pageItemNumber) {
           nextPage = true;
-        }else{
+        } else {
           nextPage = false;
         }
       }
       isLoading = false;
       notifyListeners();
       return response.statusCode;
-    } catch(error) {
+    } catch (error) {
       isLoading = false;
       stateCode = -1;
       notifyListeners();
       return -1;
     }
-
   }
 
   /// return -2 if request in progress
@@ -93,35 +88,31 @@ class NotificationsProvider extends ChangeNotifier{
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<List<AppNotification>> getRecentNotifications ({
-    @required String host,
-    @required User user,
+  Future<List<AppNotification>?> getRecentNotifications({
+    required String host,
+    required User user,
   }) async {
     Response response;
     //userId = 397.toString(); // testing id to view data
 
-    try{
+    try {
       response = await get(
-          Uri.parse(host+URLs.getNotifications
-              +"?uid=${user.id}&token=${user.token}"),
-          headers: {
-            "Content-Type":"application/json; charset=utf-8"
-          }
-      );
+          Uri.parse(
+              "$host${URLs.getNotifications}?uid=${user.id}&token=${user.token}"),
+          headers: {"Content-Type": "application/json; charset=utf-8"});
 
       stateCode = response.statusCode;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         // client's request was successfully received
         List requestsListJson = json.decode(utf8.decode(response.bodyBytes));
-        List<AppNotification> _recentNotifications = requestsListJson.map(
-                (request) => AppNotification.fromJson(request)).toList();
-        return _recentNotifications;
+        List<AppNotification> recentNotifications = requestsListJson
+            .map((request) => AppNotification.fromJson(request))
+            .toList();
+        return recentNotifications;
       }
       return null;
-
-    } catch(error) {
+    } catch (error) {
       return null;
     }
-
   }
-}
\ No newline at end of file
+}
diff --git a/old_lib/controllers/providers/api/parts_provider.dart b/old_lib/controllers/providers/api/parts_provider.dart
index 6f763f77..a2d16fde 100644
--- a/old_lib/controllers/providers/api/parts_provider.dart
+++ b/old_lib/controllers/providers/api/parts_provider.dart
@@ -1,19 +1,19 @@
 import 'dart:convert';
 
-import 'package:test_sa/controllers/api_routes/urls.dart';
-import 'package:test_sa/models/part.dart';
-import 'package:test_sa/models/user.dart';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:http/http.dart';
 
-class PartsProvider extends ChangeNotifier{
+import '../../../models/part.dart';
+import '../../../models/user.dart';
+import '../../api_routes/urls.dart';
 
+class PartsProvider extends ChangeNotifier {
   // number of items call in each request
   final pageItemNumber = 50;
 
   //reset provider data
-  void reset(){
+  void reset() {
     _parts = null;
     _stateCode = null;
   }
@@ -21,24 +21,29 @@ class PartsProvider extends ChangeNotifier{
   // state code of current request to defied error message
   // like 400 customer request failed
   // 500 service not available
-  int _stateCode;
-  int get stateCode => _stateCode;
+  int? _stateCode;
+
+  int? get stateCode => _stateCode;
 
   // true if there is next page in product list and false if not
   bool _nextPage = true;
+
   bool get nextPage => _nextPage;
 
   // contain user data
   // when user not login or register _user = null
-  List<Part> _parts;
-  List<Part> get parts => _parts;
+  List<Part>? _parts;
+
+  List<Part>? get parts => _parts;
 
   // when categories in-process _loading = true
   // done _loading = true
   // failed _loading = false
-  bool _loading;
-  bool get isLoading => _loading;
-  set isLoading(bool isLoading){
+  bool? _loading;
+
+  bool? get isLoading => _loading;
+
+  set isLoading(bool? isLoading) {
     _loading = isLoading;
     notifyListeners();
   }
@@ -48,48 +53,46 @@ class PartsProvider extends ChangeNotifier{
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<int> getParts ({String host,User user,String title}) async {
-    if(_loading == true)
-      return -2;
+  Future<int> getParts({
+    required String host,
+    required User user,
+    required String? title,
+  }) async {
+    if (_loading == true) return -2;
     _loading = true;
     notifyListeners();
     Response response;
-    try{
+    try {
       response = await get(
-          Uri.parse(
-       host + URLs.getPartNumber
-          + "?page=${(_parts?.length ?? 0) ~/pageItemNumber}"
-          + ( title == null || title.isEmpty ? "" : "&name=$title" )
-          ),
-        headers: {
-          "Content-Type":"application/json; charset=utf-8"
-        }
+        Uri.parse(
+          "$host${URLs.getPartNumber}?page=${(_parts?.length ?? 0) ~/ pageItemNumber}${title == null || title.isEmpty ? "" : "&name=$title"}",
+        ),
+        headers: {"Content-Type": "application/json; charset=utf-8"},
       );
       _stateCode = response.statusCode;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         // client's request was successfully received
         List categoriesListJson = json.decode(utf8.decode(response.bodyBytes));
-        List<Part>  _page = categoriesListJson.map((part) => Part.fromJson(part)).toList();
-        if(parts == null)
-          _parts = [];
+        List<Part> page =
+            categoriesListJson.map((part) => Part.fromJson(part)).toList();
+        if (parts == null) _parts = [];
 
-        _parts.addAll(_page);
-        if(_page.length >= pageItemNumber){
+        _parts?.addAll(page);
+        if (page.length >= pageItemNumber) {
           _nextPage = true;
-        }else{
+        } else {
           _nextPage = false;
         }
       }
       _loading = false;
       notifyListeners();
       return response.statusCode;
-    } catch(error) {
+    } catch (error) {
       _loading = false;
       _stateCode = -1;
       notifyListeners();
       return -1;
     }
-
   }
 
   /// return -2 if request in progress
@@ -97,30 +100,27 @@ class PartsProvider extends ChangeNotifier{
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<List<Part>> getPartsList ({String host,User user,String title}) async {
+  Future<List<Part>> getPartsList({
+    required String host,
+    required User user,
+    required String? title,
+  }) async {
     Response response;
-    try{
-
+    try {
       response = await get(
-          Uri.parse(
-          host + URLs.getPartNumber
-              + ( title == null || title.isEmpty ? "" : "?name=$title" )
-          ),
-          headers: {
-            "Content-Type":"application/json; charset=utf-8"
-          }
-      );
-      List<Part>  _page = [];
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+          Uri.parse(host +
+              URLs.getPartNumber +
+              (title == null || title.isEmpty ? "" : "?name=$title")),
+          headers: {"Content-Type": "application/json; charset=utf-8"});
+      List<Part> page = [];
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         // client's request was successfully received
         List categoriesListJson = json.decode(utf8.decode(response.bodyBytes));
-        _page = categoriesListJson.map((part) => Part.fromJson(part)).toList();
+        page = categoriesListJson.map((part) => Part.fromJson(part)).toList();
       }
-      return _page;
-    } catch(error) {
+      return page;
+    } catch (error) {
       return [];
     }
-
   }
-
-}
\ No newline at end of file
+}
diff --git a/old_lib/controllers/providers/api/preventive_maintenance_visits_provider.dart b/old_lib/controllers/providers/api/preventive_maintenance_visits_provider.dart
index 14103fd6..f5a1de31 100644
--- a/old_lib/controllers/providers/api/preventive_maintenance_visits_provider.dart
+++ b/old_lib/controllers/providers/api/preventive_maintenance_visits_provider.dart
@@ -1,20 +1,20 @@
 import 'dart:convert';
 
-import 'package:test_sa/controllers/api_routes/urls.dart';
-import 'package:test_sa/models/user.dart';
-import 'package:test_sa/models/visits/visit.dart';
-import 'package:test_sa/models/visits/visits_group.dart';
-import 'package:test_sa/models/visits/visits_search.dart';
 import 'package:flutter/cupertino.dart';
 import 'package:http/http.dart';
 
-class PreventiveMaintenanceVisitsProvider extends ChangeNotifier{
+import '../../../models/user.dart';
+import '../../../models/visits/visit.dart';
+import '../../../models/visits/visits_group.dart';
+import '../../../models/visits/visits_search.dart';
+import '../../api_routes/urls.dart';
 
+class PreventiveMaintenanceVisitsProvider extends ChangeNotifier {
   // number of items call in each request
   final pageItemNumber = 50;
 
   //reset provider data
-  void reset(){
+  void reset() {
     visits = null;
     nextPage = true;
     stateCode = null;
@@ -23,67 +23,58 @@ class PreventiveMaintenanceVisitsProvider extends ChangeNotifier{
   // state code of current request to defied error message
   // like 400 customer request failed
   // 500 service not available
-  int stateCode;
+  int? stateCode;
 
   // true if there is next page in product list and false if not
-  bool nextPage = true;
+  bool? nextPage = true;
 
   // list of user requests
-  List<Visit> visits;
+  List<Visit>? visits;
 
   // when requests in-process _loading = true
   // done _loading = true
   // failed _loading = false
-  bool isLoading;
+  bool? isLoading;
 
-  VisitsSearch visitsSearch = VisitsSearch();
+  VisitsSearch? visitsSearch = VisitsSearch();
 
   /// return -2 if request in progress
   /// return -1 if error happen when sending request
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<int> getVisits ({
-    @required String host,
-    @required User user,
-   // VisitsSearch visitsSearch,
+  Future<int> getVisits({
+    required String host,
+    required User user,
+    // VisitsSearch visitsSearch,
   }) async {
-    if(isLoading == true)
-      return -2;
+    if (isLoading == true) return -2;
     isLoading = true;
     Response response;
     //userId = 397.toString(); // testing id to view data
-    try{
+    try {
       response = await get(
-          Uri.parse(
-        host + URLs.getPreventiveMaintenanceVisits
-          +"?uid=${user.id}"
-          "&token=${user.token}"
-          "&page=${(visits?.length ?? 0) ~/pageItemNumber}"
-          +visitsSearch?.toSearchString() ?? ""
-          ),
-        headers: {
-            "Content-Type":"application/json; charset=utf-8"
-        }
+        Uri.parse(
+          "${host + URLs.getPreventiveMaintenanceVisits}?uid=${user.id}&token=${user.token}&page=${(visits?.length ?? 0) ~/ pageItemNumber}${visitsSearch?.toSearchString()}",
+        ),
+        headers: {"Content-Type": "application/json; charset=utf-8"},
       );
-    } catch(error) {
+    } catch (error) {
       isLoading = false;
       stateCode = -1;
       notifyListeners();
       return -1;
     }
     stateCode = response.statusCode;
-    if(response.statusCode >= 200 && response.statusCode < 300) {
+    if (response.statusCode >= 200 && response.statusCode < 300) {
       // client's request was successfully received
       List requestsListJson = json.decode(utf8.decode(response.bodyBytes));
-      List<Visit> _visits = requestsListJson.map(
-              (request) => Visit.fromJson(request)).toList();
-      if(visits == null)
-        visits = [];
-      visits.addAll(_visits);
-      if(_visits.length == pageItemNumber){
+      List<Visit> visits =
+          requestsListJson.map((request) => Visit.fromJson(request)).toList();
+      visits.addAll(visits);
+      if (visits.length == pageItemNumber) {
         nextPage = true;
-      }else{
+      } else {
         nextPage = false;
       }
     }
@@ -97,41 +88,39 @@ class PreventiveMaintenanceVisitsProvider extends ChangeNotifier{
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<int> updateGroupOfVisits ({
-    @required String host,
-    @required User user,
-    VisitsGroup group,
+  Future<int> updateGroupOfVisits({
+    required String host,
+    required User user,
+    required VisitsGroup group,
   }) async {
     Response response;
-    Map<String,String> body = group.toJson();
-    body["token"] = user.token ?? "";
+    Map<String, String> body = group.toJson();
+    body["token"] = user.token;
     body["uid"] = user.id;
     //userId = 397.toString(); // testing id to view data
-    try{
+    try {
       response = await post(
-          Uri.parse(
-        host+URLs.updatePreventiveMaintenanceVisits
-          ),
+        Uri.parse(host + URLs.updatePreventiveMaintenanceVisits),
         body: body,
       );
 
       stateCode = response.statusCode;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         // client's request was successfully received
-        group.visits.forEach((visit) {
+        for (var visit in group.visits) {
           visit.status = group.status;
           visit.actualDate = group.date.toString().split(" ").first;
-        });
+        }
         group.visits.clear();
         notifyListeners();
       }
 
       return response.statusCode;
-    } catch(error) {
+    } catch (error) {
       isLoading = false;
       stateCode = -1;
       notifyListeners();
       return -1;
     }
   }
-}
\ No newline at end of file
+}
diff --git a/old_lib/controllers/providers/api/regular_visits_provider.dart b/old_lib/controllers/providers/api/regular_visits_provider.dart
index 03737f73..06489ffd 100644
--- a/old_lib/controllers/providers/api/regular_visits_provider.dart
+++ b/old_lib/controllers/providers/api/regular_visits_provider.dart
@@ -1,21 +1,21 @@
 import 'dart:convert';
 
-import 'package:test_sa/controllers/api_routes/urls.dart';
-import 'package:test_sa/models/pantry/pentry.dart';
-import 'package:test_sa/models/user.dart';
-import 'package:test_sa/models/visits/visit.dart';
-import 'package:test_sa/models/visits/visits_group.dart';
-import 'package:test_sa/models/visits/visits_search.dart';
 import 'package:flutter/cupertino.dart';
 import 'package:http/http.dart';
 
-class RegularVisitsProvider extends ChangeNotifier{
+import '../../../models/pantry/pentry.dart';
+import '../../../models/user.dart';
+import '../../../models/visits/visit.dart';
+import '../../../models/visits/visits_group.dart';
+import '../../../models/visits/visits_search.dart';
+import '../../api_routes/urls.dart';
 
+class RegularVisitsProvider extends ChangeNotifier {
   // number of items call in each request
   final pageItemNumber = 50;
 
   //reset provider data
-  void reset(){
+  void reset() {
     visits = null;
     nextPage = true;
     stateCode = null;
@@ -24,78 +24,70 @@ class RegularVisitsProvider extends ChangeNotifier{
   // state code of current request to defied error message
   // like 400 customer request failed
   // 500 service not available
-  int stateCode;
+  int? stateCode;
 
   // true if there is next page in product list and false if not
   bool nextPage = true;
 
   // list of user requests
-  List<Visit> visits;
+  List<Visit>? visits;
 
   // when requests in-process _loading = true
   // done _loading = true
   // failed _loading = false
-  bool isLoading;
+  bool? isLoading;
 
-  VisitsSearch visitsSearch = VisitsSearch();
+  VisitsSearch? visitsSearch = VisitsSearch();
 
   /// return -2 if request in progress
   /// return -1 if error happen when sending request
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<int> getVisits ({
-    @required String host,
-    @required User user,
-   // VisitsSearch visitsSearch,
+  Future<int> getVisits({
+    required String host,
+    required User user,
+    // VisitsSearch visitsSearch,
   }) async {
-    if(isLoading == true)
+    if (isLoading == true) {
       return -2;
+    }
     isLoading = true;
     Response response;
     //userId = 397.toString(); // testing id to view data
-    try{
+    try {
       response = await get(
-          Uri.parse(
-        host+URLs.getRegularVisits
-          +"?uid=${user.id}"
-          "&token=${user.token}"
-          "&page=${(visits?.length ?? 0) ~/pageItemNumber}"
-          +visitsSearch?.toSearchString() ?? ""
-          ),
-        headers: {
-            "Content-Type":"application/json; charset=utf-8"
-        }
+        Uri.parse(
+          "$host${URLs.getRegularVisits}?uid=${user.id}&token=${user.token}&page=${(visits?.length ?? 0) ~/ pageItemNumber}${visitsSearch?.toSearchString()}",
+        ),
+        headers: {"Content-Type": "application/json; charset=utf-8"},
       );
-    } catch(error) {
+    } catch (error) {
       isLoading = false;
       stateCode = -1;
       notifyListeners();
       return -1;
     }
     stateCode = response.statusCode;
-    if(response.statusCode >= 200 && response.statusCode < 300) {
+    if (response.statusCode >= 200 && response.statusCode < 300) {
       // client's request was successfully received
-      try{
-        List requestsListJson = json.decode(utf8.decode(response.bodyBytes).replaceAll("\\", ""));
-        List<Visit> _visits = requestsListJson.map(
-                (request) => Visit.fromJson(request)
-        ).toList();
-        if(visits == null)
-          visits = [];
-        visits.addAll(_visits);
-        if(_visits.length == pageItemNumber){
+      try {
+        List requestsListJson =
+            json.decode(utf8.decode(response.bodyBytes).replaceAll("\\", ""));
+        List<Visit> visits =
+            requestsListJson.map((request) => Visit.fromJson(request)).toList();
+        visits.addAll(visits);
+        if (visits.length == pageItemNumber) {
           nextPage = true;
-        }else{
+        } else {
           nextPage = false;
         }
-      }catch(error){
+      } catch (error) {
         isLoading = false;
         stateCode = -1;
         notifyListeners();
         return -1;
       }
-
     }
     isLoading = false;
     notifyListeners();
@@ -107,30 +99,30 @@ class RegularVisitsProvider extends ChangeNotifier{
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<int> updateGroupOfVisits ({
-    @required String host,
-    @required User user,
-    VisitsGroup group,
+  Future<int> updateGroupOfVisits({
+    required String host,
+    required User user,
+    required VisitsGroup group,
   }) async {
     Response response;
-    Map<String,String> body = group.toJson();
+    Map<String, String> body = group.toJson();
     body["token"] = user.token ?? "";
     body["uid"] = user.id;
     //userId = 397.toString(); // testing id to view data
-    try{
+    try {
       response = await post(
-          Uri.parse(host+URLs.updateRegularVisits),
-          body: body,
+        Uri.parse(host + URLs.updateRegularVisits),
+        body: body,
       );
       stateCode = response.statusCode;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         // client's request was successfully received
         reset();
         notifyListeners();
       }
 
       return response.statusCode;
-    } catch(error) {
+    } catch (error) {
       isLoading = false;
       stateCode = -1;
       notifyListeners();
@@ -138,46 +130,46 @@ class RegularVisitsProvider extends ChangeNotifier{
     }
   }
 
-  Future<Pentry> getPently({String host,User user,String id}) async {
+  Future<Pentry?> getPently({
+    required String host,
+    required User user,
+    required String id,
+  }) async {
     Response response;
     response = await get(
-        Uri.parse("$host${URLs.getPentry}/$id"),
-        headers: {
-          "Content-Type":"application/json; charset=utf-8"
-        }
+      Uri.parse("$host${URLs.getPentry}/$id"),
+      headers: {"Content-Type": "application/json; charset=utf-8"},
     );
 
-    Pentry pantry;
-    if(response.statusCode >= 200 && response.statusCode < 300) {
+    Pentry? pantry;
+    if (response.statusCode >= 200 && response.statusCode < 300) {
       pantry = Pentry.fromMap(json.decode(utf8.decode(response.bodyBytes)));
     }
     return pantry;
   }
 
-  Future<int> updatePentry ({
-    @required String host,
-    @required User user,
-    @required Pentry pentry,
-    @required Visit visit,
+  Future<int> updatePentry({
+    required String host,
+    required User user,
+    required Pentry pentry,
+    required Visit visit,
   }) async {
-    try{
+    try {
       Response response;
-      Map<String,String> body = pentry.toMap();
+      Map<String, String> body = pentry.toMap();
       body["uid"] = user.id;
       body["token"] = user.token;
       response = await post(
-        Uri.parse(host+URLs.updatePentry + "/${visit.id}"),
+        Uri.parse("$host${URLs.updatePentry}/${visit.id}"),
         body: body,
       );
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         visit.status = pentry.ppmVisitStatus;
         notifyListeners();
       }
       return response.statusCode;
-
-    } catch(error) {
+    } catch (error) {
       return -1;
     }
-
   }
-}
\ No newline at end of file
+}
diff --git a/old_lib/controllers/providers/api/service_requests_provider.dart b/old_lib/controllers/providers/api/service_requests_provider.dart
index 040ed855..a0c20e45 100644
--- a/old_lib/controllers/providers/api/service_requests_provider.dart
+++ b/old_lib/controllers/providers/api/service_requests_provider.dart
@@ -2,24 +2,24 @@ import 'dart:convert';
 
 import 'package:flutter/cupertino.dart';
 import 'package:http/http.dart';
-import 'package:test_sa/controllers/api_routes/urls.dart';
-import 'package:test_sa/controllers/http_status_manger/http_status_manger.dart';
-import 'package:test_sa/models/issue.dart';
-import 'package:test_sa/models/lookup.dart';
-import 'package:test_sa/models/service_report.dart';
-import 'package:test_sa/models/service_request/service_request.dart';
-import 'package:test_sa/models/service_request/service_request_search.dart';
-import 'package:test_sa/models/subtitle.dart';
-import 'package:test_sa/models/timer_model.dart';
-import 'package:test_sa/models/user.dart';
-
-class ServiceRequestsProvider extends ChangeNotifier{
 
+import '../../../models/issue.dart';
+import '../../../models/lookup.dart';
+import '../../../models/service_report.dart';
+import '../../../models/service_request/service_request.dart';
+import '../../../models/service_request/service_request_search.dart';
+import '../../../models/subtitle.dart';
+import '../../../models/timer_model.dart';
+import '../../../models/user.dart';
+import '../../api_routes/urls.dart';
+import '../../http_status_manger/http_status_manger.dart';
+
+class ServiceRequestsProvider extends ChangeNotifier {
   // number of items call in each request
   final pageItemNumber = 50;
 
   //reset provider data
-  void reset(){
+  void reset() {
     serviceRequests = null;
     nextPage = true;
     stateCode = null;
@@ -28,121 +28,108 @@ class ServiceRequestsProvider extends ChangeNotifier{
   // state code of current request to defied error message
   // like 400 customer request failed
   // 500 service not available
-  int stateCode;
+  int? stateCode;
 
   // true if there is next page in product list and false if not
-  bool nextPage = true;
+  bool? nextPage = true;
 
   // list of user requests
-  List<ServiceRequest> serviceRequests;
+  List<ServiceRequest>? serviceRequests;
 
   // when requests in-process _loading = true
   // done _loading = true
   // failed _loading = false
-  bool isLoading;
+  bool? isLoading;
 
-  ServiceRequestSearch search = ServiceRequestSearch();
+  ServiceRequestSearch? search = ServiceRequestSearch();
 
   /// return -2 if request in progress
   /// return -1 if error happen when sending request
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<int> getRequests ({
-    @required String host,
-    @required User user,
-    @required String hospitalId,
+  Future<int> getRequests({
+    required String host,
+    required User user,
+    required String? hospitalId,
   }) async {
-    if(isLoading == true)
+    if (isLoading == true) {
       return -2;
+    }
     isLoading = true;
     Response response;
-    try{
+    try {
       response = await get(
-          Uri.parse(
-        host+URLs.getServiceRequests
-          +"?uid=${user.id}"
-          +(hospitalId == null? "" :"&client_nid=$hospitalId")
-          +"&token=${user.token}"
-          "&page=${(serviceRequests?.length ?? 0) ~/pageItemNumber}"
-          +search?.toSearchString() ?? ""
-          ),
-        headers: {
-            "Content-Type":"application/json; charset=utf-8"
-        }
+        Uri.parse(
+          "$host${URLs.getServiceRequests}?uid=${user.id}${hospitalId == null ? "" : "&client_nid=$hospitalId"}&token=${user.token}&page=${(serviceRequests?.length ?? 0) ~/ pageItemNumber}${search?.toSearchString()}",
+        ),
+        headers: {"Content-Type": "application/json; charset=utf-8"},
       );
       stateCode = response.statusCode;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         // client's request was successfully received
-        List requestsListJson = json.decode(utf8.decode(response.bodyBytes).replaceAll("\\", ""));
-        List<ServiceRequest> _serviceRequestsPage = requestsListJson.map(
-                (request) => ServiceRequest.fromJson(request)).toList();
-        if(serviceRequests == null)
-          serviceRequests = [];
-        serviceRequests.addAll(_serviceRequestsPage);
-        if(_serviceRequestsPage.length == pageItemNumber){
+        List requestsListJson =
+            json.decode(utf8.decode(response.bodyBytes).replaceAll("\\", ""));
+        List<ServiceRequest> _serviceRequestsPage = requestsListJson
+            .map((request) => ServiceRequest.fromJson(request))
+            .toList();
+        serviceRequests ??= [];
+        serviceRequests?.addAll(_serviceRequestsPage);
+        if (_serviceRequestsPage.length == pageItemNumber) {
           nextPage = true;
-        }else{
+        } else {
           nextPage = false;
         }
       }
       isLoading = false;
       notifyListeners();
       return response.statusCode;
-
-    } catch(error) {
+    } catch (error) {
       isLoading = false;
       stateCode = -1;
       notifyListeners();
       return -1;
     }
-
   }
 
   Future<ServiceRequest> getSingleServiceRequest({
-    @required String requestId,
-    @required String host,
-    @required User user,
-    @required Subtitle subtitle,
+    required String requestId,
+    required String host,
+    required User user,
+    required Subtitle subtitle,
   }) async {
     String userData = '';
-    if(user != null){
-      userData += "&uid="+user.id;
-      userData += "&token="+user.token;
-    }
+    userData += "&uid=${user.id}";
+    userData += "&token=${user.token}";
 
     Response response;
-    try{
-      response = await get(
-          Uri.parse(
-        host+URLs.getSingleServiceRequest
-            +'?call_nid=$requestId'
-            '$userData',)
-      );
-    }catch(error){
-      throw(HttpStatusManger.getStatusMessage(
-          status: -1, subtitle: subtitle));
+    try {
+      response = await get(Uri.parse(
+        '$host${URLs.getSingleServiceRequest}?call_nid=$requestId$userData',
+      ));
+    } catch (error) {
+      throw (HttpStatusManger.getStatusMessage(status: -1, subtitle: subtitle));
     }
 
     // If the call to the server was successful, parse the JSON.
-    if (response.statusCode >= 200 && response.statusCode < 300){
+    if (response.statusCode >= 200 && response.statusCode < 300) {
       // If the call to the server was successful, parse the JSON.
-      List jsonList = json.decode(utf8.decode(response.bodyBytes).replaceAll("\\", ""));
-      List<ServiceRequest> _requests = jsonList.map((i) => ServiceRequest.fromJson(i)).toList();
-      return _requests[0];
-    }else{
-      throw(HttpStatusManger.getStatusMessage(
+      List jsonList =
+          json.decode(utf8.decode(response.bodyBytes).replaceAll("\\", ""));
+      List<ServiceRequest> requests =
+          jsonList.map((i) => ServiceRequest.fromJson(i)).toList();
+      return requests[0];
+    } else {
+      throw (HttpStatusManger.getStatusMessage(
           status: response.statusCode, subtitle: subtitle));
     }
-
   }
 
-  Future<int> createRequest ({
-    @required String host,
-    @required User user,
-    @required ServiceRequest serviceRequest,
+  Future<int> createRequest({
+    required String host,
+    required User user,
+    required ServiceRequest serviceRequest,
   }) async {
-
     var body = {
       "uid": user.id,
       "token": user.token ?? "",
@@ -154,269 +141,233 @@ class ServiceRequestsProvider extends ChangeNotifier{
       "priority": (serviceRequest.priority?.id).toString(),
       "defect_types": (serviceRequest.defectType?.id).toString(),
     };
-    if(serviceRequest.audio != null){
-      body["audio"] = serviceRequest.audio;
-    }
+    body["audio"] = serviceRequest.audio;
     Response response;
-    try{
+    try {
       response = await post(
-          Uri.parse(
-          host+URLs.createRequest),
-          body: body,
+        Uri.parse(host + URLs.createRequest),
+        body: body,
       );
       stateCode = response.statusCode;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
-        if(serviceRequests != null)
+      if (response.statusCode >= 200 && response.statusCode < 300) {
+        final serviceRequests = this.serviceRequests;
+        if (serviceRequests != null) {
           serviceRequests.insert(
-              0,
-              ServiceRequest.fromJson(
-                  json.decode(utf8.decode(response.bodyBytes))[0]
-              )
+            0,
+            ServiceRequest.fromJson(
+              json.decode(utf8.decode(response.bodyBytes))[0],
+            ),
           );
+        }
         notifyListeners();
       }
       return response.statusCode;
-
-    } catch(error) {
+    } catch (error) {
       return -1;
     }
-
   }
 
-  Future<int> createIssueReport ({
-    @required String host,
-    @required User user,
-    @required Issue issue,
+  Future<int> createIssueReport({
+    required String host,
+    required User user,
+    required Issue issue,
   }) async {
     Response response;
-    Map<String,String> body = issue.toMap();
+    Map<String, String> body = issue.toMap();
     body["uid"] = user.id;
     body["token"] = user.token;
-    try{
+    try {
       response = await post(
-          Uri.parse(host+URLs.createReport),
+        Uri.parse(host + URLs.createReport),
         body: body,
       );
 
       stateCode = response.statusCode;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
-
-      }
+      if (response.statusCode >= 200 && response.statusCode < 300) {}
       return response.statusCode;
-
-    } catch(error) {
+    } catch (error) {
       return -1;
     }
-
   }
 
-  Future<int> updateDate ({
-    @required String host,
-    @required User user,
-    @required String newDate,
-    @required Lookup employee,
-    @required ServiceRequest request,
+  Future<int> updateDate({
+    required String host,
+    required User user,
+    required String newDate,
+    required Lookup employee,
+    required ServiceRequest request,
   }) async {
     Response response;
-    Map<String,String> body = {};
+    Map<String, String> body = {};
     body["uid"] = user.id;
     body["token"] = user.token;
-    body["nid"] = request.id;
-    if(newDate != null) body["date"] = newDate;
-    if(employee != null) body["ass_emp"] = employee.id.toString();
-    try{
+    body["nid"] = request.id ?? '';
+    body["date"] = newDate;
+    body["ass_emp"] = employee.id.toString();
+    try {
       response = await post(
-          Uri.parse(
-        host+URLs.updateRequestDate),
+        Uri.parse(host + URLs.updateRequestDate),
         body: body,
       );
       stateCode = response.statusCode;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         request.engineerName = employee.label;
         notifyListeners();
       }
       return response.statusCode;
-
-    } catch(error) {
+    } catch (error) {
       return -1;
     }
-
   }
 
-  Future<int> createServiceReport ({
-    @required String host,
-    @required User user,
-    @required ServiceReport report,
-    @required ServiceRequest request,
+  Future<int> createServiceReport({
+    required String host,
+    required User user,
+    required ServiceReport report,
+    required ServiceRequest request,
   }) async {
     Response response;
-    Map<String,String> body = report.toMap();
+    Map<String, String> body = report.toMap();
     body["uid"] = user.id;
     body["token"] = user.token;
-    body["job_id"] = request.id;
-    try{
+    body["job_id"] = request.id ?? '';
+    try {
       response = await post(
-          Uri.parse(
-        host+URLs.createServiceReport),
+        Uri.parse(host + URLs.createServiceReport),
         body: body,
       );
 
       stateCode = response.statusCode;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         reset();
         notifyListeners();
       }
       return response.statusCode;
-
-    } catch(error) {
-
+    } catch (error) {
       return -1;
     }
-
   }
 
-  Future<int> createDuplicatedReport ({
-    @required String host,
-    @required User user,
-    @required ServiceRequest request,
+  Future<int> createDuplicatedReport({
+    required String host,
+    required User user,
+    required ServiceRequest request,
   }) async {
     Response response;
     String userData = '';
-    if(user != null){
-      userData += "&uid="+user.id;
-      userData += "&token="+user.token;
-    }
+    userData += "&uid=${user.id}";
+    userData += "&token=${user.token}";
 
-    try{
+    try {
       response = await get(
         Uri.parse(
-            host+URLs.createDuplicatedReport
-                +"?nid=${request.id}"
-                +userData),
+          "$host${URLs.createDuplicatedReport}?nid=${request.id}$userData",
+        ),
       );
 
       stateCode = response.statusCode;
 
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         reset();
         notifyListeners();
       }
       return response.statusCode;
-
-    } catch(error) {
-
+    } catch (error) {
       return -1;
     }
-
   }
 
-  Future<int> updateServiceReport ({
-    @required String host,
-    @required User user,
-    @required ServiceReport report,
-    @required ServiceRequest request,
+  Future<int> updateServiceReport({
+    required String host,
+    required User user,
+    required ServiceReport report,
+    required ServiceRequest request,
   }) async {
     Response response;
-    Map<String,String> body = report.toMap();
+    Map<String, String> body = report.toMap();
     body["uid"] = user.id;
     body["token"] = user.token;
-    body["job_id"] = request.id;
-    body["report_id"] = request.reportID;
-    try{
+    body["job_id"] = request.id ?? '';
+    body["report_id"] = request.reportID ?? '';
+    try {
       response = await post(
-        Uri.parse(
-            host+URLs.updateServiceReport),
+        Uri.parse(host + URLs.updateServiceReport),
         body: body,
       );
       stateCode = response.statusCode;
 
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         reset();
         notifyListeners();
       }
       return response.statusCode;
-
-    } catch(error) {
-
+    } catch (error) {
       return -1;
     }
-
   }
 
-  Future<int> updateServiceReportTimer ({
-    @required String host,
-    @required User user,
-    @required TimerModel timer,
-    @required ServiceRequest request,
+  Future<int> updateServiceReportTimer({
+    required String host,
+    required User user,
+    required TimerModel timer,
+    required ServiceRequest request,
   }) async {
     Response response;
-    Map<String,String> body = {};
+    Map<String, String> body = {};
     body["uid"] = user.id;
     body["token"] = user.token;
-    body["job_id"] = request.id;
-    body["start_time"] = (timer.startAt.millisecondsSinceEpoch / 1000).toStringAsFixed(0);
-    body["end_time"] =  (timer.endAt.millisecondsSinceEpoch / 1000).toStringAsFixed(0);
-    body["working_hours"] = (timer.durationInSecond / 60 / 60).toStringAsFixed(5);
-    body["report_id"] = request.reportID;
-    try{
+    body["job_id"] = request.id ?? '';
+    body["start_time"] =
+        (timer.startAt.millisecondsSinceEpoch / 1000).toStringAsFixed(0);
+    body["end_time"] =
+        (timer.endAt.millisecondsSinceEpoch / 1000).toStringAsFixed(0);
+    body["working_hours"] =
+        (timer.durationInSecond / 60 / 60).toStringAsFixed(5);
+    body["report_id"] = request.reportID ?? '';
+    try {
       response = await post(
-        Uri.parse(
-            host+URLs.updateServiceReport),
+        Uri.parse(host + URLs.updateServiceReport),
         body: body,
       );
       //stateCode = response.statusCode;
 
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         // reset();
         // notifyListeners();
       }
       return response.statusCode;
-
-    } catch(error) {
-
+    } catch (error) {
       return -1;
     }
-
   }
 
   Future<ServiceReport> getSingleServiceReport({
-    @required String reportId,
-    @required String host,
-    @required User user,
-    @required Subtitle subtitle,
+    required String reportId,
+    required String host,
+    required User user,
+    required Subtitle subtitle,
   }) async {
     String userData = '';
-    if(user != null){
-      userData += "&uid="+user.id;
-      userData += "&token="+user.token;
-    }
+    userData += "&uid=${user.id}";
+    userData += "&token=${user.token}";
 
     Response response;
-    try{
-
-      response = await get(
-          Uri.parse(
-            host+URLs.getServiceReport
-                +'?report_id=$reportId'
-                '$userData',)
-      );
-
-    }catch(error){
-      throw(HttpStatusManger.getStatusMessage(
-          status: -1, subtitle: subtitle));
+    try {
+      response = await get(Uri.parse(
+        '$host${URLs.getServiceReport}?report_id=$reportId$userData',
+      ));
+    } catch (error) {
+      throw (HttpStatusManger.getStatusMessage(status: -1, subtitle: subtitle));
     }
 
     // If the call to the server was successful, parse the JSON.
-    if (response.statusCode >= 200 && response.statusCode < 300){
+    if (response.statusCode >= 200 && response.statusCode < 300) {
       // If the call to the server was successful, parse the JSON.
       return ServiceReport.fromJson(
-          json.decode(utf8.decode(response.bodyBytes)),reportId);
-    }else{
-      throw(HttpStatusManger.getStatusMessage(
+          json.decode(utf8.decode(response.bodyBytes)), reportId);
+    } else {
+      throw (HttpStatusManger.getStatusMessage(
           status: response.statusCode, subtitle: subtitle));
     }
-
   }
-
-
-}
\ No newline at end of file
+}
diff --git a/old_lib/controllers/providers/api/status_drop_down/employee/employee_provider.dart b/old_lib/controllers/providers/api/status_drop_down/employee/employee_provider.dart
index 04f6d5b6..d92cee28 100644
--- a/old_lib/controllers/providers/api/status_drop_down/employee/employee_provider.dart
+++ b/old_lib/controllers/providers/api/status_drop_down/employee/employee_provider.dart
@@ -3,14 +3,14 @@ import 'dart:convert';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:http/http.dart';
-import 'package:test_sa/controllers/api_routes/urls.dart';
-import 'package:test_sa/models/lookup.dart';
-import 'package:test_sa/models/user.dart';
 
-class EmployeesProvider extends ChangeNotifier{
+import '../../../../../models/lookup.dart';
+import '../../../../../models/user.dart';
+import '../../../../api_routes/urls.dart';
 
+class EmployeesProvider extends ChangeNotifier {
   //reset provider data
-  void reset(){
+  void reset() {
     _items = null;
     _stateCode = null;
   }
@@ -18,20 +18,24 @@ class EmployeesProvider extends ChangeNotifier{
   // state code of current request to defied error message
   // like 400 customer request failed
   // 500 service not available
-  int _stateCode;
-  int get stateCode => _stateCode;
+  int? _stateCode;
+
+  int? get stateCode => _stateCode;
 
   // contain user data
   // when user not login or register _user = null
-  List<Lookup> _items;
-  List<Lookup> get items => _items;
+  List<Lookup>? _items;
+
+  List<Lookup>? get items => _items;
 
   // when categories in-process _loading = true
   // done _loading = true
   // failed _loading = false
-  bool _loading;
-  bool get isLoading => _loading;
-  set isLoading(bool isLoading){
+  bool? _loading;
+
+  bool? get isLoading => _loading;
+
+  set isLoading(bool? isLoading) {
     _loading = isLoading;
     notifyListeners();
   }
@@ -41,34 +45,30 @@ class EmployeesProvider extends ChangeNotifier{
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<int> getData ({String host,User user}) async {
-    if(_loading == true)
-      return -2;
+  Future<int> getData({required String host, required User user}) async {
+    if (_loading == true) return -2;
     _loading = true;
     notifyListeners();
     Response response;
-    try{
+    try {
       response = await get(
-        Uri.parse(
-            host + URLs.getEmployees),
+        Uri.parse(host + URLs.getEmployees),
       );
       _stateCode = response.statusCode;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         // client's request was successfully received
         List categoriesListJson = json.decode(utf8.decode(response.bodyBytes));
-        _items = categoriesListJson.map((type) => Lookup.fromJson(type)).toList();
+        _items =
+            categoriesListJson.map((type) => Lookup.fromJson(type)).toList();
       }
       _loading = false;
       notifyListeners();
       return response.statusCode;
-    } catch(error) {
-
+    } catch (error) {
       _loading = false;
       _stateCode = -1;
       notifyListeners();
       return -1;
     }
-
   }
-
-}
\ No newline at end of file
+}
diff --git a/old_lib/controllers/providers/api/status_drop_down/gas_refill/gas_cylinder_size_provider.dart b/old_lib/controllers/providers/api/status_drop_down/gas_refill/gas_cylinder_size_provider.dart
index b4112034..54022842 100644
--- a/old_lib/controllers/providers/api/status_drop_down/gas_refill/gas_cylinder_size_provider.dart
+++ b/old_lib/controllers/providers/api/status_drop_down/gas_refill/gas_cylinder_size_provider.dart
@@ -3,14 +3,14 @@ import 'dart:convert';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:http/http.dart';
-import 'package:test_sa/controllers/api_routes/urls.dart';
-import 'package:test_sa/models/lookup.dart';
-import 'package:test_sa/models/user.dart';
 
-class GasCylinderSizesProvider extends ChangeNotifier{
+import '../../../../../models/lookup.dart';
+import '../../../../../models/user.dart';
+import '../../../../api_routes/urls.dart';
 
+class GasCylinderSizesProvider extends ChangeNotifier {
   //reset provider data
-  void reset(){
+  void reset() {
     _items = null;
     _loading = null;
     _stateCode = null;
@@ -19,20 +19,24 @@ class GasCylinderSizesProvider extends ChangeNotifier{
   // state code of current request to defied error message
   // like 400 customer request failed
   // 500 service not available
-  int _stateCode;
-  int get stateCode => _stateCode;
+  int? _stateCode;
+
+  int? get stateCode => _stateCode;
 
   // contain user data
   // when user not login or register _user = null
-  List<Lookup> _items;
-  List<Lookup> get items => _items;
+  List<Lookup>? _items;
+
+  List<Lookup>? get items => _items;
 
   // when categories in-process _loading = true
   // done _loading = true
   // failed _loading = false
-  bool _loading;
-  bool get isLoading => _loading;
-  set isLoading(bool isLoading){
+  bool? _loading;
+
+  bool? get isLoading => _loading;
+
+  set isLoading(bool? isLoading) {
     _loading = isLoading;
     notifyListeners();
   }
@@ -42,32 +46,35 @@ class GasCylinderSizesProvider extends ChangeNotifier{
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<int> getData ({String host,User user,}) async {
-    if(_loading == true)
+  Future<int> getData({
+    required String host,
+    required User user,
+  }) async {
+    if (_loading == true) {
       return -2;
+    }
     _loading = true;
     notifyListeners();
     Response response;
-    try{
+    try {
       response = await get(
         Uri.parse(host + URLs.getGasCylinderSize),
       );
       _stateCode = response.statusCode;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         // client's request was successfully received
         List categoriesListJson = json.decode(utf8.decode(response.bodyBytes));
-        _items = categoriesListJson.map((item) => Lookup.fromJson(item)).toList();
+        _items =
+            categoriesListJson.map((item) => Lookup.fromJson(item)).toList();
       }
       _loading = false;
       notifyListeners();
       return response.statusCode;
-    } catch(error) {
+    } catch (error) {
       _loading = false;
       _stateCode = -1;
       notifyListeners();
       return -1;
     }
-
   }
-
-}
\ No newline at end of file
+}
diff --git a/old_lib/controllers/providers/api/status_drop_down/gas_refill/gas_status_provider.dart b/old_lib/controllers/providers/api/status_drop_down/gas_refill/gas_status_provider.dart
index 24b4e018..006aeef1 100644
--- a/old_lib/controllers/providers/api/status_drop_down/gas_refill/gas_status_provider.dart
+++ b/old_lib/controllers/providers/api/status_drop_down/gas_refill/gas_status_provider.dart
@@ -1,16 +1,16 @@
 import 'dart:convert';
 
-import 'package:test_sa/controllers/api_routes/urls.dart';
-import 'package:test_sa/models/lookup.dart';
-import 'package:test_sa/models/user.dart';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:http/http.dart';
 
-class GasStatusProvider extends ChangeNotifier{
+import '../../../../../models/lookup.dart';
+import '../../../../../models/user.dart';
+import '../../../../api_routes/urls.dart';
 
+class GasStatusProvider extends ChangeNotifier {
   //reset provider data
-  void reset(){
+  void reset() {
     _items = null;
     _loading = null;
     _stateCode = null;
@@ -19,20 +19,24 @@ class GasStatusProvider extends ChangeNotifier{
   // state code of current request to defied error message
   // like 400 customer request failed
   // 500 service not available
-  int _stateCode;
-  int get stateCode => _stateCode;
+  int? _stateCode;
+
+  int? get stateCode => _stateCode;
 
   // contain user data
   // when user not login or register _user = null
-  List<Lookup> _items;
-  List<Lookup> get items => _items;
+  List<Lookup>? _items;
+
+  List<Lookup>? get items => _items;
 
   // when categories in-process _loading = true
   // done _loading = true
   // failed _loading = false
-  bool _loading;
-  bool get isLoading => _loading;
-  set isLoading(bool isLoading){
+  bool? _loading;
+
+  bool? get isLoading => _loading;
+
+  set isLoading(bool? isLoading) {
     _loading = isLoading;
     notifyListeners();
   }
@@ -42,31 +46,28 @@ class GasStatusProvider extends ChangeNotifier{
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<int> getData ({String host,User user,}) async {
-    if(_loading == true) return -2;
+  Future<int> getData({required String host, required User user}) async {
+    if (_loading == true) return -2;
     _loading = true;
     notifyListeners();
     Response response;
-    try{
-      response = await get(
-        Uri.parse(host + URLs.getGasStatus),
-      );
+    try {
+      response = await get(Uri.parse(host + URLs.getGasStatus));
       _stateCode = response.statusCode;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         // client's request was successfully received
         List categoriesListJson = json.decode(utf8.decode(response.bodyBytes));
-        _items = categoriesListJson.map((item) => Lookup.fromJson(item)).toList();
+        _items =
+            categoriesListJson.map((item) => Lookup.fromJson(item)).toList();
       }
       _loading = false;
       notifyListeners();
       return response.statusCode;
-    } catch(error) {
+    } catch (error) {
       _loading = false;
       _stateCode = -1;
       notifyListeners();
       return -1;
     }
-
   }
-
-}
\ No newline at end of file
+}
diff --git a/old_lib/controllers/providers/api/status_drop_down/gas_refill/gas_types_provider.dart b/old_lib/controllers/providers/api/status_drop_down/gas_refill/gas_types_provider.dart
index f444c233..5817bd49 100644
--- a/old_lib/controllers/providers/api/status_drop_down/gas_refill/gas_types_provider.dart
+++ b/old_lib/controllers/providers/api/status_drop_down/gas_refill/gas_types_provider.dart
@@ -1,16 +1,16 @@
 import 'dart:convert';
 
-import 'package:test_sa/controllers/api_routes/urls.dart';
-import 'package:test_sa/models/lookup.dart';
-import 'package:test_sa/models/user.dart';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:http/http.dart';
 
-class GasTypesProvider extends ChangeNotifier{
+import '../../../../../models/lookup.dart';
+import '../../../../../models/user.dart';
+import '../../../../api_routes/urls.dart';
 
+class GasTypesProvider extends ChangeNotifier {
   //reset provider data
-  void reset(){
+  void reset() {
     _items = null;
     _loading = null;
     _stateCode = null;
@@ -19,20 +19,24 @@ class GasTypesProvider extends ChangeNotifier{
   // state code of current request to defied error message
   // like 400 customer request failed
   // 500 service not available
-  int _stateCode;
-  int get stateCode => _stateCode;
+  int? _stateCode;
+
+  int? get stateCode => _stateCode;
 
   // contain user data
   // when user not login or register _user = null
-  List<Lookup> _items;
-  List<Lookup> get items => _items;
+  List<Lookup>? _items;
+
+  List<Lookup>? get items => _items;
 
   // when categories in-process _loading = true
   // done _loading = true
   // failed _loading = false
-  bool _loading;
-  bool get isLoading => _loading;
-  set isLoading(bool isLoading){
+  bool? _loading;
+
+  bool? get isLoading => _loading;
+
+  set isLoading(bool? isLoading) {
     _loading = isLoading;
     notifyListeners();
   }
@@ -42,31 +46,28 @@ class GasTypesProvider extends ChangeNotifier{
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<int> getData ({String host,User user,}) async {
-    if(_loading == true) return -2;
+  Future<int> getData({required String host, required User user}) async {
+    if (_loading == true) return -2;
     _loading = true;
     notifyListeners();
     Response response;
-    try{
-      response = await get(
-        Uri.parse(host + URLs.getGasTypes),
-      );
+    try {
+      response = await get(Uri.parse(host + URLs.getGasTypes));
       _stateCode = response.statusCode;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         // client's request was successfully received
         List categoriesListJson = json.decode(utf8.decode(response.bodyBytes));
-        _items = categoriesListJson.map((item) => Lookup.fromJson(item)).toList();
+        _items =
+            categoriesListJson.map((item) => Lookup.fromJson(item)).toList();
       }
       _loading = false;
       notifyListeners();
       return response.statusCode;
-    } catch(error) {
+    } catch (error) {
       _loading = false;
       _stateCode = -1;
       notifyListeners();
       return -1;
     }
-
   }
-
-}
\ No newline at end of file
+}
diff --git a/old_lib/controllers/providers/api/status_drop_down/pentry/pentry_status_provider.dart b/old_lib/controllers/providers/api/status_drop_down/pentry/pentry_status_provider.dart
index 8e3168d9..c02c51b3 100644
--- a/old_lib/controllers/providers/api/status_drop_down/pentry/pentry_status_provider.dart
+++ b/old_lib/controllers/providers/api/status_drop_down/pentry/pentry_status_provider.dart
@@ -3,14 +3,14 @@ import 'dart:convert';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:http/http.dart';
-import 'package:test_sa/controllers/api_routes/urls.dart';
-import 'package:test_sa/models/lookup.dart';
-import 'package:test_sa/models/user.dart';
 
-class PentryStatusProvider extends ChangeNotifier{
+import '../../../../../models/lookup.dart';
+import '../../../../../models/user.dart';
+import '../../../../api_routes/urls.dart';
 
+class PentryStatusProvider extends ChangeNotifier {
   //reset provider data
-  void reset(){
+  void reset() {
     _items = null;
     _stateCode = null;
   }
@@ -18,20 +18,24 @@ class PentryStatusProvider extends ChangeNotifier{
   // state code of current request to defied error message
   // like 400 customer request failed
   // 500 service not available
-  int _stateCode;
-  int get stateCode => _stateCode;
+  int? _stateCode;
+
+  int? get stateCode => _stateCode;
 
   // contain user data
   // when user not login or register _user = null
-  List<Lookup> _items;
-  List<Lookup> get items => _items;
+  List<Lookup>? _items;
+
+  List<Lookup>? get items => _items;
 
   // when categories in-process _loading = true
   // done _loading = true
   // failed _loading = false
-  bool _loading;
-  bool get isLoading => _loading;
-  set isLoading(bool isLoading){
+  bool? _loading;
+
+  bool? get isLoading => _loading;
+
+  set isLoading(bool? isLoading) {
     _loading = isLoading;
     notifyListeners();
   }
@@ -41,20 +45,18 @@ class PentryStatusProvider extends ChangeNotifier{
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<int> getData ({String host,User user}) async {
-    if(_loading == true)
+  Future<int> getData({required String host, required User user}) async {
+    if (_loading == true) {
       return -2;
+    }
     _loading = true;
     notifyListeners();
     Response response;
-    try{
-      response = await get(
-          Uri.parse(
-        host + URLs.getPentryStatus),
-      );
+    try {
+      response = await get(Uri.parse(host + URLs.getPentryStatus));
 
       _stateCode = response.statusCode;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         // client's request was successfully received
         List listJson = json.decode(utf8.decode(response.bodyBytes));
         _items = listJson.map((type) => Lookup.fromIntIdJson(type)).toList();
@@ -62,14 +64,11 @@ class PentryStatusProvider extends ChangeNotifier{
       _loading = false;
       notifyListeners();
       return response.statusCode;
-    } catch(error) {
-
+    } catch (error) {
       _loading = false;
       _stateCode = -1;
       notifyListeners();
       return -1;
     }
-
   }
-
-}
\ No newline at end of file
+}
diff --git a/old_lib/controllers/providers/api/status_drop_down/pentry/pentry_task_status_provider.dart b/old_lib/controllers/providers/api/status_drop_down/pentry/pentry_task_status_provider.dart
index 03370135..cde95482 100644
--- a/old_lib/controllers/providers/api/status_drop_down/pentry/pentry_task_status_provider.dart
+++ b/old_lib/controllers/providers/api/status_drop_down/pentry/pentry_task_status_provider.dart
@@ -3,14 +3,14 @@ import 'dart:convert';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:http/http.dart';
-import 'package:test_sa/controllers/api_routes/urls.dart';
-import 'package:test_sa/models/lookup.dart';
-import 'package:test_sa/models/user.dart';
 
-class PentryTaskStatusProvider extends ChangeNotifier{
+import '../../../../../models/lookup.dart';
+import '../../../../../models/user.dart';
+import '../../../../api_routes/urls.dart';
 
+class PentryTaskStatusProvider extends ChangeNotifier {
   //reset provider data
-  void reset(){
+  void reset() {
     _items = null;
     _stateCode = null;
   }
@@ -18,20 +18,24 @@ class PentryTaskStatusProvider extends ChangeNotifier{
   // state code of current request to defied error message
   // like 400 customer request failed
   // 500 service not available
-  int _stateCode;
-  int get stateCode => _stateCode;
+  int? _stateCode;
+
+  int? get stateCode => _stateCode;
 
   // contain user data
   // when user not login or register _user = null
-  List<Lookup> _items;
-  List<Lookup> get items => _items;
+  List<Lookup>? _items;
+
+  List<Lookup>? get items => _items;
 
   // when categories in-process _loading = true
   // done _loading = true
   // failed _loading = false
-  bool _loading;
-  bool get isLoading => _loading;
-  set isLoading(bool isLoading){
+  bool? _loading;
+
+  bool? get isLoading => _loading;
+
+  set isLoading(bool? isLoading) {
     _loading = isLoading;
     notifyListeners();
   }
@@ -41,35 +45,32 @@ class PentryTaskStatusProvider extends ChangeNotifier{
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<int> getData ({String host,User user}) async {
-    if(_loading == true)
+  Future<int> getData({required String host, required User user}) async {
+    if (_loading == true) {
       return -2;
+    }
     _loading = true;
     notifyListeners();
     Response response;
-    try{
-      response = await get(
-          Uri.parse(
-        host + URLs.getPentryTaskStatus),
-      );
+    try {
+      response = await get(Uri.parse(host + URLs.getPentryTaskStatus));
 
       _stateCode = response.statusCode;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         // client's request was successfully received
         List categoriesListJson = json.decode(utf8.decode(response.bodyBytes));
-        _items = categoriesListJson.map((type) => Lookup.fromIntIdJson(type)).toList();
+        _items = categoriesListJson
+            .map((type) => Lookup.fromIntIdJson(type))
+            .toList();
       }
       _loading = false;
       notifyListeners();
       return response.statusCode;
-    } catch(error) {
-
+    } catch (error) {
       _loading = false;
       _stateCode = -1;
       notifyListeners();
       return -1;
     }
-
   }
-
-}
\ No newline at end of file
+}
diff --git a/old_lib/controllers/providers/api/status_drop_down/pentry/pentry_visit_status_provider.dart b/old_lib/controllers/providers/api/status_drop_down/pentry/pentry_visit_status_provider.dart
index 09b52cbb..6176218f 100644
--- a/old_lib/controllers/providers/api/status_drop_down/pentry/pentry_visit_status_provider.dart
+++ b/old_lib/controllers/providers/api/status_drop_down/pentry/pentry_visit_status_provider.dart
@@ -3,14 +3,14 @@ import 'dart:convert';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:http/http.dart';
-import 'package:test_sa/controllers/api_routes/urls.dart';
-import 'package:test_sa/models/lookup.dart';
-import 'package:test_sa/models/user.dart';
 
-class PentryVisitStatusProvider extends ChangeNotifier{
+import '../../../../../models/lookup.dart';
+import '../../../../../models/user.dart';
+import '../../../../api_routes/urls.dart';
 
+class PentryVisitStatusProvider extends ChangeNotifier {
   //reset provider data
-  void reset(){
+  void reset() {
     _items = null;
     _stateCode = null;
   }
@@ -18,20 +18,24 @@ class PentryVisitStatusProvider extends ChangeNotifier{
   // state code of current request to defied error message
   // like 400 customer request failed
   // 500 service not available
-  int _stateCode;
-  int get stateCode => _stateCode;
+  int? _stateCode;
+
+  int? get stateCode => _stateCode;
 
   // contain user data
   // when user not login or register _user = null
-  List<Lookup> _items;
-  List<Lookup> get items => _items;
+  List<Lookup>? _items;
+
+  List<Lookup>? get items => _items;
 
   // when categories in-process _loading = true
   // done _loading = true
   // failed _loading = false
-  bool _loading;
-  bool get isLoading => _loading;
-  set isLoading(bool isLoading){
+  bool? _loading;
+
+  bool? get isLoading => _loading;
+
+  set isLoading(bool? isLoading) {
     _loading = isLoading;
     notifyListeners();
   }
@@ -41,20 +45,18 @@ class PentryVisitStatusProvider extends ChangeNotifier{
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<int> getData ({String host,User user}) async {
-    if(_loading == true)
+  Future<int> getData({required String host, required User user}) async {
+    if (_loading == true) {
       return -2;
+    }
     _loading = true;
     notifyListeners();
     Response response;
-    try{
-      response = await get(
-          Uri.parse(
-        host + URLs.getPentryVisitStatus),
-      );
+    try {
+      response = await get(Uri.parse(host + URLs.getPentryVisitStatus));
 
       _stateCode = response.statusCode;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         // client's request was successfully received
         List listJson = json.decode(utf8.decode(response.bodyBytes));
         _items = listJson.map((type) => Lookup.fromIntIdJson(type)).toList();
@@ -62,13 +64,11 @@ class PentryVisitStatusProvider extends ChangeNotifier{
       _loading = false;
       notifyListeners();
       return response.statusCode;
-    } catch(error) {
+    } catch (error) {
       _loading = false;
       _stateCode = -1;
       notifyListeners();
       return -1;
     }
-
   }
-
-}
\ No newline at end of file
+}
diff --git a/old_lib/controllers/providers/api/status_drop_down/report/service_report_defect_types_provider.dart b/old_lib/controllers/providers/api/status_drop_down/report/service_report_defect_types_provider.dart
index 50efd414..6c1c6569 100644
--- a/old_lib/controllers/providers/api/status_drop_down/report/service_report_defect_types_provider.dart
+++ b/old_lib/controllers/providers/api/status_drop_down/report/service_report_defect_types_provider.dart
@@ -3,14 +3,14 @@ import 'dart:convert';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:http/http.dart';
-import 'package:test_sa/controllers/api_routes/urls.dart';
-import 'package:test_sa/models/lookup.dart';
-import 'package:test_sa/models/user.dart';
 
-class ServiceRequestDefectTypesProvider extends ChangeNotifier{
+import '../../../../../models/lookup.dart';
+import '../../../../../models/user.dart';
+import '../../../../api_routes/urls.dart';
 
+class ServiceRequestDefectTypesProvider extends ChangeNotifier {
   //reset provider data
-  void reset(){
+  void reset() {
     _items = null;
     _stateCode = null;
   }
@@ -18,20 +18,24 @@ class ServiceRequestDefectTypesProvider extends ChangeNotifier{
   // state code of current request to defied error message
   // like 400 customer request failed
   // 500 service not available
-  int _stateCode;
-  int get stateCode => _stateCode;
+  int? _stateCode;
+
+  int? get stateCode => _stateCode;
 
   // contain user data
   // when user not login or register _user = null
-  List<Lookup> _items;
-  List<Lookup> get items => _items;
+  List<Lookup>? _items;
+
+  List<Lookup>? get items => _items;
 
   // when categories in-process _loading = true
   // done _loading = true
   // failed _loading = false
-  bool _loading;
-  bool get isLoading => _loading;
-  set isLoading(bool isLoading){
+  bool? _loading;
+
+  bool? get isLoading => _loading;
+
+  set isLoading(bool? isLoading) {
     _loading = isLoading;
     notifyListeners();
   }
@@ -41,20 +45,18 @@ class ServiceRequestDefectTypesProvider extends ChangeNotifier{
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<int> getData ({String host,User user}) async {
-    if(_loading == true)
+  Future<int> getData({required String host, required User user}) async {
+    if (_loading == true) {
       return -2;
+    }
     _loading = true;
     notifyListeners();
     Response response;
-    try{
-      response = await get(
-          Uri.parse(
-        host + URLs.getServiceReportDefectTypes),
-      );
+    try {
+      response = await get(Uri.parse(host + URLs.getServiceReportDefectTypes));
 
       _stateCode = response.statusCode;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         // client's request was successfully received
         List listJson = json.decode(utf8.decode(response.bodyBytes));
         _items = listJson.map((type) => Lookup.fromIntIdJson(type)).toList();
@@ -62,14 +64,11 @@ class ServiceRequestDefectTypesProvider extends ChangeNotifier{
       _loading = false;
       notifyListeners();
       return response.statusCode;
-    } catch(error) {
-
+    } catch (error) {
       _loading = false;
       _stateCode = -1;
       notifyListeners();
       return -1;
     }
-
   }
-
-}
\ No newline at end of file
+}
diff --git a/old_lib/controllers/providers/api/status_drop_down/report/service_report_last_calls_provider.dart b/old_lib/controllers/providers/api/status_drop_down/report/service_report_last_calls_provider.dart
index 50de291f..e228702e 100644
--- a/old_lib/controllers/providers/api/status_drop_down/report/service_report_last_calls_provider.dart
+++ b/old_lib/controllers/providers/api/status_drop_down/report/service_report_last_calls_provider.dart
@@ -3,14 +3,14 @@ import 'dart:convert';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:http/http.dart';
-import 'package:test_sa/controllers/api_routes/urls.dart';
-import 'package:test_sa/models/lookup.dart';
-import 'package:test_sa/models/user.dart';
 
-class ServiceReportLastCallsProvider extends ChangeNotifier{
+import '../../../../../models/lookup.dart';
+import '../../../../../models/user.dart';
+import '../../../../api_routes/urls.dart';
 
+class ServiceReportLastCallsProvider extends ChangeNotifier {
   //reset provider data
-  void reset(){
+  void reset() {
     _calls = null;
     _loading = null;
     _stateCode = null;
@@ -19,20 +19,24 @@ class ServiceReportLastCallsProvider extends ChangeNotifier{
   // state code of current request to defied error message
   // like 400 customer request failed
   // 500 service not available
-  int _stateCode;
-  int get stateCode => _stateCode;
+  int? _stateCode;
+
+  int? get stateCode => _stateCode;
 
   // contain user data
   // when user not login or register _user = null
-  List<Lookup> _calls;
-  List<Lookup> get calls => _calls;
+  List<Lookup>? _calls;
+
+  List<Lookup>? get calls => _calls;
 
   // when categories in-process _loading = true
   // done _loading = true
   // failed _loading = false
-  bool _loading;
-  bool get isLoading => _loading;
-  set isLoading(bool isLoading){
+  bool? _loading;
+
+  bool? get isLoading => _loading;
+
+  set isLoading(bool? isLoading) {
     _loading = isLoading;
     notifyListeners();
   }
@@ -42,35 +46,39 @@ class ServiceReportLastCallsProvider extends ChangeNotifier{
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<int> getCalls ({String host,User user,String serviceStatus}) async {
-    if(_loading == true)
-      return -2;
+  Future<int> getCalls({
+    required String host,
+    required User user,
+    String? serviceStatus,
+  }) async {
+    if (_loading == true) return -2;
     _loading = true;
     notifyListeners();
     Response response;
-    try{
+    try {
       response = await get(
-          Uri.parse(
-        host + URLs.getServiceReportLastCalls
-            +(serviceStatus == null ? "" : "?service_status=$serviceStatus")
-          ),
+        Uri.parse(
+          host +
+              URLs.getServiceReportLastCalls +
+              (serviceStatus == null ? "" : "?service_status=$serviceStatus"),
+        ),
       );
       _stateCode = response.statusCode;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         // client's request was successfully received
         List categoriesListJson = json.decode(utf8.decode(response.bodyBytes));
-        _calls = categoriesListJson.map((type) => Lookup.fromIntIdJson(type)).toList();
+        _calls = categoriesListJson
+            .map((type) => Lookup.fromIntIdJson(type))
+            .toList();
       }
       _loading = false;
       notifyListeners();
       return response.statusCode;
-    } catch(error) {
+    } catch (error) {
       _loading = false;
       _stateCode = -1;
       notifyListeners();
       return -1;
     }
-
   }
-
-}
\ No newline at end of file
+}
diff --git a/old_lib/controllers/providers/api/status_drop_down/report/service_report_priority_provider.dart b/old_lib/controllers/providers/api/status_drop_down/report/service_report_priority_provider.dart
index 58fc2d98..b966ccf5 100644
--- a/old_lib/controllers/providers/api/status_drop_down/report/service_report_priority_provider.dart
+++ b/old_lib/controllers/providers/api/status_drop_down/report/service_report_priority_provider.dart
@@ -3,14 +3,14 @@ import 'dart:convert';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:http/http.dart';
-import 'package:test_sa/controllers/api_routes/urls.dart';
-import 'package:test_sa/models/lookup.dart';
-import 'package:test_sa/models/user.dart';
 
-class ServiceRequestPriorityProvider extends ChangeNotifier{
+import '../../../../../models/lookup.dart';
+import '../../../../../models/user.dart';
+import '../../../../api_routes/urls.dart';
 
+class ServiceRequestPriorityProvider extends ChangeNotifier {
   //reset provider data
-  void reset(){
+  void reset() {
     _items = null;
     _stateCode = null;
   }
@@ -18,20 +18,24 @@ class ServiceRequestPriorityProvider extends ChangeNotifier{
   // state code of current request to defied error message
   // like 400 customer request failed
   // 500 service not available
-  int _stateCode;
-  int get stateCode => _stateCode;
+  int? _stateCode;
+
+  int? get stateCode => _stateCode;
 
   // contain user data
   // when user not login or register _user = null
-  List<Lookup> _items;
-  List<Lookup> get items => _items;
+  List<Lookup>? _items;
+
+  List<Lookup>? get items => _items;
 
   // when categories in-process _loading = true
   // done _loading = true
   // failed _loading = false
-  bool _loading;
-  bool get isLoading => _loading;
-  set isLoading(bool isLoading){
+  bool? _loading;
+
+  bool? get isLoading => _loading;
+
+  set isLoading(bool? isLoading) {
     _loading = isLoading;
     notifyListeners();
   }
@@ -41,20 +45,18 @@ class ServiceRequestPriorityProvider extends ChangeNotifier{
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<int> getData ({String host,User user}) async {
-    if(_loading == true)
+  Future<int> getData({required String host, required User user}) async {
+    if (_loading == true) {
       return -2;
+    }
     _loading = true;
     notifyListeners();
     Response response;
-    try{
-      response = await get(
-          Uri.parse(
-        host + URLs.getServiceReportPriority),
-      );
+    try {
+      response = await get(Uri.parse(host + URLs.getServiceReportPriority));
 
       _stateCode = response.statusCode;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         // client's request was successfully received
         List listJson = json.decode(utf8.decode(response.bodyBytes));
         _items = listJson.map((type) => Lookup.fromIntIdJson(type)).toList();
@@ -62,13 +64,11 @@ class ServiceRequestPriorityProvider extends ChangeNotifier{
       _loading = false;
       notifyListeners();
       return response.statusCode;
-    } catch(error) {
+    } catch (error) {
       _loading = false;
       _stateCode = -1;
       notifyListeners();
       return -1;
     }
-
   }
-
-}
\ No newline at end of file
+}
diff --git a/old_lib/controllers/providers/api/status_drop_down/report/service_report_reasons_provider.dart b/old_lib/controllers/providers/api/status_drop_down/report/service_report_reasons_provider.dart
index bac49f9f..0d3f8564 100644
--- a/old_lib/controllers/providers/api/status_drop_down/report/service_report_reasons_provider.dart
+++ b/old_lib/controllers/providers/api/status_drop_down/report/service_report_reasons_provider.dart
@@ -3,14 +3,14 @@ import 'dart:convert';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:http/http.dart';
-import 'package:test_sa/controllers/api_routes/urls.dart';
-import 'package:test_sa/models/lookup.dart';
-import 'package:test_sa/models/user.dart';
 
-class ServiceReportReasonsProvider extends ChangeNotifier{
+import '../../../../../models/lookup.dart';
+import '../../../../../models/user.dart';
+import '../../../../api_routes/urls.dart';
 
+class ServiceReportReasonsProvider extends ChangeNotifier {
   //reset provider data
-  void reset(){
+  void reset() {
     _reasons = null;
     _stateCode = null;
   }
@@ -18,20 +18,24 @@ class ServiceReportReasonsProvider extends ChangeNotifier{
   // state code of current request to defied error message
   // like 400 customer request failed
   // 500 service not available
-  int _stateCode;
-  int get stateCode => _stateCode;
+  int? _stateCode;
+
+  int? get stateCode => _stateCode;
 
   // contain user data
   // when user not login or register _user = null
-  List<Lookup> _reasons;
-  List<Lookup> get reasons => _reasons;
+  List<Lookup>? _reasons;
+
+  List<Lookup>? get reasons => _reasons;
 
   // when categories in-process _loading = true
   // done _loading = true
   // failed _loading = false
-  bool _loading;
-  bool get isLoading => _loading;
-  set isLoading(bool isLoading){
+  bool? _loading;
+
+  bool? get isLoading => _loading;
+
+  set isLoading(bool? isLoading) {
     _loading = isLoading;
     notifyListeners();
   }
@@ -41,33 +45,31 @@ class ServiceReportReasonsProvider extends ChangeNotifier{
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<int> getTypes ({String host,User user}) async {
-    if(_loading == true)
+  Future<int> getTypes({required String host, required User user}) async {
+    if (_loading == true) {
       return -2;
+    }
     _loading = true;
     notifyListeners();
     Response response;
-    try{
-      response = await get(
-          Uri.parse(
-        host + URLs.getServiceReportReasons),
-      );
+    try {
+      response = await get(Uri.parse(host + URLs.getServiceReportReasons));
       _stateCode = response.statusCode;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         // client's request was successfully received
         List categoriesListJson = json.decode(utf8.decode(response.bodyBytes));
-        _reasons = categoriesListJson.map((type) => Lookup.fromIntIdJson(type)).toList();
+        _reasons = categoriesListJson
+            .map((type) => Lookup.fromIntIdJson(type))
+            .toList();
       }
       _loading = false;
       notifyListeners();
       return response.statusCode;
-    } catch(error) {
+    } catch (error) {
       _loading = false;
       _stateCode = -1;
       notifyListeners();
       return -1;
     }
-
   }
-
-}
\ No newline at end of file
+}
diff --git a/old_lib/controllers/providers/api/status_drop_down/report/service_report_status_provider.dart b/old_lib/controllers/providers/api/status_drop_down/report/service_report_status_provider.dart
index 89cb100f..8dd8cb03 100644
--- a/old_lib/controllers/providers/api/status_drop_down/report/service_report_status_provider.dart
+++ b/old_lib/controllers/providers/api/status_drop_down/report/service_report_status_provider.dart
@@ -3,14 +3,14 @@ import 'dart:convert';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:http/http.dart';
-import 'package:test_sa/controllers/api_routes/urls.dart';
-import 'package:test_sa/models/lookup.dart';
-import 'package:test_sa/models/user.dart';
 
-class ServiceReportStatusProvider extends ChangeNotifier{
+import '../../../../../models/lookup.dart';
+import '../../../../../models/user.dart';
+import '../../../../api_routes/urls.dart';
 
+class ServiceReportStatusProvider extends ChangeNotifier {
   //reset provider data
-  void reset(){
+  void reset() {
     _status = null;
     _stateCode = null;
   }
@@ -18,20 +18,24 @@ class ServiceReportStatusProvider extends ChangeNotifier{
   // state code of current request to defied error message
   // like 400 customer request failed
   // 500 service not available
-  int _stateCode;
-  int get stateCode => _stateCode;
+  int? _stateCode;
+
+  int? get stateCode => _stateCode;
 
   // contain user data
   // when user not login or register _user = null
-  List<Lookup> _status;
-  List<Lookup> get statuses => _status;
+  List<Lookup>? _status;
+
+  List<Lookup>? get statuses => _status;
 
   // when categories in-process _loading = true
   // done _loading = true
   // failed _loading = false
-  bool _loading;
-  bool get isLoading => _loading;
-  set isLoading(bool isLoading){
+  bool? _loading;
+
+  bool? get isLoading => _loading;
+
+  set isLoading(bool? isLoading) {
     _loading = isLoading;
     notifyListeners();
   }
@@ -41,34 +45,31 @@ class ServiceReportStatusProvider extends ChangeNotifier{
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<int> getTypes ({String host,User user}) async {
-    if(_loading == true)
+  Future<int> getTypes({required String host, required User user}) async {
+    if (_loading == true) {
       return -2;
+    }
     _loading = true;
     notifyListeners();
     Response response;
-    try{
-      response = await get(
-          Uri.parse(
-        host + URLs.getServiceReportStatus),
-      );
+    try {
+      response = await get(Uri.parse(host + URLs.getServiceReportStatus));
       _stateCode = response.statusCode;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         // client's request was successfully received
         List categoriesListJson = json.decode(utf8.decode(response.bodyBytes));
-        _status = categoriesListJson.map((type) => Lookup.fromIntIdJson(type)).toList();
+        _status = categoriesListJson
+            .map((type) => Lookup.fromIntIdJson(type))
+            .toList();
       }
       _loading = false;
       notifyListeners();
       return response.statusCode;
-    } catch(error) {
-
+    } catch (error) {
       _loading = false;
       _stateCode = -1;
       notifyListeners();
       return -1;
     }
-
   }
-
-}
\ No newline at end of file
+}
diff --git a/old_lib/controllers/providers/api/status_drop_down/report/service_report_types_provider.dart b/old_lib/controllers/providers/api/status_drop_down/report/service_report_types_provider.dart
index a8b07c08..ead74013 100644
--- a/old_lib/controllers/providers/api/status_drop_down/report/service_report_types_provider.dart
+++ b/old_lib/controllers/providers/api/status_drop_down/report/service_report_types_provider.dart
@@ -3,14 +3,14 @@ import 'dart:convert';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:http/http.dart';
-import 'package:test_sa/controllers/api_routes/urls.dart';
-import 'package:test_sa/models/lookup.dart';
-import 'package:test_sa/models/user.dart';
 
-class ServiceReportTypesProvider extends ChangeNotifier{
+import '../../../../../models/lookup.dart';
+import '../../../../../models/user.dart';
+import '../../../../api_routes/urls.dart';
 
+class ServiceReportTypesProvider extends ChangeNotifier {
   //reset provider data
-  void reset(){
+  void reset() {
     _types = null;
     _stateCode = null;
   }
@@ -18,20 +18,24 @@ class ServiceReportTypesProvider extends ChangeNotifier{
   // state code of current request to defied error message
   // like 400 customer request failed
   // 500 service not available
-  int _stateCode;
-  int get stateCode => _stateCode;
+  int? _stateCode;
+
+  int? get stateCode => _stateCode;
 
   // contain user data
   // when user not login or register _user = null
-  List<Lookup> _types;
-  List<Lookup> get types => _types;
+  List<Lookup>? _types;
+
+  List<Lookup>? get types => _types;
 
   // when categories in-process _loading = true
   // done _loading = true
   // failed _loading = false
-  bool _loading;
-  bool get isLoading => _loading;
-  set isLoading(bool isLoading){
+  bool? _loading;
+
+  bool? get isLoading => _loading;
+
+  set isLoading(bool? isLoading) {
     _loading = isLoading;
     notifyListeners();
   }
@@ -41,34 +45,31 @@ class ServiceReportTypesProvider extends ChangeNotifier{
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<int> getTypes ({String host,User user}) async {
-    if(_loading == true)
+  Future<int> getTypes({required String host, required User user}) async {
+    if (_loading == true) {
       return -2;
+    }
     _loading = true;
     notifyListeners();
     Response response;
-    try{
-
-      response = await get(
-          Uri.parse(
-        host + URLs.getServiceReportTypes),
-      );
+    try {
+      response = await get(Uri.parse(host + URLs.getServiceReportTypes));
       _stateCode = response.statusCode;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         // client's request was successfully received
         List categoriesListJson = json.decode(utf8.decode(response.bodyBytes));
-        _types = categoriesListJson.map((type) => Lookup.fromIntIdJson(type)).toList();
+        _types = categoriesListJson
+            .map((type) => Lookup.fromIntIdJson(type))
+            .toList();
       }
       _loading = false;
       notifyListeners();
       return response.statusCode;
-    } catch(error) {
+    } catch (error) {
       _loading = false;
       _stateCode = -1;
       notifyListeners();
       return -1;
     }
-
   }
-
-}
\ No newline at end of file
+}
diff --git a/old_lib/controllers/providers/api/status_drop_down/report/service_types_provider.dart b/old_lib/controllers/providers/api/status_drop_down/report/service_types_provider.dart
index a5bcb0a5..a3113e92 100644
--- a/old_lib/controllers/providers/api/status_drop_down/report/service_types_provider.dart
+++ b/old_lib/controllers/providers/api/status_drop_down/report/service_types_provider.dart
@@ -3,14 +3,14 @@ import 'dart:convert';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:http/http.dart';
-import 'package:test_sa/controllers/api_routes/urls.dart';
-import 'package:test_sa/models/lookup.dart';
-import 'package:test_sa/models/user.dart';
 
-class ServiceStatusProvider extends ChangeNotifier{
+import '../../../../../models/lookup.dart';
+import '../../../../../models/user.dart';
+import '../../../../api_routes/urls.dart';
 
+class ServiceStatusProvider extends ChangeNotifier {
   //reset provider data
-  void reset(){
+  void reset() {
     _statuses = null;
     _stateCode = null;
   }
@@ -18,20 +18,24 @@ class ServiceStatusProvider extends ChangeNotifier{
   // state code of current request to defied error message
   // like 400 customer request failed
   // 500 service not available
-  int _stateCode;
-  int get stateCode => _stateCode;
+  int? _stateCode;
+
+  int? get stateCode => _stateCode;
 
   // contain user data
   // when user not login or register _user = null
-  List<Lookup> _statuses;
-  List<Lookup> get statuses => _statuses;
+  List<Lookup>? _statuses;
+
+  List<Lookup>? get statuses => _statuses;
 
   // when categories in-process _loading = true
   // done _loading = true
   // failed _loading = false
-  bool _loading;
-  bool get isLoading => _loading;
-  set isLoading(bool isLoading){
+  bool? _loading;
+
+  bool? get isLoading => _loading;
+
+  set isLoading(bool? isLoading) {
     _loading = isLoading;
     notifyListeners();
   }
@@ -41,35 +45,30 @@ class ServiceStatusProvider extends ChangeNotifier{
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<int> getTypes ({String host,User user}) async {
-    if(_loading == true)
+  Future<int> getTypes({required String host, required User user}) async {
+    if (_loading == true) {
       return -2;
+    }
     _loading = true;
     notifyListeners();
     Response response;
-    try{
-
-      response = await get(
-          Uri.parse(
-        host + URLs.getServiceTypes),
-      );
+    try {
+      response = await get(Uri.parse(host + URLs.getServiceTypes));
       _stateCode = response.statusCode;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         // client's request was successfully received
         List categoriesListJson = json.decode(utf8.decode(response.bodyBytes));
-        _statuses = categoriesListJson.map((e) => Lookup.fromIntIdJson(e)).toList();
-        
+        _statuses =
+            categoriesListJson.map((e) => Lookup.fromIntIdJson(e)).toList();
       }
       _loading = false;
       notifyListeners();
       return response.statusCode;
-    } catch(error) {
+    } catch (error) {
       _loading = false;
       _stateCode = -1;
       notifyListeners();
       return -1;
     }
-
   }
-
-}
\ No newline at end of file
+}
diff --git a/old_lib/controllers/providers/api/user_provider.dart b/old_lib/controllers/providers/api/user_provider.dart
index 843746c9..bf8c9cc2 100644
--- a/old_lib/controllers/providers/api/user_provider.dart
+++ b/old_lib/controllers/providers/api/user_provider.dart
@@ -1,32 +1,35 @@
 import 'dart:convert';
 
-import 'package:test_sa/controllers/api_routes/urls.dart';
-import 'package:test_sa/models/user.dart';
 import 'package:flutter/material.dart';
 import 'package:http/http.dart';
 
-class UserProvider extends ChangeNotifier{
+import '../../../models/user.dart';
+import '../../api_routes/urls.dart';
 
+class UserProvider extends ChangeNotifier {
   //reset provider data
-  void reset(){
+  void reset() {
     _user = null;
     _loading = false;
   }
 
   // contain user data
   // when user not login or register _user = null
-  User _user;
-  User get user => _user;
-  set user(User user) {
+  User? _user;
+
+  User? get user => _user;
+
+  set user(User? user) {
     _user = user;
     notifyListeners();
   }
 
-
   // when login or register in-process _login = true
   // when login or register is done or not start = false
   bool _loading = false;
+
   bool get isLoading => _loading;
+
   set isLoading(bool isLoading) {
     _loading = isLoading;
     notifyListeners();
@@ -38,32 +41,31 @@ class UserProvider extends ChangeNotifier{
   /// return state code if request complete may be 200, 404 or 403
   /// for more details check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<int> login ({
-    @required String host,
-    @required User user,
+  Future<int> login({
+    required String host,
+    required User user,
   }) async {
-    if(_loading == true)
+    if (_loading == true) {
       return -2;
+    }
     _loading = true;
     notifyListeners();
     Response response;
-    try{
+    try {
       response = await post(
-          Uri.parse(
-        host+URLs.login),
+        Uri.parse(host + URLs.login),
         body: await user.toLoginJson(),
       );
       _loading = false;
-      if(response.statusCode >= 200 && response.statusCode < 300) {
+      if (response.statusCode >= 200 && response.statusCode < 300) {
         // client's request was successfully received
         _user = User.fromJson(jsonDecode(utf8.decode(response.bodyBytes))[0]);
 
-
         return response.statusCode;
       }
       notifyListeners();
       return response.statusCode;
-    } catch(error) {
+    } catch (error) {
       _loading = false;
       notifyListeners();
       return -1;
@@ -76,32 +78,30 @@ class UserProvider extends ChangeNotifier{
   /// return state code if request complete may be 200, 404 or 403
   /// for more details about state codes check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<int> register ({
-    @required String host,
-    @required User user,
+  Future<int> register({
+    required String host,
+    required User user,
   }) async {
-    if(_loading == true)
+    if (_loading == true) {
       return -2;
+    }
     _loading = true;
     notifyListeners();
     Response response;
-    try{
-      response = await post(
-          Uri.parse(
-        host+URLs.register),
-        body: await user.toRegisterJson()
-      );
-    } catch(error) {
+    try {
+      response = await post(Uri.parse(host + URLs.register),
+          body: await user.toRegisterJson());
+    } catch (error) {
       _loading = false;
       notifyListeners();
       return -1;
     }
     _loading = false;
     notifyListeners();
-    if(response.statusCode >= 200 && response.statusCode < 300) {
+    if (response.statusCode >= 200 && response.statusCode < 300) {
       // client's request was successfully received
       _user = User.fromJson(jsonDecode(utf8.decode(response.bodyBytes))[0]);
-      _user.hospital = user.hospital;
+      _user?.hospital = user.hospital;
       notifyListeners();
       return response.statusCode;
     }
@@ -114,32 +114,33 @@ class UserProvider extends ChangeNotifier{
   /// return state code if request complete may be 200, 404 or 403
   /// for more details about state codes check http state manager
   /// lib\controllers\http_status_manger\http_status_manger.dart
-  Future<int> updateProfile ({
-    @required String host,
-    @required User user,
+  Future<int> updateProfile({
+    required String host,
+    required User user,
   }) async {
-    if(_loading == true)
+    if (_loading == true) {
       return -2;
+    }
     _loading = true;
     notifyListeners();
     Response response;
 
-    Map<String,dynamic> jsonObject ={};
+    Map<String, dynamic> jsonObject = {};
     jsonObject["uid"] = user.id;
     jsonObject["token"] = user.token;
-    if(user.department.id != _user.department.id)
+    if (user.department.id != _user?.department.id) {
       jsonObject["department"] = user.department.id;
-    if(user.whatsApp != _user.whatsApp)
+    }
+    if (user.whatsApp != _user?.whatsApp) {
       jsonObject["whatsapp"] = user.whatsApp;
-    if(user.phoneNumber != _user.phoneNumber)
+    }
+    if (user.phoneNumber != _user?.phoneNumber) {
       jsonObject["phone"] = user.phoneNumber;
-    try{
-      response = await post(
-          Uri.parse(
-          host+URLs.updateProfile),
-          body: jsonObject
-      );
-    } catch(error) {
+    }
+    try {
+      response =
+          await post(Uri.parse(host + URLs.updateProfile), body: jsonObject);
+    } catch (error) {
       _loading = false;
       notifyListeners();
       return -1;
@@ -148,15 +149,14 @@ class UserProvider extends ChangeNotifier{
     _loading = false;
     notifyListeners();
 
-    if(response.statusCode >= 200 && response.statusCode < 300) {
+    if (response.statusCode >= 200 && response.statusCode < 300) {
       // client's request was successfully received
       _user = User.fromJson(jsonDecode(utf8.decode(response.bodyBytes))[0]);
-      _user.hospital = user.hospital;
-      _user.department = user.department;
+      _user?.hospital = user.hospital;
+      _user?.department = user.department;
       notifyListeners();
       return response.statusCode;
     }
     return response.statusCode;
   }
-
-}
\ No newline at end of file
+}
diff --git a/old_lib/controllers/providers/settings/setting_provider.dart b/old_lib/controllers/providers/settings/setting_provider.dart
index e5df1ca3..13d90030 100644
--- a/old_lib/controllers/providers/settings/setting_provider.dart
+++ b/old_lib/controllers/providers/settings/setting_provider.dart
@@ -1,15 +1,14 @@
 import 'dart:async';
 import 'dart:convert';
 
-import 'package:test_sa/controllers/api_routes/urls.dart';
-import 'package:test_sa/models/user.dart';
 import 'package:flutter/foundation.dart';
 import 'package:shared_preferences/shared_preferences.dart';
-import 'app_settings.dart';
-
 
-class SettingProvider extends ChangeNotifier{
+import '../../../models/user.dart';
+import '../../api_routes/urls.dart';
+import 'app_settings.dart';
 
+class SettingProvider extends ChangeNotifier {
   resetSettings() async {
     SharedPreferences prefs = await SharedPreferences.getInstance();
     user = null;
@@ -21,7 +20,7 @@ class SettingProvider extends ChangeNotifier{
   bool isLoaded = false;
 
   // contain saved user data
-  User user;
+  User? user;
 
   Future<void> setUser(User user) async {
     SharedPreferences prefs = await SharedPreferences.getInstance();
@@ -30,8 +29,10 @@ class SettingProvider extends ChangeNotifier{
     notifyListeners();
   }
 
-  String _host;
-  String get host => _host;
+  String? _host;
+
+  String? get host => _host;
+
   Future<void> setHost(String host) async {
     SharedPreferences prefs = await SharedPreferences.getInstance();
     prefs.setString(ASettings.host, host);
@@ -39,8 +40,10 @@ class SettingProvider extends ChangeNotifier{
     notifyListeners();
   }
 
-  String _language;
-  String get language => _language;
+  String? _language;
+
+  String? get language => _language;
+
   Future<void> setLanguage(String currentLanguage) async {
     SharedPreferences prefs = await SharedPreferences.getInstance();
     prefs.setString(ASettings.language, currentLanguage);
@@ -48,8 +51,10 @@ class SettingProvider extends ChangeNotifier{
     notifyListeners();
   }
 
-  String _speechToText;
-  String get speechToText => _speechToText;
+  String? _speechToText;
+
+  String? get speechToText => _speechToText;
+
   Future<void> setSpeechToText(String currentLanguage) async {
     SharedPreferences prefs = await SharedPreferences.getInstance();
     prefs.setString(ASettings.speechToText, currentLanguage);
@@ -58,40 +63,38 @@ class SettingProvider extends ChangeNotifier{
   }
 
   // call loadSharedPreferences when provider initialise
-  SettingProvider(){
+  SettingProvider() {
     loadSharedPreferences();
   }
 
   // get app setting
   Future<void> loadSharedPreferences() async {
-
     SharedPreferences prefs = await SharedPreferences.getInstance();
 
-    if(prefs.containsKey(ASettings.language)){
+    if (prefs.containsKey(ASettings.language)) {
       _language = prefs.getString(ASettings.language);
-    }else{
-      _language  = 'en';
+    } else {
+      _language = 'en';
     }
 
-    if(prefs.containsKey(ASettings.speechToText)){
+    if (prefs.containsKey(ASettings.speechToText)) {
       _speechToText = prefs.getString(ASettings.speechToText);
-    }else{
-      _speechToText  = 'ar';
+    } else {
+      _speechToText = 'ar';
     }
 
-    if(prefs.containsKey(ASettings.user)){
-      String userJson = prefs.getString(ASettings.user);
-      user = User.fromJson(json.decode(userJson));
+    if (prefs.containsKey(ASettings.user)) {
+      String? userJson = prefs.getString(ASettings.user);
+      user = User.fromJson(json.decode(userJson ?? ''));
     }
 
-    if(prefs.containsKey(ASettings.host)){
+    if (prefs.containsKey(ASettings.host)) {
       _host = prefs.getString(ASettings.host);
-    } else{
+    } else {
       _host = URLs.host1;
     }
 
     isLoaded = true;
     notifyListeners();
   }
-
-}
\ No newline at end of file
+}
diff --git a/old_lib/extensions/int_extensions.dart b/old_lib/extensions/int_extensions.dart
index 5f1e672e..b913a064 100644
--- a/old_lib/extensions/int_extensions.dart
+++ b/old_lib/extensions/int_extensions.dart
@@ -1,13 +1,14 @@
-import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
-import 'package:test_sa/views/app_style/colors.dart';
+
+import '../views/app_style/colors.dart';
 
 extension IntExtensions on int {
   Widget get height => SizedBox(height: toDouble());
 
   Widget get width => SizedBox(width: toDouble());
 
-  Widget get divider => Divider(height: toDouble(), thickness: toDouble(), color: AColors.greyEF);
+  Widget get divider =>
+      Divider(height: toDouble(), thickness: toDouble(), color: AColors.greyEF);
 
   Widget get makeItSquare => SizedBox(width: toDouble(), height: toDouble());
 }
diff --git a/old_lib/models/device/device.dart b/old_lib/models/device/device.dart
index b84b8715..b5d1f486 100644
--- a/old_lib/models/device/device.dart
+++ b/old_lib/models/device/device.dart
@@ -1,15 +1,15 @@
-class Device{
-  String id;
-  String serialNumber;
-  String number;
-  String brand;
-  String model;
-  DateTime productionDate;
-  DateTime supplyDate;
-  DateTime installDate;
-  DateTime receivingDate;
-  DateTime operationDate;
-  DateTime warrantyDate;
+class Device {
+  String? id;
+  String? serialNumber;
+  String? number;
+  String? brand;
+  String? model;
+  DateTime? productionDate;
+  DateTime? supplyDate;
+  DateTime? installDate;
+  DateTime? receivingDate;
+  DateTime? operationDate;
+  DateTime? warrantyDate;
 
   Device({
     this.id,
@@ -25,7 +25,7 @@ class Device{
     this.warrantyDate,
   });
 
-  factory Device.fromJson(Map<String,dynamic> parsedJson){
+  factory Device.fromJson(Map<String, dynamic> parsedJson) {
     return Device(
       id: parsedJson["nid"] ?? parsedJson["id"],
       serialNumber: parsedJson["sn"] ?? parsedJson["value"],
@@ -41,7 +41,7 @@ class Device{
     );
   }
 
-  factory Device.fromDevice(Device device){
+  factory Device.fromDevice(Device device) {
     return Device(
       id: device.id,
       serialNumber: device.serialNumber,
@@ -58,9 +58,9 @@ class Device{
   }
 }
 
-DateTime getDateFromString(String unixDate){
-  if(unixDate == null)
+DateTime? getDateFromString(String? unixDate) {
+  if (unixDate == null) {
     return null;
-  return DateTime.fromMillisecondsSinceEpoch(
-      int.parse(unixDate));
-}
\ No newline at end of file
+  }
+  return DateTime.fromMillisecondsSinceEpoch(int.parse(unixDate));
+}
diff --git a/old_lib/models/device/device_transfer.dart b/old_lib/models/device/device_transfer.dart
index d62913ab..bb6d6d21 100644
--- a/old_lib/models/device/device_transfer.dart
+++ b/old_lib/models/device/device_transfer.dart
@@ -1,13 +1,13 @@
-import 'package:test_sa/models/device/device.dart';
-import 'package:test_sa/models/device/device_transfer_info.dart';
+import 'device.dart';
+import 'device_transfer_info.dart';
 
-class DeviceTransfer{
-  String id;
-  String userId;
-  String title;
-  Device device;
-  DeviceTransferInfo sender;
-  DeviceTransferInfo receiver;
+class DeviceTransfer {
+  String? id;
+  String? userId;
+  String? title;
+  Device? device;
+  DeviceTransferInfo? sender;
+  DeviceTransferInfo? receiver;
 
   DeviceTransfer({
     this.id,
@@ -18,33 +18,36 @@ class DeviceTransfer{
     this.receiver,
   });
 
-  bool validate(){
-    if(device == null) return false;
-    return receiver.validate();
+  bool validate() {
+    if (device == null) return false;
+    return receiver?.validate() ?? false;
   }
 
-  fromDeviceTransfer(DeviceTransfer old){
+  fromDeviceTransfer(DeviceTransfer old) {
     id = old.id;
     title = old.title;
     userId = old.userId;
-    device = Device.fromDevice(old.device);
+    device = old.device != null ? Device.fromDevice(old.device!) : null;
     final sender = DeviceTransferInfo();
-    sender.fromDetails(old.sender);
+    if (old.sender != null) {
+      sender.fromDetails(old.sender!);
+    }
     this.sender = sender;
     final receiver = DeviceTransferInfo();
-    receiver.fromDetails(old.receiver);
+    if (old.receiver != null) {
+      receiver.fromDetails(old.receiver!);
+    }
     this.receiver = receiver;
   }
 
-  factory DeviceTransfer.fromJson(Map<String,dynamic> parsedJson){
+  factory DeviceTransfer.fromJson(Map<String, dynamic> parsedJson) {
     return DeviceTransfer(
       id: parsedJson["id"],
       title: parsedJson["title"],
       userId: parsedJson["uid"],
       device: Device.fromJson(parsedJson["eq_sn"]),
-      sender: DeviceTransferInfo.fromJson(parsedJson,"sender_"),
-      receiver: DeviceTransferInfo.fromJson(parsedJson,"receiver_"),
+      sender: DeviceTransferInfo.fromJson(parsedJson, "sender_"),
+      receiver: DeviceTransferInfo.fromJson(parsedJson, "receiver_"),
     );
   }
 }
-
diff --git a/old_lib/models/device/device_transfer_info.dart b/old_lib/models/device/device_transfer_info.dart
index d3645b9d..3df2f3d2 100644
--- a/old_lib/models/device/device_transfer_info.dart
+++ b/old_lib/models/device/device_transfer_info.dart
@@ -1,17 +1,17 @@
-import 'package:test_sa/models/department.dart';
-import 'package:test_sa/models/hospital.dart';
-import 'package:test_sa/models/lookup.dart';
+import '../department.dart';
+import '../hospital.dart';
+import '../lookup.dart';
 
-class DeviceTransferInfo{
-  String userId;
-  String comment;
-  Hospital client;
-  Department department;
-  String workingHours;
-  String travelingHours;
-  String name;
-  String signature;
-  Lookup status;
+class DeviceTransferInfo {
+  String? userId;
+  String? comment;
+  Hospital? client;
+  Department? department;
+  String? workingHours;
+  String? travelingHours;
+  String? name;
+  String? signature;
+  Lookup? status;
 
   DeviceTransferInfo({
     this.userId,
@@ -25,37 +25,44 @@ class DeviceTransferInfo{
     this.status,
   });
 
-  Map<String,String>toJson(bool isSender){
-    Map<String,String> body = {};
+  Map<String, String> toJson(bool isSender) {
+    Map<String, String> body = {};
     final baseKey = isSender ? "sender_" : "receiver_";
 
-    if(comment != null && comment.isNotEmpty) body["${baseKey}comment"] = comment;
-    if(workingHours != null && workingHours.isNotEmpty) body["${baseKey}working_hours"] = workingHours;
-    if(travelingHours != null && travelingHours.isNotEmpty) body["${baseKey}travel_hours"] = comment;
-    if(status != null) body["${baseKey}status"] = status.id.toString();
-    if(signature != null && signature.isNotEmpty) body["${baseKey}image"] = signature;
+    if (comment?.isNotEmpty ?? false) body["${baseKey}comment"] = comment!;
+    if (workingHours?.isNotEmpty ?? false) {
+      body["${baseKey}working_hours"] = workingHours!;
+    }
+    if (travelingHours?.isNotEmpty ?? false) {
+      body["${baseKey}travel_hours"] = comment!;
+    }
+    final status = this.status;
+    if (status != null) body["${baseKey}status"] = status.id.toString();
+    if (signature?.isNotEmpty ?? false) body["${baseKey}image"] = signature!;
     return body;
   }
 
-  bool validate(){
-    if(client == null) return false;
-    if(department == null) return false;
+  bool validate() {
+    if (client == null) return false;
+    if (department == null) return false;
     return true;
   }
 
-  fromDetails(DeviceTransferInfo old,{bool withSignature = true}){
+  fromDetails(DeviceTransferInfo old, {bool withSignature = true}) {
     userId = old.userId;
     name = old.name;
-    client = Hospital.fromHospital(old.client);
-    department = Department.fromDepartment(old.department);
+    client = old.client != null ? Hospital.fromHospital(old.client!) : null;
+    department =
+        department != null ? Department.fromDepartment(old.department!) : null;
     workingHours = old.workingHours;
     travelingHours = old.travelingHours;
     comment = old.comment;
-    if(withSignature) signature = old.signature;
+    if (withSignature) signature = old.signature;
     status = old.status;
   }
 
-  factory DeviceTransferInfo.fromJson(Map<String,dynamic> parsedJson,String key){
+  factory DeviceTransferInfo.fromJson(
+      Map<String, dynamic> parsedJson, String key) {
     return DeviceTransferInfo(
       workingHours: parsedJson["${key}working_hours"],
       travelingHours: parsedJson["${key}travel_hours"],
@@ -69,4 +76,3 @@ class DeviceTransferInfo{
     );
   }
 }
-
diff --git a/old_lib/models/gas_refill/gas_refill_details.dart b/old_lib/models/gas_refill/gas_refill_details.dart
index f150e150..a89c218d 100644
--- a/old_lib/models/gas_refill/gas_refill_details.dart
+++ b/old_lib/models/gas_refill/gas_refill_details.dart
@@ -1,10 +1,10 @@
-import 'package:test_sa/models/lookup.dart';
+import '../lookup.dart';
 
-class GasRefillDetails{
-  Lookup type;
-  Lookup cylinderSize;
-  int requestedQuantity;
-  int deliveredQuantity;
+class GasRefillDetails {
+  Lookup? type;
+  Lookup? cylinderSize;
+  int? requestedQuantity;
+  int? deliveredQuantity;
 
   GasRefillDetails({
     this.type,
@@ -13,31 +13,34 @@ class GasRefillDetails{
     this.deliveredQuantity,
   });
 
-  bool validate(){
+  bool validate() {
     //if(cylinderSize == null) return false;
-    if(type == null) return false;
-    if(requestedQuantity == null) return false;
+    if (type == null) return false;
+    if (requestedQuantity == null) return false;
     return true;
   }
-  factory GasRefillDetails.fromJson(Map<String,dynamic> parsedJson){
+
+  factory GasRefillDetails.fromJson(Map<String, dynamic> parsedJson) {
     return GasRefillDetails(
       type: Lookup.fromJson(parsedJson["type"]),
-
       cylinderSize: Lookup.fromJson(parsedJson["size"]),
       requestedQuantity: parsedJson["requsted_qty"] == null
-          ? 0 : int.tryParse(parsedJson["requsted_qty"].toString()) ?? 0,
+          ? 0
+          : int.tryParse(parsedJson["requsted_qty"].toString()) ?? 0,
       deliveredQuantity: parsedJson["deliverd_qty"] == null
-          ? 0 : int.tryParse(parsedJson["deliverd_qty"].toString()) ?? 0,
+          ? 0
+          : int.tryParse(parsedJson["deliverd_qty"].toString()) ?? 0,
     );
   }
 
-  factory GasRefillDetails.fromDetails(GasRefillDetails details){
+  factory GasRefillDetails.fromDetails(GasRefillDetails details) {
     return GasRefillDetails(
-      type: Lookup.fromStatus(details.type),
-      cylinderSize:Lookup.fromStatus(details.cylinderSize),
+      type: details.type != null ? Lookup.fromStatus(details.type!) : null,
+      cylinderSize: details.cylinderSize != null
+          ? Lookup.fromStatus(details.cylinderSize!)
+          : null,
       requestedQuantity: details.requestedQuantity,
       deliveredQuantity: details.deliveredQuantity,
     );
   }
 }
-
diff --git a/old_lib/models/gas_refill/gas_refill_model.dart b/old_lib/models/gas_refill/gas_refill_model.dart
index 28773fac..09a8f517 100644
--- a/old_lib/models/gas_refill/gas_refill_model.dart
+++ b/old_lib/models/gas_refill/gas_refill_model.dart
@@ -1,13 +1,13 @@
-import 'package:test_sa/models/gas_refill/gas_refill_details.dart';
-import 'package:test_sa/models/lookup.dart';
+import '../lookup.dart';
+import 'gas_refill_details.dart';
 
-class GasRefillModel{
-  String id;
-  String userId;
-  String clientName;
-  String title;
-  Lookup status;
-  List<GasRefillDetails> details;
+class GasRefillModel {
+  String? id;
+  String? userId;
+  String? clientName;
+  String? title;
+  Lookup? status;
+  List<GasRefillDetails>? details;
 
   GasRefillModel({
     this.id,
@@ -18,25 +18,27 @@ class GasRefillModel{
     this.details,
   });
 
-  bool validate(){
-    if(title == null) return false;
-    if(status == null) return false;
-    if(details == null && details.isEmpty) return false;
+  bool validate() {
+    if (title == null) return false;
+    if (status == null) return false;
+    if (details == null && (details?.isEmpty ?? true)) return false;
     return true;
   }
 
-  fromGasRefillModel(GasRefillModel model){
+  fromGasRefillModel(GasRefillModel model) {
     id = model.id;
     userId = model.userId;
     clientName = model.clientName;
     title = model.title;
-    status = Lookup.fromStatus(model.status);
-    details = model.details.map((e) => GasRefillDetails.fromDetails(e)).toList();
+    status = model.status != null ? Lookup.fromStatus(model.status!) : null;
+    details = model.details
+        ?.map<GasRefillDetails>((e) => GasRefillDetails.fromDetails(e))
+        .toList();
   }
 
-  factory GasRefillModel.fromJson(Map<String,dynamic> parsedJson){
+  factory GasRefillModel.fromJson(Map<String, dynamic> parsedJson) {
     List<GasRefillDetails> details = [];
-    if(parsedJson["details"] != null){
+    if (parsedJson["details"] != null) {
       List list = parsedJson["details"];
       details = list.map((e) => GasRefillDetails.fromJson(e)).toList();
     }
@@ -50,4 +52,3 @@ class GasRefillModel{
     );
   }
 }
-
diff --git a/old_lib/models/pantry/calibration_tools.dart b/old_lib/models/pantry/calibration_tools.dart
index 2c70c6d2..5a258c6e 100644
--- a/old_lib/models/pantry/calibration_tools.dart
+++ b/old_lib/models/pantry/calibration_tools.dart
@@ -1,8 +1,8 @@
-import 'package:test_sa/models/lookup.dart';
+import '../lookup.dart';
 
-class CalibrationTool{
-  Lookup assetsNumber;
-  DateTime dataOfTesting;
+class CalibrationTool {
+  Lookup? assetsNumber;
+  DateTime? dataOfTesting;
 
   CalibrationTool({
     this.assetsNumber,
@@ -11,16 +11,21 @@ class CalibrationTool{
 
   Map<String, String> toMap() {
     return {
-      if(assetsNumber != null) 'assetsSN': (assetsNumber?.id).toString(),
-      if(dataOfTesting != null) 'dataOfTesting': (dataOfTesting.millisecondsSinceEpoch ~/ 1000).toString(),
+      if (assetsNumber != null) 'assetsSN': (assetsNumber?.id).toString(),
+      if (dataOfTesting != null)
+        'dataOfTesting':
+            ((dataOfTesting?.millisecondsSinceEpoch ?? 0) ~/ 1000).toString(),
     };
   }
 
   factory CalibrationTool.fromMap(Map<String, dynamic> map) {
     return CalibrationTool(
       assetsNumber: Lookup.fromJson(map['assetsSN']),
-      dataOfTesting: map['dataOfTesting'] == null || map['dataOfTesting'] == "" ? null :
-      DateTime.fromMillisecondsSinceEpoch(int.tryParse(map['dataOfTesting']) * 1000),
+      dataOfTesting: map['dataOfTesting'] == null || map['dataOfTesting'] == ""
+          ? null
+          : DateTime.fromMillisecondsSinceEpoch(
+              (int.tryParse(map['dataOfTesting']) ?? 0) * 1000,
+            ),
     );
   }
-}
\ No newline at end of file
+}
diff --git a/old_lib/models/pantry/contact.dart b/old_lib/models/pantry/contact.dart
index 50748bea..bda3e4a7 100644
--- a/old_lib/models/pantry/contact.dart
+++ b/old_lib/models/pantry/contact.dart
@@ -1,30 +1,29 @@
-import 'package:test_sa/models/lookup.dart';
+import '../lookup.dart';
 
-class Contact{
-  Lookup title;
-  Lookup contactPerson;
-  String job;
-  String email;
-  String telephone;
-  String landLine;
+class Contact {
+  Lookup? title;
+  Lookup? contactPerson;
+  String? job;
+  String? email;
+  String? telephone;
+  String? landLine;
 
-  Contact({
-    this.title,
-    this.contactPerson,
-    this.job,
-    this.email,
-    this.telephone,
-    this.landLine
-  });
+  Contact(
+      {this.title,
+      this.contactPerson,
+      this.job,
+      this.email,
+      this.telephone,
+      this.landLine});
 
   Map<String, String> toMap() {
     return {
-      if (title != null) 'title': title.id.toString(),
-      if (contactPerson != null) 'contactPerson': contactPerson.id.toString(),
-      if (job != null) 'job': job,
-      if (email != null) 'email': email,
-      if (telephone != null) 'telephone': telephone,
-      if (landLine != null) 'landLine': landLine,
+      if (title != null) 'title': title!.id.toString(),
+      if (contactPerson != null) 'contactPerson': contactPerson!.id.toString(),
+      if (job != null) 'job': job!,
+      if (email != null) 'email': email!,
+      if (telephone != null) 'telephone': telephone!,
+      if (landLine != null) 'landLine': landLine!,
     };
   }
 
@@ -38,4 +37,4 @@ class Contact{
       landLine: map['landLine'] as String,
     );
   }
-}
\ No newline at end of file
+}
diff --git a/old_lib/models/pantry/lookups/contact_person.dart b/old_lib/models/pantry/lookups/contact_person.dart
index 5231712c..f89c17cf 100644
--- a/old_lib/models/pantry/lookups/contact_person.dart
+++ b/old_lib/models/pantry/lookups/contact_person.dart
@@ -1,9 +1,10 @@
-import 'package:test_sa/models/lookup.dart';
+
+import '../../lookup.dart';
 
 class ContactTitle extends Lookup {
   ContactTitle({
-    int id,
-    String label
+    required int id,
+    required String label
   }):super(id: id,label: label);
 
   factory ContactTitle.fromMap(Map<String,dynamic> parsedJson){
diff --git a/old_lib/models/pantry/lookups/contact_title.dart b/old_lib/models/pantry/lookups/contact_title.dart
index 5231712c..f4edb581 100644
--- a/old_lib/models/pantry/lookups/contact_title.dart
+++ b/old_lib/models/pantry/lookups/contact_title.dart
@@ -1,15 +1,13 @@
-import 'package:test_sa/models/lookup.dart';
+import '../../lookup.dart';
 
 class ContactTitle extends Lookup {
-  ContactTitle({
-    int id,
-    String label
-  }):super(id: id,label: label);
+  ContactTitle({required int id, required String label})
+      : super(id: id, label: label);
 
-  factory ContactTitle.fromMap(Map<String,dynamic> parsedJson){
+  factory ContactTitle.fromMap(Map<String, dynamic> parsedJson) {
     return ContactTitle(
       label: parsedJson["value"],
       id: parsedJson["id"],
     );
   }
-}
\ No newline at end of file
+}
diff --git a/old_lib/models/pantry/pentry.dart b/old_lib/models/pantry/pentry.dart
index ebd855dc..967b8bdc 100644
--- a/old_lib/models/pantry/pentry.dart
+++ b/old_lib/models/pantry/pentry.dart
@@ -1,24 +1,23 @@
 import 'dart:convert';
 import 'dart:io';
 
-import 'package:test_sa/models/lookup.dart';
-import 'package:test_sa/models/pantry/calibration_tools.dart';
-import 'package:test_sa/models/pantry/pm_kit.dart';
-import 'package:test_sa/models/pantry/ppm_check_list.dart';
-import 'package:test_sa/models/timer_model.dart';
+import '../lookup.dart';
+import '../timer_model.dart';
+import 'calibration_tools.dart';
+import 'pm_kit.dart';
+import 'ppm_check_list.dart';
 
-class Pentry{
-  Lookup ppmVisitStatus;
-  Lookup status;
-  TimerModel timer;
-  DateTime actualVisitDate;
-  String travelingHours;
-  String image;
-  File imageFile;
-  // List<Contact> contacts;
-  List<PPMCheckList> ppmCheckLists;
-  List<CalibrationTool> calibrationTools;
-  List<PMKit> pmKits;
+class Pentry {
+  Lookup? ppmVisitStatus;
+  Lookup? status;
+  TimerModel? timer;
+  DateTime? actualVisitDate;
+  String? travelingHours;
+  String? image;
+  File? imageFile;
+  List<PPMCheckList>? ppmCheckLists;
+  List<CalibrationTool>? calibrationTools;
+  List<PMKit>? pmKits;
 
   Pentry({
     this.travelingHours,
@@ -34,10 +33,10 @@ class Pentry{
     this.pmKits,
   });
 
-  bool validate(){
-    if(actualVisitDate == null) return false;
-    if(timer == null && timer.endAt != null) return false;
-    if(ppmVisitStatus == null) return false;
+  bool validate() {
+    if (actualVisitDate == null) return false;
+    if (timer == null && timer?.endAt != null) return false;
+    if (ppmVisitStatus == null) return false;
     //if(status == null) return false;
 
     return true;
@@ -45,15 +44,21 @@ class Pentry{
 
   Map<String, String> toMap() {
     Map<String, String> map = {};
-    map["visit_status"] = ppmVisitStatus?.id.toString();
-    if(status != null) map["pentry_status"] = status?.id.toString();
-    if(travelingHours != null) map["traveling_hours"] = travelingHours;
-    if(imageFile != null) map["file_attachement"] = base64Encode(imageFile.readAsBytesSync());
-    map["actual_date"] = (actualVisitDate.millisecondsSinceEpoch / 1000).toStringAsFixed(0);
-    if(timer != null){
-      map["start_date"] = (timer.startAt.millisecondsSinceEpoch / 1000).toStringAsFixed(0);
-      map["end_date"] =  ((timer.endAt ?? DateTime.now()).millisecondsSinceEpoch / 1000).toStringAsFixed(0);
-      map["working_hours"] = (timer.durationInSecond / 60 / 60).toStringAsFixed(5);
+    if (ppmVisitStatus != null)
+      map["visit_status"] = ppmVisitStatus!.id.toString();
+    if (status != null) map["pentry_status"] = status!.id.toString();
+    if (travelingHours != null) map["traveling_hours"] = travelingHours!;
+    if (imageFile != null)
+      map["file_attachement"] = base64Encode(imageFile!.readAsBytesSync());
+    map["actual_date"] = ((actualVisitDate?.millisecondsSinceEpoch ?? 0) / 1000)
+        .toStringAsFixed(0);
+    if (timer != null) {
+      map["start_date"] =
+          (timer!.startAt.millisecondsSinceEpoch / 1000).toStringAsFixed(0);
+      map["end_date"] =
+          ((timer!.endAt).millisecondsSinceEpoch / 1000).toStringAsFixed(0);
+      map["working_hours"] =
+          (timer!.durationInSecond / 60 / 60).toStringAsFixed(5);
     }
     // if(contacts?.isNotEmpty == true) {
     //   for(int i = 0;i<contacts.length;i++){
@@ -62,9 +67,11 @@ class Pentry{
     //     });
     //   }
     // }
-    map["ppmCheckLists"] = jsonEncode(ppmCheckLists.map((e) => e.toMap()).toList());
-    map["calibrationTools"] = jsonEncode(calibrationTools.map((e) => e.toMap()).toList());
-    map["pmKits"] = jsonEncode(pmKits.map((e) => e.toMap()).toList());
+    map["ppmCheckLists"] =
+        jsonEncode(ppmCheckLists?.map((e) => e.toMap()).toList());
+    map["calibrationTools"] =
+        jsonEncode(calibrationTools?.map((e) => e.toMap()).toList());
+    map["pmKits"] = jsonEncode(pmKits?.map((e) => e.toMap()).toList());
     return map;
   }
 
@@ -77,22 +84,22 @@ class Pentry{
     // }
 
     List<PMKit> pmKits = [];
-    if(map['pmKits'] != null){
-      pmKits =(map['pmKits'] as List<dynamic>)
+    if (map['pmKits'] != null) {
+      pmKits = (map['pmKits'] as List<dynamic>)
           .map((e) => PMKit.fromMap(e as Map<String, dynamic>))
           .toList();
     }
 
     List<PPMCheckList> ppmCheckLists = [];
-    if(map['ppmCheckLists'] != null){
-      ppmCheckLists =(map['ppmCheckLists'] as List<dynamic>)
+    if (map['ppmCheckLists'] != null) {
+      ppmCheckLists = (map['ppmCheckLists'] as List<dynamic>)
           .map((e) => PPMCheckList.fromMap(e as Map<String, dynamic>))
           .toList();
     }
 
     List<CalibrationTool> calibrationTools = [];
-    if(map['calibrationTools'] != null){
-      calibrationTools =(map['calibrationTools'] as List<dynamic>)
+    if (map['calibrationTools'] != null) {
+      calibrationTools = (map['calibrationTools'] as List<dynamic>)
           .map((e) => CalibrationTool.fromMap(e as Map<String, dynamic>))
           .toList();
     }
@@ -102,10 +109,10 @@ class Pentry{
       actualVisitDate: getDate(map["actual_date"]),
       travelingHours: map["traveling_hours"],
       timer: TimerModel(
-        startAt: getDate(map["start_date"]),
-        endAt: getDate(map["end_date"]),
-        durationInSecond: (int.tryParse(map["working_hours"] ?? "") ?? 0) * 60 *60
-      ),
+          startAt: getDate(map["start_date"]),
+          endAt: getDate(map["end_date"]),
+          durationInSecond:
+              (int.tryParse(map["working_hours"] ?? "") ?? 0) * 60 * 60),
       // contacts: contacts,
       ppmCheckLists: ppmCheckLists,
       calibrationTools: calibrationTools,
@@ -113,8 +120,9 @@ class Pentry{
     );
   }
 
-  static getDate(String date){
-    return date == null || date.isEmpty
-        ? null : DateTime.fromMillisecondsSinceEpoch(int.tryParse(date) * 1000);
+  static getDate(String date) {
+    return date.isEmpty
+        ? null
+        : DateTime.fromMillisecondsSinceEpoch((int.tryParse(date) ?? 0) * 1000);
   }
-}
\ No newline at end of file
+}
diff --git a/old_lib/models/pantry/pm_kit.dart b/old_lib/models/pantry/pm_kit.dart
index 0a008e5f..09c9b78e 100644
--- a/old_lib/models/pantry/pm_kit.dart
+++ b/old_lib/models/pantry/pm_kit.dart
@@ -1,13 +1,14 @@
-import 'package:test_sa/models/lookup.dart';
+
+import '../lookup.dart';
 
 class PMKit{
-  Lookup itemCode;
-  String itemName;
-  String preparationTimeFrame;
-  String kitFrequencyDemand;
-  String availability;
-  String quantityNeeded;
-  String quantityReserved;
+  Lookup? itemCode;
+  String? itemName;
+  String? preparationTimeFrame;
+  String? kitFrequencyDemand;
+  String? availability;
+  String? quantityNeeded;
+  String? quantityReserved;
 
   PMKit({
     this.itemCode,
@@ -22,12 +23,12 @@ class PMKit{
   Map<String, String> toMap() {
     return {
       if(itemCode != null) 'itemCode': (itemCode?.id).toString(),
-      if(itemName != null) 'itemName': itemName,
-      if(preparationTimeFrame != null) 'preparationTimeFrame': preparationTimeFrame,
-      if(kitFrequencyDemand != null) 'kitFrequencyDemand': kitFrequencyDemand,
-      if(availability != null) 'availability': availability,
-      if(quantityNeeded != null) 'quantityNeeded': quantityNeeded,
-      if(quantityReserved != null) 'quantityReserved': quantityReserved,
+      if(itemName != null) 'itemName': itemName!,
+      if(preparationTimeFrame != null) 'preparationTimeFrame': preparationTimeFrame!,
+      if(kitFrequencyDemand != null) 'kitFrequencyDemand': kitFrequencyDemand!,
+      if(availability != null) 'availability': availability!,
+      if(quantityNeeded != null) 'quantityNeeded': quantityNeeded!,
+      if(quantityReserved != null) 'quantityReserved': quantityReserved!,
     };
   }
 
diff --git a/old_lib/models/pantry/ppm_check_list.dart b/old_lib/models/pantry/ppm_check_list.dart
index 8f1a14d7..444a1086 100644
--- a/old_lib/models/pantry/ppm_check_list.dart
+++ b/old_lib/models/pantry/ppm_check_list.dart
@@ -1,10 +1,11 @@
-import 'package:test_sa/models/lookup.dart';
+
+import '../lookup.dart';
 
 class PPMCheckList{
-  Lookup status;
-  String title;
-  String comment;
-  String measuredValue;
+  Lookup? status;
+  String? title;
+  String? comment;
+  String? measuredValue;
 
   PPMCheckList({
     this.title,
@@ -15,10 +16,10 @@ class PPMCheckList{
 
   Map<String, String> toMap() {
     return {
-      if(status != null) 'status': status?.id.toString(),
-      if(title != null) 'title': title,
-      if(comment != null) 'comment': comment,
-      if(measuredValue != null) 'measuredValue': measuredValue,
+      if(status != null) 'status': status!.id.toString(),
+      if(title != null) 'title': title!,
+      if(comment != null) 'comment': comment!,
+      if(measuredValue != null) 'measuredValue': measuredValue!,
     };
   }
 
diff --git a/old_lib/models/service_request/service_request.dart b/old_lib/models/service_request/service_request.dart
index edf66852..8cc04bd0 100644
--- a/old_lib/models/service_request/service_request.dart
+++ b/old_lib/models/service_request/service_request.dart
@@ -1,35 +1,35 @@
-import 'package:test_sa/models/lookup.dart';
+import '../lookup.dart';
 
-class ServiceRequest{
-  String id;
-  String requestCode;
-  String deviceSerialNumber;
-  String deviceId;
-  String deviceArName;
-  String deviceEnName;
-  List<String> devicePhotos;
-  String maintenanceIssue;
-  String hospitalName;
-  String hospitalId;
-  String departmentName;
-  String engineerName;
-  String date;
-  String audio;
-  int statusValue;
-  String statusLabel;
+class ServiceRequest {
+  String? id;
+  String? requestCode;
+  String? deviceSerialNumber;
+  String? deviceId;
+  String? deviceArName;
+  String? deviceEnName;
+  List<String>? devicePhotos;
+  String? maintenanceIssue;
+  String? hospitalName;
+  String? hospitalId;
+  String? departmentName;
+  String? engineerName;
+  String? date;
+  String? audio;
+  int? statusValue;
+  String? statusLabel;
 
-  bool viewReport;
-  String engineerMobile;
-  String deviceModel;
-  String faultDescription;
-  String workPerformed;
-  String visitDate;
-  DateTime nextVisitDate;
-  String jobSheetNumber;
-  String reportID;
-  String deviceNumber;
-  Lookup priority;
-  Lookup defectType;
+  bool? viewReport;
+  String? engineerMobile;
+  String? deviceModel;
+  String? faultDescription;
+  String? workPerformed;
+  String? visitDate;
+  DateTime? nextVisitDate;
+  String? jobSheetNumber;
+  String? reportID;
+  String? deviceNumber;
+  Lookup? priority;
+  Lookup? defectType;
 
   ServiceRequest({
     this.id,
@@ -48,7 +48,6 @@ class ServiceRequest{
     this.deviceId,
     this.audio,
     this.engineerName,
-
     this.viewReport = false,
     this.deviceModel,
     this.engineerMobile,
@@ -61,42 +60,46 @@ class ServiceRequest{
     this.defectType,
     this.priority,
     this.deviceNumber,
-
   });
 
-  factory ServiceRequest.fromJson(Map<String,dynamic> parsedJson){
+  factory ServiceRequest.fromJson(Map<String, dynamic> parsedJson) {
     return ServiceRequest(
       id: parsedJson["nid"],
-      requestCode: parsedJson["call_id"] ?? parsedJson["jobcode"] ,
+      requestCode: parsedJson["call_id"] ?? parsedJson["jobcode"],
       hospitalName: parsedJson["call_client"],
       deviceNumber: parsedJson["device_no"],
       deviceId: parsedJson["deviceid"],
       audio: parsedJson["audio"] ?? "",
       deviceArName: parsedJson["equipment_arabic_name"] == false
-          ? "No Name found" : parsedJson["equipment_arabic_name"],
+          ? "No Name found"
+          : parsedJson["equipment_arabic_name"],
       deviceEnName: parsedJson["equipment_english_name"] == false
-          ? "No Name found" : parsedJson["equipment_english_name"],
+          ? "No Name found"
+          : parsedJson["equipment_english_name"],
       devicePhotos: List<String>.from(parsedJson["image"]),
       deviceSerialNumber: parsedJson["call_sn"],
       date: parsedJson["call_data"],
       maintenanceIssue: parsedJson["call_complaint"] ?? parsedJson["complaint"],
       statusLabel: parsedJson["status_value"],
-      statusValue: int.tryParse(parsedJson["status"]??"-1"),
+      statusValue: int.tryParse(parsedJson["status"] ?? "-1"),
       departmentName: parsedJson["department_name"],
       engineerName: parsedJson["employee_name"],
       hospitalId: parsedJson["client"],
       reportID: parsedJson["service_report_nid"] is String
           ? parsedJson["service_report_nid"]
-          : null ,
+          : null,
       viewReport: parsedJson["service_report_nid"] is bool ? false : true,
       deviceModel: parsedJson["device_model"],
       engineerMobile: parsedJson["engineer_mobile"],
       faultDescription: parsedJson["fault_desc"],
       jobSheetNumber: parsedJson["job_sheet_number"],
       visitDate: parsedJson["visit_date"],
-      nextVisitDate:parsedJson["next_visit_date"] == null
-          ? null : DateTime.fromMillisecondsSinceEpoch(int.tryParse(parsedJson["next_visit_date"]) * 1000),
+      nextVisitDate: parsedJson["next_visit_date"] == null
+          ? null
+          : DateTime.fromMillisecondsSinceEpoch(
+              (int.tryParse(parsedJson["next_visit_date"]) ?? 0) * 1000,
+            ),
       workPerformed: parsedJson["work_performed"],
     );
   }
-}
\ No newline at end of file
+}
diff --git a/old_lib/models/service_request/service_request_search.dart b/old_lib/models/service_request/service_request_search.dart
index 257f25f5..51516636 100644
--- a/old_lib/models/service_request/service_request_search.dart
+++ b/old_lib/models/service_request/service_request_search.dart
@@ -1,10 +1,9 @@
-class ServiceRequestSearch{
-  String deviceSerialNumber;
-  String deviceName;
-  String hospital;
-  String model;
-  int statusValue;
-
+class ServiceRequestSearch {
+  String? deviceSerialNumber;
+  String? deviceName;
+  String? hospital;
+  String? model;
+  int? statusValue;
 
   ServiceRequestSearch({
     this.deviceSerialNumber,
@@ -14,33 +13,34 @@ class ServiceRequestSearch{
     this.hospital,
   });
 
-  fromSearch(ServiceRequestSearch newSearch){
+  fromSearch(ServiceRequestSearch newSearch) {
     deviceSerialNumber = newSearch.deviceSerialNumber;
     statusValue = newSearch.statusValue;
     hospital = newSearch.hospital;
     model = newSearch.model;
   }
 
-  String toSearchString(){
-    String _search = "";
-    if(deviceSerialNumber != null  && deviceSerialNumber.isNotEmpty){
-      _search += "&sn_id=$deviceSerialNumber";
+  String toSearchString() {
+    String search = "";
+    if (deviceSerialNumber != null &&
+        (deviceSerialNumber?.isNotEmpty ?? false)) {
+      search += "&sn_id=$deviceSerialNumber";
     }
 
-    if(statusValue != null){
-      _search += "&status=$statusValue";
+    if (statusValue != null) {
+      search += "&status=$statusValue";
     }
 
-    if(deviceName != null && deviceName.isNotEmpty){
-      _search += "&equipment_en_name=$deviceName";
+    if (deviceName != null && (deviceName?.isNotEmpty ?? false)) {
+      search += "&equipment_en_name=$deviceName";
     }
 
-    if(hospital != null && hospital.isNotEmpty){
-      _search += "&client=$hospital";
+    if (hospital != null && (hospital?.isNotEmpty ?? false)) {
+      search += "&client=$hospital";
     }
-    if(model != null && model.isNotEmpty){
-      _search += "&model=$model";
+    if (model != null && (model?.isNotEmpty ?? false)) {
+      search += "&model=$model";
     }
-    return _search;
+    return search;
   }
-}
\ No newline at end of file
+}