cleanup code

lib/domain/entities/carton.dart

@@ -59,23 +59,17 @@ class Carton {
   List<Carton> mixCartons;
   List<String> mixCartonIDs;
 
-  int get amount => rate != null && weight != null ? (rate * weight) : 0;
+  int get amount => (rate * weight);
 
   // String get packageNumber =>
   //     shipmentNumber + "-" + receiverNumber + " #" + boxNumber;
 
   double get actualWeight =>
-      cargoTypes == null ? 0 : cargoTypes.fold(0, (p, e) => e.weight + p);
+      cargoTypes.isEmpty ? 0 : cargoTypes.fold(0, (p, e) => e.weight + p);
 
   int getShipmentWeight(double volumetricRatio) {
-    if (length == null ||
-        length <= 0 ||
-        width == null ||
-        width <= 0 ||
-        height == null ||
-        height <= 0 ||
-        volumetricRatio == null ||
-        volumetricRatio <= 0) return 0;
+    if (length <= 0 || width <= 0 || height <= 0 || volumetricRatio <= 0)
+      return 0;
 
     return ((length * width * height) / volumetricRatio).round();
   }
@@ -113,8 +107,7 @@ class Carton {
 
     double total = 0;
     cargoTypes.forEach((e) {
-      double r =
-          e.rate - (discountByWeight != null ? (discountByWeight.discount) : 0);
+      double r = e.rate - (discountByWeight.discount);
       double amount = e.weight * r;
       total += amount;
     });

lib/domain/entities/fcs_shipment.dart

@@ -30,9 +30,13 @@ class FcsShipment {
   });
 
   factory FcsShipment.fromMap(Map<String, dynamic> map, String docID) {
-    var _cutoffDate = (map['cutoff_date'] as Timestamp);
-    var _arrivalDate = (map['arrival_date'] as Timestamp);
-    var _departureDate = (map['departure_date'] as Timestamp);
+    var _cutoffDate =
+        map['cutoff_date'] == null ? null : (map['cutoff_date'] as Timestamp);
+    var _arrivalDate =
+        map['arrival_date'] == null ? null : (map['arrival_date'] as Timestamp);
+    var _departureDate = map['departure_date'] == null
+        ? null
+        : (map['departure_date'] as Timestamp);
 
     return FcsShipment(
       id: docID,

lib/domain/entities/invoice.dart

@@ -35,7 +35,7 @@ class Invoice {
   String? invoiceURL;
 
   List<CargoType> getCargoTypes(Rate rate) {
-    if (cargoTypes != null) return cargoTypes;
+    if (cargoTypes.isNotEmpty) return cargoTypes;
 
     List<CargoType> _cargoTypes = [];
     double totalCalWeight = 0;
@@ -59,8 +59,7 @@ class Invoice {
         rate.getDiscountByWeight(totalCalWeight);
 
     _cargoTypes.forEach((e) {
-      double r =
-          e.rate - (discountByWeight != null ? discountByWeight.discount : 0);
+      double r = e.rate - discountByWeight.discount;
       e.calRate = r;
     });
     return _cargoTypes;
@@ -95,11 +94,11 @@ class Invoice {
   }
 
   double getCustomFee() {
-    return customDuties == null ? 0 : customDuties.fold(0, (p, d) => p + d.fee);
+    return customDuties.isEmpty ? 0 : customDuties.fold(0, (p, d) => p + d.fee);
   }
 
   double getDeliveryFee() {
-    return deliveryFee == null ? 0 : deliveryFee;
+    return deliveryFee;
   }
 
   double getDiscount() => discount == null ? 0 : discount!.amount;

lib/domain/entities/package.dart

@@ -38,7 +38,7 @@ class Package {
   //for packages in processing
   List<File?> photoFiles;
 
-  int get amount => rate != null && weight != null ? rate * weight : 0;
+  int get amount => rate * weight;
 
   double get price => rate.toDouble() * weight;
 

lib/domain/entities/shipment.dart

@@ -74,7 +74,8 @@ class Shipment {
   bool get isReceived => status == shipment_received_status;
 
   factory Shipment.fromMap(Map<String, dynamic> map, String id) {
-    var pd = (map['pickup_date'] as Timestamp);
+    var pd =
+        map['pickup_date'] == null ? null : (map['pickup_date'] as Timestamp);
     var pa = map['pickup_address'];
     var _pa = pa != null ? DeliveryAddress.fromMap(pa, pa["id"]) : null;
     return Shipment(

lib/domain/entities/user.dart

@@ -41,16 +41,10 @@ class User {
     }
   }
 
-  String get getUserUnseenCount => userUnseenCount != null
-      ? userUnseenCount > 100
-          ? "99+"
-          : userUnseenCount.toString()
-      : "0";
-  String get getFcsUnseenCount => fcsUnseenCount != null
-      ? fcsUnseenCount > 100
-          ? "99+"
-          : fcsUnseenCount.toString()
-      : "0";
+  String get getUserUnseenCount =>
+      userUnseenCount > 100 ? "99+" : userUnseenCount.toString();
+  String get getFcsUnseenCount =>
+      fcsUnseenCount > 100 ? "99+" : fcsUnseenCount.toString();
 
   List<String> privileges = [];
 
@@ -101,7 +95,8 @@ class User {
   }
 
   factory User.fromMap(Map<String, dynamic> map, String docID) {
-    var _date = (map['message_time'] as Timestamp);
+    var _date =
+        map['message_time'] == null ? null : (map['message_time'] as Timestamp);
 
     List<String> _privileges =
         map['privileges'] == null ? [] : map['privileges'].cast<String>();
@@ -127,7 +122,7 @@ class User {
   }
 
   bool isCustomer() {
-    return privileges == null || privileges.length == 0;
+    return privileges.length == 0;
   }
 
   bool hasSysAdmin() {
@@ -183,7 +178,7 @@ class User {
   }
 
   bool _has(String privilege) {
-    return (privileges != null ? privileges.contains(privilege) : false);
+    return (privileges.contains(privilege));
   }
 
   @override

lib/domain/exceiptions/server_exceptions.dart

@@ -1,12 +0,0 @@
-
-class ServerException  {
-  @override
-  List<Object>? get props => null;
-
-  call() {
-    return null;
-  }
-
-  @override
-  bool? get stringify => null;
-}