fix errors

lib/domain/entities/invoice.dart

@@ -1,3 +1,10 @@
+import 'package:fcs/domain/entities/cargo_type.dart';
+import 'package:fcs/domain/entities/carton.dart';
+import 'package:fcs/domain/entities/custom_duty.dart';
+import 'package:fcs/domain/entities/discount.dart';
+import 'package:fcs/domain/entities/discount_by_weight.dart';
+import 'package:fcs/domain/entities/rate.dart';
+
 import 'package.dart';
 import 'receipt.dart';
 
@@ -8,13 +15,89 @@ class Invoice {
   String customerName;
   String customerPhoneNumber;
   double amount;
-  String discount;
   String status;
   String paymentAttachment;
+  double handlingFee;
+  double deliveryFee;
+  double paidAmount;
 
   List<Package> packages;
   List<Receipt> receipts;
   List<String> receiptPhotos;
+  List<CustomDuty> customDuties;
+  List<Carton> cartons;
+  Discount discount;
+
+  List<CargoType> getCargoTypes(Rate rate) {
+    List<CargoType> cargoTypes = [];
+    double actualWeight = 0;
+    double shipmentWeight = 0;
+    cartons.forEach((c) {
+      c.cargoTypes.forEach((tc) {
+        if (cargoTypes.contains(tc)) {
+          CargoType existing = cargoTypes.firstWhere((wc) => wc.id == tc.id);
+          existing.weight += tc.weight;
+        } else {
+          cargoTypes.add(tc);
+        }
+        actualWeight += tc.weight;
+      });
+      double volume = (c.length ?? 0) * (c.width ?? 0) * (c.height ?? 0);
+      double sw = volume / rate.volumetricRatio ?? 0;
+      shipmentWeight += sw;
+    });
+
+    DiscountByWeight discountByWeight = rate.getDiscountByWeight(
+        shipmentWeight > actualWeight ? shipmentWeight : actualWeight);
+
+    cargoTypes.forEach((e) {
+      print(actualWeight > shipmentWeight);
+      double cargoWeight = actualWeight > shipmentWeight
+          ? e.weight
+          : e.weight / actualWeight * shipmentWeight;
+      double r =
+          e.rate - (discountByWeight != null ? discountByWeight.discount : 0);
+      double amount = cargoWeight * r;
+      e.calRate = r;
+      e.calWeight = cargoWeight;
+      e.amount = amount;
+    });
+    return cargoTypes;
+  }
+
+  double getTotal(Rate rate) {
+    List<CargoType> cargoTypes = getCargoTypes(rate);
+    var total = cargoTypes.fold(0.0, (p, c) => c.amount + p);
+    return total;
+  }
+
+  double getNetAmount(Rate rate) {
+    List<CargoType> cargoTypes = getCargoTypes(rate);
+    var total = cargoTypes.fold(0.0, (p, c) => c.amount + p);
+    total += getCustomFee();
+    total += getDeliveryFee();
+    total += getHandlingFee();
+    total -= getDiscount();
+    return total;
+  }
+
+  double getTotalBalance(Rate rate) {
+    return getNetAmount(rate) - (paidAmount ?? 0);
+  }
+
+  double getCustomFee() {
+    return customDuties == null ? 0 : customDuties.fold(0, (p, d) => p + d.fee);
+  }
+
+  double getHandlingFee() {
+    return handlingFee == null ? 0 : handlingFee;
+  }
+
+  double getDeliveryFee() {
+    return deliveryFee == null ? 0 : deliveryFee;
+  }
+
+  double getDiscount() => discount == null ? 0 : discount.amount;
 
   Invoice(
       {this.id,
@@ -28,6 +111,9 @@ class Invoice {
       this.paymentAttachment,
       this.packages,
       this.receiptPhotos,
+      this.customDuties,
+      this.cartons,
+      this.handlingFee,
       this.receipts});
 
   double get getAmount => packages.fold(0, (p, e) => (e.rate * e.weight) + p);