feat: product variant

lib/presentation/home/models/product_quantity.dart

@@ -5,12 +5,14 @@ import 'package:enaklo_pos/data/models/response/product_response_model.dart';
 
 class ProductQuantity {
   final Product product;
+  ProductVariant? variant;
   int quantity;
   String notes;
   ProductQuantity({
     required this.product,
     required this.quantity,
     this.notes = '',
+    this.variant,
   });
 
   @override
@@ -20,17 +22,20 @@ class ProductQuantity {
     return other is ProductQuantity &&
         other.product == product &&
         other.quantity == quantity &&
+        other.variant == variant &&
         other.notes == notes;
   }
 
   @override
-  int get hashCode => product.hashCode ^ quantity.hashCode ^ notes.hashCode;
+  int get hashCode =>
+      product.hashCode ^ quantity.hashCode ^ variant.hashCode ^ notes.hashCode;
 
   Map<String, dynamic> toMap() {
     return {
       'product': product.toMap(),
       'quantity': quantity,
       'notes': notes,
+      'variant': variant?.toMap(),
     };
   }
 
@@ -43,6 +48,7 @@ class ProductQuantity {
       'quantity': quantity,
       'price': product.price,
       'notes': notes,
+      'variant': variant?.toMap(),
     };
   }
 
@@ -55,6 +61,7 @@ class ProductQuantity {
       'quantity': quantity,
       'price': product.price,
       'notes': notes,
+      'variant': variant?.toMap(),
     };
   }
 
@@ -63,6 +70,9 @@ class ProductQuantity {
       product: Product.fromMap(map['product']),
       quantity: map['quantity']?.toInt() ?? 0,
       notes: map['notes'] ?? '',
+      variant: map['variant'] != null
+          ? ProductVariant.fromMap(map['variant'])
+          : null,
     );
   }
 
@@ -72,6 +82,9 @@ class ProductQuantity {
       product: Product.fromOrderMap(map),
       quantity: map['quantity']?.toInt() ?? 0,
       notes: map['notes'] ?? '',
+      variant: map['variant'] != null
+          ? ProductVariant.fromMap(map['variant'])
+          : null,
     );
   }
 
@@ -89,6 +102,7 @@ class ProductQuantity {
       product: product ?? this.product,
       quantity: quantity ?? this.quantity,
       notes: notes ?? this.notes,
+      variant: variant,
     );
   }
 }