feat: payment split

lib/data/models/request/payment_request.dart

@@ -78,3 +78,57 @@ class PaymentOrderItemModel {
         "amount": amount,
       };
 }
+
+class PaymentSplitBillRequest {
+  final String orderId;
+  final String paymentMethodId;
+  final String customerId;
+  final String type; // e.g., "AMOUNT" or "ITEM"
+  final int amount;
+  final List<SplitItem> items;
+
+  PaymentSplitBillRequest({
+    required this.orderId,
+    required this.paymentMethodId,
+    required this.customerId,
+    required this.type,
+    required this.amount,
+    required this.items,
+  });
+
+  Map<String, dynamic> toMap() {
+    Map<String, dynamic> data = {
+      'order_id': orderId,
+      'payment_method_id': paymentMethodId,
+      'customer_id': customerId,
+      'type': type,
+    };
+
+    if (type == "AMOUNT") {
+      data['amount'] = amount;
+    }
+
+    if (type == "ITEM") {
+      data['items'] = items.map((e) => e.toJson()).toList();
+    }
+
+    return data;
+  }
+}
+
+class SplitItem {
+  final String orderItemId;
+  final int quantity;
+
+  SplitItem({
+    required this.orderItemId,
+    required this.quantity,
+  });
+
+  Map<String, dynamic> toJson() {
+    return {
+      'order_item_id': orderItemId,
+      'quantity': quantity,
+    };
+  }
+}