eatery-service/src/main/java/com/drinkool/dtos/OrderBill.java

@@ -0,0 +1,22 @@
+package com.drinkool.dtos;
+
+import java.util.List;
+
+import org.eclipse.microprofile.graphql.NonNull;
+
+import lombok.AllArgsConstructor;
+import lombok.NoArgsConstructor;
+
+@NoArgsConstructor
+@AllArgsConstructor
+public class OrderBill {
+
+	@NonNull
+	public List<OrderItem> items;
+
+	@NonNull
+	public Double totalAmount;
+
+	@NonNull
+	public String payQr;
+}

eatery-service/src/main/java/com/drinkool/dtos/OrderItem.java

@@ -0,0 +1,20 @@
+package com.drinkool.dtos;
+
+import java.util.UUID;
+import lombok.AllArgsConstructor;
+import lombok.NoArgsConstructor;
+import org.eclipse.microprofile.graphql.NonNull;
+
+@NoArgsConstructor
+@AllArgsConstructor
+public class OrderItem {
+
+	@NonNull
+	public UUID menuItemId;
+
+	@NonNull
+	public Integer quantity;
+
+	public Double price;
+	public Double subTotal;
+}

eatery-service/src/main/java/com/drinkool/services/EateryService.java

@@ -4,6 +4,8 @@ import com.drinkool.InternalValue;
 import com.drinkool.Role;
 import com.drinkool.dtos.AddMenuItem;
 import com.drinkool.dtos.DtoMapper;
+import com.drinkool.dtos.OrderBill;
+import com.drinkool.dtos.OrderItem;
 import com.drinkool.dtos.UpdateMenuItem;
 import com.drinkool.entities.EateryEntity;
 import com.drinkool.entities.MenuItemEntity;
@@ -17,6 +19,7 @@ import jakarta.ws.rs.GET;
 import jakarta.ws.rs.Path;
 import jakarta.ws.rs.PathParam;
 import jakarta.ws.rs.core.Response;
+import java.util.ArrayList;
 import java.util.List;
 import java.util.UUID;
 import org.eclipse.microprofile.graphql.GraphQLApi;
@@ -153,4 +156,35 @@ public class EateryService {
 
 		return MenuItemEntity.list("eatery", eatery);
 	}
+
+	@Query("calculateOrderSummary")
+	public OrderBill calculateOrderSummary(
+		@Name("eateryId") UUID eateryId,
+		@Name("items") List<OrderItem> inputItems
+	) {
+		List<OrderItem> details = new ArrayList<>();
+		double grandTotal = 0;
+
+		for (OrderItem input : inputItems) {
+			MenuItemEntity itemEntity = MenuItemEntity.find(
+				"id = ?1 and eatery.id = ?2",
+				input.menuItemId,
+				eateryId
+			).firstResult();
+
+			if (itemEntity != null) {
+				OrderItem detail = new OrderItem(
+					itemEntity.id,
+					input.quantity,
+					itemEntity.price,
+					itemEntity.price * input.quantity
+				);
+
+				details.add(detail);
+				grandTotal += detail.subTotal;
+			}
+		}
+
+		return new OrderBill(details, grandTotal, "");
+	}
 }

lib/src/main/java/com/drinkool/lib/dtos/ManagerSignup.java

@@ -3,4 +3,6 @@ package com.drinkool.lib.dtos;
 public class ManagerSignup extends Signup {
 
 	public String eateryName;
+
+	public String bankAccount;
 }