feat: add bulk to cart add

src/modules/cart/cart.service.ts

@@ -3,6 +3,7 @@ import { ClientSession, Types, startSession } from "mongoose";
 
 import { CartRepository, CartShipItemRepo } from "./cart.repository";
 import { AddToCartDTO } from "./DTO/addToCart.dto";
+import { BulkAddToCartDTO } from "./DTO/bulkAddToCart.dto";
 import { CartDTO } from "./DTO/cart.dto";
 import { RemoveFromCartDTO } from "./DTO/removeFromCart.dto";
 import { UpdateCartDTO } from "./DTO/updateCart.dto";
@@ -79,6 +80,65 @@ class CartService {
     }
   }
 
+  async bulkAddToCartS(bulkAddToCartDto: BulkAddToCartDTO, userId: string) {
+    const session = await startSession();
+    session.startTransaction();
+    try {
+      const { items } = bulkAddToCartDto;
+
+      // Get or create cart
+      let cart = await this.cartRepo.model.findOne({ user: userId });
+      if (!cart) {
+        cart = (await this.cartRepo.model.create([{ user: userId }], { session }))[0];
+      }
+
+      // Validate all products before making any changes
+      for (const item of items) {
+        const existingCartItem = cart.items.find(
+          (cartItem) => cartItem.product === item.productId && cartItem.variant.toString() === item.variantId,
+        );
+        const existingQuantity = existingCartItem ? existingCartItem.quantity : 0;
+
+        await this.validateProduct(item.productId, item.variantId, existingQuantity + item.quantity);
+      }
+
+      // Process each item
+      for (const item of items) {
+        const existingCartItem = cart.items.find(
+          (cartItem) => cartItem.product === item.productId && cartItem.variant.toString() === item.variantId,
+        );
+
+        if (existingCartItem) {
+          // Update quantity if item already exists in the cart
+          existingCartItem.quantity += item.quantity;
+        } else {
+          // Add new item to the cart
+          cart.items.push({
+            product: item.productId,
+            quantity: item.quantity,
+            variant: new Types.ObjectId(item.variantId),
+          });
+        }
+      }
+
+      await cart.save({ session });
+
+      // Commit the transaction
+      await session.commitTransaction();
+      session.endSession();
+
+      return {
+        message: CartMessage.ItemAdded,
+        cart: await this.getCartS(userId),
+      };
+    } catch (error) {
+      // Rollback any changes made in the transaction
+      await session.abortTransaction();
+      session.endSession();
+      throw error; // Re-throw the error to be handled by the calling errorHandler
+    }
+  }
+
   async updateCartS(updateCartDto: UpdateCartDTO, userId: string) {
     const { productId, variantId, quantity } = updateCartDto;