add max purchase count

src/common/enums/message.enum.ts

@@ -705,6 +705,7 @@ export const enum CartMessage {
   PRODUCT_NOT_BELONGS_TO_SHOP = 'محصول به این فروشگاه تعلق ندارد',
   PRODUCT_NO_INVENTORY = 'محصول موجودی ندارد',
   INSUFFICIENT_STOCK = 'موجودی کافی نیست',
+  MAX_PURCHASE_EXCEEDED = 'تعداد درخواستی بیش از حداکثر مجاز خرید این محصول است',
   USER_NOT_FOUND = 'کاربر یافت نشد',
   ADDRESS_NOT_FOUND = 'آدرس یافت نشد',
   SHOP_NOT_FOUND = 'فروشگاه یافت نشد',

src/modules/cart/providers/cart-item.service.ts

@@ -68,6 +68,7 @@ export class CartItemService {
       shopId,
       quantityToAdd,
       existingQuantityInCart,
+      cart,
     );
 
     if (index < 0) {

src/modules/cart/providers/cart-validation.service.ts

@@ -29,14 +29,16 @@ export class CartValidationService {
   ) { }
 
   /**
-   * Validate variant exists, belongs to shop, and has sufficient stock.
+   * Validate variant exists, belongs to shop, has sufficient stock, and respects max purchase per product.
    * @param existingQuantityInCart - current quantity of this variant already in cart (for add/increment)
+   * @param cart - current cart to compute total product quantity (for max purchase validation)
    */
   async validateAndGetVariant(
     variantId: string,
     shopId: string,
     quantityToAdd: number,
     existingQuantityInCart: number = 0,
+    cart?: { items: { variantId: string; quantity: number }[] },
   ): Promise<Variant> {
     const variant = await this.productService.findOrFailVariant(variantId);
 
@@ -51,6 +53,20 @@ export class CartValidationService {
       }
     }
 
+    const maxPurchase = variant.product.maxPurchaseQuantity;
+    if (maxPurchase != null && maxPurchase > 0) {
+      const productVariantIds = variant.product.variants.getItems().map((v) => v.id);
+      const totalProductQuantityInCart =
+        cart?.items?.reduce(
+          (sum, item) => (productVariantIds.includes(item.variantId) ? sum + item.quantity : sum),
+          0,
+        ) ?? 0;
+      const newTotalProductQuantity = totalProductQuantityInCart - existingQuantityInCart + quantityToAdd;
+      if (newTotalProductQuantity > maxPurchase) {
+        throw new BadRequestException(CartMessage.MAX_PURCHASE_EXCEEDED);
+      }
+    }
+
     return variant;
   }
 

src/modules/orders/providers/orders.service.ts

@@ -361,9 +361,12 @@ export class OrdersService {
 
   private async buildOrderItemsData(cart: Cart, shopId: string): Promise<OrderItemData[]> {
     const orderItemsData: OrderItemData[] = [];
+    const productQuantityMap = new Map<string, number>();
 
     for (const cartItem of cart.items) {
-      const variant = await this.em.findOne(Variant, { id: cartItem.variantId }, { populate: ['product', 'product.shop'] });
+      const variant = await this.em.findOne(Variant, { id: cartItem.variantId }, {
+        populate: ['product', 'product.shop', 'product.variants'],
+      });
       if (!variant) throw new NotFoundException(OrderMessage.PRODUCT_NOT_FOUND);
 
       if (variant.product.shop.id !== shopId) {
@@ -374,6 +377,17 @@ export class OrdersService {
         throw new BadRequestException(CartMessage.INSUFFICIENT_STOCK);
       }
 
+      const maxPurchase = variant.product.maxPurchaseQuantity;
+      if (maxPurchase != null && maxPurchase > 0) {
+        const productId = variant.product.id;
+        const currentProductTotal = productQuantityMap.get(productId) ?? 0;
+        const newProductTotal = currentProductTotal + cartItem.quantity;
+        if (newProductTotal > maxPurchase) {
+          throw new BadRequestException(CartMessage.MAX_PURCHASE_EXCEEDED);
+        }
+        productQuantityMap.set(productId, newProductTotal);
+      }
+
       orderItemsData.push({
         variant,
         quantity: cartItem.quantity,

src/modules/products/dto/create-product.dto.ts

@@ -118,4 +118,10 @@ export class CreateProductDto {
   @ApiPropertyOptional({ example: 1 })
   order?: number;
 
+  @IsOptional()
+  @IsInt()
+  @Min(1)
+  @Type(() => Number)
+  @ApiPropertyOptional({ description: 'Maximum quantity per order; omit or null for unlimited', example: 5 })
+  maxPurchaseQuantity?: number | null;
 }

src/modules/products/entities/product.entity.ts

@@ -56,4 +56,8 @@ export class Product extends BaseEntity {
 
   @Property({ type: 'decimal', precision: 10, scale: 0, nullable: true })
   price?: number;
+
+  /** Maximum quantity per order; null means unlimited */
+  @Property({ type: 'int', nullable: true, default: null })
+  maxPurchaseQuantity: number | null = null;
 }

src/modules/products/providers/product.service.ts

@@ -43,6 +43,7 @@ export class ProductService {
         discount: rest.discount ?? 0,
         isSpecialOffer: rest.isSpecialOffer ?? false,
         order: rest.order ?? null,
+        maxPurchaseQuantity: rest.maxPurchaseQuantity ?? null,
         // map single-title/content DTO to localized fields
         title: rest.title,
         attribute: rest.attribute,
@@ -240,10 +241,12 @@ export class ProductService {
   }
 
   async findOrFailVariant(variantId: string) {
-    const variant = await this.em.findOne(Variant, { id: variantId }, { populate: ['product', 'product.shop',] });
+    const variant = await this.em.findOne(Variant, { id: variantId }, {
+      populate: ['product', 'product.shop', 'product.variants'],
+    });
 
     if (!variant) throw new NotFoundException('Variant not found');
 
-    return variant
+    return variant;
   }
 }