feat: cart and cart item services

shopping_cart/src/main/java/com/thutasann/shopping_cart/model/CartItem.java

@@ -38,7 +38,10 @@ public class CartItem {
     @JoinColumn(name = "cart_id")
     private Cart cart;
 
-    public void setToPrice() {
+    /**
+     * Custom Set Total Price Method
+     */
+    public void setTotalPrice() {
         this.totalPrice = this.unitPrice.multiply(new BigDecimal(quantity));
     }
 

shopping_cart/src/main/java/com/thutasann/shopping_cart/service/cart/CartItemService.java

@@ -1,32 +1,86 @@
 package com.thutasann.shopping_cart.service.cart;
 
+import java.math.BigDecimal;
+
 import org.springframework.stereotype.Service;
 
+import com.thutasann.shopping_cart.exceptions.ResourceNotFoundException;
+import com.thutasann.shopping_cart.model.Cart;
 import com.thutasann.shopping_cart.model.CartItem;
+import com.thutasann.shopping_cart.model.Product;
+import com.thutasann.shopping_cart.repository.CartItemRepository;
+import com.thutasann.shopping_cart.repository.CartRepository;
+import com.thutasann.shopping_cart.service.product.IProductService;
 
 import lombok.RequiredArgsConstructor;
 
 @Service
 @RequiredArgsConstructor
 public class CartItemService implements ICartItemService {
+    private final CartItemRepository cartItemRepository;
+    private final CartRepository cartRepository;
+    private final IProductService productService;
+    private final ICartService cartService;
+
     @Override
     public void AddItemToCart(Long cartId, Long productId, int quantity) {
-        throw new UnsupportedOperationException("Unimplemented method 'AddItemToCart'");
+        Cart cart = cartService.getCart(cartId);
+        Product product = productService.getProductById(productId);
+        CartItem cartItem = cart.getItems()
+                .stream()
+                .filter(item -> item.getProduct().getId().equals(productId))
+                .findFirst().orElse(new CartItem());
+
+        if (cartItem.getId() == null) {
+            cartItem.setCart(cart);
+            cartItem.setProduct(product);
+            cartItem.setQuantity(quantity);
+            cartItem.setUnitPrice(product.getPrice());
+        } else {
+            cartItem.setQuantity(cartItem.getQuantity() + quantity);
+        }
+
+        cartItem.setTotalPrice();
+        cart.addItem(cartItem);
+        cartItemRepository.save(cartItem);
+        cartRepository.save(cart);
     }
 
     @Override
     public void removeItemFromCart(Long cartId, Long productId) {
-        throw new UnsupportedOperationException("Unimplemented method 'removeItemFromCart'");
+        Cart cart = cartService.getCart(cartId);
+        CartItem cartItem = this.getCartItem(cartId, productId);
+        cart.removeItem(cartItem);
+        cartRepository.save(cart);
     }
 
     @Override
     public void updateItemQuantity(Long cartId, Long productId, int quantity) {
-        throw new UnsupportedOperationException("Unimplemented method 'updateItemQuantity'");
+        Cart cart = cartService.getCart(cartId);
+        cart.getItems()
+                .stream()
+                .filter(item -> item.getProduct().getId().equals(productId))
+                .findFirst()
+                .ifPresent(item -> {
+                    item.setQuantity(quantity);
+                    item.setUnitPrice(item.getProduct().getPrice());
+                    item.setTotalPrice();
+                });
+        BigDecimal totalAmount = cart.getItems()
+                .stream().map(CartItem::getTotalPrice)
+                .reduce(BigDecimal.ZERO, BigDecimal::add);
+        cart.setTotalAmount(totalAmount);
+        cartRepository.save(cart);
     }
 
     @Override
     public CartItem getCartItem(Long cartId, Long productId) {
-        throw new UnsupportedOperationException("Unimplemented method 'getCartItem'");
+        Cart cart = cartService.getCart(cartId);
+        return cart.getItems()
+                .stream()
+                .filter(item -> item.getProduct().getId().equals(productId))
+                .findFirst()
+                .orElseThrow(() -> new ResourceNotFoundException("Cart Item not found"));
     }
 
 }

shopping_cart/src/main/java/com/thutasann/shopping_cart/service/cart/CartService.java

@@ -1,32 +1,60 @@
 package com.thutasann.shopping_cart.service.cart;
 
+import java.math.BigDecimal;
+import java.util.concurrent.atomic.AtomicLong;
+
 import org.springframework.stereotype.Service;
 
-import com.thutasann.shopping_cart.model.CartItem;
+import com.thutasann.shopping_cart.exceptions.ResourceNotFoundException;
+import com.thutasann.shopping_cart.model.Cart;
+import com.thutasann.shopping_cart.repository.CartItemRepository;
+import com.thutasann.shopping_cart.repository.CartRepository;
 
+import jakarta.transaction.Transactional;
 import lombok.RequiredArgsConstructor;
 
 @Service
 @RequiredArgsConstructor
-public class CartService implements ICartItemService {
+public class CartService implements ICartService {
+
+    private final CartRepository cartRepository;
+    private final CartItemRepository cartItemRepository;
+    private final AtomicLong cartIdGenerator = new AtomicLong(0);
+
+    @Override
+    public Cart getCart(Long id) {
+        Cart cart = cartRepository.findById(id).orElseThrow(() -> new ResourceNotFoundException("Cart not found"));
+        BigDecimal totalAmount = cart.getTotalAmount();
+        cart.setTotalAmount(totalAmount);
+        return cart;
+    }
+
+    @Transactional
     @Override
-    public void AddItemToCart(Long cartId, Long productId, int quantity) {
-        throw new UnsupportedOperationException("Unimplemented method 'AddItemToCart'");
+    public void clearCart(Long id) {
+        Cart cart = this.getCart(id);
+        cartItemRepository.deleteAllByCartId(id);
+        cart.getItems().clear();
+        cartRepository.deleteById(id);
     }
 
     @Override
-    public void removeItemFromCart(Long cartId, Long productId) {
-        throw new UnsupportedOperationException("Unimplemented method 'removeItemFromCart'");
+    public BigDecimal getTotalPrice(Long id) {
+        Cart cart = this.getCart(id);
+        return cart.getTotalAmount();
     }
 
     @Override
-    public void updateItemQuantity(Long cartId, Long productId, int quantity) {
-        throw new UnsupportedOperationException("Unimplemented method 'updateItemQuantity'");
+    public Long initializeNewCart() {
+        Cart newCart = new Cart();
+        Long newCartId = cartIdGenerator.incrementAndGet();
+        newCart.setId(newCartId);
+        return cartRepository.save(newCart).getId();
     }
 
     @Override
-    public CartItem getCartItem(Long cartId, Long productId) {
-        throw new UnsupportedOperationException("Unimplemented method 'getCartItem'");
+    public Cart getCartByUserId(Long userId) {
+        return cartRepository.findByUserId(userId);
     }
 
 }