CartItem.java

package com.ctrlbuy.webshop.entity;

import jakarta.persistence.*;
import java.math.BigDecimal;
import java.time.LocalDateTime;

@Entity
@Table(name = "cart_items")
public class CartItem {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "cart_id", nullable = false)
    private Cart cart;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "product_id", nullable = false)
    private Product product;

    @Column(name = "quantity", nullable = false)
    private Integer quantity;

    @Column(name = "unit_price", precision = 10, nullable = false)
    private BigDecimal price;

    @Column(name = "subtotal", precision = 10)
    private BigDecimal subtotal;

    @Column(name = "created_at")
    private LocalDateTime createdAt;

    @Column(name = "updated_at")
    private LocalDateTime updatedAt;

    @PrePersist
    protected void onCreate() {
        createdAt = LocalDateTime.now();
        updatedAt = LocalDateTime.now();
        calculateSubtotal();
    }

    @PreUpdate
    protected void onUpdate() {
        updatedAt = LocalDateTime.now();
        calculateSubtotal();
    }

    // Constructors
    public CartItem() {}

    public CartItem(Cart cart, Product product, Integer quantity) {
        this.cart = cart;
        this.product = product;
        this.quantity = quantity;
        this.price = product.getPrice();
        calculateSubtotal();
    }

    public CartItem(Product product, Integer quantity) {
        this.product = product;
        this.quantity = quantity;
        this.price = product.getPrice();
        calculateSubtotal();
    }

    // Getters and Setters
    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public Cart getCart() {
        return cart;
    }

    public void setCart(Cart cart) {
        this.cart = cart;
    }

    public Product getProduct() {
        return product;
    }

    public void setProduct(Product product) {
        this.product = product;
        if (product != null) {
            this.price = product.getPrice();
            calculateSubtotal();
        }
    }

    public Integer getQuantity() {
        return quantity;
    }

    public void setQuantity(Integer quantity) {
        this.quantity = quantity;
        calculateSubtotal();
    }

    public BigDecimal getPrice() {
        return price;
    }

    public void setPrice(BigDecimal price) {
        this.price = price;
        calculateSubtotal();
    }

    public BigDecimal getSubtotal() {
        return subtotal;
    }

    public void setSubtotal(BigDecimal subtotal) {
        this.subtotal = subtotal;
    }

    public LocalDateTime getCreatedAt() {
        return createdAt;
    }

    public void setCreatedAt(LocalDateTime createdAt) {
        this.createdAt = createdAt;
    }

    public LocalDateTime getUpdatedAt() {
        return updatedAt;
    }

    public void setUpdatedAt(LocalDateTime updatedAt) {
        this.updatedAt = updatedAt;
    }

    // Business methods
    public void setUnitPrice(BigDecimal unitPrice) {
        this.price = unitPrice;
        calculateSubtotal();
    }

    public BigDecimal getUnitPrice() {
        return this.price;
    }

    public void updateQuantity(Integer newQuantity) {
        this.quantity = newQuantity;
        calculateSubtotal();
        this.updatedAt = LocalDateTime.now();
    }

    public void calculateSubtotal() {
        if (price != null && quantity != null) {
            this.subtotal = price.multiply(BigDecimal.valueOf(quantity));
        }
    }

    public void increaseQuantity() {
        this.quantity++;
        calculateSubtotal();
    }

    public void decreaseQuantity() {
        if (this.quantity > 1) {
            this.quantity--;
            calculateSubtotal();
        }
    }

    public String getProductName() {
        return product != null ? product.getName() : "Unknown Product";
    }

    public String getProductImageUrl() {
        return product != null ? product.getImageUrl() : null;
    }

    @Override
    public String toString() {
        return "CartItem{" +
                "id=" + id +
                ", product=" + (product != null ? product.getName() : "null") +
                ", quantity=" + quantity +
                ", price=" + price +
                ", subtotal=" + subtotal +
                '}';
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        CartItem cartItem = (CartItem) o;

        if (id != null ? !id.equals(cartItem.id) : cartItem.id != null) return false;
        return product != null ? product.equals(cartItem.product) : cartItem.product == null;
    }

    @Override
    public int hashCode() {
        int result = id != null ? id.hashCode() : 0;
        result = 31 * result + (product != null ? product.hashCode() : 0);
        return result;
    }
}