e-commerce/web_backend/src/main/java/org/hso/ecommerce/entities/shop/ShoppingCart.java

package org.hso.ecommerce.entities.shop;

import java.util.ArrayList;
import java.util.List;

// Not a db entity. Just for session storage
public class ShoppingCart {

    private final static int MAX_ITEMS = 10;

    private int revision;
    private ArrayList<ShoppingCartItem> items;

    public ShoppingCart() {
        clear();
    }

    public void clear() {
        items = new ArrayList<>();
        revision = (int) Math.round(Math.random() * 0xFFFF);
    }

    public List<ShoppingCartItem> getItems() {
        return items;
    }

    public int getItemCount() {
        int count = 0;

        for (ShoppingCartItem i : items) {
            count += i.getAmount();
        }

        return count;
    }

    public int getRevision() {
        return revision;
    }

    public void addArticle(Article article, int quantity) {
        this.revision++;

        for (ShoppingCartItem i : items) {
            if (i.getArticleId() == article.id) {
                i.addAmount(quantity);
                return;
            }
        }

        items.add(new ShoppingCartItem(quantity, article));
    }

    public void setArticleCount(Article article, Integer quantity) {
        this.revision++;

        boolean found = false;
        for (ShoppingCartItem i : items) {
            if (i.getArticleId() == article.id) {
                i.setAmount(quantity);
                found = true;
                break;
            }
        }
        if (!found) {
            items.add(new ShoppingCartItem(quantity, article));
        }

        items.removeIf(i -> i.getAmount() <= 0);
    }

    public int getArticleCount(Article article) {
        for (ShoppingCartItem i : items) {
            if (i.getArticleId() == article.id) {
                return i.amount;
            }
        }

        return 0;
    }

    public static class ShoppingCartItem {
        private int amount;
        private final long articleId;

        public ShoppingCartItem(int amount, Article article) {
            this.amount = amount;
            this.articleId = article.id;
        }

        public int getAmount() {
            return amount;
        }

        public void addAmount(int amount) {
            this.amount += amount;
            if (this.amount > MAX_ITEMS) {
                this.amount = MAX_ITEMS;
            }
        }

        public long getArticleId() {
            return articleId;
        }

        public void setAmount(Integer amount) {
            this.amount = amount;
            if (this.amount > MAX_ITEMS) {
                this.amount = MAX_ITEMS;
            }
        }
    }
}