import java.util.ArrayList;

/**
 * Manage the stock in a business.
 * The stock is described by zero or more Products.
 *
 * @author (your name)
 * @version (a version number or a date)
 */
public class StockManager
{
    // A list of the products.
    private ArrayList<Product> stock;

    /**
     * Initialise the stock manager.
     */
    public StockManager()
    {
        stock = new ArrayList<Product>();
    }

    /**
     * Add a product to the list.
     * @param item The item to be added.
     */
    public void addProduct(Product item)
    {   int id = item.getID();
        int stockSize = stock.size();

        System.out.println("item.getID " + id);
        Product product = findProduct(id);

        if(stockSize==0 || product == null){
            stock.add(item);
        }

       else if(product.getID() != item.getID()){
        stock.add(item);
    }
    else
        System.out.println("there is a product with this ID or something else gone wrong");
    }

    /**
     * Receive a delivery of a particular product.
     * Increase the quantity of the product by the given amount.
     * @param id The ID of the product.
     * @param amount The amount to increase the quantity by.
     */
    public void delivery(int id, int amount)
    {
        if(findProduct(id)!=null){
           Product product = findProduct(id);
           product.increaseQuantity(amount);
           System.out.println("Quantity increased by " +amount);
        }
        else{
            System.out.println("Something is wrong?");
        }
    }

    /**
     * Try to find a product in the stock with the given id.
     * @return The identified product, or null if there is none
     *         with a matching ID.
     */
    public Product findProduct(int id)
    {
       for(Product product : stock) {

             if(product.getID()==id){
                 System.out.println(product.toString());
                 return product;
        }
        }
    return null;
    }


    public Product findProduct(String name)
    {
        int index = 0;
        boolean found = false;
        int stockSize = stock.size();

        if(stockSize==0){
            //System.out.println("There is nothing to find here");
            return null;
        }


        Product stockItem = stock.get(index);

        for(; index < stockSize && !found; index++) {
            stockItem = stock.get(index);
            if(stockItem.getName().equals(name)) {
            found = true;
            //System.out.println("Stock found: " + index + " " + stockItem.getName());
        }
    }

    if(!found){
        return null;
    }
    return stockItem;
    }

    /**
     * Locate a product with the given ID, and return how
     * many of this item are in stock. If the ID does not
     * match any product, return zero.
     * @param id The ID of the product.
     * @return The quantity of the given product in stock.
     */
    public int numberInStock(int id)
    {
        Product product = null;
        int quantity = 0;

         if(findProduct(id)!=null){
            product  = findProduct(id);
            quantity = product.getQuantity();
            System.out.println(quantity);
        }
        else{
            return 0;
        }
        return quantity;
    }

    /**
     * Print details of all the products.
     */
    public void printProductDetails()
    {
            for(Product product : stock) {
            System.out.println(product.toString());
        }
    }

    public void printLowStockProducts(int upperLimit){
         for(Product product : stock) {

             if(product.getQuantity()<upperLimit){
                 System.out.println(product.toString());
        }
        }
    }
}