import java.util.ArrayList;

/**
 * Write a description of class Cart here.
 *
 * @author (your name)
 * @version (a version number or a date)
 */
public class Cart
{
    //instance vars
    private ArrayList<Item> cart;
    
    public Cart() {
        cart = new ArrayList<Item>();
    }
    
    public void addItem( Item i ) throws Exception {
        
        if ( i.getQty() < 0 || i.getPrice() < 0.00)
           throw new Exception("Qty and price must be positive");
           
        //see how many times this item is already in the cart
        int numMatches = 0;
        int index = -1;
        int qty = 0;
        for (int j=0; j< cart.size(); j++) {
           if (cart.get(j).getName().equals(i.getName())) {
              numMatches++;
              index = j;
           }
       
        }
        
        
        if (numMatches <= 0)
            cart.add(i);   //add item to cart
        else {
            //update the quantity
            qty = cart.get(index).getQty();
            qty += i.getQty();
            cart.get(index).setQty(qty);
        }
        
    }
    
    
    public double calculateTotal() {
        double total =0.0;
        for(int t=0; t< cart.size(); t++)
          total += (cart.get(t).getQty()  *  cart.get(t).getPrice());
        return total;
    }
    
    
    public void checkout() {
        System.out.println("Shopping Cart");
        for (Item x : cart) 
           System.out.println(x);
           
        System.out.printf("Total: $%.2f\n" , calculateTotal());
    }
}