import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class DeleteServlet extends HttpServlet implements SingleThreadModel {
  private Integer balance;
  private Integer total;
  private ArrayList items;
  private ArrayList prices;
  public void doPost (HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    HttpSession session = request.getSession(false);
    balance = (Integer)session.getValue("balance");
    total = (Integer)session.getValue("total");
    items = (ArrayList)session.getValue("items");
    prices = (ArrayList)session.getValue("prices");
    if(request.getParameter("Delete").equals("all")) {
      items.clear();
      prices.clear();
      balance = new Integer(balance.intValue() + total.intValue());
      total = new Integer(0);
    }
    else {
      int element = Integer.parseInt(request.getParameter("Delete"));
      total = new Integer(total.intValue() - Integer.parseInt(prices.get(element).toString()));
      balance = new Integer(balance.intValue() + Integer.parseInt(prices.get(element).toString()));
      prices.remove(element);
      items.remove(element);
    }
    session.putValue("items",items);
    session.putValue("prices",prices);
    session.putValue("total",total);
    session.putValue("balance",balance);
    response.sendRedirect("ShoppingCartServlet");
  }
}