/**
 * 
 */
package cart;

import java.util.*;
import bookInfo.*;

import javax.servlet.ServletRequest;
import javax.servlet.http.*;
import javax.servlet.jsp.PageContext;

/**
 * @author yang xueyu
 * @date 2007-2-13
 */
public class CartService {
	HttpServletRequest request=null;
    //HttpSession session = request.getSession();//獲得會話對象
	public CartService(){
		//
		
		
	}
	
	  /**
	  * 增加購物車，如果購物車中存在此商品，那么就增加新購買的數量；否則，添加商品
	  * @param pid 圖書id
	  * @param count 數量
	  * @param products 圖書列表session
	  * @return void
	  */
	public Vector addCart(String bookTitle,float price, Vector shop){
		//Vector sh;
        //把圖書放進購物車        	
		CartItem mylist=new CartItem();
	    BookInfo bk=new BookInfo();
		bk.setBookTitle(bookTitle);
		bk.setPrice(price);
		mylist.setProduct(bk);
		mylist.setCount(1);
		boolean listFlag=true;
		//Vector shop=(Vector)session.getAttribute("shop");
		if(shop==null){
			shop=new Vector();
		}
		else{
			for(int i=0;i<shop.size();i++){
				CartItem list=(CartItem)shop.elementAt(i);
				if(list.getProduct().getBookTitle()==mylist.getProduct().getBookTitle()){
					int gc=list.getCount();
					gc++;
					shop.setElementAt(list,i);
					listFlag=false;
				}
			}
		}
		if(listFlag)shop.addElement(mylist);
		//session.setAttribute("shop",shop);
		return shop;
	}
    
	  /**
	  * 刪除購物車
	  * @param pid 圖書id
	  * @param count 數量
	  * @return void
	  */
	public void delCart(int pid){
        //刪除指定pid的商品項
        //cart.removeItem(pid);
	}
	
	  /**
	  * 修改購物車
	  * @param pid 圖書id
	  * @param count 數量
	  * @return void
	  */
	public Vector modifyCart(){
        //修改購物車項的數量
		
		ServletRequest session=null;
		Vector shop=(Vector)session.getAttribute("shop");
		Vector newshop=new Vector();
		for(int i=0;i<shop.size();i++){
			String number=request.getParameter("num"+i);
			if(number.equals("")){
				System.out.println("<script language='javascript'>" +
					"alert('數量不能為空');history.back();</script>");
			}
			CartItem mylist=(CartItem)shop.elementAt(i);
			String num=request.getParameter("num"+i);
			int newnum=Integer.parseInt(num);
			mylist.setCount(newnum);
			if(newnum!=0)
			{newshop.addElement(mylist);}
		}
		//session.setAttribute("shop",newshop);
		return newshop;
	}
}