package com.sys.service;
import java.io.IOException;

import java.io.PrintWriter;

import java.io.UnsupportedEncodingException;

import javax.servlet.FilterChain;

import javax.servlet.ServletException;

import javax.servlet.http.Cookie;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

import java.security.MessageDigest;

import java.security.NoSuchAlgorithmException;

import com.sun.org.apache.xerces.internal.impl.dv.util.Base64;
import com.sys.model.SysUser;

/*

* 2014.07.01

* */

public class CookieUtil {/*

    //保存cookie时的cookieName
    private final static String cookieDomainName = "caibadmin";
    //加密cookie时的网站自定码

    private final static String webKey = "123456";
    //设置cookie有效期是两个星期，根据需要自定义
    private final static long cookieMaxAge = 60 * 60 * 24 * 7 * 2;
    //保存Cookie到客户端-------------------------------------------------------------------------
    //在CheckLogonServlet.java中被调用
    //传递进来的user对象中封装了在登陆时填写的用户名与密码

    public static void saveCookie(SysUser user, HttpServletResponse response) {
        //cookie的有效期
        long validTime = System.currentTimeMillis() + (cookieMaxAge * 5000);
        //MD5加密用户详细信息
        String cookieValueWithMd5 =getMD5(user.getUserName() + ":" + user.getPassword()

                + ":" + validTime + ":" + webKey);
        //将要被保存的完整的Cookie值
        String cookieValue = user.getUserName() + ":" + validTime + ":" + cookieValueWithMd5;
        //再一次对Cookie的值进行BASE64编码

        String cookieValueBase64 = new String(Base64.encode(cookieValue.getBytes()));
        //开始保存Cookie
        Cookie cookie = new Cookie(cookieDomainName, cookieValueBase64);
        //存两年(这个值应该大于或等于validTime)
        cookie.setMaxAge((int)cookieMaxAge);

        //cookie有效路径是网站根目录

        cookie.setPath("/caibadmin");

        //向客户端写入

        response.addCookie(cookie);

    }



    //读取Cookie,自动完成登陆操作----------------------------------------------------------------

    //在Filter程序中调用该方法,见AutoLogonFilter.java

    public static void readCookieAndLogon(HttpServletRequest request, HttpServletResponse response,

                                          FilterChain chain) throws IOException, ServletException,UnsupportedEncodingException{
        //根据cookieName取cookieValue
        Cookie cookies[] = request.getCookies();
        String cookieValue = null;
        if(cookies!=null){
        for(int i=0;i<cookies.length;i++){
            if (cookieDomainName.equals(cookies[i].getName())) {
                cookieValue = cookies[i].getValue();
                break;
            }
        }

    //如果cookieValue为空,返回,
    if(cookieValue==null){
        return;
    }
    //如果cookieValue不为空,才执行下面的代码
    //先得到的CookieValue进行Base64解码
    String cookieValueAfterDecode = new String (Base64.decode(cookieValue),"utf-8");
    //对解码后的值进行分拆,得到一个数组,如果数组长度不为3,就是非法登陆
    String cookieValues[] = cookieValueAfterDecode.split(":");
    if(cookieValues.length!=3){
        response.setContentType("text/html;charset=utf-8");
        PrintWriter out = response.getWriter();
        out.println("你正在用非正常方式进入本站...");
        out.close();
        return;
    }
    //判断是否在有效期内,过期就删除Cookie
    long validTimeInCookie = new Long(cookieValues[1]);
    if(validTimeInCookie < System.currentTimeMillis()){
        //删除Cookie
        clearCookie(response);
        response.setContentType("text/html;charset=utf-8");
        PrintWriter out = response.getWriter();
        out.println("你的Cookie已经失效,请重新登陆");
        out.close();
        return;
    }
    //取出cookie中的用户名,并到数据库中检查这个用户名,
    String username = cookieValues[0];

    //根据用户名到数据库中检查用户是否存在
//    UserDAO ud = DaoImplFactory.getInstance();
//    User user = ud.selectUserByUsername(username);
//
//    //如果user返回不为空,就取出密码,使用用户名+密码+有效时间+ webSiteKey进行MD5加密
//    if(user!=null){
//        String md5ValueInCookie = cookieValues[2];
//        String md5ValueFromUser =getMD5(user.getUserName() + ":" + user.getPassword()
//                + ":" + validTimeInCookie + ":" + webKey);
//        //将结果与Cookie中的MD5码相比较,如果相同,写入Session,自动登陆成功,并继续用户请求
//        if(md5ValueFromUser.equals(md5ValueInCookie)){
//            HttpSession session = request.getSession(true);
//            session.setAttribute("user", user);
//            chain.doFilter(request, response);
//        }

    }else{

        //返回为空执行
        response.setContentType("text/html;charset=utf-8");
        PrintWriter out = response.getWriter();
        out.println("cookie验证错误！");
        out.close();
        return;

    }

}



    //用户注销时,清除Cookie,在需要时可随时调用-----------------------------------------------------
    public static void clearCookie( HttpServletResponse response){
        Cookie cookie = new Cookie(cookieDomainName, null);
        cookie.setMaxAge(0);
        cookie.setPath("/caiadmin");
        response.addCookie(cookie);
    }

    //获取Cookie组合字符串的MD5码的字符串----------------------------------------------------------------
    public static String getMD5(String value) {
        String result = null;
        try{
            byte[] valueByte = value.getBytes();
            MessageDigest md = MessageDigest.getInstance("MD5");
            md.update(valueByte);
            result = toHex(md.digest());
        } catch (NoSuchAlgorithmException e){
            e.printStackTrace();
        }
        return result;
    }
    //将传递进来的字节数组转换成十六进制的字符串形式并返回
    private static String toHex(byte[] buffer){
        StringBuffer sb = new StringBuffer(buffer.length * 2);
        for (int i = 0; i < buffer.length; i++){
            sb.append(Character.forDigit((buffer[i] & 0xf0) >> 4, 16));
            sb.append(Character.forDigit(buffer[i] & 0x0f, 16));
        }
        return sb.toString();
    }
*/}