package utils;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.struts2.ServletActionContext;

public class CodeUtil{
	
	private Color getRandColor(int fc, int bc) {
		//给定范围获得随机颜色
		Random random = new Random();
		if (fc > 255)
	    	fc = 255;
	   	if (bc > 255)
	    	bc = 255;
	  	int r = fc + random.nextInt(bc - fc);
	  	int g = fc + random.nextInt(bc - fc);
	  	int b = fc + random.nextInt(bc - fc);
	 	return new Color(r, g, b);
	  }
	
	public void createCode(HttpServletRequest request,HttpServletResponse response){
		//设置页面不缓存
	  	response.setHeader("Pragma", "No-cache");
	 	response.setHeader("Cache-Control", "no-cache");
	  	response.setDateHeader("Expires", 0);
	 
	 	// 在内存中创建图象
	 	int width = 75, height = 32;
	 	BufferedImage image = new BufferedImage(width, height,BufferedImage.TYPE_INT_RGB);

	 	// 获取图形上下文
	 	Graphics g = image.getGraphics();

	 	//生成随机类
	 	Random random = new Random();

		// 设定背景色
		g.setColor(getRandColor(200, 250));
		g.fillRect(0, 0, width, height);

		//设定字体
		g.setFont(new Font("Times New Roman", Font.BOLD, 18));//18是设置的字体大小

		//画边框
	  	g.setColor(new Color(0, 0, 0));
	   	g.drawRect(0, 0, width - 1, height -1);// 细线围成的边框范围
	 
	   	// 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到
	   	g.setColor(getRandColor(160, 200));
	  	for (int i = 0; i < 155; i++) {
	  	int x = random.nextInt(width);
	  	int y = random.nextInt(height);
	    int xl = random.nextInt(12);
	    int yl = random.nextInt(12);
	    g.drawLine(x, y, x + xl, y + yl);
	}
	 
	   	// 取随机产生的认证码(4位数字)
	  	String sRand = "";
	   	for (int i = 0; i < 4; i++) {
	   	String rand = null;
	    //随机生成数字或者字母
	    if (random.nextInt(10) > 5) {
	    rand = String.valueOf((char)(random.nextInt(10) + 48));
	    }else {
	    rand = String.valueOf((char)(random.nextInt(26) + 65));
	    }
	   	sRand += rand;
	   	// 将认证码显示到图象中
	    g.setColor(new Color(random.nextInt(80), random.nextInt(80), random.nextInt(80)));
	    //调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
	    g.drawString(rand, 15 * i + 10, 16);
	  	}
	  
	   	// 将认证码存入SESSION
	  	request.getSession().setAttribute("rand", sRand);
	  	
	  	// 图象生效
	   	g.dispose();
	 
	  	// 输出图象到页
	   	try {
	   		//output:an OutputStream to be written to
	   		ImageIO.write(image, "JPEG", response.getOutputStream());
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
}