package com.tuoheng.common.utils;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletResponse;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.util.Base64;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;

/**
 * 获取验证码工具类
 */
public class VerifyUtil {

    private static Random random = new Random();
    /**
     * 验证码的宽
     */
    private int width = 165;
    /**
     * 验证码的高
     */
    private int height = 45;
    /**
     * 验证码中夹杂的干扰线数量
     */
    private int lineSize = 30;
    /**
     * 验证码字符个数
     */
    private int randomStrNum = 4;

    private String randomString = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWSYZ";

    /**
     * 字体的设置
     *
     * @return
     */
    private Font getFont() {
        return new Font("Times New Roman", Font.ROMAN_BASELINE, 40);
    }

    /**
     * 颜色的设置
     *
     * @param fc
     * @param bc
     * @return
     */
    private static Color getRandomColor(int fc, int bc) {

        fc = Math.min(fc, 255);
        bc = Math.min(bc, 255);

        int r = fc + random.nextInt(bc - fc - 16);
        int g = fc + random.nextInt(bc - fc - 14);
        int b = fc + random.nextInt(bc - fc - 12);

        return new Color(r, g, b);
    }

    /**
     * 干扰线的绘制
     *
     * @param g
     */
    private void drawLine(Graphics g) {
        int x = random.nextInt(width);
        int y = random.nextInt(height);
        int xl = random.nextInt(20);
        int yl = random.nextInt(10);
        g.drawLine(x, y, x + xl, y + yl);

    }

    /**
     * 随机字符的获取
     *
     * @param num
     * @return
     */
    private String getRandomString(int num) {
        num = num > 0 ? num : randomString.length();
        return String.valueOf(randomString.charAt(random.nextInt(num)));
    }

    /**
     * 字符串的绘制
     *
     * @param g
     * @param randomStr
     * @param i
     * @return
     */
    private String drawString(Graphics g, String randomStr, int i) {
        g.setFont(getFont());
        g.setColor(getRandomColor(108, 190));
        String rand = getRandomString(random.nextInt(randomString.length()));
        randomStr += rand;
        g.translate(random.nextInt(3), random.nextInt(6));
        g.drawString(rand, 40 * i + 10, 25);
        return randomStr;
    }


    /**
     * 生成随机图片
     *
     * @param response
     */
    public void getRandomCodeImage(HttpServletResponse response) {
        // BufferedImage类是具有缓冲区的Image类,Image类是用于描述图像信息的类
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
        Graphics g = image.getGraphics();
        g.fillRect(0, 0, width, height);
        g.setColor(getRandomColor(105, 189));
        g.setFont(getFont());
        // 干扰线
        for (int i = 0; i < lineSize; i++) {
            drawLine(g);
        }
        // 随机字符
        String randomStr = "";
        for (int i = 0; i < randomStrNum; i++) {
            randomStr = drawString(g, randomStr, i);
        }
        System.out.println("随机字符：" + randomStr);
        g.dispose();
        try {
            //  将图片以png格式返回,返回的是图片
            ImageIO.write(image, "PNG", response.getOutputStream());

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * 生成随机图片的base64编码字符串
     *
     * @return
     */
    public Map<String, String> getRandomCodeBase64() {
        Map<String, String> result = new HashMap<>();
        // BufferedImage类是具有缓冲区的Image类,Image类是用于描述图像信息的类
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
        Graphics g = image.getGraphics();
        g.fillRect(0, 0, width, height);
        g.setColor(getRandomColor(105, 189));
        g.setFont(getFont());
        //干扰线
        for (int i = 0; i < lineSize; i++) {
            drawLine(g);
        }

        //随机字符
        String randomStr = "";
        for (int i = 0; i < randomStrNum; i++) {
            randomStr = drawString(g, randomStr, i);
        }

        g.dispose();
        String base64String = "";
        try {
            //  直接返回图片
            //  返回 base64
            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            ImageIO.write(image, "PNG", bos);

            byte[] bytes = bos.toByteArray();
            Base64.Encoder encoder = Base64.getEncoder();
            base64String = encoder.encodeToString(bytes);

        } catch (Exception e) {
            e.printStackTrace();
        }
        result.put("randomStr", randomStr);
        result.put("img", base64String);
        return result;
    }

}
