package com.jspxcms.common.security;

import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Locale;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.lang3.StringUtils;
import org.springframework.context.ApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;

import com.octo.captcha.service.image.ImageCaptchaService;

/**
 * 验证码Servlet
 * 
 * @author liufang
 * 
 */
public class CaptchaServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
	public static final String DEFAULT_CAPTCHA_SERVICE_ID = "captchaService";
	public static final String CAPTCHA_SERVICE_ID = "captchaServiceId";
	private ImageCaptchaService captchaService;

	@Override
	public void init() throws ServletException {
		String captchaServiceId = getInitParameter(CAPTCHA_SERVICE_ID);
		if (StringUtils.isBlank(captchaServiceId)) {
			captchaServiceId = DEFAULT_CAPTCHA_SERVICE_ID;
		}
		ApplicationContext context = WebApplicationContextUtils
				.getWebApplicationContext(getServletContext());
		captchaService = context.getBean(captchaServiceId,
				ImageCaptchaService.class);
	}

	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		// Set to expire far in the past.
		resp.setDateHeader("Expires", 0);
		// Set standard HTTP/1.1 no-cache headers.
		resp.setHeader("Cache-Control", "no-store, no-cache, must-revalidate");
		// Set IE extended HTTP/1.1 no-cache headers (use addHeader).
		resp.addHeader("Cache-Control", "post-check=0, pre-check=0");
		// Set standard HTTP/1.0 no-cache header.
		resp.setHeader("Pragma", "no-cache");
		// return a jpeg
		resp.setContentType("image/jpeg");

		ServletOutputStream out = resp.getOutputStream();

		try {
			String captchaId = req.getSession(true).getId();
			// create the image with the text
			BufferedImage challenge = captchaService.getImageChallengeForID(
					captchaId, Locale.ENGLISH);
			// write the data out
			ImageIO.write(challenge, "jpg", out);
			out.flush();
		} finally {
			out.close();
		}
	}

}