package nabble.view.web.util;

import fschmidt.util.java.IoUtils;
import fschmidt.util.servlet.JtpContext;
import nabble.view.lib.UrlMappable;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.Shape;
import java.awt.geom.Ellipse2D;
import java.awt.image.BufferedImage;
import java.awt.image.RenderedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.HashMap;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Quadrants
 * 1 | 2
 * 3 | 4
 *
 * @author Hugo Teixeira
 */
public class RoundedCorner extends HttpServlet implements UrlMappable {

	private static final Pattern URL_PATTERN = Pattern.compile("/rounded/q(\\d)_([A-Fa-f0-9]{6})([A-Fa-f0-9]{2})?$");

	public Map<String,String[]> getParameterMapFromUrl(HttpServletRequest request,String mappedUrl) {
		Matcher m = URL_PATTERN.matcher(mappedUrl);
		if( !m.find() )
			throw new RuntimeException();
		Map<String,String[]> params = new HashMap<String,String[]>();
		String quadrant = m.group(1);
		params.put("quadrant",new String[]{quadrant});
		String bgColor = m.group(2) + (m.group(3) == null? "" : m.group(3));
		params.put( "bgColor", new String[]{bgColor} );
		return params;
	}

	public Pattern getUrlPattern() {
		return URL_PATTERN;
	}

	protected void service(HttpServletRequest request, HttpServletResponse response)
		throws ServletException, IOException {
		OutputStream out = response.getOutputStream();
		response.setContentType("image/png");

		JtpContext jtpContext = (JtpContext)getServletContext().getAttribute(JtpContext.attrName);
		jtpContext.setEtag(request,response);

		int quadrant = Integer.valueOf(request.getParameter("quadrant"));
		String bgColor = request.getParameter("bgColor");

		ByteArrayOutputStream baos = new ByteArrayOutputStream();
		ImageIO.write(createImage(quadrant, bgColor), "png", baos);
		final byte[] bytes = baos.toByteArray();

		InputStream in = new ByteArrayInputStream(bytes);
		try {
			IoUtils.copyAll(in,out);
		} finally {
			in.close();
		}
	}

	private RenderedImage createImage(int quadrant, String bgColor) {
		int radius = 12;
		int[] xy = { 0, 0 };
		if (quadrant == 2) xy = new int[]{ -radius, 0 };
		else if (quadrant == 3) xy = new int[]{ 0, -radius };
		else if (quadrant == 4) xy = new int[]{ -radius, -radius };

		Color bg = parseColor(bgColor);
		BufferedImage img = new BufferedImage(radius, radius, BufferedImage.TYPE_INT_ARGB);
		Graphics2D g2 = img.createGraphics();
		g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
		g2.setColor(bg);
		g2.fillRect(0, 0, radius, radius);
		g2.setComposite(AlphaComposite.getInstance(AlphaComposite.CLEAR, 0.5f));
		Shape s = new Ellipse2D.Float(xy[0], xy[1], 2 * radius, 2* radius);
		g2.fill(s);
		g2.dispose();
		return img;
	}

	private Color parseColor(String c) {
		if (c.length() == 6)
			return Color.decode("0x"+c);
		int r = Integer.parseInt(c.substring(0,2), 16);
		int g = Integer.parseInt(c.substring(2,4), 16);
		int b = Integer.parseInt(c.substring(4,6), 16);
		int a = Integer.parseInt(c.substring(6,8), 16);
		return new Color(r, g, b, a);
	}
}