package nabble.view.lib;

import java.io.IOException;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import luan.lib.json.JsonParser;
import luan.lib.parser.ParseException;
import fschmidt.util.java.IoUtils;
import nabble.model.ModelException;
import nabble.view.lib.Jtp;


public final class Recaptcha {

	public static final String JS = "<script src='https://www.google.com/recaptcha/api.js'></script>";

	public static final String DIV = "<div class='g-recaptcha' data-sitekey='6Lf12z4UAAAAAKFG8EczAb6BjVvaFM2rqHswrCP7'></div>";

	private static final String SECRET = "6Lf12z4UAAAAAChAhLaE4-pxoY7z9LAWkSJnif4s";
	private static final String URL = "https://www.google.com/recaptcha/api/siteverify";
	private static final String PARAMS = "secret="+SECRET+"&response=";

	private static String getDomainIP(String domain)
		throws UnknownHostException
	{
		int i = domain.indexOf(":");
		if( i > 0 )
			domain = domain.substring(0,i);
		return InetAddress.getByName(domain).getHostAddress();
	}

	public static void check(HttpServletRequest request) 
		throws ModelException.InvalidRecaptcha, IOException
	{
		String response = request.getParameter("g-recaptcha-response");
		String json = IoUtils.post( URL, PARAMS+response );
//System.out.println(json);
		Map map;
		try {
			map = (Map)JsonParser.parse(json);
		} catch(ParseException e) {
			throw new RuntimeException(e);
		}
		boolean success = (Boolean)map.get("success");
		if( !success )
			throw new ModelException.InvalidRecaptcha();
		String hostname = (String)map.get("hostname");
		String hostIP = getDomainIP(hostname);
		String nabbleIP = getDomainIP(Jtp.getDefaultHost());
		if( !nabbleIP.equals(hostIP) )
			throw new RuntimeException("invalid host");
	}

	private Recaptcha() {}  // never
}