/*******************************************************************************
 * Copyright 2014 Federal Chancellery Austria
 * MOA-ID has been developed in a cooperation between BRZ, the Federal
 * Chancellery Austria - ICT staff unit, and Graz University of Technology.
 * 
 * Licensed under the EUPL, Version 1.1 or - as soon they will be approved by
 * the European Commission - subsequent versions of the EUPL (the "Licence");
 * You may not use this work except in compliance with the Licence.
 * You may obtain a copy of the Licence at:
 * http://www.osor.eu/eupl/
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the Licence is distributed on an "AS IS" basis,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the Licence for the specific language governing permissions and
 * limitations under the Licence.
 * 
 * This product combines work with different licenses. See the "NOTICE" text
 * file for details on the various modules and licenses.
 * The "NOTICE" text file is part of the distribution. Any derivative works
 * that you distribute must include a readable copy of the "NOTICE" text file.
 ******************************************************************************/
/*
 * Copyright 2003 Federal Chancellery Austria
 * MOA-ID has been developed in a cooperation between BRZ, the Federal
 * Chancellery Austria - ICT staff unit, and Graz University of Technology.
 *
 * Licensed under the EUPL, Version 1.1 or - as soon they will be approved by
 * the European Commission - subsequent versions of the EUPL (the "Licence");
 * You may not use this work except in compliance with the Licence.
 * You may obtain a copy of the Licence at:
 * http://www.osor.eu/eupl/
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the Licence is distributed on an "AS IS" basis,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the Licence for the specific language governing permissions and
 * limitations under the Licence.
 *
 * This product combines work with different licenses. See the "NOTICE" text
 * file for details on the various modules and licenses.
 * The "NOTICE" text file is part of the distribution. Any derivative works
 * that you distribute must include a readable copy of the "NOTICE" text file.
 */


package at.gv.egovernment.moa.id.util;

/**
 * HTTP Utilities  
 * 
 * @author Rudolf Schamberger
 * @version $Id$
 */

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.HttpURLConnection;
import java.net.URL;

import javax.servlet.http.HttpServletRequest;

import org.apache.regexp.RE;
import org.apache.regexp.RESyntaxException;

import at.gv.egovernment.moa.util.StringUtils;

/**
 * 
 * @author Rudolf Schamberger
 *
 */
public class HTTPUtils {

  /**
   * Utility used to obtainin correct encoded HTTP content.
   * Reads a given Content adressed by HTTP-URL into String. 
   * Content encoding is considered by using the Content-Type HTTP header charset value.
   * @param URL HTTP URL to read from.
   * @return String representation of content
   * @throws IOException on data-reading problems
   */
  public static String readHttpURL(String URL) 
    throws IOException {
      
    URL url = new URL(URL);
    HttpURLConnection conn = (HttpURLConnection)url.openConnection();
    conn.setRequestMethod("GET");
    String contentType = conn.getContentType();
    RE regExp = null;
    try {
        regExp = new RE("(;.*charset=)(\"*)(.*[^\"])");
    } catch (RESyntaxException e) {
        //RESyntaxException is not possible = expr. is costant
    }
    boolean charsetSupplied = regExp.match(contentType);
    String encoding = "ISO-8859-1"; 		//default HTTP encoding 
    if (charsetSupplied) {
      encoding = regExp.getParen(3);
    }
    InputStream instream = new BufferedInputStream(conn.getInputStream());
    InputStreamReader isr = new InputStreamReader(instream, encoding);
    Reader in = new BufferedReader(isr);
    int ch;
  	StringBuffer buffer = new StringBuffer();
    while ((ch = in.read()) > -1) {
  		buffer.append((char)ch);
  	}     
    in.close();
    conn.disconnect();
    return buffer.toString();
  }
  
  	/**
  	 * Helper method to retrieve server URL including context path
  	 * @param request HttpServletRequest
  	 * @return Server URL including context path (e.g. http://localhost:8443/moa-id-auth
  	 */
  	public static String getBaseURL(HttpServletRequest request) {
		StringBuffer buffer = new StringBuffer(getServerURL(request));
		
	    // add context path if available
	    String contextPath = request.getContextPath();
	    if (!StringUtils.isEmpty(contextPath)) {
	    	buffer.append(contextPath);
	    }
		
		return buffer.toString(); 
	}
	
  	/**
  	 * Helper method to retrieve server URL
  	 * @param request HttpServletRequest
  	 * @return Server URL (e.g. http://localhost:8443)
  	 */
	public static String getServerURL(HttpServletRequest request) {
		StringBuffer buffer = new StringBuffer();
		
		// get protocol
		String protocol = request.getScheme();
		buffer.append(protocol).append("://");
		
		// server name
		buffer.append(request.getServerName());
		
		// add port if necessary
		int port = request.getServerPort();
	    if ((protocol.equals("http") && port != 80) || (protocol.equals("https") && port != 443)) {
	    	buffer.append(':');
	    	buffer.append(port);
	    }
	
	    return buffer.toString(); 
	}
	
	/**
	 * Extract the IDP PublicURLPrefix from authrequest
	 * 
	 * @param req HttpServletRequest
	 * @return PublicURLPrefix <String> which ends always without /
	 */
	public static String extractAuthURLFromRequest(HttpServletRequest req) {
	    String authURL = req.getScheme() + "://" + req.getServerName();
	    if ((req.getScheme().equalsIgnoreCase("https") && req.getServerPort()!=443) || (req.getScheme().equalsIgnoreCase("http") && req.getServerPort()!=80)) { 
	      authURL = authURL.concat(":" + req.getServerPort());
	    }
	    authURL = authURL.concat(req.getContextPath());
	    return authURL;
		
	}
	
	/**
	 * Extract the IDP requested URL from authrequest
	 * 
	 * @param req HttpServletRequest
	 * @return RequestURL <String> which ends always without /
	 */ 
	public static String extractAuthServletPathFromRequest(HttpServletRequest req) {
	    return extractAuthURLFromRequest(req).concat(req.getServletPath());
	 	
	}
	
	public static String addURLParameter(String url, String paramname,
			String paramvalue) {
		String param = paramname + "=" + paramvalue;
		if (url.indexOf("?") < 0)
			return url + "?" + param;
		else
			return url + "&" + param;
	}

}