/*
* Copyright 2003 Federal Chancellery Austria
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*     http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package at.gv.egovernment.moa.id.auth.builder;

import at.gv.egovernment.moa.id.auth.servlet.AuthServlet;
import at.gv.egovernment.moa.id.config.ConfigurationException;
import at.gv.egovernment.moa.id.config.auth.AuthConfigurationProvider;
import at.gv.egovernment.moa.id.util.MOAIDMessageProvider;
import at.gv.egovernment.moa.logging.Logger;

/**
 * Builds a DataURL parameter meant for the security layer implementation
 * to respond to.
 * 
 * @author Paul Ivancsics
 * @version $Id$
 */
public class DataURLBuilder {
	
  /**
   * Constructor for DataURLBuilder.
   */
  public DataURLBuilder() {
    super();
  }

  /**
   * Constructs a data URL for <code>VerifyIdentityLink</code> or <code>VerifyAuthenticationBlock</code>, 
   * including the <code>MOASessionID</code> as a parameter.
   * 
   * @param authBaseURL base URL (context path) of the MOA ID Authentication component,
   * 				 including a trailing <code>'/'</code>
   * @param authServletName request part of the data URL
   * @param sessionID sessionID to be included in the dataURL
   * @return String
   */
  public String buildDataURL(String authBaseURL, String authServletName, String sessionID) {

		String individualDataURLPrefix = null;
		String dataURL;
		try {      
      //check if an individual prefix is configured
      individualDataURLPrefix = AuthConfigurationProvider.getInstance().
      	getGenericConfigurationParameter(AuthConfigurationProvider.INDIVIDUAL_DATA_URL_PREFIX);
			
			if (null != individualDataURLPrefix) {
				
				//check individualDataURLPrefix
				if(!individualDataURLPrefix.startsWith("http"))
					throw(new ConfigurationException("config.13", new Object[] { individualDataURLPrefix}));

				//when ok then use it
				dataURL = individualDataURLPrefix + authServletName;
			} else 
				dataURL = authBaseURL + authServletName;
			    	
    } catch (ConfigurationException e) {
      Logger.warn(e);
      Logger.warn(MOAIDMessageProvider.getInstance().getMessage("config.12", new Object[] { authBaseURL } ));
			dataURL = authBaseURL + authServletName;
    }

    dataURL = addParameter(dataURL, AuthServlet.PARAM_SESSIONID, sessionID);
  	return dataURL;
  }

  /**
   * Method addParameter.
   * @param urlString represents the url 
   * @param paramname is the parameter to be added
   * @param value is the value of that parameter
   * @return String
   */
  private String addParameter(String urlString, String paramname, String value) {
    String url = urlString;
    if (paramname != null) {
      if (url.indexOf("?") < 0)
        url += "?";
      else
        url += "&";
      url += paramname + "=" + value;
    }
    return url;
  }
}