/*
* 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 java.security.MessageDigest;

import at.gv.egovernment.moa.id.BuildException;
import at.gv.egovernment.moa.util.Base64Utils;
import at.gv.egovernment.moa.util.Constants;

/**
 * Builder for the bPK, as defined in
 * <code>&quot;Ableitung f&uml;r die bereichsspezifische Personenkennzeichnung&quot;</code>
 * version <code>1.0.1</code> from <code>&quot;reference.e-government.gv.at&quot;</code>.
 *  
 * @author Paul Schamberger
 * @version $Id$
 */
public class BPKBuilder {

  /**
   * Builds the bPK from the given parameters. 
   * @param identificationValue Base64 encoded "Stammzahl" 
   * @param target "Bereich lt. Verordnung des BKA"
   * @return bPK in a BASE64 encoding
   * @throws BuildException if an error occurs on building the bPK
   */
  public String buildBPK(String identificationValue, String target) 
    throws BuildException {
    
    if ((identificationValue == null || 
         identificationValue.length() == 0 ||
    		 target == null || 
         target.length() == 0)) 
    {
      throw new BuildException("builder.00", 
      		                     new Object[] {"BPK", "Unvollständige Parameterangaben: identificationValue=" + 
                                             identificationValue + ",target=" + target});
    }
    String basisbegriff = identificationValue + "+" + Constants.URN_PREFIX_CDID + "+" + target;
    try {
      MessageDigest md = MessageDigest.getInstance("SHA-1");
      byte[] hash = md.digest(basisbegriff.getBytes("ISO-8859-1"));
      String hashBase64 = Base64Utils.encode(hash);
      return hashBase64;
    } catch (Exception ex) {
      throw new BuildException("builder.00", new Object[] {"bPK", ex.toString()}, ex);
    }
  }

  /**
   * Builds the wbPK from the given parameters. 
   * @param identificationValue Base64 encoded "Stammzahl" 
   * @param registerAndOrdNr type of register + "+" + number in register.
   * @return wbPK in a BASE64 encoding
   * @throws BuildException if an error occurs on building the wbPK
   */
  public String buildWBPK(String identificationValue, String registerAndOrdNr) 
    throws BuildException {
    
    if ((identificationValue == null || 
         identificationValue.length() == 0 ||
         registerAndOrdNr == null || 
         registerAndOrdNr.length() == 0)) 
    {
      throw new BuildException("builder.00", 
          new Object[] {"wbPK", "Unvollständige Parameterangaben: identificationValue=" + 
                        identificationValue + ",Register+Registernummer=" + registerAndOrdNr});
    }
    String basisbegriff = identificationValue + "+" + Constants.URN_PREFIX_WBPK + "+" + registerAndOrdNr;
    try {
      MessageDigest md = MessageDigest.getInstance("SHA-1");
      byte[] hash = md.digest(basisbegriff.getBytes("ISO-8859-1"));
      String hashBase64 = Base64Utils.encode(hash);
      return hashBase64;
    } catch (Exception ex) {
      throw new BuildException("builder.00", new Object[] {"wbPK", ex.toString()}, ex);
    }
  }

}