/**
    * Copyright 2005-2014 The Kuali Foundation
    *
    * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php
    *
   * 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 org.kuali.rice.krad.data.jpa.converters;
  
  import javax.persistence.AttributeConverter;
  import javax.persistence.Converter;
  
  import org.apache.commons.lang.StringUtils;
  import org.kuali.rice.core.api.CoreApiServiceLocator;
  import org.kuali.rice.core.api.encryption.EncryptionService;
  
  /**
   * Calls the core service to hash values going to the database.
   * 
   *  @author Kuali Rice Team (rice.collab@kuali.org)
   */
  @Converter
  public class HashConverter implements AttributeConverter<String, String> {
  
      /**
       * {@inheritDoc}
       *
       * This implementation hashes the value going to the database.
       */
  	@Override
  	public String convertToDatabaseColumn(String objectValue) {
  		// don't attempt to encrypt nulls or empty strings
  		if (objectValue == null) {
  			return null;
  		}
  		if (StringUtils.isEmpty(objectValue.toString())) {
  			return "";
  		}
  		// don't convert if already a hashed value
  		if (objectValue.toString().endsWith(EncryptionService.HASH_POST_PREFIX)) {
  			return StringUtils.stripEnd(objectValue.toString(), EncryptionService.HASH_POST_PREFIX);
  		} else {
  			try {
  				return CoreApiServiceLocator.getEncryptionService().hash(objectValue);
  			} catch (Exception e) {
  				throw new RuntimeException("Exception while attempting to hash value for DB: ", e);
  			}
  		}
  	}
  
      /**
       * {@inheritDoc}
       *
       * This implementation directly returns the hash value coming from the database.
       */
  	@Override
  	public String convertToEntityAttribute(String dataValue) {
  		// don't attempt to decrypt nulls or empty strings
  		if (dataValue == null) {
  			return null;
  		}
  		if (StringUtils.isEmpty(dataValue.toString())) {
  			return "";
  		}
  		return dataValue.toString() + EncryptionService.HASH_POST_PREFIX;
  	}
  
  }