/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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 org.apache.syncope.core.provisioning.java.propagation;
  
  import java.util.Base64;
  import java.util.Optional;
  import java.util.Set;
  import javax.xml.bind.DatatypeConverter;
  import org.apache.syncope.common.lib.types.AnyTypeKind;
  import org.apache.syncope.common.lib.types.CipherAlgorithm;
  import org.apache.syncope.core.persistence.api.dao.UserDAO;
  import org.apache.syncope.core.persistence.api.entity.ConnInstance;
  import org.apache.syncope.core.persistence.api.entity.user.User;
  import org.apache.syncope.core.provisioning.api.propagation.PropagationActions;
  import org.apache.syncope.core.provisioning.api.propagation.PropagationManager;
  import org.apache.syncope.core.provisioning.api.propagation.PropagationTaskInfo;
  import org.apache.syncope.core.spring.implementation.InstanceScope;
  import org.apache.syncope.core.spring.implementation.SyncopeImplementation;
  import org.identityconnectors.common.security.GuardedString;
  import org.identityconnectors.framework.common.objects.Attribute;
  import org.identityconnectors.framework.common.objects.AttributeBuilder;
  import org.identityconnectors.framework.common.objects.AttributeUtil;
  import org.identityconnectors.framework.common.objects.OperationalAttributes;
  import org.springframework.beans.factory.annotation.Autowired;
  import org.springframework.transaction.annotation.Transactional;
  import org.springframework.util.CollectionUtils;
  
  /**
   * Propagate a non-cleartext password out to a resource, if the PropagationManager has not already
   * added a password. The CipherAlgorithm associated with the password must match the password
   * hash algorithm property of the LDAP Connector.
   */
  @SyncopeImplementation(scope = InstanceScope.PER_CONTEXT)
  public class LDAPPasswordPropagationActions implements PropagationActions {
  
      protected static final String CLEARTEXT = "CLEARTEXT";
  
      @Autowired
      protected UserDAO userDAO;
  
      @Transactional(readOnly = true)
      @Override
      public void before(final PropagationTaskInfo taskInfo) {
          if (AnyTypeKind.USER == taskInfo.getAnyTypeKind()) {
              User user = userDAO.find(taskInfo.getEntityKey());
              if (user == null || user.getPassword() == null) {
                  return;
              }
  
              Set<Attribute> attrs = taskInfo.getPropagationData().getAttributes();
  
              String cipherAlgorithm = getCipherAlgorithm(taskInfo.getResource().getConnector());
              Optional.ofNullable(AttributeUtil.find(PropagationManager.MANDATORY_MISSING_ATTR_NAME, attrs)).
                      filter(missing -> !CollectionUtils.isEmpty(missing.getValue())
                      && OperationalAttributes.PASSWORD_NAME.equals(missing.getValue().get(0))
                      && cipherAlgorithmMatches(cipherAlgorithm, user.getCipherAlgorithm())).
                      ifPresent(missing -> {
                          attrs.remove(missing);
  
                          byte[] decodedPassword = DatatypeConverter.parseHexBinary(user.getPassword().toLowerCase());
                          String base64EncodedPassword = Base64.getEncoder().encodeToString(decodedPassword);
  
                          String cipherPlusPassword = '{' + cipherAlgorithm + '}' + base64EncodedPassword;
  
                          attrs.add(AttributeBuilder.buildPassword(new GuardedString(cipherPlusPassword.toCharArray())));
                      });
          }
      }
  
      protected String getCipherAlgorithm(final ConnInstance connInstance) {
          return connInstance.getConf().stream().
                  filter(property -> "passwordHashAlgorithm".equals(property.getSchema().getName())
                  && !property.getValues().isEmpty()).findFirst().
                  map(cipherAlgorithm -> cipherAlgorithm.getValues().get(0).toString()).
                  orElse(CLEARTEXT);
      }
  
      protected boolean cipherAlgorithmMatches(final String connectorAlgo, final CipherAlgorithm userAlgo) {
          if (userAlgo == null) {
              return false;
          }
  
          if (connectorAlgo.equals(userAlgo.name())) {
             return true;
         }
 
         // Special check for "SHA" and "SSHA" (user pulled from LDAP)
         return ("SHA".equals(connectorAlgo) && userAlgo.name().startsWith("SHA"))
                 || ("SSHA".equals(connectorAlgo) && userAlgo.name().startsWith("SSHA"));
     }
 }