/**
    * Copyright 2005-2013 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.kew.impl.document.security;
  
  import org.apache.commons.lang.StringUtils;
  import org.kuali.rice.core.api.exception.RiceIllegalArgumentException;
  import org.kuali.rice.kew.api.document.Document;
  import org.kuali.rice.kew.api.extension.ExtensionDefinition;
  import org.kuali.rice.kew.api.extension.ExtensionRepositoryService;
  import org.kuali.rice.kew.api.extension.ExtensionUtils;
  import org.kuali.rice.kew.framework.document.security.DocumentSecurityDirective;
  import org.kuali.rice.kew.framework.document.security.DocumentSecurityHandlerService;
  import org.kuali.rice.kew.framework.document.security.DocumentSecurityAttribute;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  /**
   * Reference implementation of the DocumentSecurityHandlerService.
   *
   * @author Kuali Rice Team (rice.collab@kuali.org)
   */
  public class DocumentSecurityHandlerServiceImpl implements DocumentSecurityHandlerService {
  
      private ExtensionRepositoryService extensionRepositoryService;
  
      @Override
      public List<String> getAuthorizedDocumentIds(String principalId, List<DocumentSecurityDirective> documentSecurityDirectives ) {
          if (StringUtils.isBlank(principalId)) {
              throw new RiceIllegalArgumentException("principalId was null or blank");
          }
          if (documentSecurityDirectives == null) {
              documentSecurityDirectives = Collections.emptyList();
          }
          List<String> authorizedDocumentIds = new ArrayList<String>();
          Map<String, DocumentSecurityAttribute> securityAttributeCache = new HashMap<String, DocumentSecurityAttribute>();
          for (DocumentSecurityDirective documentSecurityDirective : documentSecurityDirectives) {
              List<DocumentSecurityAttribute> attributesToApply = loadSecurityAttributes(documentSecurityDirective, securityAttributeCache);
              for (Document document : documentSecurityDirective.getDocuments()) {
                  // if it's already authorized, we don't need to do anything
                  if (!authorizedDocumentIds.contains(document.getDocumentId())) {
                      for (DocumentSecurityAttribute securityAttribute : attributesToApply) {
                          if (securityAttribute.isAuthorizedForDocument(principalId, document)) {
                              authorizedDocumentIds.add(document.getDocumentId());
                              break;
                          }
                      }
                  }
              }
          }
          return authorizedDocumentIds;
      }
  
      protected List<DocumentSecurityAttribute> loadSecurityAttributes(DocumentSecurityDirective documentSecurityDirective,
              Map<String, DocumentSecurityAttribute> securityAttributeCache) {
          List<DocumentSecurityAttribute> securityAttributes = new ArrayList<DocumentSecurityAttribute>();
          for (String documentSecurityAttributeName : documentSecurityDirective.getDocumentSecurityAttributeNames()) {
              securityAttributes.add(loadAndCacheSecurityAttribute(documentSecurityAttributeName, securityAttributeCache));
          }
          return securityAttributes;
      }
  
      protected DocumentSecurityAttribute loadAndCacheSecurityAttribute(String securityAttributeName, Map<String, DocumentSecurityAttribute> securityAttributeCache) {
          if (securityAttributeCache.containsKey(securityAttributeName)) {
              return securityAttributeCache.get(securityAttributeName);
          }
          ExtensionDefinition extensionDefinition = extensionRepositoryService.getExtensionByName(securityAttributeName);
          if (extensionDefinition == null) {
              throw new RiceIllegalArgumentException("Failed to locate a SecurityAttribute with the given name: " + securityAttributeName);
          }
          DocumentSecurityAttribute securityAttribute = loadSecurityAttribute(extensionDefinition);
          securityAttributeCache.put(securityAttributeName, securityAttribute);
          return securityAttribute;
      }
  
      protected DocumentSecurityAttribute loadSecurityAttribute(ExtensionDefinition extensionDefinition) {
          Object securityAttribute = ExtensionUtils.loadExtension(extensionDefinition);
          if (securityAttribute == null) {
              throw new RiceIllegalArgumentException("Failed to load SecurityAttribute for: " + extensionDefinition);
          }
          return (DocumentSecurityAttribute)securityAttribute;
      }
  
     public ExtensionRepositoryService getExtensionRepositoryService() {
         return extensionRepositoryService;
     }
 
     public void setExtensionRepositoryService(ExtensionRepositoryService extensionRepositoryService) {
         this.extensionRepositoryService = extensionRepositoryService;
     }
 
 }