/**
    * 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.krms.impl.repository.language;
  
  import org.apache.commons.lang.StringUtils;
  import org.apache.velocity.exception.VelocityException;
  import org.kuali.rice.krms.api.repository.language.NaturalLanguageTemplate;
  import org.kuali.rice.krms.api.repository.language.NaturalLanguageTemplaterContract;
  import org.kuali.rice.krms.api.repository.proposition.PropositionParameterType;
  import org.kuali.rice.krms.api.repository.type.KrmsTypeDefinitionContract;
  import org.kuali.rice.krms.api.repository.type.KrmsTypeRepositoryService;
  import org.kuali.rice.krms.impl.repository.KrmsTypeRepositoryServiceImpl;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  /**
   * This class translates requirement components into a specific
   * natural language. This class is not thread safe.
   */
  public class PropositionNaturalLanguageTemplater implements NaturalLanguageTemplaterContract {
      /**
       * SLF4J logging framework
       */
      private final static Logger logger = LoggerFactory.getLogger(PropositionNaturalLanguageTemplater.class);
  
      private TranslationContextRegistry<TranslationContext> translationContextRegistry;
  
      private KrmsTypeRepositoryService krmsTypeRepositoryService = new KrmsTypeRepositoryServiceImpl();
  
      /**
       * Relational operator token.
       */
      public final static String OPERATOR_TOKEN = "relationalOperator";
      /**
       * An integer value token.
       */
      public final static String CONSTANT_VALUE_TOKEN = "intValue";
  
      /**
       * Velocity template engine.
       */
      private VelocityTemplateEngine templateEngine = new VelocityTemplateEngine();
  
  
      /**
       * Constructs a new proposition natural language templater.
       */
      public PropositionNaturalLanguageTemplater() {
      }
  
  
      /**
       * Sets the template context registry.
       *
       * @param translationContextRegistry Template context registry
       */
      public void setTranslationContextRegistry(
              final TranslationContextRegistry<TranslationContext> translationContextRegistry) {
          this.translationContextRegistry = translationContextRegistry;
      }
  
      public String translate(NaturalLanguageTemplate naturalLanguageTemplate, Map<String, Object> parametersMap) {
  
          if (naturalLanguageTemplate == null) {
              return StringUtils.EMPTY;
          }
  
          Map<String, Object> contextMap = null;
          try {
              contextMap = buildContextMap(naturalLanguageTemplate.getTypeId(), parametersMap);
          } catch (Exception e) {
              e.printStackTrace();  //TODO hand back to service.
          }
  
          try {
              String nl = this.templateEngine.evaluate(contextMap, naturalLanguageTemplate.getTemplate());
              if (logger.isInfoEnabled()) {
                  logger.info("nl=" + nl);
              }
              return nl;
          } catch (VelocityException e) {
              String msg = "Generating template for proposition failed: template='" + naturalLanguageTemplate.getTemplate() + "', contextMap=" + contextMap;
             logger.error(msg, e);
             //TODO hand back to service throw new Exception(msg);
         }
         return "Error";
     }
 
     /**
      * Builds a proposition type context map.
      *
      * @param typeId        the natural language template id
      * @param parametersMap map containing the proposition parameter types and their values
      * @throws java.lang.Exception Creating context map failed
      */
     private Map<String, Object> buildContextMap(String typeId, Map<String, Object> parametersMap) throws Exception {
 
         Map<String, Object> contextMap = new HashMap<String, Object>();
         //Add proposition constant to contextMap.
         if (parametersMap.containsKey(PropositionParameterType.CONSTANT.getCode())) {
             contextMap.put(CONSTANT_VALUE_TOKEN, (String) parametersMap.get(PropositionParameterType.CONSTANT.getCode()));
         }
         //Add proposition operator to contextMap.
         if (parametersMap.containsKey(PropositionParameterType.OPERATOR.getCode())) {
             contextMap.put(OPERATOR_TOKEN, (String) parametersMap.get(PropositionParameterType.OPERATOR.getCode()));
         }
         //Access type service to retrieve type name.
         KrmsTypeDefinitionContract type = getKrmsTypeRepositoryService().getTypeById(typeId);
         List<TranslationContext> translationContextList = this.translationContextRegistry.get(type.getName());
         if (translationContextList == null || translationContextList.isEmpty()) {
             return contextMap;
         }
 
         for (TranslationContext translationContext : translationContextList) {
             Map<String, Object> cm = translationContext.createContextMap(parametersMap);
             contextMap.putAll(cm);
         }
 
         if (logger.isInfoEnabled()) {
             logger.info("contextMap=" + contextMap);
         }
         return contextMap;
     }
 
 
     private KrmsTypeRepositoryService getKrmsTypeRepositoryService() {
         return krmsTypeRepositoryService;
     }
 
     public void setKrmsTypeRepositoryService(KrmsTypeRepositoryService krmsTypeRepositoryService) {
         this.krmsTypeRepositoryService = krmsTypeRepositoryService;
     }
 
 }