/**
    * Copyright 2005-2012 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.rule;
  
  import org.kuali.rice.core.api.exception.RiceIllegalArgumentException;
  import org.kuali.rice.kew.api.KewApiServiceLocator;
  import org.kuali.rice.kew.api.extension.ExtensionDefinition;
  import org.kuali.rice.kew.api.extension.ExtensionUtils;
  import org.kuali.rice.kew.api.rule.RuleExtension;
  import org.kuali.rice.kew.api.rule.RuleTemplateAttribute;
  import org.kuali.rice.kew.engine.RouteContext;
  import org.kuali.rice.kew.framework.KewFrameworkServiceLocator;
  import org.kuali.rice.kew.framework.rule.attribute.WorkflowRuleAttributeHandlerService;
  import org.kuali.rice.kew.routeheader.DocumentContent;
  import org.kuali.rice.kew.rule.bo.RuleAttribute;
  import org.kuali.rice.kew.rule.bo.RuleTemplateAttributeBo;
  import org.kuali.rice.kew.rule.xmlrouting.GenericXMLRuleAttribute;
  import org.kuali.rice.kew.service.KEWServiceLocator;
  import org.kuali.rice.kew.api.KewApiConstants;
  
  import java.util.ArrayList;
  import java.util.List;
  
  
  /**
   * Standard rule expression implementation that evaluates the attributes associated with the rule definition 
   * @author Kuali Rice Team (rice.collab@kuali.org)
   */
  class WorkflowAttributeRuleExpression implements RuleExpression {
      
  	public RuleExpressionResult evaluate(Rule rule, RouteContext context) {
          
  		org.kuali.rice.kew.api.rule.Rule ruleDefinition =
                  org.kuali.rice.kew.api.rule.Rule.Builder.create(rule.getDefinition()).build();
          boolean match = isMatch(ruleDefinition, context.getDocumentContent());
          if (match) {
              return new RuleExpressionResult(rule, match, ruleDefinition.getRuleResponsibilities());
          }
  		return new RuleExpressionResult(rule, match);
      }
  
      public boolean isMatch(org.kuali.rice.kew.api.rule.Rule ruleDefinition, DocumentContent docContent) {
          if (ruleDefinition.getRuleTemplate() == null) {
              // this can happen if neither rule template nor expression was specified in the rule definition
              // because WorkflowAttributeRuleExpression is the default expression implementation, we should
              // handle this here in order to support rules that fire unconditionally (and just return a statically
              // configured list of responsibilities)
              // the alternative is to either detect this situation in the rule xml parser or RuleImpl, and either substitute
              // a different RuleExpression implementation (a "default default" one) in the configuration, or at runtime,
              // that simply implements the one-liner of returning responsibilities.
              // doing this in the existing WorkflowAttributeRuleExpression implementation introduces the least change
              // or compatibilities issues, and avoids pushing compensating logic into RuleImpl
              return true;
          }
          //RuleBaseValues rule = KEWServiceLocator.getRuleService().getRuleByName(ruleDefinition.getName());
          for (RuleTemplateAttribute ruleTemplateAttribute : ruleDefinition.getRuleTemplate().getActiveRuleTemplateAttributes()) {
              String attributeName = ruleTemplateAttribute.getRuleAttribute().getName();
              WorkflowRuleAttributeHandlerService wrahs = KewFrameworkServiceLocator.getWorkflowRuleAttributeHandlerService();
              if (!wrahs.isWorkflowRuleAttribute(attributeName)) {
                  continue;
              }
              //WorkflowRuleAttribute routingAttribute = (WorkflowRuleAttribute) ruleTemplateAttribute.getWorkflowAttribute();
              ExtensionDefinition extensionDefinition = KewApiServiceLocator.getExtensionRepositoryService().getExtensionByName(attributeName);
              Object attribute = ExtensionUtils.loadExtension(extensionDefinition);
              if (attribute == null) {
                  throw new RiceIllegalArgumentException("Failed to load WorkflowRuleAttribute for: " + extensionDefinition);
              }
              if (!WorkflowRuleAttribute.class.isAssignableFrom(attribute.getClass())) {
                  throw new RiceIllegalArgumentException("Failed to locate a WorkflowRuleAttribute with the given name: " + attributeName);
              }
              if (attribute instanceof XmlConfiguredAttribute) {
                  ((XmlConfiguredAttribute)attribute).setExtensionDefinition(extensionDefinition);
              }
  
              WorkflowRuleAttribute routingAttribute = (WorkflowRuleAttribute)attribute;
  
             ExtensionDefinition ruleAttribute = ruleTemplateAttribute.getRuleAttribute();
              if (ruleAttribute.getType().equals(KewApiConstants.RULE_XML_ATTRIBUTE_TYPE)) {
                  ((GenericXMLRuleAttribute) routingAttribute).setExtensionDefinition(ruleAttribute);
              }
              String className = ruleAttribute.getResourceDescriptor();
              List<RuleExtension> editedRuleExtensions = new ArrayList();
              for (RuleExtension extension : ruleDefinition.getRuleExtensions()) {
                  if (extension.getRuleTemplateAttribute().getRuleAttribute().getResourceDescriptor().equals(className)) {
                      editedRuleExtensions.add(extension);
                  }
             }
             if (!routingAttribute.isMatch(docContent, editedRuleExtensions)) {
                 return false;
             }
         }
         return true;
     }
 
 }