/**
    * Copyright 2005-2015 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.kim.impl.common.attribute;
  
  import com.google.common.collect.Iterables;
  import org.kuali.rice.core.api.criteria.AndPredicate;
  import org.kuali.rice.core.api.criteria.CompositePredicate;
  import org.kuali.rice.core.api.criteria.CriteriaValue;
  import org.kuali.rice.core.api.criteria.MultiValuedPredicate;
  import org.kuali.rice.core.api.criteria.OrPredicate;
  import org.kuali.rice.core.api.criteria.Predicate;
  import org.kuali.rice.core.api.criteria.PropertyPathPredicate;
  import org.kuali.rice.core.api.criteria.QueryByCriteria;
  import org.kuali.rice.core.api.criteria.SingleValuedPredicate;
  import org.kuali.rice.core.api.criteria.Transform;
  
  import java.util.ArrayList;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Set;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  import static org.kuali.rice.core.api.criteria.PredicateFactory.*;
  
  /**
   * this is an internal class used by kim service implementations that have generic lookup methods for classes
   * with "attributes".
   */
  public final class AttributeTransform implements Transform<QueryByCriteria, QueryByCriteria> {
  
      private static final Transform<QueryByCriteria, QueryByCriteria> INSTANCE = new AttributeTransform();
      private static final String ATTRIBUTE_DETAILS_ATTRIBUTE_VALUE = "attributeDetails.attributeValue";
      private static final String ATTRIBUTE_DETAILS_ATTRIBUTE_NAME = "attributeDetails.kimAttribute.attributeName";
      private static final String ATTRIBUTES_REGEX = "^attributes\\[\\w*\\]$";
      private static final Pattern ATTRIBUTES_PATTERN = Pattern.compile(ATTRIBUTES_REGEX);
  
      private AttributeTransform() {
  
      }
  
      @Override
      public QueryByCriteria apply(final QueryByCriteria input) {
          QueryByCriteria.Builder builder = QueryByCriteria.Builder.create(input);
          builder.setPredicates(applyPredicate(input.getPredicate()));
          return builder.build();
      }
  
      private Predicate applyPredicate(final Predicate input) {
          if (input instanceof PropertyPathPredicate) {
              String pp = ((PropertyPathPredicate) input).getPropertyPath();
              if (isAttributesPredicate(pp)) {
                  final String attributeName = pp.substring(pp.indexOf('[') + 1, pp.indexOf(']'));
  
                  final Predicate attrValue;
                  if (input instanceof SingleValuedPredicate) {
                      final CriteriaValue<?> value = ((SingleValuedPredicate) input).getValue();
                      attrValue = dynConstruct(input.getClass().getSimpleName(), ATTRIBUTE_DETAILS_ATTRIBUTE_VALUE, value.getValue());
                  } else if (input instanceof MultiValuedPredicate) {
                      final Set<? extends CriteriaValue<?>> values = ((MultiValuedPredicate) input).getValues();
                      List<Object> l = new ArrayList<Object>();
                      for (CriteriaValue<?> v : values) {
                          l.add(v.getValue());
                      }
  
                      attrValue = dynConstruct(input.getClass().getSimpleName(), ATTRIBUTE_DETAILS_ATTRIBUTE_VALUE, l.toArray());
                  } else {
                      attrValue = dynConstruct(input.getClass().getSimpleName(), ATTRIBUTE_DETAILS_ATTRIBUTE_VALUE);
                  }
                  return and(equal(ATTRIBUTE_DETAILS_ATTRIBUTE_NAME, attributeName), attrValue);
              }
          } else if (input instanceof CompositePredicate) {
              return applyCompositePredicate((CompositePredicate) input);
          }
  
          return input;
      }
  
      private Predicate applyCompositePredicate(final CompositePredicate input) {
          Set<Predicate> appliedPredicates = new HashSet<Predicate>();
  
          for (Predicate predicate : input.getPredicates()) {
              appliedPredicates.add(applyPredicate(predicate));
          }
  
          Predicate[] appliedPredicatesArray = Iterables.toArray(appliedPredicates, Predicate.class);
 
         if (input instanceof AndPredicate) {
             return and(appliedPredicatesArray);
         } else if (input instanceof OrPredicate) {
             return or(appliedPredicatesArray);
         }
 
         return input;
     }
 
     private boolean isAttributesPredicate(String pp) {
         Matcher matcher = ATTRIBUTES_PATTERN.matcher(pp);
         return matcher.matches();
     }
 
     public static Transform<QueryByCriteria, QueryByCriteria> getInstance() {
         return INSTANCE;
     }
 }