package org.kuali.student.r2.common.criteria.transform;

 import static org.kuali.rice.core.api.criteria.PredicateFactory.and;

 import static org.kuali.rice.core.api.criteria.PredicateFactory.equal;

 import java.util.regex.Matcher;

 import java.util.regex.Pattern;

 import org.kuali.rice.core.api.criteria.Predicate;

 import org.kuali.rice.core.api.criteria.PropertyPathPredicate;

 import org.kuali.rice.core.framework.persistence.jpa.criteria.Criteria;

 public class AttributeTransform extends BaseTransform {

     private static final String ATTRIBUTE_PROPERTY = "attributes";

     private static final String ATTRIBUTE_ALIAS = "attr";

     private static final String ATTRIBUTE_VALUE = "value";

     private static final String ATTRIBUTE_KEY = "key";

     private static final String ATTRIBUTES_REGEX = "^attributes\\[\\w*\\]$";

     private static final Pattern ATTRIBUTES_PATTERN = Pattern.compile(ATTRIBUTES_REGEX);

     private AttributeTransform() {

     }

     @Override

     public Predicate apply(final Predicate input, Criteria criteria) {

         if (input instanceof PropertyPathPredicate) {

             String pp = ((PropertyPathPredicate) input).getPropertyPath();

             if (isAttributesPredicate(pp)) {

                 criteria.join(ATTRIBUTE_PROPERTY, ATTRIBUTE_ALIAS, false, true);

                 final String attributeName = pp.substring(pp.indexOf('[') + 1, pp.indexOf(']'));

                 final Predicate attrValue = this.createPredicate(input, getPropertyDesc() + ATTRIBUTE_VALUE);

                 return and(equal(getPropertyDesc() + ATTRIBUTE_KEY, attributeName), attrValue);

             }

         }

         return input;

     }

     private String getPropertyDesc(){

         return Criteria.JPA_ALIAS_PREFIX + "'" + ATTRIBUTE_ALIAS + "'" + Criteria.JPA_ALIAS_SUFFIX + ".";

     }

     private boolean isAttributesPredicate(String pp) {

         Matcher matcher = ATTRIBUTES_PATTERN.matcher(pp);

         return matcher.matches();

     }

 }