/*
    * Copyright 2009 The Kuali Foundation.
    * 
    * Licensed under the Educational Community License, Version 1.0 (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/ecl1.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.ole.sec.service.impl;
  
  import java.util.Map;
  
  import org.apache.commons.lang.StringUtils;
  import org.kuali.ole.sec.SecConstants;
  import org.kuali.ole.sec.service.AccessPermissionEvaluator;
  import org.kuali.rice.kim.api.identity.Person;
  
  
  /**
   * @see org.kuali.ole.sec.service.AccessPermissionEvaluator
   */
  public class AccessPermissionEvaluatorImpl implements AccessPermissionEvaluator {
      private static final org.apache.log4j.Logger LOG = org.apache.log4j.Logger.getLogger(AccessPermissionEvaluatorImpl.class);
  
      protected String constraintCode;
      protected String operatorCode;
      protected String propertyValue;
      protected Map<String, Object> otherKeyFieldValues;
      protected Person person;
      protected String[] matchValues;
      protected boolean performEqualMatch;
      protected boolean performLessThanMatch;
      protected boolean performGreaterThanMatch;
      protected boolean allowConstraint;
      protected boolean notOperator;
  
      public AccessPermissionEvaluatorImpl() {
          super();
  
          performEqualMatch = false;
          performLessThanMatch = false;
          performGreaterThanMatch = false;
          allowConstraint = false;
          notOperator = false;
      }
  
      /**
       * @see org.kuali.ole.sec.service.AccessPermissionEvaluator#valueIsAllowed(java.lang.String)
       */
      public boolean valueIsAllowed(String value) {
          boolean allowed = false;
  
          initializeAfterPropsSet();
  
          boolean match = false;
          for (int i = 0; i < matchValues.length; i++) {
              String matchValue = matchValues[i];
  
              if (isMatch(matchValue, value)) {
                  match = true;
                  break;
              }
          }
  
          if ((allowConstraint && notOperator) || (!allowConstraint && !notOperator)) {
              allowed = !match;
          }
          else {
              allowed = match;
          }
  
          return allowed;
      }
  
      /**
       * Determines whether two values match performing an equal, greater than, or less than check and also considering wildcards
       * 
       * @param matchValue String value to match, can contain the * wildcard
       * @param value String value to compare
       * @return boolean true if values match, false otherwise
       */
      protected boolean isMatch(String matchValue, String value) {
          boolean match = false;
  
          boolean performWildcardMatch = false;
          if (StringUtils.contains(matchValue, SecConstants.SecurityValueSpecialCharacters.WILDCARD_CHARACTER)) {
              matchValue = StringUtils.remove(matchValue, SecConstants.SecurityValueSpecialCharacters.WILDCARD_CHARACTER);
              performWildcardMatch = true;
          }
  
          if (performEqualMatch) {
              if (performWildcardMatch) {
                 match = value.startsWith(matchValue);
             }
             else {
                 match = value.equals(matchValue);
             }
         }
 
         if (!match && performLessThanMatch) {
             match = value.compareTo(matchValue) < 0;
         }
 
         if (!match && performGreaterThanMatch) {
             match = value.compareTo(matchValue) > 0;
         }
 
         return match;
     }
 
     /**
      * Hooks for permission evaluators to do additional setup after properties have been set
      */
     protected void initializeAfterPropsSet() {
         if (StringUtils.contains(constraintCode, SecConstants.SecurityConstraintCodes.ALLOWED)) {
             allowConstraint = true;
         }
 
         if (SecConstants.SecurityDefinitionOperatorCodes.EQUAL.equals(operatorCode) || SecConstants.SecurityDefinitionOperatorCodes.NOT_EQUAL.equals(operatorCode) || SecConstants.SecurityDefinitionOperatorCodes.LESS_THAN_EQUAL.equals(operatorCode)
                 || SecConstants.SecurityDefinitionOperatorCodes.GREATER_THAN_EQUAL.equals(operatorCode)) {
             performEqualMatch = true;
         }
 
         if (SecConstants.SecurityDefinitionOperatorCodes.LESS_THAN.equals(operatorCode) || SecConstants.SecurityDefinitionOperatorCodes.LESS_THAN_EQUAL.equals(operatorCode)) {
             performLessThanMatch = true;
         }
 
         if (SecConstants.SecurityDefinitionOperatorCodes.GREATER_THAN.equals(operatorCode) || SecConstants.SecurityDefinitionOperatorCodes.GREATER_THAN_EQUAL.equals(operatorCode)) {
             performGreaterThanMatch = true;
         }
         
         if (SecConstants.SecurityDefinitionOperatorCodes.NOT_EQUAL.equals(operatorCode)) {
             notOperator = true;
         }
 
         setMatchValues();
     }
 
     /**
      * Sets the values to match on based on given value and other properties
      */
     protected void setMatchValues() {
         if (StringUtils.contains(propertyValue, SecConstants.SecurityValueSpecialCharacters.MULTI_VALUE_SEPERATION_CHARACTER)) {
             matchValues = StringUtils.split(propertyValue, SecConstants.SecurityValueSpecialCharacters.MULTI_VALUE_SEPERATION_CHARACTER);
         }
         else {
             matchValues = new String[1];
             matchValues[0] = propertyValue;
         }
     }
 
     /**
      * @see org.kuali.ole.sec.service.AccessPermissionEvaluator#setConstraintCode(java.lang.String)
      */
     public void setConstraintCode(String constraintCode) {
         this.constraintCode = constraintCode;
     }
 
     /**
      * @see org.kuali.ole.sec.service.AccessPermissionEvaluator#setOperatorCode(java.lang.String)
      */
     public void setOperatorCode(String operatorCode) {
         this.operatorCode = operatorCode;
     }
 
     /**
      * @see org.kuali.ole.sec.service.AccessPermissionEvaluator#setPropertyValue(java.lang.String)
      */
     public void setPropertyValue(String propertyValue) {
         this.propertyValue = propertyValue;
     }
 
     /**
      * @see org.kuali.ole.sec.service.AccessPermissionEvaluator#setOtherKeyFieldValueMap(java.util.Map)
      */
     public void setOtherKeyFieldValueMap(Map<String, Object> otherKeyFieldValues) {
         this.otherKeyFieldValues = otherKeyFieldValues;
     }
 
     /**
      * @see org.kuali.ole.sec.service.AccessPermissionEvaluator#setPerson(org.kuali.rice.kim.api.identity.Person)
      */
     public void setPerson(Person person) {
         this.person = person;
     }
 
 }