/**
    * Copyright 2005-2011 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.krad.workflow.service.impl;
  
  import org.joda.time.DateTime;
  import org.kuali.rice.core.api.util.type.KualiDecimal;
  import org.kuali.rice.kew.api.document.attribute.DocumentAttribute;
  import org.kuali.rice.kew.api.document.attribute.DocumentAttributeDateTime;
  import org.kuali.rice.kew.api.document.attribute.DocumentAttributeDecimal;
  import org.kuali.rice.kew.api.document.attribute.DocumentAttributeFactory;
  import org.kuali.rice.kew.api.document.attribute.DocumentAttributeInteger;
  import org.kuali.rice.kew.api.document.attribute.DocumentAttributeString;
  import org.kuali.rice.kew.api.KewApiConstants;
  import org.kuali.rice.kns.service.BusinessObjectMetaDataService;
  import org.kuali.rice.kns.service.KNSServiceLocator;
  import org.kuali.rice.krad.bo.BusinessObject;
  import org.kuali.rice.krad.bo.PersistableBusinessObject;
  import org.kuali.rice.krad.datadictionary.DocumentCollectionPath;
  import org.kuali.rice.krad.datadictionary.DocumentValuePathGroup;
  import org.kuali.rice.krad.datadictionary.RoutingAttribute;
  import org.kuali.rice.krad.datadictionary.RoutingTypeDefinition;
  import org.kuali.rice.krad.datadictionary.SearchingTypeDefinition;
  import org.kuali.rice.krad.datadictionary.WorkflowAttributes;
  import org.kuali.rice.krad.document.Document;
  import org.kuali.rice.krad.service.PersistenceStructureService;
  import org.kuali.rice.krad.util.DataTypeUtil;
  import org.kuali.rice.krad.util.ObjectUtils;
  import org.kuali.rice.krad.workflow.attribute.DataDictionarySearchableAttribute;
  import org.kuali.rice.krad.workflow.service.WorkflowAttributePropertyResolutionService;
  
  import java.math.BigDecimal;
  import java.math.BigInteger;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  import java.util.Stack;
  
  /**
   * The default implementation of the WorkflowAttributePropertyResolutionServiceImpl
   */
  public class WorkflowAttributePropertyResolutionServiceImpl implements WorkflowAttributePropertyResolutionService {
      
      private PersistenceStructureService persistenceStructureService;
      private BusinessObjectMetaDataService businessObjectMetaDataService;
  
      /**
       * Using the proper RoutingTypeDefinition for the current routing node of the document, aardvarks out the proper routing type qualifiers
       */
      public List<Map<String, String>> resolveRoutingTypeQualifiers(Document document, RoutingTypeDefinition routingTypeDefinition) {
          List<Map<String, String>> qualifiers = new ArrayList<Map<String, String>>();
          
          if (routingTypeDefinition != null) {
              document.populateDocumentForRouting();
              RoutingAttributeTracker routingAttributeTracker = new RoutingAttributeTracker(routingTypeDefinition.getRoutingAttributes());
              for (DocumentValuePathGroup documentValuePathGroup : routingTypeDefinition.getDocumentValuePathGroups()) {
                  qualifiers.addAll(resolveDocumentValuePath(document, documentValuePathGroup, routingAttributeTracker));
                  routingAttributeTracker.reset();
              }
          }
          return qualifiers;
      }
      
      /**
       * Resolves all of the values in the given DocumentValuePathGroup from the given BusinessObject
       * @param businessObject the business object which is the source of values
       * @param group the DocumentValuePathGroup which tells us which values we want
       * @return a List of Map<String, String>s
       */
      protected List<Map<String, String>> resolveDocumentValuePath(BusinessObject businessObject, DocumentValuePathGroup group, RoutingAttributeTracker routingAttributeTracker) {
          List<Map<String, String>> qualifiers;
          Map<String, String> qualifier = new HashMap<String, String>();
          if (group.getDocumentValues() == null && group.getDocumentCollectionPath() == null) {
              throw new IllegalStateException("A document value path group must have the documentValues property set, the documentCollectionPath property set, or both.");
          }
          if (group.getDocumentValues() != null) {
              addPathValuesToQualifier(businessObject, group.getDocumentValues(), routingAttributeTracker, qualifier);
          }
          if (group.getDocumentCollectionPath() != null) {
              qualifiers = resolveDocumentCollectionPath(businessObject, group.getDocumentCollectionPath(), routingAttributeTracker);
              qualifiers = cleanCollectionQualifiers(qualifiers);
              for (Map<String, String> collectionElementQualifier : qualifiers) {
                  copyQualifications(qualifier, collectionElementQualifier);
             }
         } else {
             qualifiers = new ArrayList<Map<String, String>>();
             qualifiers.add(qualifier);
         }
         return qualifiers;
     }
     
     /**
      * Resolves document values from a collection path on a given business object
      * @param businessObject the business object which has a collection, each element of which is a source of values
      * @param collectionPath the information about what values to pull from each element of the collection
      * @return a List of Map<String, String>s
      */
     protected List<Map<String, String>> resolveDocumentCollectionPath(BusinessObject businessObject, DocumentCollectionPath collectionPath, RoutingAttributeTracker routingAttributeTracker) {
         List<Map<String, String>> qualifiers = new ArrayList<Map<String, String>>();
         final Collection collectionByPath = getCollectionByPath(businessObject, collectionPath.getCollectionPath());
         if (!ObjectUtils.isNull(collectionByPath)) {
             if (collectionPath.getNestedCollection() != null) {
                 // we need to go through the collection...
                 for (Object collectionElement : collectionByPath) {
                     // for each element, we need to get the child qualifiers
                     if (collectionElement instanceof BusinessObject) {
                         List<Map<String, String>> childQualifiers = resolveDocumentCollectionPath((BusinessObject)collectionElement, collectionPath.getNestedCollection(), routingAttributeTracker);
                         for (Map<String, String> childQualifier : childQualifiers) {
                             Map<String, String> qualifier = new HashMap<String, String>();
                             routingAttributeTracker.checkPoint();
                             // now we need to get the values for the current element of the collection
                             addPathValuesToQualifier(collectionElement, collectionPath.getDocumentValues(), routingAttributeTracker, qualifier);
                             // and move all the child keys to the qualifier
                             copyQualifications(childQualifier, qualifier);
                             qualifiers.add(qualifier);
                             routingAttributeTracker.backUpToCheckPoint();
                         }
                     }
                 }
             } else {
                 // go through each element in the collection
                 for (Object collectionElement : collectionByPath) {
                     Map<String, String> qualifier = new HashMap<String, String>();
                     routingAttributeTracker.checkPoint();
                     addPathValuesToQualifier(collectionElement, collectionPath.getDocumentValues(), routingAttributeTracker, qualifier);
                     qualifiers.add(qualifier);
                     routingAttributeTracker.backUpToCheckPoint();
                 }
             }
         }
         return qualifiers;
     }
     
     /**
      * Returns a collection from a path on a business object
      * @param businessObject the business object to get values from
      * @param collectionPath the path to that collection
      * @return hopefully, a collection of objects
      */
     protected Collection getCollectionByPath(BusinessObject businessObject, String collectionPath) {
         return (Collection)getPropertyByPath(businessObject, collectionPath.trim());
     }
     
     /**
      * Aardvarks values out of a business object and puts them into an Map<String, String>, based on a List of paths
      * @param businessObject the business object to get values from
      * @param paths the paths of values to get from the qualifier
      * @param routingAttributes the RoutingAttribute associated with this qualifier's document value
      * @param qualifier the qualifier to put values into
      */
     protected void addPathValuesToQualifier(Object businessObject, List<String> paths, RoutingAttributeTracker routingAttributes, Map<String, String> qualifier) {
         if (ObjectUtils.isNotNull(paths)) {
             for (String path : paths) {
                 // get the values for the paths of each element of the collection
                 final Object value = getPropertyByPath(businessObject, path.trim());
                 if (value != null) {
                     qualifier.put(routingAttributes.getCurrentRoutingAttribute().getQualificationAttributeName(), value.toString());
                 }
                 routingAttributes.moveToNext();
             }
         }
     }
     
     /**
      * Copies all the values from one qualifier to another
      * @param source the source of values
      * @param target the place to write all the values to
      */
     protected void copyQualifications(Map<String, String> source, Map<String, String> target) {
         for (String key : source.keySet()) {
             target.put(key, source.get(key));
         }
     }
 
     /**
      * Resolves all of the searching values to index for the given document, returning a list of SearchableAttributeValue implementations
      *
      */
     public List<DocumentAttribute> resolveSearchableAttributeValues(Document document, WorkflowAttributes workflowAttributes) {
         List<DocumentAttribute> valuesToIndex = new ArrayList<DocumentAttribute>();
         if (workflowAttributes != null && workflowAttributes.getSearchingTypeDefinitions() != null) {
             for (SearchingTypeDefinition definition : workflowAttributes.getSearchingTypeDefinitions()) {
                 valuesToIndex.addAll(aardvarkValuesForSearchingTypeDefinition(document, definition));
             }
         }
         return valuesToIndex;
     }
     
     /**
      * Pulls SearchableAttributeValue values from the given document for the given searchingTypeDefinition
      * @param document the document to get search values from
      * @param searchingTypeDefinition the current SearchingTypeDefinition to find values for
      * @return a List of SearchableAttributeValue implementations
      */
     protected List<DocumentAttribute> aardvarkValuesForSearchingTypeDefinition(Document document, SearchingTypeDefinition searchingTypeDefinition) {
         List<DocumentAttribute> searchAttributes = new ArrayList<DocumentAttribute>();
         
         final List<Object> searchValues = aardvarkSearchValuesForPaths(document, searchingTypeDefinition.getDocumentValues());
         for (Object value : searchValues) {
             try {
                 final DocumentAttribute searchableAttributeValue = buildSearchableAttribute(((Class<? extends BusinessObject>)Class.forName(searchingTypeDefinition.getSearchingAttribute().getBusinessObjectClassName())), searchingTypeDefinition.getSearchingAttribute().getAttributeName(), value);
                 if (searchableAttributeValue != null) {
                     searchAttributes.add(searchableAttributeValue);
                 }
             }
             catch (ClassNotFoundException cnfe) {
                 throw new RuntimeException("Could not find instance of class "+searchingTypeDefinition.getSearchingAttribute().getBusinessObjectClassName(), cnfe);
             }
         }
         return searchAttributes;
     }
     
     /**
      * Pulls values as objects from the document for the given paths
      * @param document the document to pull values from
      * @param paths the property paths to pull values
      * @return a List of values as Objects
      */
     protected List<Object> aardvarkSearchValuesForPaths(Document document, List<String> paths) {
         List<Object> searchValues = new ArrayList<Object>();
         for (String path : paths) {
             flatAdd(searchValues, getPropertyByPath(document, path.trim()));
         }
         return searchValues;
     }
     
     /**
      * Removes empty Map<String, String>s from the given List of qualifiers
      * @param qualifiers a List of Map<String, String>s holding qualifiers for responsibilities
      * @return a cleaned up list of qualifiers
      */
     protected List<Map<String, String>> cleanCollectionQualifiers(List<Map<String, String>> qualifiers) {
        List<Map<String, String>> cleanedQualifiers = new ArrayList<Map<String, String>>();
        for (Map<String, String> qualifier : qualifiers) {
            if (qualifier.size() > 0) {
                cleanedQualifiers.add(qualifier);
            }
        }
        return cleanedQualifiers;
     }
 
     public String determineFieldDataType(Class<? extends BusinessObject> businessObjectClass, String attributeName) {
         return DataTypeUtil.determineFieldDataType(businessObjectClass, attributeName);
     }
 
     /**
      * Using the type of the sent in value, determines what kind of SearchableAttributeValue implementation should be passed back 
      * @param attributeKey
      * @param value
      * @return
      */
     public DocumentAttribute buildSearchableAttribute(Class<? extends BusinessObject> businessObjectClass, String attributeKey, Object value) {
         if (value == null) return null;
         final String fieldDataType = determineFieldDataType(businessObjectClass, attributeKey);
         if (fieldDataType.equals(KewApiConstants.SearchableAttributeConstants.DATA_TYPE_STRING)) return buildSearchableStringAttribute(attributeKey, value); // our most common case should go first
         if (fieldDataType.equals(KewApiConstants.SearchableAttributeConstants.DATA_TYPE_FLOAT) && DataTypeUtil.isDecimaltastic(value.getClass())) return buildSearchableRealAttribute(attributeKey, value);
         if (fieldDataType.equals(KewApiConstants.SearchableAttributeConstants.DATA_TYPE_DATE) && DataTypeUtil.isDateLike(value.getClass())) return buildSearchableDateTimeAttribute(attributeKey, value);
         if (fieldDataType.equals(KewApiConstants.SearchableAttributeConstants.DATA_TYPE_LONG) && DataTypeUtil.isIntsy(value.getClass())) return buildSearchableFixnumAttribute(attributeKey, value);
         if (fieldDataType.equals(DataDictionarySearchableAttribute.DATA_TYPE_BOOLEAN) && DataTypeUtil.isBooleanable(value.getClass())) return buildSearchableYesNoAttribute(attributeKey, value);
         return buildSearchableStringAttribute(attributeKey, value);
     }
     
     /**
      * Builds a date time SearchableAttributeValue for the given key and value
      * @param attributeKey the key for the searchable attribute
      * @param value the value that will be coerced to date/time data
      * @return the generated SearchableAttributeDateTimeValue
      */
     protected DocumentAttributeDateTime buildSearchableDateTimeAttribute(String attributeKey, Object value) {
         return DocumentAttributeFactory.createDateTimeAttribute(attributeKey, new DateTime(value));
     }
     
     /**
      * Builds a "float" SearchableAttributeValue for the given key and value
      * @param attributeKey the key for the searchable attribute
      * @param value the value that will be coerced to "float" data
      * @return the generated SearchableAttributeFloatValue
      */
     protected DocumentAttributeDecimal buildSearchableRealAttribute(String attributeKey, Object value) {
         BigDecimal decimalValue = null;
         if (value instanceof BigDecimal) {
             decimalValue = (BigDecimal)value;
         } else if (value instanceof KualiDecimal) {
             decimalValue = ((KualiDecimal)value).bigDecimalValue();
         } else {
             decimalValue = new BigDecimal(((Number)value).doubleValue());
         }
         return DocumentAttributeFactory.createDecimalAttribute(attributeKey, decimalValue);
     }
     
     /**
      * Builds a "integer" SearchableAttributeValue for the given key and value
      * @param attributeKey the key for the searchable attribute
      * @param value the value that will be coerced to "integer" type data
      * @return the generated SearchableAttributeLongValue
      */
     protected DocumentAttributeInteger buildSearchableFixnumAttribute(String attributeKey, Object value) {
         BigInteger integerValue = null;
         if (value instanceof BigInteger) {
             integerValue = (BigInteger)value;
         } else {
             integerValue = BigInteger.valueOf(((Number)value).longValue());
         }
         return DocumentAttributeFactory.createIntegerAttribute(attributeKey, integerValue);
     }
     
     /**
      * Our last ditch attempt, this builds a String SearchableAttributeValue for the given key and value
      * @param attributeKey the key for the searchable attribute
      * @param value the value that will be coerced to a String
      * @return the generated SearchableAttributeStringValue
      */
     protected DocumentAttributeString buildSearchableStringAttribute(String attributeKey, Object value) {
         return DocumentAttributeFactory.createStringAttribute(attributeKey, value.toString());
     }
     
     /**
      * This builds a String SearchableAttributeValue for the given key and value, correctly correlating booleans
      * @param attributeKey the key for the searchable attribute
      * @param value the value that will be coerced to a String
      * @return the generated SearchableAttributeStringValue
      */
     protected DocumentAttributeString buildSearchableYesNoAttribute(String attributeKey, Object value) {
         final String boolValueAsString = booleanValueAsString((Boolean)value);
         return DocumentAttributeFactory.createStringAttribute(attributeKey, boolValueAsString);
    }
     
     /**
      * Converts the given boolean value to "" for null, "Y" for true, "N" for false
      * @param booleanValue the boolean value to convert
      * @return the corresponding String "Y","N", or ""
      */
     private String booleanValueAsString(Boolean booleanValue) {
         if (booleanValue == null) return "";
         if (booleanValue.booleanValue()) return "Y";
         return "N";
     }
 
     public Object getPropertyByPath(Object object, String path) {
         if (object instanceof Collection) return getPropertyOfCollectionByPath((Collection)object, path);
 
         final String[] splitPath = headAndTailPath(path);
         final String head = splitPath[0];
         final String tail = splitPath[1];
         
         if (object instanceof PersistableBusinessObject && tail != null) {
             if (getBusinessObjectMetaDataService().getBusinessObjectRelationship((BusinessObject) object, head) != null) {
                 ((PersistableBusinessObject)object).refreshReferenceObject(head);
 
             }
         }
         final Object headValue = ObjectUtils.getPropertyValue(object, head);
         if (!ObjectUtils.isNull(headValue)) {
             if (tail == null) {
                 return headValue;
             } else {
                 // we've still got path left...
                 if (headValue instanceof Collection) {
                     // oh dear, a collection; we've got to loop through this
                     Collection values = makeNewCollectionOfSameType((Collection)headValue);
                     for (Object currentElement : (Collection)headValue) {
                         flatAdd(values, getPropertyByPath(currentElement, tail));
                     }
                     return values;
                 } else {
                     return getPropertyByPath(headValue, tail);
                 }
             }
         }
         return null;
     }
     
     /**
      * Finds a child object, specified by the given path, on each object of the given collection
      * @param collection the collection of objects
      * @param path the path of the property to retrieve
      * @return a Collection of the values culled from each child
      */
     public Collection getPropertyOfCollectionByPath(Collection collection, String path) {
         Collection values = makeNewCollectionOfSameType(collection);
         for (Object o : collection) {
             flatAdd(values, getPropertyByPath(o, path));
         }
         return values;
     }
     
     /**
      * Makes a new collection of exactly the same type of the collection that was handed to it
      * @param collection the collection to make a new collection of the same type as
      * @return a new collection.  Of the same type.
      */
     public Collection makeNewCollectionOfSameType(Collection collection) {
         if (collection instanceof List) return new ArrayList();
         if (collection instanceof Set) return new HashSet();
         try {
             return collection.getClass().newInstance();
         }
         catch (InstantiationException ie) {
             throw new RuntimeException("Couldn't instantiate class of collection we'd already instantiated??", ie);
         }
         catch (IllegalAccessException iae) {
             throw new RuntimeException("Illegal Access on class of collection we'd already accessed??", iae);
         }
     }
     
     /**
      * Splits the first property off from a path, leaving the tail
      * @param path the path to split
      * @return an array; if the path is nested, the first element will be the first part of the path up to a "." and second element is the rest of the path while if the path is simple, returns the path as the first element and a null as the second element
      */
     protected String[] headAndTailPath(String path) {
         final int firstDot = path.indexOf('.');
         if (firstDot < 0) {
             return new String[] { path, null };
         }
         return new String[] { path.substring(0, firstDot), path.substring(firstDot + 1) };
     }
     
     /**
      * Convenience method which makes sure that if the given object is a collection, it is added to the given collection flatly
      * @param c a collection, ready to be added to
      * @param o an object of dubious type
      */
     protected void flatAdd(Collection c, Object o) {
         if (o instanceof Collection) {
             c.addAll((Collection) o);
         } else {
             c.add(o);
         }
     }
 
     /**
      * Gets the persistenceStructureService attribute. 
      * @return Returns the persistenceStructureService.
      */
     public PersistenceStructureService getPersistenceStructureService() {
         return persistenceStructureService;
     }
 
     /**
      * Sets the persistenceStructureService attribute value.
      * @param persistenceStructureService The persistenceStructureService to set.
      */
     public void setPersistenceStructureService(PersistenceStructureService persistenceStructureService) {
         this.persistenceStructureService = persistenceStructureService;
     }
     
     /**
      * Inner helper class which will track which routing attributes have been used
      */
     class RoutingAttributeTracker {
         
         private List<RoutingAttribute> routingAttributes;
         private int currentRoutingAttributeIndex;
         private Stack<Integer> checkPoints;
         
         /**
          * Constructs a WorkflowAttributePropertyResolutionServiceImpl
          * @param routingAttributes the routing attributes to track
          */
         public RoutingAttributeTracker(List<RoutingAttribute> routingAttributes) {
             this.routingAttributes = routingAttributes;
             checkPoints = new Stack<Integer>();
         }
         
         /**
          * @return the routing attribute hopefully associated with the current qualifier
          */
         public RoutingAttribute getCurrentRoutingAttribute() {
             return routingAttributes.get(currentRoutingAttributeIndex);
         }
         
         /**
          * Moves this routing attribute tracker to its next routing attribute
          */
         public void moveToNext() {
             currentRoutingAttributeIndex += 1;
         }
         
         /**
          * Check points at the current routing attribute, so that this position is saved
          */
         public void checkPoint() {
             checkPoints.push(new Integer(currentRoutingAttributeIndex));
         }
         
         /**
          * Returns to the point of the last check point
          */
         public void backUpToCheckPoint() {
             currentRoutingAttributeIndex = checkPoints.pop().intValue();
         }
         
         /**
          * Resets this RoutingAttributeTracker, setting the current RoutingAttribute back to the top one and
          * clearing the check point stack
          */
         public void reset() {
             currentRoutingAttributeIndex = 0;
             checkPoints.clear();
         }
     }
 
     protected BusinessObjectMetaDataService getBusinessObjectMetaDataService() {
         if ( businessObjectMetaDataService == null ) {
             businessObjectMetaDataService = KNSServiceLocator.getBusinessObjectMetaDataService();
         }
         return businessObjectMetaDataService;
     }
 }