/**
    * 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.krad.uif.lifecycle.initialize;
  
  import org.apache.commons.lang.StringUtils;
  import org.kuali.rice.krad.datadictionary.AttributeDefinition;
  import org.kuali.rice.krad.service.DataDictionaryService;
  import org.kuali.rice.krad.service.KRADServiceLocatorWeb;
  import org.kuali.rice.krad.uif.UifConstants;
  import org.kuali.rice.krad.uif.UifPropertyPaths;
  import org.kuali.rice.krad.uif.component.BindingInfo;
  import org.kuali.rice.krad.uif.field.DataField;
  import org.kuali.rice.krad.uif.field.InputField;
  import org.kuali.rice.krad.uif.lifecycle.ViewLifecycle;
  import org.kuali.rice.krad.uif.lifecycle.ViewLifecycleTaskBase;
  import org.kuali.rice.krad.uif.util.ComponentFactory;
  import org.kuali.rice.krad.uif.util.ObjectPropertyUtils;
  import org.kuali.rice.krad.uif.view.ExpressionEvaluator;
  import org.kuali.rice.krad.uif.view.View;
  import org.kuali.rice.krad.util.KRADConstants;
  
  import java.util.List;
  import java.util.Map;
  import java.util.Map.Entry;
  
  /**
   * Performs initialization on data fields based on attributes found in the data dictionary.
   * 
   * @author Kuali Rice Team (rice.collab@kuali.org)
   */
  public class InitializeDataFieldFromDictionaryTask extends ViewLifecycleTaskBase<DataField> {
  
      /**
       * Constructor.
       * 
       * @param phase The initialize phase for the data field.
       */
      public InitializeDataFieldFromDictionaryTask() {
          super(DataField.class);
      }
  
      /**
       * Sets properties of the <code>InputField</code> (if blank) to the corresponding attribute
       * entry in the data dictionary
       *
       * {@inheritDoc}
       */
      @Override
      protected void performLifecycleTask() {
          DataField field = (DataField) getElementState().getElement();
  
          AttributeDefinition attributeDefinition = null;
  
          String dictionaryAttributeName = field.getDictionaryAttributeName();
          String dictionaryObjectEntry = field.getDictionaryObjectEntry();
  
          Map<String, String> propertyExpressions = field.getPropertyExpressions();
  
          if (dictionaryAttributeName == null && propertyExpressions.containsKey(UifPropertyPaths.DICTIONARY_ATTR_NAME)) {
              ExpressionEvaluator expressionEvaluator = ViewLifecycle.getExpressionEvaluator();
              dictionaryAttributeName = propertyExpressions.get(UifPropertyPaths.DICTIONARY_ATTR_NAME);
  
              if (dictionaryAttributeName.contains(UifConstants.DEFAULT_PATH_BIND_ADJUST_PREFIX)) {
                  dictionaryAttributeName = dictionaryAttributeName.replace(UifConstants.DEFAULT_PATH_BIND_ADJUST_PREFIX,
                          "");
              } else if (dictionaryAttributeName.contains(UifConstants.LINE_PATH_BIND_ADJUST_PREFIX)) {
                  // It is not possible to add both the collection and index to the context at this time.  Until
                  // the dictionaryAttributeName expression can be properly evaluated, get the attribute definition for
                  // the field by looking at the first item in the collection if an item exists.
  
                  List<Object> collection = ObjectPropertyUtils.getPropertyValue(ViewLifecycle.getModel(),
                         field.getBindingInfo().getCollectionPath());
  
                  if (!collection.isEmpty()) {
                      dictionaryAttributeName = dictionaryAttributeName.replace(UifConstants.LINE_PATH_BIND_ADJUST_PREFIX,
                              field.getBindingInfo().getCollectionPath() + "[0].");
                  } else {
                      dictionaryAttributeName = null;
                  }
              }
  
              dictionaryAttributeName = (String) expressionEvaluator.evaluateExpression(field.getContext(),
                      dictionaryAttributeName);
          }
  
          if (!(dictionaryAttributeName == null && propertyExpressions.containsKey(UifPropertyPaths.DICTIONARY_ATTR_NAME))) {
 
             // if entry given but not attribute name, use field name as attribute name
             if (StringUtils.isNotBlank(dictionaryObjectEntry) && StringUtils.isBlank(dictionaryAttributeName)) {
                 dictionaryAttributeName = field.getPropertyName();
             }
 
             // if dictionary entry and attribute set, attempt to find definition
             if (StringUtils.isNotBlank(dictionaryAttributeName) && StringUtils.isNotBlank(dictionaryObjectEntry)) {
                 attributeDefinition = KRADServiceLocatorWeb.getDataDictionaryService().getAttributeDefinition(
                         dictionaryObjectEntry, dictionaryAttributeName);
             }
 
             // if definition not found, recurse through path
             if (attributeDefinition == null) {
                 BindingInfo fieldBindingInfo = field.getBindingInfo();
                 String collectionPath = fieldBindingInfo.getCollectionPath();
 
                 String propertyPath;
                 if (StringUtils.isNotBlank(collectionPath)) {
                     StringBuilder propertyPathBuilder = new StringBuilder();
 
                     String bindingObjectPath = fieldBindingInfo.getBindingObjectPath();
                     if (StringUtils.isNotBlank(bindingObjectPath)) {
                         propertyPathBuilder.append(bindingObjectPath).append('.');
                     }
 
                     propertyPathBuilder.append(collectionPath).append('.');
 
                     String bindByNamePrefix = fieldBindingInfo.getBindByNamePrefix();
                     if (StringUtils.isNotBlank(bindByNamePrefix)) {
 
                         // fix for both collectionPath and bindByNamePrefix being set,
                         // wherein the bindByNamePrefix contains the collectionPath
                         if (!bindByNamePrefix.startsWith(collectionPath)) {
                             propertyPathBuilder.append(bindByNamePrefix).append('.');
                         }
                     }
 
                     propertyPathBuilder.append(fieldBindingInfo.getBindingName());
                     propertyPath = propertyPathBuilder.toString();
                 } else {
                     propertyPath = field.getBindingInfo().getBindingPath();
                 }
 
                 attributeDefinition = findNestedDictionaryAttribute(propertyPath);
             }
 
             // if a definition was found, initialize field from definition
             if (attributeDefinition != null) {
                 field.copyFromAttributeDefinition(attributeDefinition);
             }
         }
 
         // if control still null, assign default
         if (field instanceof InputField) {
             InputField inputField = (InputField) field;
             if (inputField.getControl() == null) {
                 inputField.setControl(ComponentFactory.getTextControl());
             }
         }
     }
 
     /**
      * Determines the name of a data dictionary entry based on the portion of the path leading up to
      * the attribute name.
      * 
      * <p>
      * The property path passed in is checked first against
      * {@link View#getObjectPathToConcreteClassMapping()} for a full or partial match. If no match
      * is found then property type relative to the model involved in the current view lifecycle is
      * returned, where applicable.
      * </p>
      * 
      * @param dictionaryEntryPrefix Portion of a property path referring to the entry that has the
      *        attribute.
      * @return The name of the dictionary entry indicated by the property path.
      */
     private String getDictionaryEntryName(String dictionaryEntryPrefix) {
         if (StringUtils.isEmpty(dictionaryEntryPrefix)) {
             return dictionaryEntryPrefix;
         }
         
         Map<String, Class<?>> modelClasses = ViewLifecycle.getView().getObjectPathToConcreteClassMapping();
         Class<?> dictionaryModelClass = modelClasses.get(dictionaryEntryPrefix);
 
         // full match
         if (dictionaryModelClass != null) {
             return dictionaryModelClass.getName();
         }
 
         // in case of partial match, holds the class that matched and the
         // property so we can get by reflection
         Class<?> modelClass = null;
         String modelProperty = dictionaryEntryPrefix;
 
         int bestMatchLength = 0;
         int modelClassPathLength = dictionaryEntryPrefix.length();
 
         // check if property path matches one of the modelClass entries
         synchronized (modelClasses) {
             // synchronizing on modelClasses prevents ConcurrentModificationException during
             // asynchronous lifecycle processing
             for (Entry<String, Class<?>> modelClassEntry : modelClasses.entrySet()) {
                 String path = modelClassEntry.getKey();
                 int pathlen = path.length();
 
                 if (dictionaryEntryPrefix.startsWith(path) && pathlen > bestMatchLength
                         && modelClassPathLength > pathlen && dictionaryEntryPrefix.charAt(pathlen) == '.') {
                     bestMatchLength = pathlen;
                     modelClass = modelClassEntry.getValue();
                     modelProperty = dictionaryEntryPrefix.substring(pathlen + 1);
                 }
             }
         }
 
         if (modelClass != null) {
             // if a partial match was found, look up the property type based on matched model class
             dictionaryModelClass = ObjectPropertyUtils.getPropertyType(modelClass, modelProperty);
         }
 
         if (dictionaryModelClass == null) {
             // If no full or partial match, look up based on the model directly
             dictionaryModelClass = ObjectPropertyUtils.getPropertyType(ViewLifecycle.getModel(), dictionaryEntryPrefix);
         }
 
         return dictionaryModelClass == null ? null : dictionaryModelClass.getName();
     }
 
     /**
      * Recursively drills down the property path (if nested) to find an AttributeDefinition, the
      * first attribute definition found will be returned
      * 
      * <p>
      * e.g. suppose parentPath is 'document' and propertyPath is 'account.subAccount.name', first
      * the property type for document will be retrieved using the view metadata and used as the
      * dictionary entry, with the propertyPath as the dictionary attribute, if an attribute
      * definition exists it will be returned. Else, the first part of the property path is added to
      * the parent, making the parentPath 'document.account' and the propertyPath 'subAccount.name',
      * the method is then called again to perform the process with those parameters. The recursion
      * continues until an attribute field is found, or the propertyPath is no longer nested
      * </p>
      * 
      * @param propertyPath path of the property to use as dictionary attribute and to drill down on
      * @return AttributeDefinition if found, or Null
      */
     protected AttributeDefinition findNestedDictionaryAttribute(String propertyPath) {
         DataField field = (DataField) getElementState().getElement();
 
         String fieldBindingPrefix = null;
         String dictionaryAttributePath = propertyPath;
 
         if (field.getBindingInfo().isBindToMap()) {
             fieldBindingPrefix = "";
             if (!field.getBindingInfo().isBindToForm() && StringUtils.isNotBlank(
                     field.getBindingInfo().getBindingObjectPath())) {
                 fieldBindingPrefix = field.getBindingInfo().getBindingObjectPath();
             }
             if (StringUtils.isNotBlank(field.getBindingInfo().getBindByNamePrefix())) {
                 if (StringUtils.isNotBlank(fieldBindingPrefix)) {
                     fieldBindingPrefix += "." + field.getBindingInfo().getBindByNamePrefix();
                 } else {
                     fieldBindingPrefix = field.getBindingInfo().getBindByNamePrefix();
                 }
             }
 
             dictionaryAttributePath = field.getBindingInfo().getBindingName();
         }
 
         if (StringUtils.isEmpty(dictionaryAttributePath)) {
             return null;
         }
 
         if (StringUtils.startsWith(dictionaryAttributePath, KRADConstants.LOOKUP_RANGE_LOWER_BOUND_PROPERTY_PREFIX)) {
             dictionaryAttributePath = StringUtils.substringAfter(dictionaryAttributePath, KRADConstants.LOOKUP_RANGE_LOWER_BOUND_PROPERTY_PREFIX);
         }
         
         DataDictionaryService ddService = KRADServiceLocatorWeb.getDataDictionaryService();
         
         String dictionaryAttributeName = ObjectPropertyUtils.getCanonicalPath(dictionaryAttributePath);
         String dictionaryEntryPrefix = fieldBindingPrefix;
         
         AttributeDefinition attribute = null;
         String dictionaryEntryName = null;
         
         int i = dictionaryAttributeName.indexOf('.');
         while (attribute == null && i != -1) {
             
             if (dictionaryEntryPrefix != null) {
                 dictionaryEntryName = getDictionaryEntryName(dictionaryEntryPrefix);
                 dictionaryEntryPrefix += '.' + dictionaryAttributeName.substring(0, i);
             } else {
                 dictionaryEntryName = null;
                 dictionaryEntryPrefix = dictionaryAttributeName.substring(0, i);
             }
 
             if (dictionaryEntryName != null) {
                 attribute = ddService.getAttributeDefinition(dictionaryEntryName, dictionaryAttributeName);
             }
             
             if (attribute == null) {
                 dictionaryAttributeName = dictionaryAttributeName.substring(i+1);
                 i = dictionaryAttributeName.indexOf('.');
             }
         }
         
         if (attribute == null && dictionaryEntryPrefix != null) {
             dictionaryEntryName = getDictionaryEntryName(dictionaryEntryPrefix);
             
             if (dictionaryEntryName != null) {
                 attribute = ddService.getAttributeDefinition(dictionaryEntryName, dictionaryAttributeName);
             }
         }
         
         // if a definition was found, update the fields dictionary properties
         if (attribute != null) {
             field.setDictionaryObjectEntry(dictionaryEntryName);
             field.setDictionaryAttributeName(dictionaryAttributeName);
         }
 
         return attribute;
     }
 
 }