/**
    * Copyright 2005-2014 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.util;
  
  import java.util.Collection;
  import java.util.Map;
  
  import org.apache.commons.lang.StringUtils;
  import org.kuali.rice.krad.uif.component.BindingInfo;
  import org.kuali.rice.krad.uif.field.DataField;
  import org.kuali.rice.krad.uif.view.View;
  import org.springframework.beans.PropertyValues;
  import org.springframework.beans.factory.config.TypedStringValue;
  
  /**
   * Provides methods for getting property values, types, and paths within the
   * context of a <code>View</code>
   *
   * <p>
   * The view provides a special map named 'abstractTypeClasses' that indicates
   * concrete classes that should be used in place of abstract property types that
   * are encountered on the object graph. This classes takes into account that map
   * while dealing with properties. e.g. suppose we have propertyPath
   * 'document.name' on the form, with the type of the document property set to
   * the interface Document. Using class introspection we would get back the
   * interface type for document and this would not be able to get the property
   * type for name. Using the view map, we can replace document with a concrete
   * class and then use it to get the name property
   * </p>
   *
   * @author Kuali Rice Team (rice.collab@kuali.org)
   */
  public class ViewModelUtils {
  
      /**
       * Determines the associated type for the property within the View context
       *
       * <p>
       * Property path is full path to property from the View Form class. The abstract type classes
       * map configured on the View will be consulted for any entries that match the property path. If the
       * property path given contains a partial match to an abstract class (somewhere on path is an abstract
       * class), the property type will be retrieved based on the given concrete class to use and the part
       * of the path remaining. If no matching entry is found, standard reflection is used to get the type
       * </p>
       *
       * @param view view instance providing the context (abstract map)
       * @param model the model
       * @param propertyPath full path to property to retrieve type for (relative to the form class)
       * @return Class<?> type of property in model, or Null if type could not be determined
       * @see org.kuali.rice.krad.uif.view.View#getObjectPathToConcreteClassMapping()
       */
      public static Class<?> getPropertyTypeByClassAndView(View view, Object model, String propertyPath) {
          if (StringUtils.isBlank(propertyPath)) {
              return null;
          }
  
          Class<?> propertyType = null;
  
          // in case of partial match, holds the class that matched and the
          // property so we can get by reflection
          Class<?> modelClass = null;
          String modelProperty = propertyPath;
  
          int bestMatchLength = 0;
  
          // removed collection indexes from path for matching
          String flattenedPropertyPath = propertyPath.replaceAll("\\[.+\\]", "");
  
          // check if property path matches one of the modelClass entries
          Map<String, Class<?>> modelClasses = view.getObjectPathToConcreteClassMapping();
          for (String path : modelClasses.keySet()) {
              // full match
              if (StringUtils.equals(path, flattenedPropertyPath)) {
                  propertyType = modelClasses.get(path);
                  break;
              }
  
              // partial match
              if (flattenedPropertyPath.startsWith(path) && (path.length() > bestMatchLength)) {
                  bestMatchLength = path.length();
  
                  modelClass = modelClasses.get(path);
                  modelProperty = StringUtils.removeStart(flattenedPropertyPath, path);
                  modelProperty = StringUtils.removeStart(modelProperty, ".");
              }
          }
 
         // if full match not found, get type based on reflection
         if (propertyType == null) {
             if (modelClass == null) {
                 // no match, check model instance directly
                 propertyType = ObjectPropertyUtils.getPropertyType(model, propertyPath);
             } else {
                 // partial match, check modelClass
                 propertyType = ObjectPropertyUtils.getPropertyType(modelClass, modelProperty);
             }
         }
 
         return propertyType;
     }
 
     /**
      * Gets the parent object path of the data field
      *
      * @param field
      * @return parent object path
      */
     public static String getParentObjectPath(DataField field) {
         StringBuilder parentObjectPath = new StringBuilder();
         
         BindingInfo fieldBindingInfo = field.getBindingInfo();
 
         String objectPath = fieldBindingInfo.getBindingObjectPath();
         if (!fieldBindingInfo.isBindToForm() && StringUtils.isNotBlank(objectPath)) {
             parentObjectPath.append(objectPath);
         }
 
         String propertyPrefix = fieldBindingInfo.getBindByNamePrefix();
         if (StringUtils.isNotBlank(propertyPrefix)) {
             
             if (parentObjectPath.length() > 0) {
                 parentObjectPath.append('.');
             }
             
             parentObjectPath.append(propertyPrefix);
         }
 
         return parentObjectPath.toString();
     }
 
     /**
      * Determines the associated type for the property within the View context
      *
      * <p>
      * If the parent object instance is not null, get the class through it.  Otherwise, use the following logic:
      * The abstract type classes map configured on the View will be consulted for any entries that match
      * the property path. If the parent object path for the given field contains a partial match to an
      * abstract class (somewhere on path is an abstract class), the property type will be retrieved based
      * on the given concrete class to use and the part of the path remaining. If no matching entry is found,
      * standard reflection is used to get the type
      * </p>
      *
      * @param view view instance providing the context (abstract map)
      * @param model object model
      * @param field field to retrieve type for
      * @return the class of the object instance if not null or the type of property in model, or Null if type could not be determined
      * @see org.kuali.rice.krad.uif.view.View#getObjectPathToConcreteClassMapping()
      */
     public static Class<?> getParentObjectClassForMetadata(View view, Object model, DataField field) {
         String parentObjectPath = getParentObjectPath(field);
 
         return getObjectClassForMetadata(view, model, parentObjectPath);
     }
 
     /**
      * Determines the associated type for the property within the View context
      *
      * <p>
      * If the parent object instance is not null, get the class through it.  Otherwise, use the following logic:
      * The abstract type classes map configured on the View will be consulted for any entries that match
      * the property path. If the parent object path for the given field contains a partial match to an
      * abstract class (somewhere on path is an abstract class), the property type will be retrieved based
      * on the given concrete class to use and the part of the path remaining. If no matching entry is found,
      * standard reflection is used to get the type
      * </p>
      *
      * @param view view instance providing the context (abstract map)
      * @param model object model
      * @param propertyPath full path to property to retrieve type for (relative to the form class)
      * @return the class of the object instance if not null or the type of property in model, or Null if type could not be determined
      * @see org.kuali.rice.krad.uif.view.View#getObjectPathToConcreteClassMapping()
      */
     public static Class<?> getObjectClassForMetadata(View view, Object model, String propertyPath) {
         // get class by object instance if not null
         Object parentObject = ObjectPropertyUtils.getPropertyValue(model, propertyPath);
         if (parentObject != null) {
             return parentObject.getClass();
         }
 
         // get class by property type with abstract map check
         return getPropertyTypeByClassAndView(view, model, propertyPath);
     }
 
     /**
      * Retrieves the parent object if it exists or attempts to create a new instance
      *
      * @param view view instance providing the context (abstract map)
      * @param model object model
      * @param field field to retrieve type for
      * @return the class of the object instance if not null or the type of property in model, or Null if type could not be determined
      * @see org.kuali.rice.krad.uif.view.View#getObjectPathToConcreteClassMapping()
      */
     public static Object getParentObjectForMetadata(View view, Object model, DataField field) {
         // default to model as parent
         Object parentObject = model;
 
         String parentObjectPath = getParentObjectPath(field);
         if (StringUtils.isNotBlank(parentObjectPath)) {
             parentObject = ObjectPropertyUtils.getPropertyValue(model, parentObjectPath);
 
             // attempt to create new instance if parent is null or is a
             // collection or map
             if ((parentObject == null) || Collection.class.isAssignableFrom(parentObject.getClass()) ||
                     Map.class.isAssignableFrom(parentObject.getClass())) {
                 try {
                     Class<?> parentObjectClass = getPropertyTypeByClassAndView(view, model, parentObjectPath);
                     if (parentObjectClass != null) {
                         parentObject = parentObjectClass.newInstance();
                     }
                 } catch (InstantiationException e) {
                     // swallow exception and let null be returned
                 } catch (IllegalAccessException e) {
                     // swallow exception and let null be returned
                 }
             }
         }
 
         return parentObject;
     }
 
     /**
      * Helper method for getting the string value of a property from a {@link PropertyValues}
      *
      * @param propertyValues property values instance to pull from
      * @param propertyName name of property whose value should be retrieved
      * @return String value for property or null if property was not found
      */
     public static String getStringValFromPVs(PropertyValues propertyValues, String propertyName) {
         String propertyValue = null;
 
         if ((propertyValues != null) && propertyValues.contains(propertyName)) {
             Object pvValue = propertyValues.getPropertyValue(propertyName).getValue();
             if (pvValue instanceof TypedStringValue) {
                 TypedStringValue typedStringValue = (TypedStringValue) pvValue;
                 propertyValue = typedStringValue.getValue();
             } else if (pvValue instanceof String) {
                 propertyValue = (String) pvValue;
             }
         }
 
         return propertyValue;
     }
 }