/**
    * This file Copyright (c) 2013 Magnolia International
    * Ltd.  (http://www.magnolia-cms.com). All rights reserved.
    *
    *
    * This file is dual-licensed under both the Magnolia
    * Network Agreement and the GNU General Public License.
    * You may elect to use one or the other of these licenses.
    *
   * This file is distributed in the hope that it will be
   * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
   * implied warranty of MERCHANTABILITY or FITNESS FOR A
   * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
   * Redistribution, except as permitted by whichever of the GPL
   * or MNA you select, is prohibited.
   *
   * 1. For the GPL license (GPL), you can redistribute and/or
   * modify this file under the terms of the GNU General
   * Public License, Version 3, as published by the Free Software
   * Foundation.  You should have received a copy of the GNU
   * General Public License, Version 3 along with this program;
   * if not, write to the Free Software Foundation, Inc., 51
   * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * 2. For the Magnolia Network Agreement (MNA), this file
   * and the accompanying materials are made available under the
   * terms of the MNA which accompanies this distribution, and
   * is available at http://www.magnolia-cms.com/mna.html
   *
   * Any modifications to this file must keep this entire header
   * intact.
   *
   */
  package info.magnolia.ui.form.field.transformer.basic;
  
  import info.magnolia.ui.form.field.definition.ConfiguredFieldDefinition;
  import info.magnolia.ui.form.field.transformer.Transformer;
  import info.magnolia.ui.form.field.transformer.UndefinedPropertyType;
  import info.magnolia.ui.vaadin.integration.jcr.DefaultProperty;
  
  import java.util.Locale;
  
  import javax.inject.Inject;
  
  import com.vaadin.data.Item;
  import com.vaadin.data.Property;
  
  /**
   * Basic implementation of a {@link Transformer}.<br>
   * This handler is used for most of the basic fields (textBox, Date, ...).<br>
   * His responsibility is to: <br>
   * - retrieve or create a basic property from the related item <br>
   * - update the item property value in case of changes performed on the related field.
   *
   * @param <T>
   */
  public class BasicTransformer<T> implements Transformer<T> {
  
      protected Item relatedFormItem;
      protected final ConfiguredFieldDefinition definition;
  
      protected String basePropertyName;
      protected String i18NPropertyName;
      private Locale locale;
      protected Class<T> type;
  
      @Inject
      public BasicTransformer(Item relatedFormItem, ConfiguredFieldDefinition definition, Class<T> type) {
          this.definition = definition;
          this.relatedFormItem = relatedFormItem;
          this.basePropertyName = definition.getName();
          if (hasI18NSupport()) {
              this.i18NPropertyName = this.basePropertyName;
          }
          setType(type);
      }
  
      @Override
      public void writeToItem(T newValue) {
          Property<T> p = getOrCreateProperty(type);
          p.setValue(newValue);
      }
  
      @Override
      public T readFromItem() {
          String defaultValue = definition.getDefaultValue();
          Property<T> p = getOrCreateProperty(type);
          if (definition.isReadOnly()) {
              p.setReadOnly(true);
          }
          return p.getValue();
      }
  
      /**
       * If the value type is not initialize by the field factory ({@link UndefinedPropertyType}), check if the property already exist in the Item.<br>
       * If the Item has already this property, return the property value type.<br>
       * Else return the default type 'String'
       */
      protected void setType(Class<T> typeFromDefinition) {
         if (typeFromDefinition.isAssignableFrom(UndefinedPropertyType.class)) {
             String propertyName = definePropertyName();
             Property<T> property = relatedFormItem.getItemProperty(propertyName);
             if (property != null) {
                 this.type = (Class<T>) property.getType();
             } else {
                 this.type = (Class<T>) String.class;
             }
         } else {
             this.type = typeFromDefinition;
         }
     }
 
     /**
      * If the desired property (propertyName) already exist in the JcrNodeAdapter, return this property<br>
      * else create a new {@link Property}.<br>
      * If the defaultValueString is empty or null, return a typed null value property.
      *
      * @param <T>
      */
     @SuppressWarnings("unchecked")
     protected <T> Property<T> getOrCreateProperty(Class<T> type) {
         String propertyName = definePropertyName();
         Property<T> property = relatedFormItem.getItemProperty(propertyName);
 
         if (property == null) {
             property = new DefaultProperty<T>(type, null);
             relatedFormItem.addItemProperty(propertyName, property);
         }
         return property;
     }
 
     /**
      * Based on the i18n information, define the property name to use.
      */
     protected String definePropertyName() {
         String propertyName = this.basePropertyName;
 
         if (hasI18NSupport()) {
             propertyName = this.i18NPropertyName;
         }
         return propertyName;
     }
 
     // //////
     // I18N support
     // /////
 
     @Override
     public void setLocale(Locale locale) {
         this.locale = locale;
     }
 
     @Override
     public void setI18NPropertyName(String i18nPropertyName) {
         this.i18NPropertyName = i18nPropertyName;
     }
 
     @Override
     public Locale getLocale() {
         return this.locale;
     }
 
     @Override
     public String getBasePropertyName() {
         return basePropertyName;
     }
 
     @Override
     public boolean hasI18NSupport() {
         return definition.isI18n();
     }
 
     @Override
     public Class<T> getType() {
         return type;
     }
 
 }