/**
    * This file Copyright (c) 2018 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.field;
  
  import info.magnolia.ui.framework.datasource.components.ItemResolver;
  
  import java.util.Objects;
  import java.util.Optional;
  
  import com.vaadin.ui.Button;
  import com.vaadin.ui.Component;
  import com.vaadin.ui.CustomField;
  import com.vaadin.ui.HorizontalLayout;
  import com.vaadin.ui.NativeButton;
  import com.vaadin.ui.TextField;
  import com.vaadin.ui.VerticalLayout;
  
  
  /**
   * A custom field displaying a text field and a button for bringing up a component enabling to choose an item.
   *
   * @param <T> item type to choose.
   */
  public class LinkField<T> extends CustomField<T> {
  
      private final VerticalLayout rootLayout = new VerticalLayout();
      private final HorizontalLayout linkLayout = new HorizontalLayout();
      private final TextField textField = new TextField();
      private final Button selectButton = new NativeButton();
      private final ItemResolver<T> itemResolver;
  
      private T value;
  
      private boolean editable;
      private Component contentPreview;
      private String buttonCaptionNew;
      private String buttonCaptionOther;
  
      public LinkField(ItemResolver<T> itemResolver) {
          Objects.requireNonNull(itemResolver);
          this.itemResolver = itemResolver;
      }
  
      @Override
      protected Component initContent() {
          addStyleName("linkfield");
  
          rootLayout.setSizeFull();
          rootLayout.setSpacing(true);
  
          textField.setWidth(100, Unit.PERCENTAGE);
          textField.addValueChangeListener(event -> {
              // null value means "remove the currently selected link"
              T value = itemResolver.getItemByPath(event.getValue()).orElse(null);
              setValue(value);
          });
  
          linkLayout.setSizeFull();
          linkLayout.addComponent(textField);
          linkLayout.setExpandRatio(textField, 1);
  
          if (!textField.isReadOnly()) {
              selectButton.addStyleName("magnoliabutton");
              linkLayout.addComponent(selectButton);
              linkLayout.setExpandRatio(selectButton, 0);
          }
  
          rootLayout.addComponent(linkLayout);
 
         addValueChangeListener(event -> updateComponents());
         updateComponents();
 
         return rootLayout;
     }
 
     @Override
     public void setReadOnly(boolean readOnly) {
         super.setReadOnly(readOnly);
         textField.setReadOnly(readOnly);
     }
 
     @Override
     protected void doSetValue(T value) {
         this.value = value;
         // user is shown the item's path
         Optional.ofNullable(value).ifPresent(val -> textField.setValue(itemResolver.getPath(val)));
     }
 
     @Override
     public T getValue() {
         return value;
     }
 
     @Override
     public boolean isEmpty() {
         return getValue() == null;
     }
 
     public boolean isEditable() {
         return editable;
     }
 
     public void setEditable(boolean editable) {
         this.editable = editable;
     }
 
     public void setButtonCaptionNew(String buttonCaptionNew) {
         this.buttonCaptionNew = buttonCaptionNew;
     }
 
     public void setButtonCaptionOther(String buttonCaptionOther) {
         this.buttonCaptionOther = buttonCaptionOther;
     }
 
     public void setPlaceholder(String placeholder) {
         textField.setPlaceholder(placeholder);
     }
 
     public void setDisableOnClick(boolean disable) {
         selectButton.setDisableOnClick(disable);
     }
 
     public void addClickListener(Button.ClickListener buttonClickListener) {
         selectButton.addClickListener(buttonClickListener);
     }
 
     @Override
     public void setEnabled(boolean enabled) {
         super.setEnabled(enabled);
         textField.setEnabled(enabled);
         selectButton.setEnabled(enabled);
     }
 
     public void setContentPreview(Component contentPreviewComponent) {
         if (contentPreview != null) {
             rootLayout.removeComponent(contentPreview);
         }
         rootLayout.addComponentAsFirst(contentPreviewComponent);
         contentPreview = contentPreviewComponent;
     }
 
     /*
      * Set text field as read only if desired. In this case, remove the add button, else update the button label.
      */
     private void updateComponents() {
         if (!isEditable() && !isEmpty()) {
             textField.setReadOnly(true);
             if (linkLayout.getComponentIndex(selectButton) != -1) {
                 linkLayout.removeComponent(selectButton);
             }
         } else {
             setButtonCaptionAndDescription();
 
         }
     }
 
     private void setButtonCaptionAndDescription() {
         final String caption = isEmpty() ? buttonCaptionNew : buttonCaptionOther;
         selectButton.setCaption(caption);
         selectButton.setDescription(caption);
     }
 }