/**
    * This file Copyright (c) 2021 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.icons.MagnoliaIcons;
  import info.magnolia.ui.preview.ItemPreviewComponent;
  
  import java.util.Objects;
  import java.util.Optional;
  
  import com.vaadin.data.HasValue;
  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.VerticalLayout;
  
  
  /**
   * A custom field displaying an inner field and a button for bringing up a component enabling to choose an item.
   */
  public abstract class AbstractLinkField<T, P> extends CustomField<T> {
  
      static final String REMOVE_BUTTON = "remove-button";
      static final String MAGNOLIA_BUTTON = "magnoliabutton";
      static final String SELECT_NEW_BUTTON = "select-new-button";
      static final String LINK_FIELD = "linkfield";
  
      private final VerticalLayout rootLayout = new VerticalLayout();
      private final HorizontalLayout linkLayout = new HorizontalLayout();
      private final Button selectButton = new NativeButton();
      private final HasValue<T> hasValue;
      private final Button removeButton = new Button(MagnoliaIcons.DELETE, event -> setValue(null));
      private final Component innerComponent;
  
      private boolean editable;
      private Component contentPreview;
      private String buttonCaptionNew;
  
      AbstractLinkField(HasValue<T> innerComponent) {
          this.hasValue = innerComponent;
          this.innerComponent = (Component) innerComponent;
      }
  
      @Override
      protected Component initContent() {
          addStyleName(LINK_FIELD);
  
          rootLayout.setMargin(false);
          rootLayout.setSizeFull();
          rootLayout.setSpacing(true);
  
          hasValue.setRequiredIndicatorVisible(false);
          hasValue.addValueChangeListener(event -> doSetValue((T) event.getValue()));
          innerComponent.setCaption(null);
          innerComponent.setWidth(100, Unit.PERCENTAGE);
  
          linkLayout.setSizeFull();
          linkLayout.addComponent(innerComponent);
          linkLayout.setExpandRatio(innerComponent, 1);
          linkLayout.setSpacing(false);
  
          if (!isReadOnly()) {
              removeButton.setVisible(getOptionalValue().isPresent());
              removeButton.addStyleName(REMOVE_BUTTON);
              linkLayout.addComponent(removeButton);
  
             selectButton.addStyleName(MAGNOLIA_BUTTON);
             selectButton.setCaption(buttonCaptionNew);
             selectButton.addStyleName(SELECT_NEW_BUTTON);
             linkLayout.addComponent(selectButton);
             linkLayout.setExpandRatio(selectButton, 0);
         }
 
         rootLayout.addComponent(linkLayout);
         updateComponents();
 
         return rootLayout;
     }
 
     @Override
     protected void doSetValue(T value) {
         hasValue.setValue(value);
         setRemoveButtonVisibility(value);
         updateComponents();
     }
 
     @Override
     public T getValue() {
         return hasValue.getValue();
     }
 
     @Override
     public boolean isEmpty() {
         return Objects.equals(getValue(), getEmptyValue());
     }
 
     public boolean isEditable() {
         return editable;
     }
 
     public void setEditable(boolean editable) {
         this.editable = editable;
     }
 
     public void setButtonCaptionNew(String buttonCaptionNew) {
         this.buttonCaptionNew = buttonCaptionNew;
     }
 
     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);
         innerComponent.setEnabled(enabled);
         selectButton.setEnabled(enabled);
     }
 
     public void setContentPreview(Component contentPreviewComponent) {
         if (contentPreview != null) {
             rootLayout.removeComponent(contentPreview);
         }
         rootLayout.addComponentAsFirst(contentPreviewComponent);
         contentPreview = contentPreviewComponent;
     }
 
     public void setContentPreview(ItemPreviewComponent<P> contentPreviewComponent) {
         hasValue.addValueChangeListener(event -> {
             P item = getSelectedItem().orElse(null);
             contentPreviewComponent.onValueChange(item);
             contentPreviewComponent.setVisible(item != null);
         });
         setContentPreview((Component) contentPreviewComponent);
     }
 
     @Override
     public void setReadOnly(boolean readOnly) {
         super.setReadOnly(readOnly);
         hasValue.setReadOnly(readOnly);
     }
     /*
      * Set inner field as read only if desired. In this case, remove the add button, else update the button label.
      */
     private void updateComponents() {
         if (!isEditable() && !isEmpty()) {
             setReadOnly(true);
             if (linkLayout.getComponentIndex(selectButton) != -1) {
                 linkLayout.removeComponent(selectButton);
             }
             if (linkLayout.getComponentIndex(removeButton) != -1) {
                 linkLayout.removeComponent(removeButton);
             }
         }
     }
 
     private void setRemoveButtonVisibility(T value) {
         removeButton.setVisible(!Objects.equals(value, getEmptyValue()));
     }
 
     @Override
     public T getEmptyValue() {
         return hasValue.getEmptyValue();
     }
 
     public abstract Optional<P> getSelectedItem();
 
     public abstract void setSelectedItem(P item);
 }