/**
    * 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.framework;
  
  import info.magnolia.ui.framework.datasource.DatasourceHolder;
  import info.magnolia.ui.framework.ioc.Destructible;
  import info.magnolia.ui.framework.ioc.ViewComponentProvider;
  import info.magnolia.ui.framework.ioc.ViewContextKeyRegistry;
  import info.magnolia.objectfactory.ComponentProvider;
  import info.magnolia.ui.api.view.View;
  import info.magnolia.ui.framework.ioc.BeanStore;
  import info.magnolia.ui.framework.ioc.CurrentUiContextReference;
  import info.magnolia.ui.framework.ioc.SessionStore;
  import info.magnolia.ui.framework.ioc.UiContextReference;
  import info.magnolia.util.Util;
  
  import java.util.Optional;
  
  import com.vaadin.ui.Component;
  import com.vaadin.ui.ComponentContainer;
  
  /**
   * View interface enhanced with some IoC-like capabilities based on the idea
   * that each view is bound the {@link BeanStore} and is able to store objects
   * inside of it, access the parent stores etc.
   */
  public interface UiFrameworkView extends View {
  
      /**
       * Convenience method implementation.
       */
      @Override
      default Component asVaadinComponent() {
          if (this instanceof Component) {
              return (Component) this;
          } else {
              throw new RuntimeException(String.format("%s was expected to be an instance of Component but it's not", this.getClass().getName()));
          }
      }
  
      /**
       * Cleans up the related bean store, un-registers this
       * view from the {@link ViewContextKeyRegistry view registry},
       * detaches the from the parent Vaadin component,
       * recursively destroys the child views.
       */
      default void destroy() {
          Optional.ofNullable(asVaadinComponent().getParent())
                  .filter(ComponentContainer.class::isInstance)
                  .map(ComponentContainer.class::cast)
                  .ifPresent(parent -> parent.removeComponent(this.asVaadinComponent()));
  
          final ViewContextKeyRegistry viewContextRegistry = ViewContextKeyRegistry.access();
  
          viewContextRegistry.getChildViews(getCurrentViewReference()).forEach(UiFrameworkView::destroy);
  
          // this is important to first clean-up the bean store
          // and only then - un-register the the current view
          // because otherwise the store will be in-accessible
          // via view context registry
          final BeanStore beanStore = accessViewBeanStore();
          beanStore.forEach((key, instance) -> {
              if (instance instanceof Destructible) {
                  ((Destructible) instance).destroy();
              }
          });
  
          beanStore.clear();
         
         viewContextRegistry.unRegister(this);
     }
 
     /**
      * Put an instance into the view's bean storage, making it
      * injectable with {@link ViewComponentProvider}.
      *
      * @param <T>
      *     type of the shared instance
      */
     default <T> void bindInstance(Class<T> type, T instance) {
         accessViewBeanStore().put(type, instance);
     }
 
     /**
      * Create and bind an instance of the view context. The provided argument is typically an interface,
      * whose implementation is auto-generated on the fly.
      *
      * The instance of the view context is the stored in the view's bean storage and share
      * in similar fashion link {@link #bindInstance(Class, Object)} does.
      *
      * @param <T>
      *     type of the view context
      */
     default <T extends ViewContext> T bindContext(Class<? extends T> contextClass) {
         final T context = new ViewContextProxy().createViewContext(contextClass);
         accessViewBeanStore().put(contextClass, context);
         return context;
     }
 
     /**
      * Shares datasource definition information with the sub-views and components.
      * Datasource definition provides framework with the hints regarding which
      * implementation to choose for the domain-specific interfaces.
      *
      * @see info.magnolia.ui.framework.datasource.DatasourceComponent
      * @see info.magnolia.ui.framework.datasource.DatasourceBundle
      * @see info.magnolia.ui.framework.datasource.DatasourceSupport
      */
     default void bindDatasourceDefinition(Object definition) {
         accessViewBeanStore().put(DatasourceHolder.class, new DatasourceHolder(definition));
     }
 
     /**
      * Convenience wrapper around {@link ComponentProvider} capabilities.
      * Creates and instance of a type specified by a passed {@link WithImplementation} instance.
      *
      * @param <T>
      *     type of an instance to be created
      */
     default <T> T create(WithImplementation<T> definition, Object... args) {
         return getComponentProvider().newInstance(definition.getImplementationClass(), Util.appendToArray(args, definition));
     }
 
     /**
      * Convenience wrapper around {@link ComponentProvider} capabilities.
      *
      * @param <T>
      *     type of an instance to be created
      */
     default <T> T create(Class type, Object... args) {
         //noinspection unchecked
         return getComponentProvider().newInstance((Class<T>) type, args);
     }
 
     /**
      * Get {@link ViewProvider} utility.
      */
     default ViewProvider getViewProvider() {
         return new ViewProviderImpl(getCurrentViewReference());
     }
 
     default ComponentProvider getComponentProvider() {
         return new ViewComponentProvider(getCurrentViewReference());
     }
 
     default UiContextReference getCurrentViewReference() {
         return ViewContextKeyRegistry.access()
                 .lookUp(this)
                 .orElseGet(() -> CurrentUiContextReference.get().getUiContextReference());
     }
 
     default BeanStore accessViewBeanStore() {
         return SessionStore.access().getBeanStore(getCurrentViewReference());
     }
 }