/**
    * 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.contentapp.browser;
  
  import info.magnolia.ui.api.app.AppContext;
  import info.magnolia.ui.api.app.SubAppContext;
  import info.magnolia.ui.contentapp.ContentBrowserSubApp;
  import info.magnolia.ui.contentapp.browser.actionbar.ActionbarView;
  import info.magnolia.ui.contentapp.browser.context.LocationContext;
  import info.magnolia.ui.contentapp.browser.context.ValueContext;
  import info.magnolia.ui.contentapp.configuration.BrowserDescriptor;
  import info.magnolia.ui.contentapp.configuration.WorkbenchDefinition;
  import info.magnolia.ui.framework.ContextProperty;
  import info.magnolia.ui.framework.UiFrameworkView;
  import info.magnolia.ui.framework.ViewDefinition;
  import info.magnolia.ui.framework.ViewProvider;
  import info.magnolia.ui.framework.datasource.DatasourceComponent;
  import info.magnolia.ui.framework.datasource.components.ItemResolver;
  import info.magnolia.ui.framework.datasource.components.SelectedItems;
  
  import java.util.Objects;
  import java.util.Optional;
  
  import javax.inject.Inject;
  
  import com.vaadin.ui.CustomComponent;
  import com.vaadin.ui.HorizontalLayout;
  import com.vaadin.ui.VerticalLayout;
  
  /**
   * View part of the new browser sub-app.
   *
   * @param <T> item type.
   * @param <DS> data source definition type.
   */
  public class Browser<T, DS> extends CustomComponent implements UiFrameworkView {
  
      private final ContextProperty<ContentBrowserSubApp.BrowserLocation> location;
      private final ValueContext<T> valueContext;
      private final SubAppContext subAppContext;
      private final AppContext appContext;
      private final ItemResolver<T> itemResolver;
  
      @Inject
      public Browser(
              BrowserDescriptor<T, DS> descriptor,
              SubAppContext subAppContext,
              AppContext appContext,
              @DatasourceComponent ItemResolver<T> itemResolver) {
          this.subAppContext = subAppContext;
          this.appContext = appContext;
          this.itemResolver = itemResolver;
  
          valueContext = bindContext(ValueContext.class);
          location = bindContext(LocationContext.class).location();
  
          valueContext.current().observe(valueOptional ->
                  valueOptional.ifPresent(selectedItems ->
                          location.mutate(location -> pushItemPathIntoLocation(selectedItems, location))));
  
          location.observe(locationOptional ->
                  locationOptional.ifPresent(location -> {
                      final ContextProperty<SelectedItems<T>> currentValue = valueContext.current();
                      final Optional<String> currentPath = currentValue.value().flatMap(selectedItems ->  selectedItems.getFirst().map(itemResolver::getPath));
  
                      if (currentPath.map(path -> !Objects.equals(path, location.getNodePath())).orElse(false)) {
                          itemResolver.getItemByPath(location.getNodePath()).ifPresent(t -> currentValue.set(SelectedItems.of(t)));
                      }
                 }));
 
         layout(descriptor);
     }
 
     private void pushItemPathIntoLocation(SelectedItems<T> selectedItems, ContentBrowserSubApp.BrowserLocation location) {
         selectedItems.getFirst().ifPresent(value -> {
             location.updateNodePath(itemResolver.getPath(value));
             this.updateLocation(location);
         });
     }
 
     private void updateLocation(ContentBrowserSubApp.BrowserLocation location) {
         appContext.updateSubAppLocation(subAppContext, location);
     }
 
     private void layout(BrowserDescriptor<T, DS> descriptor) {
         final HorizontalLayout workbenchWrapper = new HorizontalLayout();
         workbenchWrapper.setSizeFull();
 
         final ViewProvider viewProvider = getViewProvider();
 
         final WorkbenchDefinition<T> workbenchDefinition = descriptor.getWorkbench();
         final Workbench<T> workbench = viewProvider.create("workbench", workbenchDefinition.getImplementationClass(), workbenchDefinition);
         workbench.onContentViewTypeChange(viewId -> location.mutate(location -> location.updateViewType(viewId)));
         workbench.setTitle(descriptor.getLabel());
 
         workbenchWrapper.addComponentsAndExpand(workbench);
         workbenchWrapper.addComponents(viewProvider.create("actionbar", ActionbarView.class, descriptor.getActionbar()));
 
         @SuppressWarnings("unchecked")
         final UiFrameworkView statusBar = getViewProvider().create(
                 ViewDefinition.builder()
                         .withName("statusbar")
                         .withImplementationClass(StatusBar.class)
                         .build());
 
         VerticalLayout browser = new VerticalLayout(workbenchWrapper, statusBar.asVaadinComponent());
         browser.setSizeFull();
         browser.setSpacing(false);
         browser.setMargin(false);
         browser.setExpandRatio(workbenchWrapper, 1f);
         browser.setExpandRatio(statusBar.asVaadinComponent(), 0);
         browser.addStyleName("browser");
 
         setCompositionRoot(browser);
         setSizeFull();
     }
 
     public void setLocation(ContentBrowserSubApp.BrowserLocation location) {
         this.location.set(location);
     }
 }