/**
    * This file Copyright (c) 2012-2015 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.cms.security.Permission;
  import info.magnolia.cms.security.PermissionUtil;
  import info.magnolia.cms.security.operations.AccessDefinition;
  import info.magnolia.context.MgnlContext;
  import info.magnolia.event.EventBus;
  import info.magnolia.jcr.util.NodeUtil;
  import info.magnolia.jcr.util.SessionUtil;
  import info.magnolia.objectfactory.ComponentProvider;
  import info.magnolia.ui.actionbar.ActionbarPresenter;
  import info.magnolia.ui.actionbar.definition.ActionbarDefinition;
  import info.magnolia.ui.actionbar.definition.ActionbarGroupDefinition;
  import info.magnolia.ui.actionbar.definition.ActionbarItemDefinition;
  import info.magnolia.ui.actionbar.definition.ActionbarSectionDefinition;
  import info.magnolia.ui.api.action.ActionDefinition;
  import info.magnolia.ui.api.action.ActionExecutor;
  import info.magnolia.ui.api.app.SubAppContext;
  import info.magnolia.ui.api.app.SubAppEventBus;
  import info.magnolia.ui.api.availability.AvailabilityDefinition;
  import info.magnolia.ui.api.availability.AvailabilityRule;
  import info.magnolia.ui.api.location.Location;
  import info.magnolia.ui.contentapp.ContentSubAppView;
  import info.magnolia.ui.framework.app.BaseSubApp;
  import info.magnolia.ui.vaadin.actionbar.ActionPopup;
  import info.magnolia.ui.vaadin.integration.jcr.JcrItemUtil;
  import info.magnolia.ui.workbench.definition.WorkbenchDefinition;
  import info.magnolia.ui.workbench.event.ItemRightClickedEvent;
  import info.magnolia.ui.workbench.event.SearchEvent;
  import info.magnolia.ui.workbench.event.SelectionChangedEvent;
  import info.magnolia.ui.workbench.event.ViewTypeChangedEvent;
  import info.magnolia.ui.workbench.search.SearchPresenterDefinition;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import javax.inject.Inject;
  import javax.inject.Named;
  import javax.jcr.Item;
  import javax.jcr.Node;
  import javax.jcr.Property;
  import javax.jcr.RepositoryException;
  
  import org.apache.commons.lang.StringUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.vaadin.peter.contextmenu.ContextMenu;
  
  import com.vaadin.server.ExternalResource;
  
  /**
   * Base implementation of a content subApp. A content subApp displays a collection of data represented inside a {@link info.magnolia.ui.workbench.ContentView} created by the {@link info.magnolia.ui.workbench.WorkbenchPresenter}.
   * 
   * <pre>
   *  <p>
   *      This class Provides sensible implementation for services shared by all content subApps.
   *      Out-of-the-box it will handle the following:
   *  </p>
   * 
   *  <ul>
   *      <li>location updates when switching views, selecting items or performing searches: see {@link #locationChanged(Location)}
   *      <li>restoring the browser app status when i.e. coming from a bookmark: see {@link #start(Location)}
   *  </ul>
   * In order to perform those tasks this class registers non-overridable handlers for the following events:
   *  <ul>
   *      <li> {@link SelectionChangedEvent}
  *      <li> {@link ViewTypeChangedEvent}
  *      <li> {@link SearchEvent}
  *  </ul>
  * Subclasses can augment the default behavior and perform additional tasks by overriding the following methods:
  *  <ul>
  *      <li>{@link #onSubAppStart()}
  *      <li>{@link #locationChanged(Location)}
  *      <li>{@link #updateActionbar(ActionbarPresenter)}
  *  </ul>
  * </pre>
  * 
  * @see BrowserPresenter
  * @see info.magnolia.ui.contentapp.ContentSubAppView
  * @see info.magnolia.ui.contentapp.ContentApp
  * @see BrowserLocation
  */
 public class BrowserSubApp extends BaseSubApp<ContentSubAppView> {
 
     private static final Logger log = LoggerFactory.getLogger(BrowserSubApp.class);
 
     private final BrowserPresenter browser;
     private final EventBus subAppEventBus;
     private ActionExecutor actionExecutor;
     private ComponentProvider componentProvider;
     private String workbenchRoot;
 
     @Inject
     public BrowserSubApp(ActionExecutor actionExecutor, final SubAppContext subAppContext, final ContentSubAppView view, final BrowserPresenter browser, final @Named(SubAppEventBus.NAME) EventBus subAppEventBus, final ComponentProvider componentProvider) {
         super(subAppContext, view);
         if (subAppContext == null || view == null || browser == null || subAppEventBus == null) {
             throw new IllegalArgumentException("Constructor does not allow for null args. Found SubAppContext = " + subAppContext + ", ContentSubAppView = " + view + ", BrowserPresenter = " + browser + ", EventBus = " + subAppEventBus);
         }
         this.browser = browser;
         this.subAppEventBus = subAppEventBus;
         this.actionExecutor = actionExecutor;
         this.componentProvider = componentProvider;
         this.workbenchRoot = ((BrowserSubAppDescriptor) subAppContext.getSubAppDescriptor()).getWorkbench().getPath();
     }
 
     /**
      * Performs some routine tasks needed by all content subapps before the view is displayed.
      * The tasks are:
      * <ul>
      * <li>setting the current location
      * <li>setting the browser view
      * <li>restoring the browser status: see {@link #restoreBrowser(BrowserLocation)}
      * <li>calling {@link #onSubAppStart()} a hook-up method subclasses can override to perform additional work.
      * </ul>
      */
     @Override
     public ContentSubAppView start(final Location location) {
         BrowserLocation l = BrowserLocation.wrap(location);
         super.start(l);
         getView().setContentView(browser.start());
         restoreBrowser(l);
         registerSubAppEventsHandlers(subAppEventBus, this);
 
         return getView();
     }
 
     /**
      * Restores the browser status based on the information available in the location object. This is used e.g. when starting a subapp based on a
      * bookmark. I.e. given a bookmark containing the following URI fragment
      * <p>
      * {@code
      * #app:myapp:browser;/foo/bar:list
      * }
      * <p>
      * this method will select the path <code>/foo/bar</code> in the workspace used by the app, set the view type as <code>list</code> and finally update the available actions.
      * <p>
      * In case of a search view the URI fragment will look similar to the following one {@code
      * #app:myapp:browser;/:search:qux
      * }
      * <p>
      * then this method will select the root path, set the view type as <code>search</code>, perform a search for "qux" in the workspace used by the app and finally update the available actions.
      * 
      * @see BrowserSubApp#updateActionbar(ActionbarPresenter)
      * @see BrowserSubApp#start(Location)
      * @see Location
      */
     protected void restoreBrowser(final BrowserLocation location) {
         String path = ("/".equals(workbenchRoot) ? "" : workbenchRoot) + location.getNodePath();
         String viewType = location.getViewType();
 
         if (!getBrowser().hasViewType(viewType)) {
             if (!StringUtils.isBlank(viewType)) {
                 log.warn("Unknown view type [{}], returning to default view type.", viewType);
             }
             viewType = getBrowser().getDefaultViewType();
             location.updateViewType(viewType);
             getAppContext().updateSubAppLocation(getSubAppContext(), location);
         }
         String query = location.getQuery();
 
         BrowserSubAppDescriptor subAppDescriptor = (BrowserSubAppDescriptor) getSubAppContext().getSubAppDescriptor();
         final String workspaceName = subAppDescriptor.getWorkbench().getWorkspace();
 
         String itemId = null;
         try {
             itemId = JcrItemUtil.getItemId(SessionUtil.getNode(workspaceName, path));
 
             // MGNLUI-1475: item might have not been found if path doesn't exist
             if (itemId == null) {
                 itemId = JcrItemUtil.getItemId(SessionUtil.getNode(workspaceName, workbenchRoot));
                 BrowserLocation newLocation = getCurrentLocation();
                 newLocation.updateNodePath("/");
 
                 getAppContext().updateSubAppLocation(getSubAppContext(), newLocation);
             }
         } catch (RepositoryException e) {
             log.warn("Could not retrieve item at path {} in workspace {}", path, workspaceName);
         }
         List<String> ids = new ArrayList<String>();
         if (itemId != null) {
             ids.add(itemId);
         }
         getBrowser().resync(ids, viewType, query);
         updateActionbar(getBrowser().getActionbarPresenter());
     }
 
     /**
      * Show the actionPopup for the specified item at the specified coordinates.
      */
     public void showActionPopup(String absItemPath, int x, int y) {
 
         // If there's no actionbar configured we don't want to show an empty action popup
         BrowserSubAppDescriptor subAppDescriptor = (BrowserSubAppDescriptor) getSubAppContext().getSubAppDescriptor();
         ActionbarDefinition actionbarDefinition = subAppDescriptor.getActionbar();
         if (actionbarDefinition == null) {
             return;
         }
 
         ActionPopup actionPopup = browser.getView().getActionPopup();
 
         updateActionPopup(actionPopup);
         actionPopup.open(x, y);
     }
 
     /**
      * Update the items in the actionPopup based on the selected item and the ActionPopup availability configuration.
      * This method can be overriden to implement custom conditions diverging from {@link #updateActionbar(info.magnolia.ui.actionbar.ActionbarPresenter)}.
      */
     private void updateActionPopup(ActionPopup actionPopup) {
 
         actionPopup.removeAllItems();
 
         BrowserSubAppDescriptor subAppDescriptor = (BrowserSubAppDescriptor) getSubAppContext().getSubAppDescriptor();
         WorkbenchDefinition workbench = subAppDescriptor.getWorkbench();
         ActionbarDefinition actionbarDefinition = subAppDescriptor.getActionbar();
         if (actionbarDefinition == null) {
             return;
         }
         List<ActionbarSectionDefinition> sections = actionbarDefinition.getSections();
 
         try {
             String workbenchRootItemId = JcrItemUtil.getItemId(workbench.getWorkspace(), workbench.getPath());
             List<String> selectedItemIds = getBrowser().getSelectedItemIds();
             List<Item> items = getJcrItemsExceptOne(workbench.getWorkspace(), selectedItemIds, workbenchRootItemId);
 
             // Figure out which section to show, only one
             ActionbarSectionDefinition sectionDefinition = getVisibleSection(sections, items);
 
             // If there no section matched the selection we just hide everything
             if (sectionDefinition == null) {
                 return;
             }
 
             // Evaluate availability of each action within the section
             ContextMenu.ContextMenuItem menuItem = null;
             for (ActionbarGroupDefinition groupDefinition : sectionDefinition.getGroups()) {
                 for (ActionbarItemDefinition itemDefinition : groupDefinition.getItems()) {
 
                     String actionName = itemDefinition.getName();
                     menuItem = addActionPopupItem(subAppDescriptor, actionPopup, itemDefinition, items);
                     menuItem.setEnabled(actionExecutor.isAvailable(actionName, items.toArray(new Item[items.size()])));
                 }
 
                 // Add group separator.
                 if (menuItem != null) {
                     menuItem.setSeparatorVisible(true);
                 }
             }
             if (menuItem != null) {
                 menuItem.setSeparatorVisible(false);
             }
         } catch (RepositoryException e) {
             log.error("Failed to updated actionbar", e);
         }
     }
 
     /**
      * Add an additional menu item on the actionPopup.
      */
     private ContextMenu.ContextMenuItem addActionPopupItem(BrowserSubAppDescriptor subAppDescriptor, ActionPopup actionPopup, ActionbarItemDefinition itemDefinition, List<javax.jcr.Item> items) {
         String actionName = itemDefinition.getName();
 
         ActionDefinition action = subAppDescriptor.getActions().get(actionName);
         String label = action.getLabel();
         String iconFontCode = ActionPopup.ICON_FONT_CODE + action.getIcon();
         ExternalResource iconFontResource = new ExternalResource(iconFontCode);
         ContextMenu.ContextMenuItem menuItem = actionPopup.addItem(label, iconFontResource);
         // Set data variable so that the event handler can determine which action to launch.
         menuItem.setData(actionName);
 
         return menuItem;
     }
 
     /**
      * Update the items in the actionbar based on the selected item and the action availability configuration.
      * This method can be overriden to implement custom conditions diverging from {@link #updateActionPopup(info.magnolia.ui.vaadin.actionbar.ActionPopup)}.
      * 
      * @see #restoreBrowser(BrowserLocation)
      * @see #locationChanged(Location)
      * @see ActionbarPresenter
      */
     public void updateActionbar(ActionbarPresenter actionbar) {
 
         BrowserSubAppDescriptor subAppDescriptor = (BrowserSubAppDescriptor) getSubAppContext().getSubAppDescriptor();
         WorkbenchDefinition workbench = subAppDescriptor.getWorkbench();
         ActionbarDefinition actionbarDefinition = subAppDescriptor.getActionbar();
         if (actionbarDefinition == null) {
             return;
         }
         List<ActionbarSectionDefinition> sections = actionbarDefinition.getSections();
 
         try {
             String workbenchRootItemId = JcrItemUtil.getItemId(workbench.getWorkspace(), workbench.getPath());
             List<String> selectedItemIds = getBrowser().getSelectedItemIds();
             List<Item> items = getJcrItemsExceptOne(workbench.getWorkspace(), selectedItemIds, workbenchRootItemId);
 
             // Figure out which section to show, only one
             ActionbarSectionDefinition sectionDefinition = getVisibleSection(sections, items);
 
             // If there no section matched the selection we just hide everything
             if (sectionDefinition == null) {
                 for (ActionbarSectionDefinition section : sections) {
                     actionbar.hideSection(section.getName());
                 }
                 return;
             }
 
             // Hide all other sections
             for (ActionbarSectionDefinition section : sections) {
                 if (section != sectionDefinition) {
                     actionbar.hideSection(section.getName());
                 }
             }
 
             // Show our section
             actionbar.showSection(sectionDefinition.getName());
 
             // Evaluate availability of each action within the section
             for (ActionbarGroupDefinition groupDefinition : sectionDefinition.getGroups()) {
                 for (ActionbarItemDefinition itemDefinition : groupDefinition.getItems()) {
 
                     String actionName = itemDefinition.getName();
                     if (actionExecutor.isAvailable(actionName, items.toArray(new Item[items.size()]))) {
                         actionbar.enable(actionName);
                     } else {
                         actionbar.disable(actionName);
                     }
                 }
             }
         } catch (RepositoryException e) {
             log.error("Failed to updated actionbar", e);
             for (ActionbarSectionDefinition section : sections) {
                 actionbar.hideSection(section.getName());
             }
         }
     }
 
     private ActionbarSectionDefinition getVisibleSection(List<ActionbarSectionDefinition> sections, List<Item> items) throws RepositoryException {
         for (ActionbarSectionDefinition section : sections) {
             if (isSectionVisible(section, items))
                 return section;
         }
         return null;
     }
 
     private boolean isSectionVisible(ActionbarSectionDefinition section, List<Item> items) throws RepositoryException {
         AvailabilityDefinition availability = section.getAvailability();
 
         // Validate that the user has all required roles - only once
         if (!availability.getAccess().hasAccess(MgnlContext.getUser())) {
             return false;
         }
 
         if (items != null) {
             // section must be visible for all items
             for (Item item : items) {
                 if (!isSectionVisible(section, item)) {
                     return false;
                 }
             }
         }
         return true;
     }
 
     private boolean isSectionVisible(ActionbarSectionDefinition section, Item item) throws RepositoryException {
         AvailabilityDefinition availability = section.getAvailability();
 
         // if a rule class is set, verify it first
         if ((availability.getRuleClass() != null)) {
             // if the rule class cannot be instantiated, or the rule returns false
             AvailabilityRule rule = componentProvider.newInstance(availability.getRuleClass());
             if (rule == null || !rule.isAvailable(item)) {
                 return false;
             }
         }
 
         // Evaluate write permission if specified
         if (availability.isWritePermissionRequired() && !MgnlContext.getUser().hasRole(AccessDefinition.DEFAULT_SUPERUSER_ROLE)) {
             try {
                 Node node = item instanceof Property ? ((Property) item).getParent() : (Node) item;
                 if (!PermissionUtil.isGranted(node, Permission.WRITE)) {
                     return false;
                 }
             } catch (RepositoryException e) {
                 log.warn("Could not evaluate write permission for {}.", item);
             }
         }
 
         // If this is the root item we display the section only if the root property is set
         if (item == null) {
             return availability.isRoot();
         }
 
         // If its a property we display it only if the properties property is set
         if (!item.isNode()) {
             return availability.isProperties();
         }
 
         // If node is selected and the section is available for nodes
         if (availability.isNodes()) {
             // if no node type defined, the for all node types
             if (availability.getNodeTypes().isEmpty()) {
                 return true;
             }
             // else the node must match at least one of the configured node types
             for (String nodeType : availability.getNodeTypes()) {
                 if (NodeUtil.isNodeType((Node) item, nodeType)) {
                     return true;
                 }
             }
 
         }
         return false;
     }
 
     protected final BrowserPresenter getBrowser() {
         return browser;
     }
 
     /**
      * The default implementation selects the path in the current workspace and updates the available actions in the actionbar.
      */
     @Override
     public void locationChanged(final Location location) {
         super.locationChanged(location);
         restoreBrowser(BrowserLocation.wrap(location));
     }
 
     /**
      * Wraps the current DefaultLocation in a {@link BrowserLocation}. Providing getter and setters for used parameters.
      */
     @Override
     public BrowserLocation getCurrentLocation() {
         return BrowserLocation.wrap(super.getCurrentLocation());
     }
 
     /*
      * Registers general purpose handlers for the following events:
      * <ul>
      * <li> {@link ItemSelectedEvent}
      * <li> {@link ViewTypeChangedEvent}
      * <li> {@link SearchEvent}
      * </ul>
      */
     private void registerSubAppEventsHandlers(final EventBus subAppEventBus, final BrowserSubApp subApp) {
         final ActionbarPresenter actionbar = subApp.getBrowser().getActionbarPresenter();
         subAppEventBus.addHandler(SelectionChangedEvent.class, new SelectionChangedEvent.Handler() {
 
             @Override
             public void onSelectionChanged(SelectionChangedEvent event) {
                 BrowserLocation location = getCurrentLocation();
                 try {
                     Item selected = JcrItemUtil.getJcrItem(event.getWorkspace(), JcrItemUtil.parseNodeIdentifier(event.getFirstItemId()));
                     if (selected == null) {
                         // nothing is selected at the moment
                         location.updateNodePath("");
                     } else {
                         location.updateNodePath(StringUtils.removeStart(selected.getPath(), "/".equals(workbenchRoot) ? "" : workbenchRoot));
                     }
                 } catch (RepositoryException e) {
                     log.warn("Could not get jcrItem with itemId " + event.getFirstItemId() + " from workspace " + event.getWorkspace(), e);
                 }
                 getAppContext().updateSubAppLocation(getSubAppContext(), location);
                 updateActionbar(actionbar);
             }
         });
 
         subAppEventBus.addHandler(ItemRightClickedEvent.class, new ItemRightClickedEvent.Handler() {
 
             @Override
             public void onItemRightClicked(ItemRightClickedEvent event) {
                 String absItemPath;
                 try {
                     absItemPath = event.getItem().getJcrItem().getPath();
 
                     showActionPopup(absItemPath, event.getClickX(), event.getClickY());
                 } catch (RepositoryException e) {
                     log.warn("Could not get jcrItem with itemId " + event.getItemId() + " from workspace " + event.getWorkspace(), e);
                 }
 
             }
         });
 
         subAppEventBus.addHandler(ViewTypeChangedEvent.class, new ViewTypeChangedEvent.Handler() {
 
             @Override
             public void onViewChanged(ViewTypeChangedEvent event) {
                 BrowserLocation location = getCurrentLocation();
                 // remove search term from fragment when switching back
                 if (location.getViewType().equals(SearchPresenterDefinition.VIEW_TYPE)
                         && !event.getViewType().equals(SearchPresenterDefinition.VIEW_TYPE)) {
                     location.updateQuery("");
                 }
                 location.updateViewType(event.getViewType());
                 getAppContext().updateSubAppLocation(getSubAppContext(), location);
                 updateActionbar(actionbar);
             }
         });
 
         subAppEventBus.addHandler(SearchEvent.class, new SearchEvent.Handler() {
 
             @Override
             public void onSearch(SearchEvent event) {
                 BrowserLocation location = getCurrentLocation();
                 if (StringUtils.isNotBlank(event.getSearchExpression())) {
                     location.updateViewType(SearchPresenterDefinition.VIEW_TYPE);
                 }
                 location.updateQuery(event.getSearchExpression());
                 getAppContext().updateSubAppLocation(getSubAppContext(), location);
                 updateActionbar(actionbar);
             }
         });
     }
 
     public static List<Item> getJcrItemsExceptOne(final String workspaceName, List<String> ids, String itemIdToExclude) {
         List<Item> items = JcrItemUtil.getJcrItems(workspaceName, ids);
         if (itemIdToExclude == null) {
             return items;
         }
         for (int i = 0; i < items.size(); i++) {
             try {
                 if (itemIdToExclude.equals(JcrItemUtil.getItemId(items.get(i)))) {
                     items.set(i, null);
                 }
             } catch (RepositoryException e) {
                 log.debug("Cannot get item ID for item [{}].", items.get(i));
             }
         }
         return items;
     }
 }