/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.hadoop.eclipse.dfs;

import org.apache.hadoop.eclipse.ImageLibrary;
import org.apache.hadoop.eclipse.actions.DFSActionImpl;
import org.eclipse.jface.action.Action;
import org.eclipse.jface.action.IMenuManager;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.ui.IActionBars;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.actions.ActionFactory;
import org.eclipse.ui.navigator.CommonActionProvider;
import org.eclipse.ui.navigator.ICommonActionConstants;
import org.eclipse.ui.navigator.ICommonActionExtensionSite;
import org.eclipse.ui.navigator.ICommonMenuConstants;

/**
 * Allows the user to delete and refresh items in the DFS tree
 */

public class ActionProvider extends CommonActionProvider {

  private static ICommonActionExtensionSite site;

  public ActionProvider() {
  }

  /* @inheritDoc */
  @Override
  public void init(ICommonActionExtensionSite site) {
    if (ActionProvider.site != null) {
      System.err.printf("%s: Multiple init()\n", this.getClass()
          .getCanonicalName());
      return;
    }
    super.init(site);
    ActionProvider.site = site;
  }

  /* @inheritDoc */
  @Override
  public void fillActionBars(IActionBars actionBars) {
    actionBars.setGlobalActionHandler(ActionFactory.DELETE.getId(),
        new DFSAction(DFSActions.DELETE));
    actionBars.setGlobalActionHandler(ActionFactory.REFRESH.getId(),
        new DFSAction(DFSActions.REFRESH));

    if (site == null)
      return;

    if ((site.getStructuredViewer().getSelection() instanceof IStructuredSelection)
        && (((IStructuredSelection) site.getStructuredViewer()
            .getSelection()).size() == 1)
        && (((IStructuredSelection) site.getStructuredViewer()
            .getSelection()).getFirstElement() instanceof DFSFile)) {

      actionBars.setGlobalActionHandler(ICommonActionConstants.OPEN,
          new DFSAction(DFSActions.OPEN));
    }

    actionBars.updateActionBars();
  }

  /* @inheritDoc */
  @Override
  public void fillContextMenu(IMenuManager menu) {
    /*
     * Actions on multiple selections
     */
    menu.appendToGroup(ICommonMenuConstants.GROUP_EDIT, new DFSAction(
        DFSActions.DELETE));

    menu.appendToGroup(ICommonMenuConstants.GROUP_OPEN, new DFSAction(
        DFSActions.REFRESH));

    menu.appendToGroup(ICommonMenuConstants.GROUP_NEW, new DFSAction(
        DFSActions.DOWNLOAD));

    if (site == null)
      return;

    ISelection isel = site.getStructuredViewer().getSelection();
    if (!(isel instanceof IStructuredSelection))
      return;

    /*
     * Actions on single selections only
     */

    IStructuredSelection issel = (IStructuredSelection) isel;
    if (issel.size() != 1)
      return;
    Object element = issel.getFirstElement();

    if (element instanceof DFSFile) {
      menu.appendToGroup(ICommonMenuConstants.GROUP_OPEN, new DFSAction(
          DFSActions.OPEN));

    } else if (element instanceof DFSFolder) {
      menu.appendToGroup(ICommonMenuConstants.GROUP_NEW, new DFSAction(
          DFSActions.MKDIR));
      menu.appendToGroup(ICommonMenuConstants.GROUP_NEW, new DFSAction(
          DFSActions.UPLOAD_FILES));
      menu.appendToGroup(ICommonMenuConstants.GROUP_NEW, new DFSAction(
          DFSActions.UPLOAD_DIR));

    } else if (element instanceof DFSLocation) {
      menu.appendToGroup(ICommonMenuConstants.GROUP_OPEN, new DFSAction(
          DFSActions.RECONNECT));

    } else if (element instanceof DFSLocationsRoot) {
      menu.appendToGroup(ICommonMenuConstants.GROUP_OPEN, new DFSAction(
          DFSActions.DISCONNECT));
    }

  }

  /**
   * Representation of an action on a DFS entry in the browser
   */
  public static class DFSAction extends Action {

    private final String id;

    private final String title;

    private DFSActions action;

    public DFSAction(String id, String title) {
      this.id = id;
      this.title = title;
    }

    public DFSAction(DFSActions action) {
      this.id = action.id;
      this.title = action.title;
    }

    /* @inheritDoc */
    @Override
    public String getText() {
      return this.title;
    }

    /* @inheritDoc */
    @Override
    public ImageDescriptor getImageDescriptor() {
      return ImageLibrary.get(getActionDefinitionId());
    }

    /* @inheritDoc */
    @Override
    public String getActionDefinitionId() {
      return id;
    }

    /* @inheritDoc */
    @Override
    public void run() {
      DFSActionImpl action = new DFSActionImpl();
      action.setActivePart(this, PlatformUI.getWorkbench()
          .getActiveWorkbenchWindow().getActivePage().getActivePart());
      action.selectionChanged(this, site.getStructuredViewer()
          .getSelection());
      action.run(this);
    }

    /* @inheritDoc */
    @Override
    public boolean isEnabled() {
      return true;
    }
  }
}