/*
 * DebouncedCommand.java
 *
 * Copyright (C) 2022 by Posit Software, PBC
 *
 * Unless you have received this program directly from Posit Software pursuant
 * to the terms of a commercial license agreement with Posit Software, then
 * this program is licensed to you under the terms of version 3 of the
 * GNU Affero General Public License. This program is distributed WITHOUT
 * ANY EXPRESS OR IMPLIED WARRANTY, INCLUDING THOSE OF NON-INFRINGEMENT,
 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Please refer to the
 * AGPL (http://www.gnu.org/licenses/agpl-3.0.txt) for more details.
 *
 */
package org.rstudio.core.client;

import com.google.gwt.user.client.Timer;

public abstract class DebouncedCommand
{
   public DebouncedCommand(int delayMs)
   {
      timer_ = new Timer()
      {
         @Override
         public void run()
         {
            execute();
         }
      };

      delayMs_ = delayMs;
      suspended_ = false;
   }

   public void nudge()
   {
      if (!suspended_)
         timer_.schedule(delayMs_);
   }

   public void suspend()
   {
      timer_.cancel();
      suspended_ = true;
   }

   // Cancel a pending (scheduled-but-not-yet-fired) execution without latching
   // the command off the way suspend() does -- subsequent nudges are still
   // honored. Used to drop a debounced action that a newer action has made
   // obsolete (e.g. cancelling a queued replace preview when Replace All runs).
   public void cancelPending()
   {
      timer_.cancel();
   }

   public void resume()
   {
      suspended_ = false;
   }

   public boolean isRunning()
   {
      return timer_.isRunning();
   }

   protected abstract void execute();

   private final Timer timer_;
   private final int delayMs_;
   private boolean suspended_;
}