/**
 * Copyright 2010 Google Inc.
 *
 * Licensed 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.waveprotocol.wave.client.widget.toolbar.buttons;

import com.google.gwt.dom.client.Element;
import com.google.gwt.user.client.ui.Widget;

/**
 * A {@link ToolbarButtonUi} which records its state to have delegate (proxy)
 * displays set. When set, the stored state is copied into the proxy and
 * delegated to from then on.
 *
 * @author kalman@google.com (Benjamin Kalman)
 */
public final class ToolbarButtonUiProxy implements ToolbarButtonUi {

  /** Delegate display, set in {@link #setDelegate}. */
  private ToolbarButtonUi delegate;

  // State specific to ToolbarButtonUi.
  private Listener listener;
  private Boolean isDown;

  // Delegate all other state to a ToolbarButtonViewProxy.
  private final ToolbarButtonViewProxy proxy = new ToolbarButtonViewProxy();

  public ToolbarButtonUiProxy(ToolbarButtonUi delegate) {
    setDelegate(delegate);
  }

  /**
   * Sets the delegate, copying in state.
   */
  public void setDelegate(ToolbarButtonUi delegate) {
    if (this.delegate != delegate) {
      this.delegate = delegate;
      proxy.setDelegate(delegate);
      copyUiStateInto(delegate);
    }
  }

  private void copyUiStateInto(ToolbarButtonUi display) {
    if (listener != null) {
      display.setListener(listener);
    }
    if (isDown != null) {
      display.setDown(isDown);
    }
  }

  /**
   * @return the display currently being delegated to
   */
  public ToolbarButtonUi getDelegate() {
    return delegate;
  }

  /**
   * @return the {@link ToolbarButtonView.State} of the toolbar, exposed for
   *         the overflow toolbar
   */
  public State hackGetState() {
    return proxy.hackGetState();
  }

  @Override
  public void setDown(boolean isDown) {
    this.isDown = isDown;
    if (delegate != null) {
      delegate.setDown(isDown);
    }
  }

  @Override
  public void setListener(Listener listener) {
    this.listener = listener;
    if (delegate != null) {
      delegate.setListener(listener);
    }
  }

  //
  // Trivial delegation to a ToolbarButtonViewProxy.
  //

  @Override
  public void addDebugClass(String dc) {
    proxy.addDebugClass(dc);
  }

  @Override
  public Widget hackGetWidget() {
    return proxy.hackGetWidget();
  }

  @Override
  public void removeDebugClass(String dc) {
    proxy.removeDebugClass(dc);
  }

  @Override
  public void setShowDropdownArrow(boolean showDropdown) {
    proxy.setShowDropdownArrow(showDropdown);
  }

  @Override
  public void setShowDivider(boolean showDivider) {
    proxy.setShowDivider(showDivider);
  }

  @Override
  public void setState(State state) {
    proxy.setState(state);
  }

  @Override
  public void setText(String text) {
    proxy.setText(text);
  }

  @Override
  public void setTooltip(String tooltip) {
    proxy.setTooltip(tooltip);
  }

  @Override
  public void setVisualElement(Element element) {
    proxy.setVisualElement(element);
  }
}