/*
 * Copyright 2007 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 com.google.gwt.user.client.ui;

import com.google.gwt.event.logical.shared.AttachEvent;
import com.google.gwt.junit.client.GWTTestCase;
import com.google.gwt.user.client.DOM;
import com.google.gwt.user.client.Element;

/**
 * Tests the semantics and ordering of onAttach/onDetach/onLoad/onUnload.
 */
public class WidgetOnLoadTest extends GWTTestCase {

  static class TestPanel extends FlowPanel {
    int onAttachOrder;
    int onLoadOrder;
    int onDetachOrder;
    int onUnloadOrder;
    boolean domAttachedOnLoad;
    boolean domAttachedOnUnload;

    @Override
    protected void onAttach() {
      onAttachOrder = ++orderIndex;
      super.onAttach();
    }

    @Override
    protected void onDetach() {
      onDetachOrder = ++orderIndex;
      super.onDetach();
    }

    @Override
    protected void onLoad() {
      onLoadOrder = ++orderIndex;
      domAttachedOnLoad = isElementAttached(getElement());
      super.onLoad();
    }

    @Override
    protected void onUnload() {
      onUnloadOrder = ++orderIndex;
      domAttachedOnUnload = isElementAttached(getElement());
      super.onUnload();
    }
  }

  static class TestWidget extends Label {
    int onAttachOrder;
    int onLoadOrder;
    int onDetachOrder;
    int onUnloadOrder;
    boolean domAttachedOnLoad;
    boolean domAttachedOnUnload;

    @Override
    protected void onAttach() {
      onAttachOrder = ++orderIndex;
      super.onAttach();
    }

    @Override
    protected void onDetach() {
      onDetachOrder = ++orderIndex;
      super.onDetach();
    }

    @Override
    protected void onLoad() {
      domAttachedOnLoad = isElementAttached(getElement());
      onLoadOrder = ++orderIndex;
      super.onLoad();
    }

    @Override
    protected void onUnload() {
      onUnloadOrder = ++orderIndex;
      domAttachedOnUnload = isElementAttached(getElement());
      super.onUnload();
    }
  }

  static int orderIndex;

  static boolean isElementAttached(Element elem) {
    return DOM.isOrHasChild(RootPanel.getBodyElement(), elem);
  }

  @Override
  public String getModuleName() {
    return "com.google.gwt.user.User";
  }

  public void testOnLoadAndUnloadOrder() {
    class TestAttachHandler implements AttachEvent.Handler {
      int handleAttachOrder;
      int handleDetachOrder;

      public void onAttachOrDetach(AttachEvent event) {
        if (event.isAttached()) {
          handleAttachOrder = ++orderIndex;
        } else {
          handleDetachOrder = ++orderIndex;
        }
      }
    }

    TestPanel tp = new TestPanel();
    TestAttachHandler tpa = new TestAttachHandler();
    tp.addAttachHandler(tpa);

    TestWidget tw = new TestWidget();
    TestAttachHandler twa = new TestAttachHandler();
    tw.addAttachHandler(twa);

    tp.add(tw);
    RootPanel.get().add(tp);
    RootPanel.get().remove(tp);

    /*
     * Ensure that each panel/widget's onAttach/onDetach are called before their
     * associated onLoad/onUnload, and before attach events are fired
     */
    assertTrue(tp.onAttachOrder < tp.onLoadOrder);
    assertTrue(tp.onDetachOrder < tp.onUnloadOrder);
    assertTrue(tw.onAttachOrder < tw.onLoadOrder);
    assertTrue(tw.onLoadOrder < twa.handleAttachOrder);
    assertTrue(tp.onLoadOrder < tpa.handleAttachOrder);
    assertTrue(tw.onDetachOrder < tw.onUnloadOrder);
    assertTrue(tw.onUnloadOrder < twa.handleDetachOrder);
    assertTrue(tp.onUnloadOrder < tpa.handleDetachOrder);

    /*
     * Ensure that the panel's onAttach/onDetach is called before its child's
     * onAttach/onDetach.
     */
    assertTrue(tp.onAttachOrder < tw.onAttachOrder);
    assertTrue(tp.onDetachOrder < tw.onDetachOrder);

    /*
     * Ensure that the panel's onLoad is only called after its widgets are
     * attached/loaded, and likewise for the attach event listeners
     */
    assertTrue(tp.onLoadOrder > tw.onLoadOrder);
    assertTrue(tpa.handleAttachOrder > twa.handleAttachOrder);

    /*
     * Ensure that the panel's onUnload is called before its widgets are
     * detached/unloaded.
     */
    assertTrue(tp.onUnloadOrder < tw.onUnloadOrder);
    assertTrue(tpa.handleDetachOrder < twa.handleDetachOrder);

    /*
     * Make sure each widget/panel's elements are actually still attached to the
     * DOM during onLoad/onUnload.
     */
    assertTrue(tp.domAttachedOnLoad);
    assertTrue(tp.domAttachedOnUnload);
    assertTrue(tw.domAttachedOnLoad);
    assertTrue(tw.domAttachedOnUnload);
  }
}