/*
 * Copyright 2008 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.core.client.GWT;
import com.google.gwt.dom.client.Element;
import com.google.gwt.dom.client.Node;
import com.google.gwt.junit.client.GWTTestCase;
import com.google.gwt.safehtml.client.SafeHtmlTemplates;
import com.google.gwt.safehtml.shared.SafeHtml;

import java.util.Locale;

/**
 * Tests the HTMLPanel widget.
 */
public class HTMLPanelTest extends GWTTestCase {
  static class Adder implements HasWidgetsTester.WidgetAdder {
    @Override
    public void addChild(HasWidgets container, Widget child) {
      ((HTMLPanel) container).add(child, "w00t");
    }
  }

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

  /**
   * A SafeHtmlTemplates interface for testing.
   */
  public interface TestTemplates extends SafeHtmlTemplates {
    @Template("<table><tr><td>{0} <span id='labelHere'></span></td></tr></table>")
    SafeHtml tableTemplate(String body);
  }

  /**
   * Tests {@link HTMLPanel#add(Widget)}.
   */
  public void testAdd() {
    Label labelA = new Label("A");
    Label labelB = new Label("B");
    HTMLPanel p = new HTMLPanel("<div></div>");
    p.add(labelA);
    p.add(labelB);

    // Ensure that both Labels have the correct parent.
    Element first = p.getElement().getFirstChildElement();
    assertSame(labelA.getElement(), first.getNextSiblingElement());
    assertSame(labelB.getElement(), labelA.getElement().getNextSiblingElement());
    assertNull(labelB.getElement().getNextSiblingElement());
  }

  /**
   * Tests {@link HTMLPanel#add(Widget, String)}.
   */
  public void testAddToElementWithId() {
    Label labelA = new Label("A"), labelB = new Label("B");
    HTMLPanel p = new HTMLPanel("<div id=\"a\"></div><div id=\"b\"></div>");
    p.add(labelA, "a");
    p.add(labelB, "b");
    // Ensure that both Label's have the correct parent.
    assertEquals("a", labelA.getElement().getParentElement().getId());
    assertEquals("b", labelB.getElement().getParentElement().getId());
  }

  /**
   * Tests {@link HTMLPanel#add(Widget, Element)}.
   */
  public void testAddToElement() {
    Label labelA = new Label("A"), labelB = new Label("B");
    HTMLPanel p = new HTMLPanel("<div class=\"a\"></div><div class=\"b\"></div>");
    Element first = p.getElement().getFirstChildElement();
    Element second = first.getNextSiblingElement();

    p.add(labelA, first);
    p.add(labelB, second);
    // Ensure that both Label's have the correct parent.
    assertEquals("a", labelA.getElement().getParentElement().getClassName());
    assertEquals("b", labelB.getElement().getParentElement().getClassName());
  }

  /**
   * This is meant to catch an issue created by a faulty optimization. To
   * optimize add() when the HTMLPanel is unattached, we would originally move
   * its element to a hidden div so that getElementById() would work.
   * Unfortunately, we didn't move it back to its original parent, causing a
   * problem in the case described in this test.
   */
  public void testAddPartiallyAttached() {
    SimplePanel sp = new SimplePanel();
    HTMLPanel p = new HTMLPanel("<div id='foo'></div>");

    // Add the HTMLPanel to another panel before adding the button.
    sp.add(p);

    // Add a button the HTMLPanel, causing the panel's element to be attached
    // to the DOM.
    p.add(new Button("foo"), "foo");

    // If all goes well, the HTMLPanel's element should still be properly
    // connected to the SimplePanel's element.
    assertTrue(sp.getElement().isOrHasChild(p.getElement()));
  }

  /**
   * Tests child attachment order using {@link HasWidgetsTester}.
   */
  public void testAttachDetachOrder() {
    HTMLPanel p = new HTMLPanel("<div id='w00t'></div>");
    HasWidgetsTester.testAll(p, new Adder(), true);
  }

  /**
   * Ensures that attachToDomAndGetElement() puts the HTMLPanel back exactly
   * where it was in the DOM originally.
   */
  public void testAttachDoesntMangleChildOrder() {
    FlowPanel fp = new FlowPanel();

    Button ba = new Button("before");
    Button bb = new Button("after");

    HTMLPanel hp = new HTMLPanel("<div id='foo'></div>");

    fp.add(ba);
    fp.add(hp);
    fp.add(bb);

    hp.add(new Button("foo"), "foo");

    assertTrue(fp.getElement().isOrHasChild(hp.getElement()));
    assertTrue(ba.getElement().getNextSibling() == hp.getElement());
    assertTrue(hp.getElement().getNextSibling() == bb.getElement());
  }

  /**
   * Ensures that {@link HTMLPanel#addAndReplaceElement(Widget, String)} puts
   * the widget in exactly the right place in the DOM.
   */
  public void testAddAndReplaceElement() {
    HTMLPanel hp = new HTMLPanel("<div id='parent'>foo<span id='placeholder'></span>bar</div>");
    Button button = new Button("my button");

    hp.addAndReplaceElement(button, "placeholder");

    assertParentId(button, "parent");
    assertIsBetweenSiblings(button, "foo", "bar");
  }

  /**
   * Ensures that {@link HTMLPanel#addAndReplaceElement(Widget, Element)} puts
   * the widget in exactly the right place in the DOM.
   */
  @SuppressWarnings("deprecation")
  public void testAddAndReplaceElementForUserElement() {
    HTMLPanel hp = new HTMLPanel("<div id='parent'>foo<span id='placeholder'></span>bar</div>");
    RootPanel.get().add(hp);
    Element placeholder = hp.getElementById("placeholder");
    Button button = new Button("my button");

    hp.addAndReplaceElement(button, placeholder);

    assertParentId(button, "parent");
    assertIsBetweenSiblings(button, "foo", "bar");
  }

  /**
   * Ensures that overloaded version of
   * {@link HTMLPanel#addAndReplaceElement(IsWidget, Element)}
   * for IsWidget puts the widget in exactly the right place in the DOM.
   */
  public void testAddAndReplaceElementForUserElementAsIsWidget() {
    HTMLPanel hp = new HTMLPanel("<div id='parent'>foo<span id='placeholder'></span>bar</div>");
    RootPanel.get().add(hp);
    Element placeholder = hp.getElementById("placeholder");
    Button button = new Button("my button");
    // IsWidget reference to call the overloaded version
    IsWidget isWidget = button;

    hp.addAndReplaceElement(isWidget, placeholder);

    assertParentId(button, "parent");
    assertIsBetweenSiblings(button, "foo", "bar");
  }

  /**
   * Ensures that {@link HTMLPanel#addAndReplaceElement(Widget, Element)} puts
   * the widget in exactly the right place in the DOM.
   */
  public void testAddAndReplaceElementForElement() {
    HTMLPanel hp = new HTMLPanel("<div id='parent'>foo<span id='placeholder'></span>bar</div>");
    RootPanel.get().add(hp);
    Element placeholder = hp.getElementById("placeholder");
    Button button = new Button("my button");

    hp.addAndReplaceElement(button, placeholder);

    assertParentId(button, "parent");
    assertIsBetweenSiblings(button, "foo", "bar");
  }

  /**
   * Tests {@link HTMLPanel#addAndReplaceElement(Widget, String)}.
   */
  public void testAddAndReplaceElementById() {
    HTMLPanel hp = new HTMLPanel("<div id='parent'>foo<span id='placeholder'></span>bar</div>");
    RootPanel.get().add(hp);
    Button button = new Button("my button");

    hp.addAndReplaceElement(button, "placeholder");

    assertParentId(button, "parent");
    assertIsBetweenSiblings(button, "foo", "bar");
  }

  /**
   * Tests {@link HTMLPanel#addAndReplaceElement(IsWidget, String)}.
   */
  public void testAddAndReplaceElementByIdAsIsWidget() {
    HTMLPanel hp = new HTMLPanel("<div id='parent'>foo<span id='placeholder'></span>bar</div>");
    RootPanel.get().add(hp);
    Button button = new Button("my button");

    // IsWidget cast to call the overloaded version
    hp.addAndReplaceElement((IsWidget) button, "placeholder");

    assertParentId(button, "parent");
    assertIsBetweenSiblings(button, "foo", "bar");
  }

  /**
   * Ensures that {@link HTMLPanel#addAndReplaceElement(Widget, Element)}
   * correctly removes (physically and logically) the replaced element if the
   * element is an ancestor of a widget.
   */
  @SuppressWarnings("deprecation")
  public void testAddAndReplaceElementLogicalDetachWidgetChildOfElement() {
    HTMLPanel hp = new HTMLPanel("<div id=\"container\"></div>");
    RootPanel.get().add(hp);

    hp.getElement().setId("parent");

    Button button1 = new Button("my button 1");
    Button button2 = new Button("my button 2");
    Button button3 = new Button("my button 3");
    Button button4 = new Button("my button 4");

    hp.add(button1);
    hp.add(button2, "container");
    hp.add(button3, "container");
    assertEquals(3, hp.getWidgetCount());

    hp.addAndReplaceElement(button4, "container");
    assertEquals(2, hp.getWidgetCount()); // 1,2,3 -> 1,4

    assertParentId(button1, "parent");
    assertEquals(hp, button1.getParent());
    assertNull(button2.getElement().getParentElement());
    assertNull(button2.getParent());
    assertNull(button3.getElement().getParentElement());
    assertNull(button3.getParent());
    assertParentId(button4, "parent");
    assertEquals(hp, button4.getParent());
  }

  /**
   * Ensures that {@link HTMLPanel#addAndReplaceElement(Widget, Element)}
   * correctly removes (physically and logically) the replaced element if the
   * element itself is a widget (but not the same as the replacement).
   */
  @SuppressWarnings("deprecation")
  public void testAddAndReplaceElementLogicalDetachWidgetIsElement() {
    HTMLPanel hp = new HTMLPanel("");
    RootPanel.get().add(hp);

    hp.getElement().setId("parent");

    Button button1 = new Button("my button 1");
    Button button2 = new Button("my button 2");
    Button button3 = new Button("my button 3");

    hp.add(button1);
    hp.add(button2);
    assertEquals(2, hp.getWidgetCount());

    hp.addAndReplaceElement(button3, button1.getElement());
    assertEquals(2, hp.getWidgetCount()); // 1,2 -> 2,3

    assertNull(button1.getElement().getParentElement());
    assertNull(button1.getParent());
    assertParentId(button2, "parent");
    assertEquals(hp, button2.getParent());
    assertParentId(button3, "parent");
    assertEquals(hp, button3.getParent());
  }

  /**
   * Ensures that {@link HTMLPanel#addAndReplaceElement(Widget, Element)}
   * correctly removes (physically and logically) and reattaches the replaced
   * element if the element both the widget being replaced and the replacement.
   */
  @SuppressWarnings("deprecation")
  public void testAddAndReplaceElementSameWidget() {
    HTMLPanel hp = new HTMLPanel("");
    RootPanel.get().add(hp);

    hp.getElement().setId("parent");

    Button button1 = new Button("my button 1");
    Button button2 = new Button("my button 2");

    hp.add(button1);
    hp.add(button2);
    assertEquals(2, hp.getWidgetCount());

    hp.addAndReplaceElement(button1, button1.getElement());
    assertEquals(2, hp.getWidgetCount()); // 1,2 -> 1,2

    assertParentId(button1, "parent");
    assertEquals(hp, button1.getParent());
    assertParentId(button1, "parent");
    assertEquals(hp, button1.getParent());
  }

  /**
   * Tests table root tag.
   */
  public void testCustomRootTagAsTable() {
    HTMLPanel hp = new HTMLPanel("table", "<tr><td>Hello <span id='labelHere'></span></td></tr>");
    InlineLabel label = new InlineLabel("World");
    hp.addAndReplaceElement(label, "labelHere");

    Element parent = label.getElement().getParentElement();
    assertEquals("td", parent.getTagName().toLowerCase(Locale.ROOT));

    parent = parent.getParentElement();
    assertEquals("tr", parent.getTagName().toLowerCase(Locale.ROOT));

    while (parent != null && parent != hp.getElement()) {
      parent = parent.getParentElement();
    }

    assertNotNull(parent);
    assertEquals("table", parent.getTagName().toLowerCase(Locale.ROOT));
  }

  /**
   * Tests h3 root tag with initially empty HTML contents.
   */
  public void testCustomRootTagEmptyHtml() {
    HTMLPanel hp = new HTMLPanel("h3", "");

    Element element = hp.getElement();
    assertEquals("h3", element.getTagName().toLowerCase(Locale.ROOT));
    assertEquals("", element.getInnerText());
  }

  /**
   * Ensure that {@link HTMLPanel#getElementById(String)} behaves properly in
   * both attached and unattached states.
   */
  public void testGetElementById() {
    HTMLPanel hp = new HTMLPanel("foo<div id='toFind'>bar</div>baz");

    // Get the element twice, once before and once after attachment.
    Element elem0 = hp.getElementById("toFind");
    RootPanel.get().add(hp);
    Element elem1 = hp.getElementById("toFind");

    // Make sure we got the same element in both cases.
    assertEquals(elem0, elem1);
  }

  /**
   * Tests that the HTMLPanel's element is not moved from its original location
   * when {@link HTMLPanel#add(Widget, String)} is called on it while it is
   * unattached.
   */
  public void testElementIsUnmoved() {
    HTMLPanel unattached = new HTMLPanel("<div id='unattached'></div>");
    HTMLPanel attached = new HTMLPanel("<div id='attached'></div>");

    RootPanel.get().add(attached);

    Element unattachedParentElem = unattached.getElement().getParentElement();
    Element attachedParentElem = attached.getElement().getParentElement();

    unattached.add(new Button("unattached"), "unattached");
    attached.add(new Button("attached"), "attached");

    assertEquals("Unattached's parent element should be unaffected", unattachedParentElem,
        unattached.getElement().getParentElement());
    assertEquals("Unattached's parent element should be unaffected", attachedParentElem, attached
        .getElement().getParentElement());
  }

  /**
   * Tests SafeHtml constructor.
   */
  public void testSafeHtml() {
    TestTemplates templates = GWT.create(TestTemplates.class);
    SafeHtml table = templates.tableTemplate("Hello");

    HTMLPanel hp = new HTMLPanel(table);
    InlineLabel label = new InlineLabel("World");
    hp.addAndReplaceElement(label, "labelHere");

    Element parent = label.getElement().getParentElement();
    assertEquals("td", parent.getTagName().toLowerCase(Locale.ROOT));

    parent = parent.getParentElement();
    assertEquals("tr", parent.getTagName().toLowerCase(Locale.ROOT));

    // Look for the table in the main panel div
    Element firstChild = null;
    while (parent != null && parent != hp.getElement()) {
      firstChild = parent;
      parent = parent.getParentElement();
    }

    assertNotNull(parent);
    assertEquals("div", parent.getTagName().toLowerCase(Locale.ROOT));
    assertEquals("table", firstChild.getTagName().toLowerCase(Locale.ROOT));
  }

  /**
   * Asserts that the widget w is between the given previous and next nodes.
   * 
   * @param w the widget
   * @param previous the expected previous node string representation of the
   *          widget
   * @param next the expected next node string representation of the widget
   */
  private void assertIsBetweenSiblings(Widget w, String previous, String next) {
    Node prevNode = w.getElement().getPreviousSibling();
    assertEquals(previous, prevNode.getNodeValue());

    Node nextNode = w.getElement().getNextSibling();
    assertEquals(next, nextNode.getNodeValue());
  }

  /**
   * Asserts that the parent id of the widget is the given one.
   * 
   * @param w the widget
   * @param expected the expected parent id of w
   */
  private void assertParentId(Widget w, String expected) {
    assertEquals(expected, w.getElement().getParentElement().getId());
  }
}