// Copyright 2012 Google Inc. All Rights Reserved.
//
// 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.collide.client.code;

import com.google.collide.client.AppContext;
import com.google.collide.client.code.gotodefinition.GoToDefinitionRenderer;
import com.google.collide.client.util.CssUtils;
import com.google.collide.client.util.Elements;
import com.google.collide.mvp.CompositeView;
import com.google.collide.mvp.UiComponent;
import com.google.gwt.resources.client.CssResource;

import elemental.html.DivElement;
import elemental.html.Element;

/**
 * The main content area on the CodePerspective.
 *
 */
public class EditableContentArea extends UiComponent<EditableContentArea.View> {

  /**
   * Static factory method for obtaining an instance of the EditableContentArea.
   */
  public static EditableContentArea create(
      View view, AppContext appContext, EditorBundle editorBundle) {
    final EditorToolBar toolBar = EditorToolBar.create(
        view.getEditorToolBarView(), FileSelectedPlace.PLACE, appContext, editorBundle);
    // Hook presenter in the editor bundle to the view in the header
    editorBundle.getBreadcrumbs().setView(view.getBreadcrumbsView());
    return new EditableContentArea(view, toolBar);
  }

  /**
   * Type for things that can be added to the content area of the CodePerspective.
   */
  public interface Content {

    /**
     * @return The {@link Element} that we set as the contents of the content
     *         area.
     */
    Element getContentElement();
    
    /**
     * Called when the content is displayed.
     *
     * It's possible that element returned by {@link #getContentElement()} was removed from DOM and
     * re-added, so this callback is a good place to re-initialize any values that may have been
     * cleared.
     */
    void onContentDisplayed();
  }

  /**
   * Style names.
   */
  public interface Css extends CssResource {
    String base();

    String contentHeader();

    String contentContainer();

    int editableContentAreaRight();
  }

  public interface Resources
      extends
      GoToDefinitionRenderer.Resources,
      EditorToolBar.Resources,
      WorkspaceLocationBreadcrumbs.Resources,
      NoFileSelectedPanel.Resources,
      UneditableDisplay.Resources {

    @Source({"com/google/collide/client/common/constants.css", "EditableContentArea.css"})
    Css editableContentAreaCss();
  }

  /**
   * The View for the EditableContentArea.
   */
  public static class View extends CompositeView<Void> {
    private DivElement header;
    private DivElement content;
    private final WorkspaceLocationBreadcrumbs.View breadcrumbsView;
    private final EditorToolBar.View editorToolBarView;
    private final Css css;

    public View(Resources res) {
      super(Elements.createDivElement(res.editableContentAreaCss().base()));
      this.css = res.editableContentAreaCss();

      // Instantiate sub-views.
      this.breadcrumbsView = new WorkspaceLocationBreadcrumbs.View(res);
      this.editorToolBarView = new EditorToolBar.View(res);

      createDom();
    }

    public Element getContentElement() {
      return content;
    }

    public Element getHeaderElement() {
      return header;
    }

    public EditorToolBar.View getEditorToolBarView() {
      return editorToolBarView;
    }

    public WorkspaceLocationBreadcrumbs.View getBreadcrumbsView() {
      return breadcrumbsView;
    }

    public int getDefaultEditableContentAreaRight() {
      return css.editableContentAreaRight();
    }

    private void createDom() {
      Element elem = getElement();
      header = Elements.createDivElement(css.contentHeader());
      content = Elements.createDivElement(css.contentContainer());

      elem.appendChild(header);
      elem.appendChild(content);
      header.appendChild(breadcrumbsView.getElement());
      header.appendChild(editorToolBarView.getElement());
    }
  }

  private Content currentContent;
  private final EditorToolBar toolBar;

  EditableContentArea(View view, EditorToolBar toolBar) {
    super(view);
    this.toolBar = toolBar;
  }

  public EditorToolBar getEditorToolBar() {
    return toolBar;
  }

  public Content getCurrentContent() {
    return currentContent;
  }

  /**
   * Sets the contents of the content area under the header.
   * 
   * @param content the content to display, or null to clear content
   * @param showHistoryIcon whether or not to show the history button for this content.
   */
  public void setContent(Content content, boolean showHistoryIcon) {
    if (currentContent == content) {
      return;
    }

    if (currentContent != null) {
      currentContent.getContentElement().removeFromParent();
    }

    getView().getContentElement().setInnerHTML("");
    if (content != null) {
      getView().getContentElement().appendChild(content.getContentElement());
    }
    currentContent = content;
    currentContent.onContentDisplayed();

    getEditorToolBar().getView().setHistoryButtonVisible(showHistoryIcon);

    setLocationBreadcrumbsVisibility(true);
  }

  /**
   * Sets the contents of the content area under the header. Assumes content can
   * display history and shows history icon. (Use
   * {@link #setContent(Content, boolean)} to customize).
   * 
   * @param content the content to display, or null to clear content
   */
  public void setContent(Content content) {
    setContent(content, true);
  }

  public void setLocationBreadcrumbsVisibility(boolean visible) {
    CssUtils.setDisplayVisibility2(getView().breadcrumbsView.getElement(), visible);
  }
}