package com.sduk.client;

import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.user.client.History;
import com.google.gwt.user.client.HistoryListener;
import com.google.gwt.user.client.ui.DockPanel;
import com.google.gwt.user.client.ui.HasAlignment;
import com.google.gwt.user.client.ui.HTML;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.user.client.ui.VerticalPanel;

import com.sduk.client.Sink.SinkInfo;


/**
 * Entry point classes define <code>onModuleLoad()</code>.
 */
public class gbpAjax implements EntryPoint, HistoryListener {

  protected SinkList list = new SinkList();
  private SinkInfo curInfo;
  private Sink curSink;
  private HTML description = new HTML();
  private DockPanel panel = new DockPanel();
  private DockPanel sinkContainer;

  public void onHistoryChanged(String token) {
    // Find the SinkInfo associated with the history context. If one is
    // found, show it (It may not be found, for example, when the user mis-
    // types a URL, or on startup, when the first context will be "").
    SinkInfo info = list.find(token);
    if (info == null) {
      showInfo();
      return;
    }
    show(info, false);
  }


	  /**
   * This is the entry point method.
   */
  public void onModuleLoad() {
    loadSinks();

    // Put the sink list on the left, and add the outer dock panel to the
    // root.
    sinkContainer = new DockPanel();
    sinkContainer.setStyleName("ks-Sink");

    VerticalPanel vp = new VerticalPanel();
    vp.setWidth("100%");
    vp.add(description);
    vp.add(sinkContainer);

    description.setStyleName("ks-Info");

    list.setWidth("120px");
    panel.add(list, DockPanel.WEST);
    panel.setSpacing(10);
    panel.add(vp, DockPanel.CENTER);

    panel.setCellVerticalAlignment(list, HasAlignment.ALIGN_TOP);
    panel.setCellWidth(vp, "100%");

    History.addHistoryListener(this);
    RootPanel.get().add(panel);

    // Show the initial screen.
    String initToken = History.getToken();
    if (initToken.length() > 0) {
      onHistoryChanged(initToken);
    } else {
      showInfo();
    }
  }

  public void show(SinkInfo info, boolean affectHistory) {
    // Don't bother re-displaying the existing sink. This can be an issue
    // in practice, because when the history context is set, our
    // onHistoryChanged() handler will attempt to show the currently-visible
    // sink.
    if (info == curInfo) {
      return;
    }
    curInfo = info;
	    // Remove the old sink from the display area.
    if (curSink != null) {
      curSink.onHide();
      sinkContainer.remove(curSink);
    }

    // Get the new sink instance, and display its description in the
    // sink list.
    curSink = info.getInstance();
    list.setSinkSelection(info.getName());
    description.setHTML(info.getDescription());

    // If affectHistory is set, create a new item on the history stack. This
    // will ultimately result in onHistoryChanged() being called. It will call
    // show() again, but nothing will happen because it will request the exact
    // same sink we're already showing.
    if (affectHistory) {
      History.newItem(info.getName());
    }

    // Display the new sink.
    sinkContainer.add(curSink, DockPanel.CENTER);
    sinkContainer.setCellWidth(curSink, "100%");
    sinkContainer.setCellHeight(curSink, "100%");
    sinkContainer.setCellVerticalAlignment(curSink, DockPanel.ALIGN_TOP);
    curSink.onShow();
  }

  /**
   * Adds all sinks to the list. Note that this does not create actual instances
   * of all sinks yet (they are created on-demand). This can make a significant
   * difference in startup time.
   */
  protected void loadSinks() {
    list.addSink(Info.init());
    list.addSink(NigelCohen.init());
    list.addSink(BruceDenny.init());
    list.addSink(TomJonesBerney.init());
    list.addSink(Contact.init());
  }

  private void showInfo() {
    show(list.find("Home"), false);
  }
}