/*******************************************************************************
 * Copyright (c) 2011 BSI Business Systems Integration AG.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     BSI Business Systems Integration AG - initial API and implementation
 *******************************************************************************/
package org.eclipse.scout.rt.ui.rap.window.desktop;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;

import org.eclipse.rap.rwt.lifecycle.WidgetUtil;
import org.eclipse.scout.rt.client.ui.desktop.DesktopEvent;
import org.eclipse.scout.rt.client.ui.desktop.DesktopListener;
import org.eclipse.scout.rt.client.ui.desktop.IDesktop;
import org.eclipse.scout.rt.client.ui.form.IForm;
import org.eclipse.scout.rt.ui.rap.IRwtEnvironment;
import org.eclipse.scout.rt.ui.rap.util.BrowserInfo;
import org.eclipse.scout.rt.ui.rap.util.RwtUtility;
import org.eclipse.scout.rt.ui.rap.window.DefaultFormBoundsProvider;
import org.eclipse.scout.rt.ui.rap.window.IFormBoundsProvider;
import org.eclipse.scout.rt.ui.rap.window.IRwtScoutPart;
import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.StackLayout;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.layout.RowData;
import org.eclipse.swt.layout.RowLayout;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Listener;

/**
 * @author Andreas Hoegger
 * @since 3.8.0
 */
public class RwtScoutViewStack extends Composite implements IRwtScoutViewStack {
  private static final long serialVersionUID = 1L;

  private static final String VARIANT_VIEW_PART = "viewPart";
  private static final String VARIANT_VIEW_PART_NO_RADIUS = "viewPartNoRadius";
  private static final String VARIANT_VIEW_TAB_AREA = "formTabArea";

  private int heightHint = SWT.DEFAULT;
  private int widthHint = SWT.DEFAULT;
  private IRwtEnvironment m_uiEnvironment;
  private HashMap<IForm, RwtScoutDesktopForm> m_openForms;
  private ArrayList<RwtScoutDesktopForm> m_formStack;
  private Map<IForm, IFormBoundsProvider> m_formBoundsProviders;
  private P_DesktopListner m_desktopListener;
  private Composite m_tabBar;

  private Composite m_container;

  public RwtScoutViewStack(Composite parent, IRwtEnvironment uiEnvironment) {
    super(parent, SWT.NONE);
    m_uiEnvironment = uiEnvironment;
    m_openForms = new HashMap<IForm, RwtScoutDesktopForm>();
    m_formStack = new ArrayList<RwtScoutDesktopForm>(3);
    m_formBoundsProviders = new HashMap<IForm, IFormBoundsProvider>();
    addListener(SWT.Resize, new P_ResizeListener());
    m_desktopListener = new P_DesktopListner();
    getUiEnvironment().getScoutDesktop().addDesktopListener(m_desktopListener);
    setData(WidgetUtil.CUSTOM_VARIANT, getVariant());
    createContent(this);
  }

  protected String getVariant() {
    BrowserInfo info = RwtUtility.getBrowserInfo();
    if (info != null && info.isMozillaFirefox()) {
      return VARIANT_VIEW_PART;
    }
    else {
      return VARIANT_VIEW_PART_NO_RADIUS;
    }
  }

  protected void createContent(Composite parent) {
    if (isTabBarCreationEnabled()) {
      m_tabBar = getUiEnvironment().getFormToolkit().createComposite(parent);
      m_tabBar.setData(WidgetUtil.CUSTOM_VARIANT, VARIANT_VIEW_TAB_AREA);
    }
    m_container = getUiEnvironment().getFormToolkit().createComposite(parent);

    // layout
    GridLayout layout = new GridLayout(1, true);
    layout.horizontalSpacing = 0;
    layout.marginHeight = 0;
    layout.marginTop = 0;
    layout.marginWidth = 0;
    layout.verticalSpacing = 0;
    parent.setLayout(layout);

    if (m_tabBar != null) {
      GridData tabBarData = new GridData(GridData.FILL_HORIZONTAL | GridData.GRAB_HORIZONTAL);
      tabBarData.exclude = false;
      m_tabBar.setLayoutData(tabBarData);

      RowLayout tabBarLayout = new RowLayout();
      tabBarLayout.marginBottom = 0;
      tabBarLayout.marginLeft = 0;
      tabBarLayout.marginTop = 0;
      m_tabBar.setLayout(tabBarLayout);
    }

    GridData containerData = new GridData(GridData.FILL_HORIZONTAL | GridData.FILL_VERTICAL | GridData.GRAB_HORIZONTAL | GridData.GRAB_VERTICAL);
    m_container.setLayoutData(containerData);

    StackLayout containerLayout = new StackLayout();
    m_container.setLayout(containerLayout);
  }

  @Override
  public IRwtEnvironment getUiEnvironment() {
    return m_uiEnvironment;
  }

  protected Map<IForm, IFormBoundsProvider> getFormBoundsProviders() {
    return m_formBoundsProviders;
  }

  @Override
  public IRwtScoutPart addForm(IForm form) {
    IFormBoundsProvider formBoundsProvider = createFormBoundsProvider(form, getUiEnvironment());
    m_formBoundsProviders.put(form, formBoundsProvider);
    initPreferredSize(formBoundsProvider);

    RwtScoutDesktopForm ui = createRwtScoutDesktopForm();
    ViewStackTabButton button = null;
    if (m_tabBar != null) {
      button = new ViewStackTabButton(m_tabBar);
      button.setLayoutData(new RowData(SWT.DEFAULT, 22));
      button.addViewTabListener(new P_ViewTabSelectionListener(ui));
    }
    ui.createPart(this, m_container, button, form, getUiEnvironment());
    m_formStack.add(0, ui);
    m_openForms.put(form, ui);
    setPartVisibleImpl(form);
    return ui;
  }

  /**
   * Creates a new instance of {@link RwtScoutDesktopForm}.
   * <p>
   * May be overridden to create a custom instance.
   */
  protected RwtScoutDesktopForm createRwtScoutDesktopForm() {
    return new RwtScoutDesktopForm();
  }

  protected void initPreferredSize(IFormBoundsProvider boundsProvider) {
    if (boundsProvider == null) {
      return;
    }

    Rectangle formBounds = boundsProvider.getBounds();
    if (formBounds != null) {
      setWidthHint(formBounds.width);
      setHeightHint(formBounds.height);
    }
    else {
      setWidthHint(-1);
      setHeightHint(-1);
    }
  }

  protected IFormBoundsProvider createFormBoundsProvider(IForm scoutForm, IRwtEnvironment uiEnvironment) {
    return new DefaultFormBoundsProvider(scoutForm, uiEnvironment);
  }

  @Override
  public boolean isPartVisible(IRwtScoutPart part) {
    //resolve
    part = m_openForms.get(part.getScoutObject());
    if (part == null) {
      return false;
    }
    StackLayout stackLayout = (StackLayout) m_container.getLayout();
    return RwtUtility.isAncestorOf(stackLayout.topControl, part.getUiContainer());
  }

  @Override
  public void setPartVisible(IRwtScoutPart part) {
    //resolve
    part = m_openForms.get(part.getScoutObject());
    if (part == null) {
      return;
    }
    setPartVisibleImpl(part.getScoutObject());
  }

  private void removeForm(IForm form) {
    RwtScoutDesktopForm uiForm = m_openForms.remove(form);
    if (uiForm != null) {
      m_formStack.remove(uiForm);
      IForm topForm = null;
      if (m_formStack.size() > 0) {
        topForm = m_formStack.get(0).getScoutObject();
      }
      setPartVisibleImpl(topForm);
    }
    m_formBoundsProviders.remove(form);
  }

  protected void setPartVisibleImpl(IForm form) {
    RwtScoutDesktopForm uiForm = m_openForms.get(form);
    if (uiForm != null) {
      StackLayout stackLayout = (StackLayout) m_container.getLayout();
      stackLayout.topControl = uiForm.getUiContainer();
      if (m_tabBar != null && m_formStack.remove(uiForm)) {
        GridData tabBarData = (GridData) m_tabBar.getLayoutData();
        if (m_formStack.isEmpty()) {
          m_tabBar.setVisible(false);
          tabBarData.exclude = true;
        }
        else {
          m_tabBar.setVisible(true);
          tabBarData.exclude = false;
          for (RwtScoutDesktopForm f : m_formStack) {
            f.getTabButton().setActive(false);
          }
          uiForm.getTabButton().setActive(true);
        }
        m_formStack.add(0, uiForm);
      }
    }
    getParent().layout(true, true);
  }

  /**
   * Controls whether the tab bar should be created at all. May be overridden.
   * <p>
   * Default is true.
   */
  protected boolean isTabBarCreationEnabled() {
    return true;
  }

  @Override
  public boolean getVisible() {
    return m_container.getChildren().length > 0;
  }

  @Override
  public int getHeightHint() {
    return heightHint;
  }

  @Override
  public void setHeightHint(int heightHint) {
    this.heightHint = heightHint;
  }

  @Override
  public int getWidthHint() {
    return widthHint;
  }

  @Override
  public void setWidthHint(int widthHint) {
    this.widthHint = widthHint;
  }

  private void handleScoutDesktopEvent(DesktopEvent e) {
    switch (e.getType()) {
      case DesktopEvent.TYPE_FORM_ENSURE_VISIBLE:
        setPartVisibleImpl(e.getForm());
        break;
      case DesktopEvent.TYPE_FORM_REMOVED:
        removeForm(e.getForm());
        break;
      case DesktopEvent.TYPE_DESKTOP_CLOSED:
        handleDesktopClosed(e.getDesktop());
        break;
    }
  }

  private void handleDesktopClosed(IDesktop desktop) {
    desktop.removeDesktopListener(m_desktopListener);
    m_desktopListener = null;
  }

  private class P_ViewTabSelectionListener implements IViewTabSelectionListener {
    private final RwtScoutDesktopForm m_form;

    public P_ViewTabSelectionListener(RwtScoutDesktopForm form) {
      m_form = form;
    }

    @Override
    public void handleEvent(ViewTabSelectionEvent event) {
      if (event.getEventType() == ViewTabSelectionEvent.TYPE_VIEW_TAB_SELECTION) {
        Runnable job = new Runnable() {
          @Override
          public void run() {
            m_form.getScoutObject().getUIFacade().fireFormActivatedFromUI();
          }
        };
        getUiEnvironment().invokeScoutLater(job, 0);
        setPartVisibleImpl(m_form.getScoutObject());
      }
      else if (event.getEventType() == ViewTabSelectionEvent.TYPE_VIEW_TAB_CLOSE_SELECTION) {
        Runnable job = new Runnable() {
          @Override
          public void run() {
            m_form.getScoutObject().getUIFacade().fireFormClosingFromUI();
          }
        };
        getUiEnvironment().invokeScoutLater(job, 0);
      }

    }
  } // end class P_ViewTabSelectionListener

  private class P_DesktopListner implements DesktopListener {
    @Override
    public void desktopChanged(final DesktopEvent e) {
      if (getUiEnvironment().getDisplay() != null && !getUiEnvironment().getDisplay().isDisposed()) {
        Runnable t = new Runnable() {
          @Override
          public void run() {
            handleScoutDesktopEvent(e);
          }
        };
        getUiEnvironment().invokeUiLater(t);
      }
    }
  }

  private class P_ResizeListener implements Listener {

    private static final long serialVersionUID = 1L;

    @Override
    public void handleEvent(Event event) {
      if (event.type == SWT.Resize) {
        handleResized();
      }
    }

    private void handleResized() {
      if (isDisposed() || m_formBoundsProviders.isEmpty()) {
        return;
      }

      for (IFormBoundsProvider formBoundsProvider : m_formBoundsProviders.values()) {
        formBoundsProvider.storeBounds(getBounds());
      }
    }

  }

}