/*******************************************************************************
 * Copyright (c) 2012 Rushan R. Gilmullin and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0 
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 * 
 * Contributors:
 *     Rushan R. Gilmullin - initial API and implementation
 *******************************************************************************/

package org.eclipse.osbp.vaaclipse.presentation.renderers;

import java.util.List;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import javax.inject.Inject;

import org.eclipse.e4.core.services.events.IEventBroker;
import org.eclipse.e4.ui.model.application.ui.MElementContainer;
import org.eclipse.e4.ui.model.application.ui.MUIElement;
import org.eclipse.e4.ui.model.application.ui.advanced.MArea;
import org.eclipse.e4.ui.model.application.ui.advanced.MPlaceholder;
import org.eclipse.e4.ui.model.application.ui.basic.MPartSashContainer;
import org.eclipse.e4.ui.model.application.ui.basic.MPartSashContainerElement;
import org.eclipse.e4.ui.model.application.ui.basic.MPartStack;
import org.eclipse.e4.ui.workbench.IPresentationEngine;
import org.eclipse.e4.ui.workbench.UIEvents;
import org.eclipse.e4.ui.workbench.modeling.EModelService;
import org.eclipse.osbp.vaaclipse.api.VaadinExecutorService;
import org.eclipse.osbp.vaaclipse.presentation.utils.HierarchyUtils;
import org.eclipse.osbp.vaaclipse.widgets.StackWidget;
import org.eclipse.osbp.vaaclipse.widgets.StackWidget.StateListener;
import org.osgi.service.event.Event;
import org.osgi.service.event.EventHandler;

import com.vaadin.ui.AbstractOrderedLayout;
import com.vaadin.ui.Component;
import com.vaadin.ui.HorizontalLayout;
import com.vaadin.ui.VerticalLayout;

/**
 * @author rushan
 * 
 */
public class AreaRenderer extends VaadinRenderer {
	@Inject
	IEventBroker eventBroker;

	@Inject
	VaadinExecutorService executorService;

	private EventHandler childrenHandler = new EventHandler() {
		public void handleEvent(Event event) {
			Object changedObj = event.getProperty(UIEvents.EventTags.ELEMENT);

			// Stacks can not contains another stacks (yes, theoretically it can
			// contains the stack in child placeholder, but
			// we search only top level stacks)
			if (changedObj instanceof MPartStack)
				return;

			@SuppressWarnings("unchecked")
			MElementContainer<? extends MUIElement> changedElement = (MElementContainer<MUIElement>) changedObj;

			if (!changedElement.isToBeRendered()
					|| changedElement.getWidget() == null)
				return;

			String eventType = (String) event
					.getProperty(UIEvents.EventTags.TYPE);
			MUIElement child = null;
			if (UIEvents.EventTypes.ADD.equals(eventType))
				child = (MUIElement) event
						.getProperty(UIEvents.EventTags.NEW_VALUE);
			else if (UIEvents.EventTypes.REMOVE.equals(eventType))
				child = (MUIElement) event
						.getProperty(UIEvents.EventTags.OLD_VALUE);

			if (child == null || !child.isToBeRendered())
				return;

			if (!(child instanceof MPartStack || child instanceof MPartSashContainer))
				return;

			processChangedElement(changedElement);
		}
	};

	private EventHandler toBeRenderedHandler = new EventHandler() {
		public void handleEvent(Event event) {

			MUIElement changedElement = (MUIElement) event
					.getProperty(UIEvents.EventTags.ELEMENT);

			if (!(changedElement instanceof MPartStack || changedElement instanceof MPartSashContainer))
				return;

			processChangedElement(changedElement);
		}
	};

	private void processChangedElement(MUIElement changedElement) {
		MArea area = null;
		// if it is area we directly process it
		if (changedElement instanceof MArea)
			area = (MArea) changedElement;
		else {// otherwise we find parent area
			int loc = modelService.getElementLocation(changedElement);
			if (loc != EModelService.IN_SHARED_AREA)
				return;

			area = findArea(changedElement);
		}

		if (area != null) {
			final MArea closureArea = area;
			executorService.invokeLater(closureArea, new Runnable() {

				@Override
				public void run() {
					refreshTopRightState(closureArea);
				}
			});
		}
	}

	private MArea findArea(MUIElement element) {
		MUIElement parent = element.getParent();
		while (parent != null) {
			if (parent instanceof MArea)
				return (MArea) parent;
			parent = parent.getParent();
		}
		return null;
	}

	@PostConstruct
	public void subscribe() {
		eventBroker.subscribe(UIEvents.ElementContainer.TOPIC_CHILDREN,
				childrenHandler);
		eventBroker.subscribe(UIEvents.UIElement.TOPIC_TOBERENDERED,
				toBeRenderedHandler);
	}

	@PreDestroy
	public void unsubscribe() {
		eventBroker.unsubscribe(childrenHandler);
		eventBroker.unsubscribe(toBeRenderedHandler);
	}

	@Override
	public void createWidget(MUIElement element,
			MElementContainer<MUIElement> parent) {
		if (!(element instanceof MArea))
			return;

		MArea area = (MArea) element;
		AbstractOrderedLayout areaComp;
		if (area.isHorizontal())
			areaComp = new HorizontalLayout();
		else
			areaComp = new VerticalLayout();
		areaComp.addStyleName("org_eclipse_osbp_vaaclipse_area");
		areaComp.setSizeFull();
		element.setWidget(areaComp);
	}

	@Override
	public void processContents(MElementContainer<MUIElement> container) {
		MArea area = (MArea) (MElementContainer<?>) container;
		AbstractOrderedLayout parentPane = (AbstractOrderedLayout) area
				.getWidget();
		parentPane.removeAllComponents();
		for (MUIElement element : area.getChildren()) {
			if (element.isToBeRendered()) {
				if (element instanceof MPlaceholder)
					element = ((MPlaceholder) element).getRef();
				parentPane.addComponent((Component) element.getWidget());
			}
		}

		refreshTopRightState(area);
	}

	/**
	 * This method finds the top right part stack (located in top right corner)
	 * and apply its maximize and minimize buttons to entire area. Then hide the
	 * maximize and minimize buttons of other stacks in this area. So, there are
	 * implemented the eclipse3-like approach to manage area (in e4 swt renderer
	 * is used other way - if more than one stack is located in area, the top
	 * container-tabfolder is created for entire area and buttons of this
	 * container folder is used - i found this way is too heavy-weight).
	 */
	@SuppressWarnings("restriction")
	private void refreshTopRightState(final MArea area) {
		MPartStack topLeftStak = HierarchyUtils.findTopLeftFolder(area);
		if (topLeftStak != null) {
			StackWidget topLeftStackWidget = (StackWidget) topLeftStak
					.getWidget();
			if (topLeftStackWidget != null) {
				topLeftStackWidget.setMinMaxEnabled(true);
				topLeftStackWidget.removeAllStateListeners();

				topLeftStackWidget.addStateListener(new StateListener() {

					@Override
					public void stateChanged(int newState, int oldState) {
						MPlaceholder ph = area.getCurSharedRef();
						if (oldState == 0 && newState == 1)
							setState(ph, IPresentationEngine.MAXIMIZED);
						else if (oldState == 1 && newState == 0)
							setState(ph, null);
						else if (oldState == 1 && newState == -1) {
							ph.getTags().remove(IPresentationEngine.MINIMIZED);
							ph.getTags().remove(IPresentationEngine.MAXIMIZED);
							ph.getTags().add(IPresentationEngine.MINIMIZED);
						} else if (oldState == -1 && newState == 0) {
							ph.getTags().remove(
									IPresentationEngine.MINIMIZED_BY_ZOOM);
							ph.getTags().remove(IPresentationEngine.MINIMIZED);
						} else if (oldState == 0 && newState == -1)
							setState(ph, IPresentationEngine.MINIMIZED);
					}

					private void setState(MUIElement element, String state) {
						element.getTags().remove(
								IPresentationEngine.MINIMIZED_BY_ZOOM);
						if (IPresentationEngine.MINIMIZED.equals(state)) {
							element.getTags().remove(
									IPresentationEngine.MAXIMIZED);
							element.getTags()
									.add(IPresentationEngine.MINIMIZED);
						} else if (IPresentationEngine.MAXIMIZED.equals(state)) {
							element.getTags().remove(
									IPresentationEngine.MINIMIZED);
							element.getTags()
									.add(IPresentationEngine.MAXIMIZED);
						} else {
							element.getTags().remove(
									IPresentationEngine.MINIMIZED);
							element.getTags().remove(
									IPresentationEngine.MAXIMIZED);
						}
					}
				});
			}

			List<MPartStack> stacks = modelService.findElements(area, null,
					MPartStack.class, null);

			for (MPartStack stack : stacks) {
				if (stack.isToBeRendered() && stack != topLeftStak) {
					StackWidget stackWidget = (StackWidget) stack.getWidget();
					if (stackWidget != null) {
						stackWidget.setMinMaxEnabled(false);
						stackWidget.removeAllStateListeners();
					}
				}
			}
		}
	}

	@Override
	public void addChildGui(MUIElement child,
			MElementContainer<MUIElement> element) {
		if (!(child instanceof MPartSashContainerElement))
			return;

		AbstractOrderedLayout areaWidget = (AbstractOrderedLayout) element
				.getWidget();
		int index = indexOf(child, element);
		areaWidget.addComponent((Component) child.getWidget(), index);
	}
}