/*******************************************************************************
 * Copyright (c) 2007, 2010 Association for Decentralized Information Management
 * in Industry THTH ry.
 * 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:
 *     VTT Technical Research Centre of Finland - initial API and implementation
 *******************************************************************************/
package org.simantics.g2d.element.handler.impl;

import java.awt.geom.Point2D;
import java.lang.reflect.Method;
import java.util.Map;

import org.simantics.g2d.canvas.ICanvasContext;
import org.simantics.g2d.diagram.participant.DiagramParticipant;
import org.simantics.g2d.element.ElementUtils;
import org.simantics.g2d.element.IElement;
import org.simantics.g2d.element.handler.Clickable;
import org.simantics.scenegraph.g2d.events.MouseEvent;
import org.simantics.scenegraph.g2d.events.MouseEvent.MouseButtonReleasedEvent;
import org.simantics.scenegraph.g2d.events.MouseEvent.MouseDragBegin;
import org.simantics.scenegraph.g2d.events.MouseEvent.MouseExitEvent;
import org.simantics.utils.datastructures.hints.IHintContext.Key;
import org.simantics.utils.datastructures.hints.IHintContext.KeyOf;
import org.simantics.utils.threads.Executable;
import org.simantics.utils.threads.IThreadWorkQueue;
import org.simantics.utils.threads.SyncListenerList;
import org.simantics.utils.threads.ThreadUtils;

/**
 * Base implementation for button handlers
 * 
 * 
 * @author Toni Kalajainen
 */
public abstract class AbstractClickable extends AbstractGrabbable implements Clickable {
	
	private static final long serialVersionUID = -8329973386869163106L;
	
	public static Key HOVER_KEY = new KeyOf(Boolean.class, "HOVER");
	public static Key PRESS_STATUS_KEY = new KeyOf(PressStatus.class, "PRESS_STATUS");
	
	public AbstractClickable(Double strayDistance) {
		super(1000.0);
	}
	
	public AbstractClickable() {
		super();
	}	

	/**
	 * Get element press status
	 * @param e
	 * @param ctx
	 * @return
	 */
	public PressStatus getPressStatus(IElement e, ICanvasContext ctx)
	{
		Map<Integer, GrabInfo> gis = getGrabs(e, ctx);
		if (gis==null || gis.size()==0) {
			Boolean hover = e.getHint(HOVER_KEY);
			if (hover != null && hover)
				return PressStatus.HOVER;
			return PressStatus.NORMAL;
		}
		
		// is held down 
		boolean held = false;
		boolean pressing = false;
		
		for (GrabInfo gi : gis.values()) {
			held = true;
			pressing |= onPickCheck(e, ctx, gi.pointerId, gi.dragPosElement);
			if (pressing) break;
		}		
		
		if (pressing) return PressStatus.PRESSED;
		if (held) return PressStatus.HELD;
		Boolean hover = e.getHint(HOVER_KEY);
		if (hover != null && hover)
			return PressStatus.HOVER;

		return PressStatus.NORMAL;
	}
	
	
	@Override
	public boolean handleMouseEvent(IElement e, ICanvasContext ctx,
			MouseEvent me) {
		//System.out.println("AbstractClickable.hME element:" + e + " me:" + me);
		boolean b = super.handleMouseEvent(e, ctx, me);
		Boolean hovering;
		// DND drag starts causes DragBegin + ButtonReleasedEvents, and hovering must be set false
		if (!(me instanceof MouseExitEvent || me instanceof MouseDragBegin || me instanceof MouseButtonReleasedEvent))
			hovering = Boolean.valueOf(onPickCheck(e, ctx, me.mouseId, ElementUtils.controlToElementCoordinate(e, ctx, me.controlPosition, null)));
		else
			hovering = false;
		if (!hovering.equals(e.getHint(HOVER_KEY))) {
			e.setHint(HOVER_KEY, hovering);
		}
		
		// hackety hack
		PressStatus newStatus = getPressStatus(e, ctx);
		if (!newStatus.equals(e.getHint(PRESS_STATUS_KEY)))
			e.setHint(PRESS_STATUS_KEY, newStatus) ;
		return b;
	}
	
	@Override
	protected void onDrag(GrabInfo gi, ICanvasContext ctx) {
		
	}

	@Override
	protected void onGrab(GrabInfo gi, ICanvasContext ctx) {
	}

	@Override
	protected void onGrabCancel(GrabInfo gi, ICanvasContext ctx) {
	}

	@Override
	protected void onRelease(GrabInfo gi, ICanvasContext ctx) {
		// pick is pick until last mouse releases
		if (getGrabCount(gi.e, ctx)>0) return;
		
		boolean pick = onPickCheck(gi.e, ctx, gi.pointerId, gi.dragPosElement);
		if (pick) {
			onClicked(gi, ctx);
			fireClicked(gi.e, ctx);
		}
	}
	
	protected boolean onGrabCheck(IElement e, ICanvasContext ctx, int pointerId, Point2D pickPos)
	{
		Point2D elementPos = ElementUtils.controlToElementCoordinate(e, ctx, pickPos, null); 
		return onPickCheck(e, ctx, pointerId, elementPos);
	}
	
	protected abstract void onClicked(GrabInfo gi, ICanvasContext ctx);
	
	/**
	 * Pick check in element coordinates
	 * @param e
	 * @param ctx
	 * @param pointerId
	 * @param pickPos
	 * @return
	 */
	protected abstract boolean onPickCheck(IElement e, ICanvasContext ctx, int pointerId, Point2D pickPos);


	private static final Key KEY_CLICK_LISTENERS = new KeyOf(SyncListenerList.class);
	
	@Override
	public void addListener(final IElement e, final ICanvasContext ctx, final IThreadWorkQueue thread, final ClickListener listener) {
		ThreadUtils.syncExec(ctx.getThreadAccess(), new Runnable() {
			@Override
			public void run() {
				DiagramParticipant dp = ctx.getSingleItem(DiagramParticipant.class);
				SyncListenerList<ClickListener> list = dp.getElementHint(e, KEY_CLICK_LISTENERS);
				if (list==null) {
					list = new SyncListenerList<ClickListener>(ClickListener.class);
					dp.setElementHint(e, KEY_CLICK_LISTENERS, list);
				}
				list.add(thread, listener);
			}});		
	}

	@Override
	public void removeListener(final IElement e, final ICanvasContext ctx, final IThreadWorkQueue thread, final ClickListener listener) {
		ThreadUtils.syncExec(ctx.getThreadAccess(), new Runnable() {
			@Override
			public void run() {
				DiagramParticipant dp = ctx.getSingleItem(DiagramParticipant.class);
				SyncListenerList<ClickListener> list = dp.getElementHint(e, KEY_CLICK_LISTENERS);
				if (list==null) return;
				list.remove(thread, listener);
				if (list.isEmpty())
					dp.removeElementHint(e, KEY_CLICK_LISTENERS);
			}});		
	}		
	
	private final static Method onClick = SyncListenerList.getMethod(ClickListener.class, "onClick");
	public void fireClicked(IElement e, ICanvasContext ctx)
	{
		DiagramParticipant dp = ctx.getSingleItem(DiagramParticipant.class);
		SyncListenerList<ClickListener> list = dp.getElementHint(e, KEY_CLICK_LISTENERS);
		if (list==null) return;
		Executable exes[] = list.getExecutables(onClick, e, ctx);
		ThreadUtils.multiSyncExec(exes);
	}
	
}