/*******************************************************************************
 * 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.tooltip;

import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;

import javax.swing.ToolTipManager;

import org.simantics.g2d.diagram.participant.AbstractDiagramParticipant;
import org.simantics.g2d.element.IElement;
import org.simantics.scenegraph.g2d.events.MouseEvent;
import org.simantics.scenegraph.g2d.events.EventHandlerReflection.EventHandler;
import org.simantics.scenegraph.g2d.events.MouseEvent.MouseButtonPressedEvent;
import org.simantics.scenegraph.g2d.events.command.CommandEvent;
import org.simantics.scenegraph.g2d.events.command.Commands;
import org.simantics.utils.datastructures.hints.IHintContext.Key;
import org.simantics.utils.datastructures.hints.IHintContext.KeyOf;
import org.simantics.utils.threads.ThreadUtils;

public abstract class BaseTooltipParticipant extends AbstractDiagramParticipant implements ITooltipParticipant {

    // Element hint key for tooltips
    public static Key TOOLTIP_KEY = new KeyOf(TooltipProvider.class, "TOOLTIP");

    public int tooltipDelay = ToolTipManager.sharedInstance().getInitialDelay();

    private IElement tooltipElement;
    private TooltipProvider creator;
    private boolean tooltipShowing = false;

    private Future<?> delayRunnable = null;

    private int x = 0;
    private int y = 0;

    @EventHandler(priority = 0)
    public boolean handleKeyEvent(CommandEvent e) {
        if (e.command == Commands.FOCUS_TOOLTIP) {
            //System.out.println("Focus");
            if (tooltipShowing && creator instanceof FocusableTooltipProvider) {
                ((FocusableTooltipProvider)creator).focus();
            }
        }
        return false;
    }

    @EventHandler(priority = Integer.MAX_VALUE)
    public boolean handleMouseEvent(MouseEvent e) {
        if (e.screenPosition != null) {
            x = (int)e.screenPosition.getX();
            y = (int)e.screenPosition.getY();
        }
        if (tooltipShowing) {

            if (e instanceof MouseButtonPressedEvent) {
                // this hides focused tooltip if mouse is clicked somewhere else that on the tooltip
                hideTooltip();
            }
        }
        return  false;
    }

    /**
     * Shows tooltip immediately
     */
    public synchronized void showTooltip() {
        if (tooltipElement == null)
            return;
        creator.showTooltip(tooltipElement,x,y);
        tooltipShowing = true;
    }

    private void launchThread() {
        if (delayRunnable != null) {
            delayRunnable.cancel(false);
            delayRunnable = null;
        }
        delayRunnable = ThreadUtils.getNonBlockingWorkExecutor().schedule(new Runnable() {
            @Override
            public void run() {
                showTooltip();
            }
        }, tooltipDelay, TimeUnit.MILLISECONDS);
    }

    /**
     * Tries to show tooltip for given element
     * Does not show tooltip instantly, but uses delay
     * @param element
     */
    public synchronized void showTooltipFor(IElement element) {
        //System.out.println("showTooltipFor " + element);
        if (tooltipShowing && (creator instanceof FocusableTooltipProvider) && ((FocusableTooltipProvider)creator).hasFocus())
            return;
        creator = element.getHint(TOOLTIP_KEY);
        if (creator != null) {
            tooltipElement = element;
            launchThread();
        } else {
            hideTooltip();
        }
    }

    /**
     * Hides tooltip, if one is showing
     */
    public synchronized void hideTooltip() {
        //System.out.println("hideTooltip");
        if (tooltipShowing && (creator instanceof FocusableTooltipProvider) && ((FocusableTooltipProvider)creator).hasFocus())
            return;
        if (creator != null && tooltipShowing)
            creator.hideTooltip(tooltipElement);
        creator = null;
        tooltipElement = null;
        tooltipShowing = false;
    }

}