/*******************************************************************************
 * 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.utils;

import java.util.function.Supplier;

import org.simantics.g2d.canvas.Hints;
import org.simantics.g2d.canvas.ICanvasContext;
import org.simantics.g2d.diagram.DiagramHints;
import org.simantics.g2d.diagram.IDiagram;
import org.simantics.scenegraph.g2d.events.command.Command;
import org.simantics.scenegraph.g2d.events.command.CommandEvent;
import org.simantics.scenegraph.g2d.events.command.Commands;
import org.simantics.utils.threads.IThreadWorkQueue;
import org.simantics.utils.threads.ThreadUtils;

/**
 * @author Toni Kalajainen
 * @author Tuukka Lehtonen
 */
public class CanvasUtils {

    /**
     * Enqueue a command in the event queue of the specified canvas context.
     * 
     * @param ctx queue context
     * @param commandId ID of the command to queue
     * 
     * @see #sendCommand(ICanvasContext, Command)
     */
    public static void sendCommand(ICanvasContext ctx, String commandId)
    {
        sendCommand(ctx, new Command(commandId));
    }

    /**
     * Enqueue a command in the event queue of the specified canvas context.
     * 
     * @param ctx queue context
     * @param cmd the command to queue
     */
    public static void sendCommand(ICanvasContext ctx, Command cmd)
    {
        CommandEvent e = new CommandEvent(ctx, System.currentTimeMillis(), cmd);
        ctx.getEventQueue().queueEvent(e);
    }

    /**
     * A utility for scheduling a zoom-to-fit operation when an Eclipse
     * workbench editor is initially opened.
     * 
     * <p>
     * There are two asynchronous calls, first into the workbench (SWT) UI
     * thread and then into the canvas context thread. This will guarantee that
     * the parenting SWT control has been resized to its actual size instead of
     * the initial (0,0) size which widgets start out at. In order to perform a
     * zoom-to-fit operation we simply have to know the bounds of the parenting
     * control. Thus, we need to ensure that this information is available and
     * correct.
     * 
     * @param swtThread
     * @param disposed
     * @param canvasContext
     * @param diagramToFit
     */
    public static void scheduleZoomToFit(IThreadWorkQueue swtThread, final Supplier<Boolean> disposed,
            final ICanvasContext canvasContext, final IDiagram diagramToFit)
    {
        scheduleZoomToFit(swtThread, disposed, canvasContext, diagramToFit, true);
    }

    /**
     * A utility for scheduling a zoom-to-fit operation when an Eclipse
     * workbench editor is initially opened.
     * 
     * <p>
     * There are two asynchronous calls, first into the workbench (SWT) UI
     * thread and then into the canvas context thread. This will guarantee that
     * the parenting SWT control has been resized to its actual size instead of
     * the initial (0,0) size which widgets start out at. In order to perform a
     * zoom-to-fit operation we simply have to know the bounds of the parenting
     * control. Thus, we need to ensure that this information is available and
     * correct.
     * 
     * @param swtThread
     * @param disposed
     * @param canvasContext
     * @param diagramToFit
     * @param zoomToFit
     */
    public static void scheduleZoomToFit(IThreadWorkQueue swtThread, final Supplier<Boolean> disposed,
            final ICanvasContext canvasContext, final IDiagram diagramToFit, boolean zoomToFit)
    {
        if (diagramToFit == null)
            throw new IllegalStateException("source diagram is null");

        Boolean canvasZoomToFit = canvasContext.getHintStack().getHint(DiagramHints.KEY_INITIAL_ZOOM_TO_FIT);
        diagramToFit.setHint(Hints.KEY_DISABLE_PAINTING, Boolean.TRUE);
        if (zoomToFit && !Boolean.FALSE.equals(canvasZoomToFit))
            diagramToFit.setHint(DiagramHints.KEY_INITIAL_ZOOM_TO_FIT, Boolean.TRUE);

        ThreadUtils.asyncExec(swtThread, new Runnable() {
            @Override
            public void run() {
                if (disposed.get() || canvasContext.isDisposed())
                    return;

                ThreadUtils.asyncExec(canvasContext.getThreadAccess(), new Runnable() {
                    @Override
                    public void run() {
                        if (disposed.get() || canvasContext.isDisposed())
                            return;

                        Boolean zoomToFit = diagramToFit.removeHint(DiagramHints.KEY_INITIAL_ZOOM_TO_FIT);
                        diagramToFit.removeHint(Hints.KEY_DISABLE_PAINTING);

                        if (Boolean.TRUE.equals(zoomToFit))
                            CanvasUtils.sendCommand(canvasContext, Commands.ZOOM_TO_FIT);
                        CanvasUtils.sendCommand(canvasContext, Commands.ENABLE_PAINTING);
                    }
                });
            }
        });
    }

}