/*******************************************************************************
 * 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.diagram.ui;

import java.awt.geom.Point2D;

import org.eclipse.jface.action.GroupMarker;
import org.eclipse.jface.action.IMenuListener2;
import org.eclipse.jface.action.IMenuManager;
import org.eclipse.jface.action.MenuManager;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.MenuAdapter;
import org.eclipse.swt.events.MenuEvent;
import org.eclipse.swt.events.MenuListener;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Menu;
import org.eclipse.ui.IWorkbenchActionConstants;
import org.eclipse.ui.IWorkbenchPartSite;
import org.simantics.g2d.canvas.ICanvasContext;
import org.simantics.g2d.canvas.impl.AbstractCanvasParticipant;
import org.simantics.g2d.canvas.impl.DependencyReflection.Dependency;
import org.simantics.g2d.diagram.DiagramHints;
import org.simantics.g2d.participant.TransformUtil;
import org.simantics.scenegraph.g2d.events.EventHandlerReflection.EventHandler;
import org.simantics.scenegraph.g2d.events.command.CommandEvent;
import org.simantics.scenegraph.g2d.events.command.ShowPopup;
import org.simantics.utils.datastructures.hints.HintListenerAdapter;
import org.simantics.utils.datastructures.hints.IHintContext.Key;
import org.simantics.utils.datastructures.hints.IHintListener;
import org.simantics.utils.datastructures.hints.IHintObservable;
import org.simantics.utils.ui.SWTDPIUtil;

/**
 * A participant that initializes an SWT pop-up menu and registers it with the
 * Eclipse workbench if a workbench site is provided. The client can specify the
 * ID of the menu to create which allows the user to control contributions via
 * Eclipse's declarative command mechanisms.
 * 
 * @author Tuukka Lehtonen
 */
public class SWTPopupMenuParticipant extends AbstractCanvasParticipant {

    @Dependency
    WorkbenchSelectionProvider wbsp;
    @Dependency
    TransformUtil              trUtil;

    IWorkbenchPartSite         site;
    Control                    control;
    Display                    display;
    MenuManager                menuManager;
    String                     menuId;

    IHintListener popupListener = new HintListenerAdapter() {
        @Override
        public void hintChanged(IHintObservable sender, Key key, Object oldValue, Object newValue) {
            if (key == DiagramHints.SHOW_POPUP_MENU) {
                if (newValue != null) {
                    Control c = control;
                    if (display.isDisposed() || c == null || c.isDisposed())
                        return;

                    showPopup((Point2D) newValue);
                }
            }
        }
    };

    IMenuListener2 menuManagerListener = new IMenuListener2() {
        @Override
        public void menuAboutToShow(IMenuManager manager) {
            manager.add(new GroupMarker(IWorkbenchActionConstants.WB_START));
//            manager.add(new GroupMarker(IWorkbenchActionConstants.NEW_EXT));
//            manager.add(new GroupMarker(IWorkbenchActionConstants.IMPORT_EXT));
//            manager.add(new Separator(IWorkbenchActionConstants.MB_ADDITIONS));
//            manager.add(new GroupMarker(IWorkbenchActionConstants.WB_END));
        }
        @Override
        public void menuAboutToHide(IMenuManager manager) {
        }
    };

    MenuListener menuListener = new MenuAdapter() {
        @Override
        public void menuShown(MenuEvent e) {
        	SWTPopupMenuParticipant.this.menuShown(e);
        }
        @Override
        public void menuHidden(MenuEvent e) {
        	SWTPopupMenuParticipant.this.menuHidden(e);
        }
    };
    
    protected void menuShown(MenuEvent e) {
        asyncExec(new Runnable() {
            @Override
            public void run() {
                final long time = System.currentTimeMillis();
                //System.out.println("popup shown: " + time);
                setHint(DiagramHints.POPUP_MENU_SHOWN, time);
                removeHint(DiagramHints.POPUP_MENU_HIDDEN);
                
            }
        });
    }
    
    protected void menuHidden(MenuEvent e) {
        asyncExec(new Runnable() {
            @Override
            public void run() {
                final long time = System.currentTimeMillis();
                //System.out.println("popup closed: " + time);
                removeHint(DiagramHints.POPUP_MENU_SHOWN);
                setHint(DiagramHints.POPUP_MENU_HIDDEN, time);
            }
        });
    }

    /**
     * NOTE: this constructor must currently be invoked from the SWT display
     * thread.
     * 
     * @param site
     * @param control
     * @param menuId
     * @deprecated use {@link #SWTPopupMenuParticipant(IWorkbenchPartSite, Control, Display, String)} instead
     */
    public SWTPopupMenuParticipant(IWorkbenchPartSite site, Control control, String menuId) {
        this(site, control, control.getDisplay(), menuId);
    }

    public SWTPopupMenuParticipant(IWorkbenchPartSite site, Control control, Display display, String menuId) {
        super();
        this.site = site;
        this.control = control;
        this.display = display;
        this.menuId = menuId;
        control.addListener(SWT.Dispose, new Listener() {

            @Override
            public void handleEvent(Event event) {
                runDispose();
            }
            
        });
    }

    protected void runDispose() {
    	SWTPopupMenuParticipant.this.control = null;
        if(menuManager != null) {
            menuManager.removeAll();
            menuManager.dispose();
            menuManager = null;
        }
    }
    
    @Override
    public void addedToContext(ICanvasContext ctx) {
        super.addedToContext(ctx);

        display.asyncExec(new Runnable() {
            @Override
            public void run() {
               createControl();
            }
        });

        getHintStack().addKeyHintListener(DiagramHints.SHOW_POPUP_MENU, popupListener);
    }
    
    protected void createControl() {
    	 if (control == null || control.isDisposed())
             return;
         menuManager = createPopupMenu();
         if (menuManager != null) {
             Menu menu = menuManager.createContextMenu(control);
             menu.addMenuListener(menuListener);
             control.setMenu(menu);
             if (site != null) {
                 site.registerContextMenu(menuManager.getId(), menuManager, wbsp);
             }
         }
    }

    @Override
    public void removedFromContext(ICanvasContext ctx) {
        getHintStack().removeKeyHintListener(DiagramHints.SHOW_POPUP_MENU, popupListener);
        super.removedFromContext(ctx);
    }

    protected MenuManager createPopupMenu() {
        final MenuManager mm = new MenuManager("Canvas Popup", menuId);
        mm.setRemoveAllWhenShown(true);
        mm.addMenuListener(menuManagerListener);
        return mm;
    }

    @EventHandler(priority = 0)
    public boolean handleCommands(CommandEvent e) {
        if (e.command instanceof ShowPopup) {
            showPopup(((ShowPopup) e.command).getControlPosition());
            return true;
        }
        return false;
    }

    /**
     * @param newValue
     * @thread canvas-thread (AWT)
     */
    protected void showPopup(Point2D cp) {
        setHint(DiagramHints.POPUP_MENU_CONTROL_POSITION, cp);
        setHint(DiagramHints.POPUP_MENU_CANVAS_POSITION, trUtil.controlToCanvas(cp, null));
        display.asyncExec(() -> {
            if (control == null || control.isDisposed())
                return;
            Point p = control.toDisplay( SWTDPIUtil.downscaleSwtToInteger(cp) );
            menuManager.getMenu().setLocation(p);
            menuManager.getMenu().setVisible(true);
        });
    }

}