/*******************************************************************************
 * Copyright (c) 2007, 2014 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
 *     Semantum Oy - support SHIFT+left double click browsing outside of model configuration
 *******************************************************************************/
package org.simantics.modeling.ui.diagramEditor.handlers;

import java.util.Set;

import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.ui.IWorkbenchPartSite;
import org.eclipse.ui.PartInitException;
import org.eclipse.ui.PlatformUI;
import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.common.request.PossibleIndexRoot;
import org.simantics.db.common.request.UniqueRead;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.layer0.variable.RVI;
import org.simantics.db.layer0.variable.Variable;
import org.simantics.db.layer0.variable.Variables;
import org.simantics.db.management.ISessionContext;
import org.simantics.diagram.flag.FlagUtil;
import org.simantics.diagram.stubs.DiagramResource;
import org.simantics.diagram.ui.DiagramModelHints;
import org.simantics.g2d.canvas.impl.DependencyReflection.Dependency;
import org.simantics.g2d.diagram.participant.AbstractDiagramParticipant;
import org.simantics.g2d.diagram.participant.Selection;
import org.simantics.g2d.element.ElementHints;
import org.simantics.g2d.element.IElement;
import org.simantics.layer0.utils.operations.IOperation;
import org.simantics.modeling.ModelingOperationConstants;
import org.simantics.modeling.ModelingResources;
import org.simantics.modeling.actions.NavigateToTarget;
import org.simantics.modeling.ui.Activator;
import org.simantics.scenegraph.g2d.events.EventHandlerReflection.EventHandler;
import org.simantics.scenegraph.g2d.events.MouseEvent.MouseDoubleClickedEvent;
import org.simantics.structural.stubs.StructuralResource2;
import org.simantics.ui.workbench.IResourceEditorInput2;
import org.simantics.ui.workbench.ResourceEditorInput2;
import org.simantics.utils.datastructures.persistent.ContextMap;
import org.simantics.utils.ui.ErrorLogger;
import org.simantics.utils.ui.workbench.WorkbenchUtils;

/**
 * StructuralBrowsingHandler supports visual browsing into subcomponents through
 * mouse events.
 * 
 * @author Tuukka Lehtonen
 */
public class StructuralBrowsingHandler extends AbstractDiagramParticipant {

    @Dependency
    Selection             selection;
    IWorkbenchPartSite    site;
    ISessionContext       sessionContext;
    IResourceEditorInput2 input;

    public StructuralBrowsingHandler(IWorkbenchPartSite site, ISessionContext sessionContext, IResourceEditorInput2 input) {
        assert site != null;

        this.site = site;
        this.sessionContext = sessionContext;
        this.input = input;
    }

    @EventHandler(priority = 0)
    public boolean handleDoubleClick(MouseDoubleClickedEvent me) {
        if (sessionContext == null || diagram == null)
            return false;
        
        Set<IElement> sel = selection.getSelection(0);
        if (sel.size() == 1) {
            IElement e = sel.iterator().next();
            Object data = e.getHint(ElementHints.KEY_OBJECT);
            final Resource runtime = diagram.getHint(DiagramModelHints.KEY_DIAGRAM_RUNTIME_RESOURCE);
            if (data instanceof Resource) {
                final Resource element = (Resource) data;
                final int stateMask = me.stateMask;
                try {
                    return sessionContext.getSession().syncRequest(new UniqueRead<Boolean>() {
                        @Override
                        public Boolean perform(ReadGraph graph) throws DatabaseException {
                            return browse(graph, element, runtime, stateMask);
                        }
                    });
                } catch (DatabaseException e1) {
                    ErrorLogger.defaultLogError(e1);
                }
            }
        }

        return false;
    }
    
    private boolean browse(ReadGraph graph, Resource element, Resource runtimeDiagram, int stateMask) throws DatabaseException {
        DiagramResource DIA = DiagramResource.getInstance(graph);
        ModelingResources mr = ModelingResources.getInstance(graph);
        DiagramResource dr = DiagramResource.getInstance(graph);
        StructuralResource2 sr = StructuralResource2.getInstance(graph);

        if (graph.isInstanceOf(element, dr.Flag)) {
            ContextMap parameters = new ContextMap();
            parameters.put(ModelingOperationConstants.WORKBENCH_WINDOW, site.getWorkbenchWindow());
            parameters.put(ModelingOperationConstants.WORKBENCH_PART, site.getPart());
            parameters.put(IOperation.SUBJECT, element);
            new NavigateToTarget().exec(graph.getSession(), parameters);
            // Return true only if the flag is joined somewhere and navigation is possible.
            return FlagUtil.isJoined(graph, element);
        }

        if((stateMask & MouseDoubleClickedEvent.SHIFT_MASK) == 0)
            return false;

        if(runtimeDiagram == null || !graph.isInstanceOf(runtimeDiagram, DIA.RuntimeDiagram))
            return false;

        final Resource component = graph.getPossibleObject(element, mr.ElementToComponent);
        if (component == null)
            return false;

        Resource type = graph.getPossibleType(component, sr.Component);
        if (type == null)
            return false;
        if(graph.hasStatement(type, sr.ComponentType_Locked))
            return false;

        Resource definedBy = graph.getPossibleObject(type, sr.IsDefinedBy);
        if (definedBy == null)
            return false;

        final Resource diagram = graph.getPossibleObject(definedBy, mr.CompositeToDiagram);
        if (diagram == null)
            return false;

        Resource model = input.getModel(graph);
        RVI subprocessRVI = null;

        String rvis = (String) graph.getPossibleRelatedValue(runtimeDiagram, DIA.RuntimeDiagram_HasRVI);
        if (rvis != null) {
            RVI rvi = RVI.fromResourceFormat(graph, rvis);
            Variable base = Variables.getConfigurationContext(graph, model);
            Variable current = rvi.resolve(graph, base);
            Variable subprocess = current.browse(graph, component);
            subprocessRVI = subprocess.getRVI(graph);
        } else {
            // Not in a model configuration context.
            // Probably in a component type configuration.
            // Use the index root of the diagram to be opened as model[0]
            // and leave subprocessRVI[0] as null.
            model = graph.syncRequest(new PossibleIndexRoot(definedBy));
        }

        PlatformUI.getWorkbench().getDisplay().asyncExec(navigateToSubstructure(diagram, model, subprocessRVI));
        return true;
    }

    private Runnable navigateToSubstructure(final Resource diagram, final Resource model, final RVI subprocessRVI) {
        return new Runnable() {
            @Override
            public void run() {
                try {
                    WorkbenchUtils.openEditor(site.getId(), new ResourceEditorInput2(site.getId(), diagram, model, subprocessRVI));
                } catch (PartInitException e) {
                    Activator.getDefault().getLog().log(new Status(IStatus.ERROR, Activator.PLUGIN_ID, "Failed to open editor, see exception for details.", e));
                }
            }
        };
    }

}