/*******************************************************************************
 * 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.modeling.ui.diagramEditor;

import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;

import org.eclipse.ui.PlatformUI;
import org.simantics.Simantics;
import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.common.request.PossibleIndexRoot;
import org.simantics.db.common.request.PossibleTypedParent;
import org.simantics.db.common.request.ReadRequest;
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.diagram.stubs.DiagramResource;
import org.simantics.g2d.canvas.ICanvasContext;
import org.simantics.g2d.diagram.DiagramHints;
import org.simantics.layer0.Layer0;
import org.simantics.modeling.ComponentUtils;
import org.simantics.modeling.ModelingResources;
import org.simantics.modeling.actions.NavigateToTarget;
import org.simantics.modeling.ui.Activator;
import org.simantics.structural.stubs.StructuralResource2;
import org.simantics.ui.workbench.editor.AbstractResourceEditorAdapter;
import org.simantics.utils.datastructures.Pair;
import org.simantics.utils.threads.ThreadUtils;

/**
 * @author Tuukka Lehtonen
 */
public class OpenDiagramFromConfigurationAdapter extends AbstractResourceEditorAdapter {

    private static final String EDITOR_ID = "org.simantics.modeling.ui.diagramEditor"; //$NON-NLS-1$

    public OpenDiagramFromConfigurationAdapter() {
        super(Messages.OpenDiagramFromConfigurationAdapter_DiagramEditor, Activator.COMPOSITE_ICON);
    }

    protected String getEditorId(ReadGraph g, Resource composite) throws DatabaseException {
        ModelingResources MOD = ModelingResources.getInstance(g);
        String preferredEditorId = g.getPossibleRelatedValue(composite, MOD.PreferredDiagramEditorID);
        if(preferredEditorId != null)
            return preferredEditorId;
        else
            return EDITOR_ID;
    }

    @Override
    public boolean canHandle(ReadGraph g, Resource r) throws DatabaseException {
    	Resource diagram = getDiagram(g, r, Collections.emptySet());
    	if(diagram == null)
    	    return false;
    	
    	// Check if the diagram is locked, because of the locked component type
    	return !isLocked(g, diagram);
    	
//        return ComponentUtils.compositeHasDiagram(g, r) /*|| ComponentUtils.componentHasDiagram(g, r)*/;
    }
    
    public static boolean isLocked(ReadGraph g, Resource diagram) throws DatabaseException {
        StructuralResource2 STR = StructuralResource2.getInstance(g);
        Resource componentType = g.syncRequest(new PossibleTypedParent(diagram, STR.ComponentType));
        if(componentType == null)
            return false; // Not part of a component type
        
        return g.hasStatement(componentType, STR.ComponentType_Locked);
    }

    @Override
    public void openEditor(final Resource r) throws Exception {
        Simantics.getSession().asyncRequest(new ReadRequest() {
            @Override
            public void run(ReadGraph g) throws DatabaseException {
                openEditor(g, r, getEditorId(g, r));
            }
        });
    }

    /**
     * @param g
     * @param configurationComposite
     * @param editorId
     * @throws DatabaseException
     */
    public static boolean openEditor(ReadGraph g, Resource configurationComposite, final String editorId) throws DatabaseException {
        return openEditor(g, configurationComposite, editorId, Collections.emptySet());
    }

    protected static Resource getDiagram(ReadGraph graph, Resource r, final Collection<Object> selectedObjects) throws DatabaseException {

    	Layer0 L0 = Layer0.getInstance(graph);
    	DiagramResource DIA = DiagramResource.getInstance(graph);
    	
    	if(graph.isInstanceOf(r, DIA.Diagram)) return r;
    	
        Resource diagram = ComponentUtils.getPossibleCompositeDiagram(graph, r);
        if(diagram != null) return diagram;
        
        // TODO: what if the selected objects are from different diagrams?
        if (selectedObjects.size() > 0) {
            Set<Resource> diagrams = new HashSet<>();
            for (Object o : selectedObjects) {
                if (o instanceof Resource) {
                    Resource res = (Resource)o;
                    if (graph.isInstanceOf(res, DIA.Element)) {
                        diagrams.add(graph.getPossibleObject(res, L0.PartOf));
                    }
                }
            }
            if (diagrams.size() == 1) {
                return diagrams.iterator().next();
            }
        }
        return null;

    }

    public static Pair<Resource, RVI> getModelAndRVI(ReadGraph graph, Resource configurationComposite) throws DatabaseException {
        Variable compositeVariable = Variables.getPossibleVariable(graph, configurationComposite);
        if (compositeVariable == null)
            return null;

        Layer0 L0 = Layer0.getInstance(graph);
        StructuralResource2 STR = StructuralResource2.getInstance(graph);
        boolean isComponentType = graph.hasStatement(configurationComposite, STR.Defines);
        Resource rviContext = graph.syncRequest(new PossibleTypedParent(configurationComposite, L0.RVIContext));

        if (isComponentType || rviContext == null) {
            Resource indexRoot = graph.sync(new PossibleIndexRoot(configurationComposite));
            if (indexRoot == null)
                return null;

            return Pair.make(indexRoot, null);
        }

        final Resource model = Variables.getPossibleModel(graph, compositeVariable);
        if (model == null)
            return null;
        final RVI rvi = compositeVariable.getPossibleRVI(graph);

        return Pair.make(model, rvi);
    }

    /**
     * @param g
     * @param configurationComposite
     * @param editorId
     * @param selectedObjects
     * @throws DatabaseException
     */
    public static boolean openEditor(ReadGraph g, Resource r, String editorId, Collection<Object> selectedObjects) throws DatabaseException {
        Resource diagram = getDiagram(g, r, selectedObjects);
        Resource configurationComposite = diagram != null ? ComponentUtils.getPossibleDiagramComposite(g, diagram) : null;
        Pair<Resource, RVI> modelAndRVI = configurationComposite != null ? getModelAndRVI(g, configurationComposite) : null;
        //System.out.println("modelAndRVI: " + modelAndRVI);
        if (modelAndRVI == null)
            return false;
        scheduleOpenEditor(editorId, diagram, modelAndRVI.first, modelAndRVI.second, selectedObjects);
        return true;
    }

    /**
     * @param g
     * @param configurationComposite
     * @param editorId
     * @param selectedObjects
     * @throws DatabaseException
     */
    public static boolean openEditor(ReadGraph g, Resource r, String editorId, Collection<Object> selectedObjects, Resource model, RVI rvi) throws DatabaseException {
        Resource diagram = getDiagram(g, r, selectedObjects);
        if (diagram == null)
            return false;
        scheduleOpenEditor(editorId, diagram, model, rvi, selectedObjects);
        return true;
    }

    /**
     * @param g
     * @param configurationComposite
     * @param editorId
     * @param selectedObjects
     * @throws DatabaseException
     */
    private static void scheduleOpenEditor(String editorId, Resource diagram, Resource model, RVI rvi, Collection<Object> selectedObjects) throws DatabaseException {
        Runnable editorActivator = NavigateToTarget.editorActivator(editorId, diagram, model, rvi, part -> {
            if (selectedObjects.isEmpty())
                return;
            ICanvasContext openedCanvas = (ICanvasContext) part.getAdapter(ICanvasContext.class);
            assert openedCanvas != null;
            // CanvasContext-wide denial of initial zoom-to-fit on diagram open.
            openedCanvas.getDefaultHintContext().setHint(DiagramHints.KEY_INITIAL_ZOOM_TO_FIT, Boolean.FALSE);
            ThreadUtils.asyncExec(openedCanvas.getThreadAccess(),
                    NavigateToTarget.elementSelectorZoomer(openedCanvas, selectedObjects, false));
        });
        PlatformUI.getWorkbench().getDisplay().asyncExec(editorActivator);
    }

}