package org.simantics.district.network.ui.contributions;

import java.util.List;

import javax.inject.Named;

import org.eclipse.e4.core.di.annotations.CanExecute;
import org.eclipse.e4.core.di.annotations.Execute;
import org.eclipse.e4.ui.di.AboutToShow;
import org.eclipse.e4.ui.model.application.MApplication;
import org.eclipse.e4.ui.model.application.ui.basic.MPart;
import org.eclipse.e4.ui.model.application.ui.menu.ItemType;
import org.eclipse.e4.ui.model.application.ui.menu.MHandledMenuItem;
import org.eclipse.e4.ui.model.application.ui.menu.MMenuElement;
import org.eclipse.e4.ui.model.application.ui.menu.MMenuFactory;
import org.eclipse.e4.ui.services.IServiceConstants;
import org.eclipse.ui.IEditorPart;
import org.simantics.Simantics;
import org.simantics.databoard.Bindings;
import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.common.request.UnaryRead;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.request.Write;
import org.simantics.district.network.DistrictNetworkUtil;
import org.simantics.district.network.ontology.DistrictNetworkResource;
import org.simantics.district.network.ui.DistrictDiagramEditor;
import org.simantics.district.network.ui.internal.Activator;
import org.simantics.ui.workbench.IResourceEditorInput;
import org.simantics.ui.workbench.e4.E4WorkbenchUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class ToggleTrackChanges {

    private static final Logger LOGGER = LoggerFactory.getLogger(ToggleTrackChanges.class);
    private static final String COMMAND_ID = "org.simantics.district.network.ui.command.toggletrackchanges";

    @AboutToShow
    public void aboutToShow(@Named(IServiceConstants.ACTIVE_PART) MPart mActiveEditorPart, MApplication app, List<MMenuElement> items) {
        Resource diagram = getDiagramFromEditorInput(mActiveEditorPart);
        if (diagram != null) {
            MHandledMenuItem menuItem = MMenuFactory.INSTANCE.createHandledMenuItem();
            menuItem.setType(ItemType.CHECK);
            menuItem.setLabel("Track Changes");
            menuItem.setContributorURI(Activator.PLUGIN_ID);
            menuItem.setCommand(app.getCommand(COMMAND_ID));
            menuItem.setSelected(isTrackChangesEnabled(diagram));
            items.add(menuItem);
        }
    }
    
    @CanExecute
    public boolean canExecute(@Named(IServiceConstants.ACTIVE_PART) MPart mActiveEditorPart) {
        IEditorPart activeEditorPart = E4WorkbenchUtils.getActiveIEditorPart(mActiveEditorPart);
        if (activeEditorPart == null)
            return false;
        if (!(activeEditorPart instanceof DistrictDiagramEditor))
            return false;
        return true;
    }

    @Execute
    public void toggleTrackChanges(@Named(IServiceConstants.ACTIVE_PART) MPart mActiveEditorPart) {
        Resource diagram = getDiagramFromEditorInput(mActiveEditorPart);
        if (diagram != null) {
            Simantics.getSession()
                    .asyncRequest((Write) graph -> graph.claimLiteral(diagram,
                            DistrictNetworkResource.getInstance(graph).Diagram_trackChangesEnabled,
                            !DistrictNetworkUtil.trackChangesEnabled(graph, diagram), Bindings.BOOLEAN));
        }
    }

    private static boolean isTrackChangesEnabled(Resource diagram) {
        try {
            return Simantics.getSession().syncRequest(new TrackChangesEnabledRequest(diagram));
        } catch (DatabaseException e) {
            LOGGER.error("Could not check if track changes is enabled for diagram {}", diagram, e);
            return false;
        }
    }

    private static Resource getDiagramFromEditorInput(MPart mActiveEditorPart) {
        IEditorPart activeEditorPart = E4WorkbenchUtils.getActiveIEditorPart(mActiveEditorPart);
        if (activeEditorPart == null)
            return null;
        if (!(activeEditorPart instanceof DistrictDiagramEditor))
            return null;
        IResourceEditorInput input = (IResourceEditorInput) activeEditorPart.getEditorInput();
        return input.getResource();
    }

    private static class TrackChangesEnabledRequest extends UnaryRead<Resource, Boolean> {

        public TrackChangesEnabledRequest(Resource diagram) {
            super(diagram);
        }

        @Override
        public Boolean perform(ReadGraph graph) throws DatabaseException {
            return DistrictNetworkUtil.trackChangesEnabled(graph, parameter);
        }
    }
}