package org.simantics.district.region.ui.handlers;

import java.awt.Shape;
import java.util.HashSet;
import java.util.List;
import java.util.Objects;
import java.util.Set;
import java.util.stream.Collectors;

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.model.application.ui.basic.MPart;
import org.eclipse.e4.ui.services.IServiceConstants;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.IEditorPart;
import org.eclipse.ui.IWorkbenchPart;
import org.simantics.Simantics;
import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.common.request.ReadRequest;
import org.simantics.db.common.request.UniqueRead;
import org.simantics.db.exception.DatabaseException;
import org.simantics.district.region.DiagramRegions;
import org.simantics.district.region.DiagramRegions.DiagramRegion;
import org.simantics.g2d.canvas.ICanvasContext;
import org.simantics.g2d.diagram.IDiagram;
import org.simantics.g2d.diagram.handler.PickRequest;
import org.simantics.g2d.diagram.handler.impl.PickContextImpl;
import org.simantics.g2d.element.ElementHints;
import org.simantics.g2d.element.IElement;
import org.simantics.modeling.actions.NavigateToTarget;
import org.simantics.ui.workbench.action.DefaultActions;
import org.simantics.utils.threads.ThreadUtils;
import org.simantics.utils.ui.ISelectionUtils;
import org.simantics.utils.ui.workbench.WorkbenchUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class ZoomToRegionHandler {

    private static final Logger LOGGER = LoggerFactory.getLogger(ZoomToRegionHandler.class);
    public static final String COMMAND_ID = "org.simantics.district.region.ui.commands.zoomToRegion";
    public static final String LABEL = "Zoom To Region";
    
    @CanExecute
    public boolean canExecute() {
        return true;
    }
    
    @Execute
    public void execute(@Named(IServiceConstants.ACTIVE_SHELL) Shell activeShell,
            @Named(IServiceConstants.ACTIVE_PART) MPart part,
            @Named(IServiceConstants.ACTIVE_SELECTION) ISelection selection) {
        DiagramRegion region = ISelectionUtils.filterSingleSelection(selection, DiagramRegion.class);
        zoomTo((Control) part.getWidget(), activeShell.getDisplay(), region.getResource());
    }

    public static void zoomTo(Control control, Display display, Resource region) {
        Resource dia;
        try {
            dia = Simantics.getSession().syncRequest(new UniqueRead<Resource>() {
                
                @Override
                public Resource perform(ReadGraph graph) throws DatabaseException {
                    return DiagramRegions.getDiagramForRegion(graph, region);
                }
            });
            
            // get currently active workbench part
            IWorkbenchPart beforePerformingDefaultAction = WorkbenchUtils.getActiveWorkbenchPart();
            IEditorPart activeEditor = WorkbenchUtils.getActiveEditor();
            LOGGER.info("activeWorkbenchPart {}", beforePerformingDefaultAction);
            LOGGER.info("activeEditor {}", activeEditor);
            DefaultActions.performDefaultAction(control, dia);
            Simantics.getSession().asyncRequest(new ReadRequest() {
                
                @Override
                public void run(ReadGraph graph) throws DatabaseException {
                    Shape shp = DiagramRegions.coordinatesToShape(graph, region);
                    display.asyncExec(() -> {
                        IWorkbenchPart afterPerformingDefaultAction = WorkbenchUtils.getActiveWorkbenchPart();
                        LOGGER.info("afterActiveWorkbenchPart {}", afterPerformingDefaultAction);
                        int tries = 0;
                        while (Objects.equals(beforePerformingDefaultAction, afterPerformingDefaultAction) && tries <= 10) {
                            try {
                                Thread.sleep(150);
                            } catch (InterruptedException e) {
                                LOGGER.error("Could not sleep", e);
                            }
                            afterPerformingDefaultAction = WorkbenchUtils.getActiveEditor();
                            LOGGER.info("afterActiveWorkbenchPart {}", afterPerformingDefaultAction);
                            tries++;
                        }
                        LOGGER.info("afterActiveWorkbenchPart {}", afterPerformingDefaultAction);
                        if (beforePerformingDefaultAction.equals(afterPerformingDefaultAction)) {
                            LOGGER.warn("No can do");
                        } else if (afterPerformingDefaultAction != null) {
                            // Okay, get the IDiagram now
                            IDiagram diagram = afterPerformingDefaultAction.getAdapter(IDiagram.class);
                            if (diagram == null)
                                LOGGER.warn("No can do - no IDiagram available");
                            else {
                                Set<IElement> elems = new HashSet<>();
                                PickContextImpl.INSTANCE.pick(diagram, new PickRequest(shp), elems);
                                ICanvasContext context = afterPerformingDefaultAction.getAdapter(ICanvasContext.class);
                                List<Object> collect = elems.stream().map(el -> el.getHint(ElementHints.KEY_OBJECT)).collect(Collectors.toList());
                                ThreadUtils.asyncExec(context.getThreadAccess(), NavigateToTarget.elementSelectorZoomer(context, collect, false));
                            }
                        } else {
                            LOGGER.info("afterPerforming is null");
                        }
                    });
                }
            });
        } catch (DatabaseException e) {
            LOGGER.error("Could not zoom to region", e);
        }
    }
}