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

import java.util.Collection;
import java.util.List;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.TimeUnit;

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.services.IServiceConstants;
import org.eclipse.jface.viewers.ISelection;
import org.simantics.Simantics;
import org.simantics.databoard.Bindings;
import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.WriteGraph;
import org.simantics.db.common.request.WriteRequest;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.layer0.SelectionHints;
import org.simantics.db.layer0.util.RemoverUtil;
import org.simantics.db.request.Read;
import org.simantics.diagram.stubs.DiagramResource;
import org.simantics.district.network.ontology.DistrictNetworkResource;
import org.simantics.utils.threads.ThreadUtils;
import org.simantics.utils.ui.ISelectionUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class PasteDistrictVertexHandler {

    private static final Logger LOGGER = LoggerFactory.getLogger(PasteDistrictVertexHandler.class);

    @CanExecute
    public boolean canExecute(@Named(IServiceConstants.ACTIVE_SELECTION) ISelection selection) {
        List<Resource> elements = ISelectionUtils.getPossibleKeys(selection, SelectionHints.KEY_MAIN, Resource.class);
        if (elements.size() < 1)
            return false;
        try {
            return Simantics.getSession().syncRequest(new Read<Boolean>() {

                @Override
                public Boolean perform(ReadGraph graph) throws DatabaseException {
                    DistrictNetworkResource DN = DistrictNetworkResource.getInstance(graph);
                    for (Resource selection : elements) {
                        if (!graph.isInstanceOf(selection, DN.Element)) {
                            return false;
                        }
                    }
                    return true;
                }
            });
        } catch (DatabaseException e) {
            LOGGER.error("Could not evaluate if mapping can be changed for selection {}", elements, e);
            return false;
        }
    }

    @Execute
    public void execute(@Named(IServiceConstants.ACTIVE_SELECTION) Object selection) {
        final List<Resource> elements = ISelectionUtils.getPossibleKeys(selection, SelectionHints.KEY_MAIN, Resource.class);
        final List<Resource> copiedElements = CopyDistrictVertexHandler.elements; // TODO: this could be implemented more nicely with clipboard ?
        boolean cut = CopyDistrictVertexHandler.cut;
        
        Resource targetElement = elements.get(0);
        Resource sourceElement = copiedElements.get(0);
        
        try {
            Simantics.getSession().syncRequest(new WriteRequest() {
                
                @Override
                public void perform(WriteGraph graph) throws DatabaseException {
                    DistrictNetworkResource DN = DistrictNetworkResource.getInstance(graph);
                    
                    Resource sourceMappedElement = graph.getPossibleObject(sourceElement, DN.MappedComponent);
                    Resource targetMappedElement = graph.getPossibleObject(targetElement, DN.MappedComponent);
                    if (sourceMappedElement != null)
                        RemoverUtil.remove(graph, sourceMappedElement);
                    if (targetMappedElement != null)
                        RemoverUtil.remove(graph, targetMappedElement);
                    ThreadUtils.getNonBlockingWorkExecutor().schedule(() -> {
                        Simantics.getSession().asyncRequest(new WriteRequest() {
                            
                            @Override
                            public void perform(WriteGraph graph) throws DatabaseException {
                                //copyMapping(graph, DN, sourceElement, targetElement);
                                copyLocation(graph, DN, sourceElement, targetElement, cut);
                                copyVertexInverses(graph, DN, sourceElement, targetElement, cut);
                                copyElevation(graph, DN, sourceElement, targetElement, cut);
                            }
                        });                        
                    }, 200, TimeUnit.MILLISECONDS);
                }
                
                private void copyMapping(WriteGraph graph, DistrictNetworkResource DN, Resource sourceElement, Resource targetElement) throws DatabaseException {
                    Resource sourceMapping = graph.getSingleObject(sourceElement, DN.Mapping);
                    Resource targetMapping = graph.getSingleObject(targetElement, DN.Mapping);
                    if (cut) {
                        graph.deny(sourceElement, DN.Mapping);
                        graph.claim(sourceElement, DN.Mapping, targetMapping);
                    }
                    graph.deny(targetElement, DN.Mapping);
                    graph.claim(targetElement, DN.Mapping, sourceMapping);
                }

                private void copyElevation(WriteGraph graph, DistrictNetworkResource DN, Resource sourceElement, Resource targetElement, boolean cut) throws DatabaseException {
                    double sourceElevation = graph.getRelatedValue(sourceElement, DN.Vertex_HasElevation, Bindings.DOUBLE);
                    double targetElevation = graph.getRelatedValue(targetElement, DN.Vertex_HasElevation, Bindings.DOUBLE);
                    if (cut) {
                        graph.deny(sourceElement, DN.Vertex_HasElevation);
                        graph.claimLiteral(sourceElement, DN.Vertex_HasElevation, targetElevation, Bindings.DOUBLE);
                    }
                    graph.deny(targetElement, DN.Vertex_HasElevation);
                    graph.claimLiteral(targetElement, DN.Vertex_HasElevation, sourceElevation, Bindings.DOUBLE);
                }

                private void copyLocation(WriteGraph graph, DistrictNetworkResource DN, Resource sourceElement, Resource targetElement, boolean cut) throws DatabaseException {
                    DiagramResource DIA = DiagramResource.getInstance(graph);
                    double[] sourceLocation = graph.getRelatedValue(sourceElement, DIA.HasLocation, Bindings.DOUBLE_ARRAY);
                    double[] targetLocation = graph.getRelatedValue(targetElement, DIA.HasLocation, Bindings.DOUBLE_ARRAY);
                    if (cut) {
                        graph.deny(sourceElement, DIA.HasLocation);
                        graph.claimLiteral(sourceElement, DIA.HasLocation, targetLocation, Bindings.DOUBLE_ARRAY);
                    }
                    graph.deny(targetElement, DIA.HasLocation);
                    graph.claimLiteral(targetElement, DIA.HasLocation, sourceLocation, Bindings.DOUBLE_ARRAY);
                }
                
                private void copyVertexInverses(WriteGraph graph, DistrictNetworkResource DN, Resource sourceElement, Resource targetElement, boolean cut) throws DatabaseException {
                    Collection<Resource> sourceStartVertex_inverse = graph.getObjects(sourceElement, DN.HasStartVertex_Inverse);
                    Collection<Resource> sourceEndVertex_inverse = graph.getObjects(sourceElement, DN.HasEndVertex_Inverse);
                    Collection<Resource> targetStartVertex_inverse = graph.getObjects(targetElement, DN.HasStartVertex_Inverse);
                    Collection<Resource> targetEndVertex_inverse = graph.getObjects(targetElement, DN.HasEndVertex_Inverse);
                    graph.deny(sourceElement, DN.HasStartVertex_Inverse);
                    graph.deny(sourceElement, DN.HasEndVertex_Inverse);
                    graph.deny(targetElement, DN.HasStartVertex_Inverse);
                    graph.deny(targetElement, DN.HasEndVertex_Inverse);
                    for (Resource startVertexInverse : sourceStartVertex_inverse) {
                        graph.claim(targetElement, DN.HasStartVertex_Inverse, startVertexInverse);
                    }
                    for (Resource targetVertexInverse : targetStartVertex_inverse) {
                        graph.claim(sourceElement, DN.HasStartVertex_Inverse, targetVertexInverse);
                    }
                    for (Resource endVertexInverse : sourceEndVertex_inverse) {
                        graph.claim(targetElement, DN.HasEndVertex_Inverse, endVertexInverse);
                    }
                    for (Resource targetVertexInverse : targetEndVertex_inverse) {
                        graph.claim(sourceElement, DN.HasEndVertex_Inverse, targetVertexInverse);
                    }
                }
            });
        } catch (DatabaseException e) {
            e.printStackTrace();
        }
        
    }
}