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

import java.util.Collection;
import java.util.List;
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.Statement;
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.DistrictNetworkUtil;
import org.simantics.district.network.ontology.DistrictNetworkResource;
import org.simantics.layer0.Layer0;
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;
        }
    }
    
    private static Resource doCopy(WriteGraph graph, Resource diagram, Resource target, Resource source) throws DatabaseException {
		DiagramResource DIA = DiagramResource.getInstance(graph);
		DistrictNetworkResource DN = DistrictNetworkResource.getInstance(graph);
		double[] location = graph.getRelatedValue(target, DIA.HasLocation, Bindings.DOUBLE_ARRAY);
		double elevation = graph.getRelatedValue(target, DN.Vertex_HasElevation, Bindings.DOUBLE);
		Resource vertex = DistrictNetworkUtil.createVertex(graph, diagram, location, elevation);
		copySourceToTarget(graph, source, vertex);
		return vertex;
    }

    private static void copySourceToTarget(WriteGraph graph, Resource source, Resource target) throws DatabaseException {
    	Layer0 L0 = Layer0.getInstance(graph);
    	DistrictNetworkResource DN = DistrictNetworkResource.getInstance(graph);
    	graph.deny(target, DN.HasMapping);
    	
		Collection<Statement> statements = graph.getStatements(source, L0.HasProperty);
		Collection<Statement> assertedStatements = graph.getAssertedStatements(source, L0.HasProperty);
		statements.removeAll(assertedStatements);
		for (Statement stm : statements) {
			if (!graph.hasStatement(target, stm.getPredicate())) {
				graph.claim(target, stm.getPredicate(), stm.getObject());
			}
		}
    }

	private static void copyVertexInverses(WriteGraph graph, Resource sourceElement, Resource targetElement) throws DatabaseException {
		DistrictNetworkResource DN = DistrictNetworkResource.getInstance(graph);
		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);
		}
	}
    
    private static void deleteExistingTarget(WriteGraph graph, Resource target) throws DatabaseException {
    	RemoverUtil.remove(graph, target);
    }
    
    @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 && cut)
                        RemoverUtil.remove(graph, sourceMappedElement);
                    if (targetMappedElement != null)
                        RemoverUtil.remove(graph, targetMappedElement);
                }
            });
            ThreadUtils.getNonBlockingWorkExecutor().schedule(() -> {
                try {
					Simantics.getSession().syncRequest(new WriteRequest() {

						@Override
						public void perform(WriteGraph graph) throws DatabaseException {
							Layer0 L0 = Layer0.getInstance(graph);

							Resource diagram = graph.getSingleObject(sourceElement, L0.PartOf);
							Resource newTarget = doCopy(graph, diagram, targetElement, sourceElement);
							if (cut) {
								Resource newSource = doCopy(graph, diagram, sourceElement, targetElement);
								copyVertexInverses(graph, sourceElement, newSource);
								deleteExistingTarget(graph, sourceElement);
							}
							copyVertexInverses(graph, targetElement, newTarget);
							deleteExistingTarget(graph, targetElement);
						}
					});
				} catch (DatabaseException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
            }, 500, TimeUnit.MILLISECONDS);

//        	ThreadUtils.getNonBlockingWorkExecutor().schedule(() -> {
//                Simantics.getSession().asyncRequest(new WriteRequest() {
//                    
//                    @Override
//                    public void perform(WriteGraph graph) throws DatabaseException {
//                        DistrictNetworkResource DN = DistrictNetworkResource.getInstance(graph);
//                        //copyMapping(graph, DN, sourceElement, targetElement);
//                        copyLocation(graph, DN, sourceElement, targetElement, cut);
//                        copyVertexInverses(graph, DN, sourceElement, targetElement, cut);
//                        copyElevation(graph, DN, sourceElement, targetElement, cut);
//                    }
//                    
//                    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);
//                    }
//                    

//                    
//                    
//                });
//            }, 500, TimeUnit.MILLISECONDS);

        } catch (DatabaseException e) {
            e.printStackTrace();
        }
        
    }
}