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

import java.awt.geom.AffineTransform;
import java.awt.geom.NoninvertibleTransformException;
import java.awt.geom.Point2D;
import java.lang.reflect.InvocationTargetException;
import java.util.List;
import java.util.Optional;
import java.util.concurrent.TimeUnit;

import javax.inject.Named;

import org.eclipse.core.commands.ParameterizedCommand;
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.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.WriteGraph;
import org.simantics.db.common.request.ReadRequest;
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.ModelledCRS;
import org.simantics.district.network.ontology.DistrictNetworkResource;
import org.simantics.district.network.ui.DNEdgeBuilder;
import org.simantics.district.network.ui.DistrictDiagramEditor;
import org.simantics.district.network.ui.NetworkDrawingParticipant;
import org.simantics.g2d.canvas.ICanvasContext;
import org.simantics.g2d.participant.MouseUtil;
import org.simantics.g2d.participant.MouseUtil.MouseInfo;
import org.simantics.ui.workbench.e4.E4WorkbenchUtils;
import org.simantics.utils.threads.ThreadUtils;
import org.simantics.utils.ui.ISelectionUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class ChangeRoutePointToVertexHandler {

    private static final Logger LOGGER = LoggerFactory.getLogger(ChangeRoutePointToVertexHandler.class);
    static List<Resource> elements;
    static boolean cut = true;

    @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.Edge)) {
                            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_PART) MPart mActiveEditorPart, @Named(IServiceConstants.ACTIVE_SELECTION) Object selection, ParameterizedCommand command) {
        final List<Resource> elements = ISelectionUtils.getPossibleKeys(selection, SelectionHints.KEY_MAIN, Resource.class);
        
        Resource edge = elements.get(0);
        try {
            Point2D mouseClicked = mouseClickedOnEditor(mActiveEditorPart);
            if (mouseClicked != null) {
                
                IEditorPart activeEditorPart = E4WorkbenchUtils.getActiveIEditorPart(mActiveEditorPart);
                if (activeEditorPart == null)
                    return;
                if (!(activeEditorPart instanceof DistrictDiagramEditor))
                    return;
                DistrictDiagramEditor editor = (DistrictDiagramEditor) activeEditorPart;
                Resource diagram = editor.getInputResource();
                
                Simantics.getSession().asyncRequest(new ReadRequest() {
                    
                    @Override
                    public void run(ReadGraph graph) throws DatabaseException {
                        DistrictNetworkResource DN = DistrictNetworkResource.getInstance(graph);
                        double[] detailedGeom = graph.getPossibleRelatedValue(edge, DN.Edge_HasGeometry, Bindings.DOUBLE_ARRAY);
                        if (detailedGeom != null) {
                            double closestDistance = Double.MAX_VALUE;
                            Point2D closestPoint = null;
                            int j = 0;
                            for (int i = 0; i < detailedGeom.length; i += 2) {
                                double x = detailedGeom[i];
                                double y = detailedGeom[i + 1];
                                Point2D currentPoint = new Point2D.Double(x, y);
                                double currentDistance = mouseClicked.distance(currentPoint);
                                if (currentDistance < closestDistance) {
                                    closestDistance = currentDistance;
                                    closestPoint = currentPoint;
                                    j = i;
                                }
                            }
                            
                            final Point2D finalClosestPoint = closestPoint;
                            
                            DiagramResource DIA = DiagramResource.getInstance(graph);
                            Resource currentStartVertex = graph.getSingleObject(edge, DN.HasStartVertex);
                            double[] currentStartVertexCoords = graph.getRelatedValue(currentStartVertex, DIA.HasLocation, Bindings.DOUBLE_ARRAY);
                            Resource currentEndVertex = graph.getSingleObject(edge, DN.HasEndVertex);
                            double[] currentEndVertexCoords = graph.getRelatedValue(currentEndVertex, DIA.HasLocation, Bindings.DOUBLE_ARRAY);
                            
                            double[] detailedLeftEdgeGeometryCoords = new double[j];
                            for (int k = 0; k < j; k += 2) {
                                double x = detailedGeom[k];
                                double y = detailedGeom[k + 1];
                                detailedLeftEdgeGeometryCoords[k] = x;
                                detailedLeftEdgeGeometryCoords[k + 1] = y;
                            }
                            
                            double[] detailedRightEdgeGeometryCoords = new double[detailedGeom.length - j - 2];
                            int i = 0;
                            for (int k = j + 2; k < detailedGeom.length; k += 2) {
                                double x = detailedGeom[k];
                                double y = detailedGeom[k + 1];
                                detailedRightEdgeGeometryCoords[i++] = x;
                                detailedRightEdgeGeometryCoords[i++] = y;
                            }
                            
                            Simantics.getSession().asyncRequest(new WriteRequest() {
                                
                                @Override
                                public void perform(WriteGraph graph) throws DatabaseException {
                                    RemoverUtil.remove(graph, edge);
                                    
                                    ThreadUtils.getNonBlockingWorkExecutor().schedule(() -> {
                                        Simantics.getSession().asyncRequest(new WriteRequest() {
                                            
                                            @Override
                                            public void perform(WriteGraph graph) throws DatabaseException {
                                                // we might have closest point
                                                if (finalClosestPoint != null) {
                                                    Resource mapping = graph.getSingleObject(diagram, DistrictNetworkResource.getInstance(graph).VertexDefaultMapping);
                                                    double[] midVertexCoords = new double[] { finalClosestPoint.getX(), finalClosestPoint.getY() };
                                                    Resource createdVertex = DistrictNetworkUtil.createVertex(graph, diagram, midVertexCoords, 0, mapping);

                                                    Optional<Resource> leftEdge = DNEdgeBuilder.create(graph, diagram, currentStartVertexCoords, 0, midVertexCoords, 0, detailedLeftEdgeGeometryCoords, 0.001);
                                                    Optional<Resource> rightEdge = DNEdgeBuilder.create(graph, diagram, midVertexCoords, 0, currentEndVertexCoords, 0, detailedRightEdgeGeometryCoords, 0.001);
                                                    
                                                }
                                            }
                                        });
                                    }, 500, TimeUnit.MILLISECONDS);
                                    
                                }
                            });
                            
                        } else {
                            // no can do - or it would be possible to split the edge here in to two different edges
                        }
                    }
                });
            } else {
                LOGGER.warn("No mouseClicked for editor {}", mActiveEditorPart);
            }
        } catch (InvocationTargetException e) {
            LOGGER.error("Could not change route point to vertex", e);
        }
    }

    private static Point2D mouseClickedOnEditor(MPart mActiveEditorPart) throws InvocationTargetException {
        IEditorPart activeEditorPart = E4WorkbenchUtils.getActiveIEditorPart(mActiveEditorPart);
        if (activeEditorPart == null)
            return null;
        if (!(activeEditorPart instanceof DistrictDiagramEditor))
            return null;
        DistrictDiagramEditor editor = (DistrictDiagramEditor) activeEditorPart;
       
        ICanvasContext ctx = editor.getAdapter(ICanvasContext.class);
        NetworkDrawingParticipant drawingParticipant = ctx.getAtMostOneItemOfClass(NetworkDrawingParticipant.class);
        AffineTransform drawingTransform = drawingParticipant.getTransform();
        MouseUtil util = ctx.getAtMostOneItemOfClass(MouseUtil.class);
        MouseInfo mouseInfo = util.getMousePressedInfo(0);
        if (mouseInfo == null) {
            return null;
        }
        Point2D canvasPosition = mouseInfo.canvasPosition;
        Point2D transformed = null;
        try {
            transformed = drawingTransform.inverseTransform(canvasPosition, new Point2D.Double());
        } catch (NoninvertibleTransformException e) {
            LOGGER.error("Could not create inverse transform of {}", drawingTransform, e);
            throw new InvocationTargetException(e);
        }
        double x = ModelledCRS.xToLongitude(transformed.getX());
        double y = ModelledCRS.yToLatitude(-transformed.getY());
        return new Point2D.Double(x, y);
    }
}