package org.simantics.district.network.ui;

import java.awt.geom.Rectangle2D;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Optional;

import org.simantics.databoard.Bindings;
import org.simantics.db.Resource;
import org.simantics.db.WriteGraph;
import org.simantics.db.common.request.ObjectsWithType;
import org.simantics.db.exception.BindingException;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.exception.ManyObjectsForFunctionalRelationException;
import org.simantics.db.exception.ServiceException;
import org.simantics.db.layer0.util.Layer0Utils;
import org.simantics.diagram.stubs.DiagramResource;
import org.simantics.diagram.synchronization.IModifiableSynchronizationContext;
import org.simantics.diagram.synchronization.SynchronizationHints;
import org.simantics.diagram.synchronization.graph.GraphSynchronizationHints;
import org.simantics.diagram.synchronization.graph.layer.GraphLayerManager;
import org.simantics.district.network.DistrictNetworkUtil;
import org.simantics.district.network.ontology.DistrictNetworkResource;
import org.simantics.g2d.diagram.IDiagram;
import org.simantics.layer0.Layer0;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.vividsolutions.jts.geom.Envelope;
import com.vividsolutions.jts.index.quadtree.Quadtree;

public class DNEdgeBuilder {

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

    private Resource diagramResource;
    private IDiagram diagram;
    private GraphLayerManager glm;

    public DNEdgeBuilder(Resource diagramResource, IDiagram diagram) {
        this.diagramResource = diagramResource;
        this.diagram = diagram;
        
        IModifiableSynchronizationContext context = diagram.getHint(SynchronizationHints.CONTEXT);
        glm = context.get(GraphSynchronizationHints.GRAPH_LAYER_MANAGER);
    }

    public static Optional<Resource> create(WriteGraph graph, Resource diagramResource, double[] start, double startElevation, double[] end, double endElevation, double padding) throws DatabaseException {
        Collection<Resource> vertices = graph.syncRequest(new ObjectsWithType(diagramResource, Layer0.getInstance(graph).ConsistsOf, DistrictNetworkResource.getInstance(graph).Vertex));
        double halfPadding = padding / 2;

        Quadtree vv = new Quadtree();
        for (Resource vertex : vertices) {
            double[] coords = graph.getRelatedValue2(vertex, DiagramResource.getInstance(graph).HasLocation, Bindings.DOUBLE_ARRAY);
            double x1 = coords[0] - halfPadding;
            double y1= coords[1] - halfPadding;
            double x2 = coords[0] + halfPadding;
            double y2= coords[1] + halfPadding;
            Envelope e = new Envelope(x1, x2, y1, y2);
            vv.insert(e, new ResourceVertex(vertex, coords, false));
        }
        return create(graph, vv, diagramResource, null, start, startElevation, end, endElevation, padding, false);
    }
    
    public static Optional<Resource> create(WriteGraph graph, Quadtree vertices, Resource diagramResource, Resource mapping, double[] start, double startElevation, double[] end, double endElevation, double padding, boolean writeElevationToEdgeFromPoints) throws DatabaseException {
        
        DistrictNetworkResource DN = DistrictNetworkResource.getInstance(graph);

     // 2. Add vertices
        Resource startVertex = getOrCreateVertex(graph, diagramResource, vertices, start, startElevation, padding);
        Resource endVertex = getOrCreateVertex(graph, diagramResource, vertices, end, endElevation, padding);
        if (startVertex.equals(endVertex)) {
            LOGGER.info("Circular edges are not supported, startVertex: {}, endVertex: {}", startVertex, endVertex);
            return Optional.empty();
        }
        
        // 1. Get diagram edge to construct
        Resource edge = getOrCreateEdge(graph, diagramResource, mapping);
        
        if (writeElevationToEdgeFromPoints) {
            graph.claimLiteral(edge, DN.Edge_HasElevation, calculateElevationFromVertices(graph, startVertex, endVertex), Bindings.DOUBLE);
        }
        
        graph.claim(edge, DN.HasStartVertex, startVertex);
        graph.claim(edge, DN.HasEndVertex, endVertex);
        
        // We need to put GraphLayer to newLayers so...
//        for (Resource layer : graph.getObjects(diagramResource, DiagramResource.getInstance(graph).HasLayer)) {
//            IGraphLayerUtil layerUtil = graph.adapt(graph.getSingleObject(layer, Layer0.getInstance(graph).InstanceOf), IGraphLayerUtil.class);
//            
//            GraphLayer gl = layerUtil.loadLayer(graph, layer);
//            gl.forEachTag(tag -> {
//                DiagramGraphUtil.tag(graph, startVertex, tag, true);
//                DiagramGraphUtil.tag(graph, endVertex, tag, true);
//            });
//        }
//        
        return Optional.of(edge);
    }
    private static double calculateElevationFromVertices(WriteGraph graph, Resource startVertex, Resource endVertex) throws ManyObjectsForFunctionalRelationException, BindingException, ServiceException {
        DistrictNetworkResource DN = DistrictNetworkResource.getInstance(graph);
        Double startElevation = graph.getPossibleRelatedValue(startVertex, DN.Vertex_HasElevation, Bindings.DOUBLE);
        Double endElevation = graph.getPossibleRelatedValue(endVertex, DN.Vertex_HasElevation, Bindings.DOUBLE);
        if (startElevation != null && endElevation != null) {
            return (startElevation + endElevation) / 2;
        }
        return 0;
    }

    public void create(WriteGraph graph,  double[] start, double startElevation, double[] end, double endElevation, double padding) throws DatabaseException {
        
        Optional<Resource> edge = create(graph, diagramResource, start, startElevation, end, endElevation, padding);
        // 7. Put the element on all the currently active layers if possible.
        if (glm != null) {
            putOnActiveLayer(graph, edge.get());
        }
        
        Layer0Utils.addCommentMetadata(graph, "Added edge " + edge.get());
        graph.markUndoPoint();
    }
    
    private void putOnActiveLayer(WriteGraph graph, Resource res) throws DatabaseException {
        glm.removeFromAllLayers(graph, res);
        glm.putElementOnVisibleLayers(diagram, graph, res);
    }

    private static Resource getOrCreateVertex(WriteGraph graph, Resource diagramResource, Quadtree qtree, double[] coords, double elevation, double padding) throws DatabaseException {
        Resource vertex = null;
        double halfPadding = padding / 2;
        double maxDistance = Double.MAX_VALUE;
        double x1 = coords[0] - halfPadding;
        double y1= coords[1] - halfPadding;
        double x2 = coords[0] + halfPadding;
        double y2= coords[1] + halfPadding;
        Envelope e = new Envelope(x1, x2, y1, y2);
        
        List result = qtree.query(e);
        List<ResourceVertex> vertices = (List<ResourceVertex>) result;
        for (ResourceVertex vertx : vertices) {
            Rectangle2D existing = new Rectangle2D.Double(vertx.coords[0] - halfPadding, vertx.coords[1] - halfPadding, padding, padding);
            Rectangle2D tobecreated = new Rectangle2D.Double(x1, y1, padding, padding);
            if (existing.intersects(tobecreated)) {
                double dist = Math.sqrt((Math.pow(coords[0] - vertx.coords[0], 2) + (Math.pow(coords[1] - vertx.coords[1], 2))));
                if (dist <= maxDistance) {
                    vertex = vertx.vertex;
                    maxDistance = dist;
                }
            }
        }
        if (vertex == null) {
            vertex = DistrictNetworkUtil.createVertex(graph, diagramResource, coords, elevation); 
            qtree.insert(e, new ResourceVertex(vertex, coords, false));
        }
        return vertex;
    }

    private static Resource getOrCreateEdge(WriteGraph graph, Resource diagramResource, Resource mapping) throws DatabaseException {
        return DistrictNetworkUtil.createEdge(graph, diagramResource, mapping);
    }

    public static class ResourceVertex {
        
        final boolean isConsumer;
        final Resource vertex;
        final double[] coords;
        
        public ResourceVertex(Resource vertex, double[] coords, boolean isConsumer) {
            this.vertex = vertex;
            this.coords = coords;
            this.isConsumer = isConsumer;
        }
    }
}