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

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.geom.Line2D;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import org.simantics.Simantics;
import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.common.procedure.adapter.TransientCacheListener;
import org.simantics.db.common.request.ResourceRead;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.layer0.util.Layer0Utils;
import org.simantics.diagram.profile.StyleBase;
import org.simantics.diagram.stubs.DiagramResource;
import org.simantics.district.network.DistrictNetworkUtil;
import org.simantics.district.network.ontology.DistrictNetworkResource;
import org.simantics.district.network.ui.nodes.DistrictNetworkNodeUtils;
import org.simantics.layer0.Layer0;
import org.simantics.modeling.ModelingResources;
import org.simantics.scenegraph.INode;
import org.simantics.scenegraph.g2d.G2DNode;
import org.simantics.scenegraph.profile.EvaluationContext;
import org.simantics.scenegraph.profile.common.ProfileVariables;
import org.simantics.scenegraph.utils.GeometryUtils;
import org.simantics.scl.compiler.top.ValueNotFound;
import org.simantics.scl.osgi.SCLOsgi;
import org.simantics.scl.runtime.SCLContext;
import org.simantics.scl.runtime.function.Function1;
import org.simantics.structural.stubs.StructuralResource2;

public class ConnectionLineStyle extends StyleBase<List<Point2D>> {
	
	public static class ConnectionLineNode extends G2DNode {
		private static final BasicStroke STROKE = new BasicStroke(1.f, BasicStroke.CAP_BUTT, BasicStroke.JOIN_MITER, 1.f, new float[] {4.f, 2.f}, 0.f);
		private static final Color[] colors = { Color.RED, Color.GREEN, Color.BLUE, Color.ORANGE, Color.CYAN, Color.PINK };
		
		private float strokeWidth;
		private Line2D[] lines;

		public ConnectionLineNode() {
			super();
		}
		
		private static final long serialVersionUID = 1L;

		@Override
		public Rectangle2D getBoundsInLocal() {
			return null;
		}

		@Override
		public Rectangle2D getBoundsInLocal(boolean b) {
			return null;
		}

		@Override
		public Rectangle2D getBounds() {
			return null;
		}
		
		public void setStrokeWidth(float w) {
			strokeWidth = w;
		}
		
		public void setPoints(List<Point2D> result) {
			Point2D p0 = DistrictNetworkNodeUtils.calculatePoint2D(result.get(0), null);
			lines = new Line2D[result.size() - 1];
			for (int i = 1; i < result.size(); i++) 
			{
				Point2D p = result.get(i);
				lines[i-1] = p != null ? new Line2D.Double(p0, DistrictNetworkNodeUtils.calculatePoint2D(p, null)) : null;
			}
		}
		
		@Override
		public void render(Graphics2D g2d) {
			if (lines == null || lines.length == 0)
				return;
			
			// Keep fixed line width on screen
			float scaleRecip = (float) GeometryUtils.getScale(g2d.getTransform());
			g2d.setStroke(GeometryUtils.scaleStroke(STROKE, strokeWidth / scaleRecip));
			
			for (int i = 0; i < lines.length; i++) {
				if (lines[i] != null) {
					g2d.setColor(colors[i % colors.length]);
					g2d.draw(lines[i]);
				}
			}
		}
	}
	
	@Override
	public List<Point2D> calculateStyle(ReadGraph graph, Resource runtimeDiagram, Resource entry, Resource groupItem)
			throws DatabaseException {
		DistrictNetworkResource DN = DistrictNetworkResource.getInstance(graph);
		ModelingResources MOD = ModelingResources.getInstance(graph);
		StructuralResource2 STR = StructuralResource2.getInstance(graph);
		
		Resource vertex = groupItem;
		if (!graph.isInstanceOf(vertex, DN.Vertex))
			return Collections.emptyList();
		
		double[] coords = graph.getRelatedValue(vertex, DiagramResource.getInstance(graph).HasLocation);
		
		Resource component = DistrictNetworkUtil.getMappedComponentCached(graph, vertex);
		if (component == null)
			return Collections.emptyList();
		
		Resource componentType = graph.getPossibleType(component, STR.Component);
		if (componentType == null)
			return Collections.emptyList();
		
		Function1<Resource, List<Resource>> fun = getConnectedComponentsFunctionCached(graph, componentType);
		if (fun == null)
			return Collections.emptyList();

		List<Resource> components = Simantics.applySCLRead(graph, fun, component);
		
		if (components == null || components.isEmpty())
			return Collections.emptyList();
		
		List<Point2D> result = new ArrayList<>(components.size() + 1);
		result.add(new Point2D.Double(coords[0], coords[1]));
		for (Resource comp : components) {
			Resource e = comp != null ? graph.getPossibleObject(comp, MOD.ComponentToElement) : null;
			Resource mappingElement = e != null ? graph.getPossibleObject(e, DN.MappedFromElement) : null;
			if (mappingElement != null) {
				double[] coords2 = graph.getRelatedValue(mappingElement, DiagramResource.getInstance(graph).HasLocation);
				result.add(new Point2D.Double(coords2[0], coords2[1]));
			}
			else {
				result.add(null);
			}
		}
		
		return result;
	}
	
	@Override
	public void applyStyleForNode(EvaluationContext observer, INode parent, List<Point2D> result) {
		if (result == null || result.size() < 2) {
			ProfileVariables.denyChild(parent, "*", "districtNetworkConnection");
			return;
		}
		
		ConnectionLineNode node = ProfileVariables.claimChild(parent, "*", "districtNetworkConnection", ConnectionLineNode.class, observer);
		if (node == null)
			return;
		
		node.setPoints(result);
		node.setZIndex(0);
		node.setStrokeWidth(2.f);
	}

	@Override
	protected void cleanupStyleForNode(EvaluationContext evaluationContext, INode parent) {
		ProfileVariables.denyChild(parent, "*", "districtNetworkConnection");
	}
	
	private static Function1<Resource, List<Resource>> getConnectedComponentsFunctionCached(ReadGraph graph, Resource componentType)
			throws DatabaseException {
		return graph.syncRequest(new ConnectedComponentsFunctionRequest(componentType), TransientCacheListener.instance());
	}
	
	private static final class ConnectedComponentsFunctionRequest
			extends ResourceRead<Function1<Resource, List<Resource>>> {
		public ConnectedComponentsFunctionRequest(Resource resource) {
			super(resource);
		}

		@SuppressWarnings("unchecked")
		@Override
		public Function1<Resource, List<Resource>> perform(ReadGraph graph) throws DatabaseException {
			Resource actionsModule = Layer0Utils.getPossibleChild(graph, resource, "Actions");
			if (actionsModule == null || !graph.isInstanceOf(actionsModule, Layer0.getInstance(graph).SCLModule))
				return null;
			
			String uri = graph.getURI(actionsModule);
			SCLContext sclContext = SCLContext.getCurrent();
			Object oldGraph = sclContext.get("graph");
			try {
				sclContext.put("graph", graph);
				return (Function1<Resource, List<Resource>>) SCLOsgi.MODULE_REPOSITORY.getValue(uri, "getConnectedComponents");
			} catch (ValueNotFound e1) {
				return null;
			} finally {
				sclContext.put("graph", oldGraph);
			}
		}
	}
}