package org.simantics.diagram.svg.export;


import java.awt.Point;
import java.util.concurrent.Semaphore;
import java.util.concurrent.atomic.AtomicReference;

import org.apache.batik.svggen.SVGGraphics2D;
import org.simantics.Simantics;
import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.common.ResourceArray;
import org.simantics.db.common.request.PossibleIndexRoot;
import org.simantics.db.common.request.UniqueRead;
import org.simantics.db.common.utils.NameUtils;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.exception.ValidationException;
import org.simantics.db.management.ISessionContext;
import org.simantics.db.request.Read;
import org.simantics.diagram.elements.DiagramNodeUtil;
import org.simantics.diagram.export.ImagePrinter;
import org.simantics.diagram.stubs.DiagramResource;
import org.simantics.g2d.canvas.impl.CanvasContext;
import org.simantics.g2d.scenegraph.ICanvasSceneGraphProvider;
import org.simantics.layer0.Layer0;
import org.simantics.modeling.ModelingResources;
import org.simantics.structural.stubs.StructuralResource2;
import org.simantics.structural2.StructuralVariables;
import org.simantics.utils.DataContainer;
import org.simantics.utils.datastructures.Pair;
import org.simantics.utils.page.MarginUtils.Margins;
import org.simantics.utils.threads.ThreadUtils;
import org.simantics.utils.threads.WorkerThread;


public class DiagramToSVG {
	
	
	public static String diagramToSVG(Resource diagram) {

		try {
			ImagePrinter.ImageExportPlan exportPlan = new ImagePrinter.ImageExportPlan();
			exportPlan.margin = 0.05;
			exportPlan.dpi = 96.0;
			exportPlan.diagram = diagram;
			return render(diagram,exportPlan);
		} catch (Exception e) {
			e.printStackTrace();
			return "<b>error</b> "+ e.getMessage();
		}
 
		
	}
	
	public static String diagramToSVG(Resource diagram, int width, int height) {

		try {
			ImagePrinter.ImageExportPlan exportPlan = new ImagePrinter.ImageExportPlan();
			exportPlan.margin = 0.05;
			exportPlan.size = new Point(width, height);
			exportPlan.diagram = diagram;
			return render(diagram,exportPlan);
		} catch (Exception e) {
			e.printStackTrace();
			return "<b>error</b> "+ e.getMessage();
		}
 
		
	}
	
	public static String diagramToSVG(Resource diagram, double dpi) {

		try {
			ImagePrinter.ImageExportPlan exportPlan = new ImagePrinter.ImageExportPlan();
			exportPlan.margin = 0.05;
			exportPlan.dpi = dpi;
			exportPlan.diagram = diagram;
			return render(diagram,exportPlan);
		} catch (Exception e) {
			e.printStackTrace();
			return "<b>error</b> "+ e.getMessage();
		}
 
		
	}
	
	public static String diagramToSVG(Resource diagram, ImagePrinter.ImageExportPlan exportPlan, Margins margins, SVGGraphics2D svgGenerator) {

		try {
			return render(diagram,exportPlan,margins,svgGenerator);
		} catch (Exception e) {
			e.printStackTrace();
			return "<b>error</b> "+ e.getMessage();
		}
		
 	}
	
	private static String render(final Resource input, final ImagePrinter.ImageExportPlan exportPlan) throws Exception {
		return render(input, exportPlan, null, SVGBuilder.defaultSVGGenerator()); 
	}
	
	private static String render(final Resource input, final ImagePrinter.ImageExportPlan exportPlan, Margins margins, SVGGraphics2D svgExporter) throws Exception {
		Resource diagram = Simantics.getSession().syncRequest(new Read<Resource>() {
			@Override
			public Resource perform(ReadGraph graph) throws DatabaseException {
				DiagramResource DIA = DiagramResource.getInstance(graph);
				if (graph.isInstanceOf(input, DIA.Diagram))
					return input;
				StructuralResource2 SR = StructuralResource2.getInstance(graph);
				ModelingResources MOD = ModelingResources.getInstance(graph);
				Layer0 L0 = Layer0.getInstance(graph);
				if (graph.isInstanceOf(input, SR.Composite)) {
					Resource possibleDiagram = graph.getPossibleObject(input, MOD.CompositeToDiagram);
					if (possibleDiagram != null)
						return possibleDiagram;
					for (Resource r : graph.getObjects(input, L0.ConsistsOf)) {
						if (graph.isInstanceOf(r, SR.Composite)) {
							possibleDiagram = graph.getPossibleObject(input, MOD.CompositeToDiagram);
							if (possibleDiagram != null)
								return possibleDiagram;
						}
					}
				}
				return null;
			}
		});
		if (diagram == null)
			throw new DatabaseException("Input " + input + " cannot be resolved as diagram");
		
		
	
		
		final WorkerThread thread = new WorkerThread("Diagram Image Painter");
		thread.start();
		
        final CanvasContext ctx = new CanvasContext(thread);
        final AtomicReference<ICanvasSceneGraphProvider> sgProvider = new AtomicReference<ICanvasSceneGraphProvider>();
		final ISessionContext sessionContext = Simantics.getSessionContext();
		final DataContainer<String> result = new DataContainer<String>(null);
		final DataContainer<Exception> exception = new DataContainer<Exception>(null);
        try {
            final Semaphore done = new Semaphore(0);
            // IMPORTANT: Load diagram in a different thread than the canvas context thread!
            ThreadUtils.getBlockingWorkExecutor().execute(new Runnable() {
                @Override
                public void run() {
                    try {
                        Pair<Resource, String> modelAndRVI = sessionContext.getSession().syncRequest(new UniqueRead<Pair<Resource, String>>() {
                            @Override
                            public Pair<Resource, String> perform(ReadGraph graph) throws DatabaseException {
                                return new Pair<Resource, String>( resolveModel(graph, exportPlan.diagram ), resolveRVI(graph, exportPlan.diagram) );
                            }
                        });

                        ICanvasSceneGraphProvider provider = DiagramNodeUtil.loadSceneGraphProvider(ctx, modelAndRVI.first, exportPlan.diagram, modelAndRVI.second);
                        sgProvider.set( provider );
                        
                        ThreadUtils.asyncExec(thread, new Runnable() {
                            @Override
                            public void run() {
                                try {
                                    SVGBuilder chassis = margins != null ?
                                    		new SVGBuilder(exportPlan.dpi,exportPlan.size,margins) :
                                    		new SVGBuilder(exportPlan.dpi,exportPlan.size,exportPlan.margin);
                                    
                                    result.set(chassis.paint(ctx, svgExporter));
                                } catch (Exception e) {
                                	exception.set(e);
                                } finally {
                                    done.release();
                                }
                            }
                        });
                    } catch (DatabaseException e) {
                    	exception.set(e);
                        done.release();
                    } catch (Throwable e) {
                    	exception.set(new DatabaseException(e));
                        done.release();
                    } finally {
                        done.release();
                    }
                }
            });

            done.acquire(2);
            if (exception.get() != null)
                throw exception.get();
            return result.get();
        } finally {
            if (sgProvider.get() != null)
                sgProvider.get().dispose();
            ctx.dispose();
        }
	}
	
	private static Resource resolveModel(ReadGraph graph, Resource diagram) throws DatabaseException {
    	ModelingResources mod = ModelingResources.getInstance(graph);
        Resource composite = graph.getSingleObject(diagram, mod.DiagramToComposite);
        Resource model = graph.syncRequest(new PossibleIndexRoot(composite));
        if (model == null)
            throw new ValidationException("no model found for composite " + NameUtils.getSafeName(graph, composite));
        return model;
    }



    private static String resolveRVI(ReadGraph graph, Resource diagram) throws DatabaseException {
    	ModelingResources mod = ModelingResources.getInstance(graph);
        Resource composite = graph.getSingleObject(diagram, mod.DiagramToComposite);
        final ResourceArray compositePath = StructuralVariables.getCompositeArray(graph, composite);
        final ResourceArray variablePath = compositePath.removeFromBeginning(1);
        return StructuralVariables.getRVI(graph, variablePath);
    }

}