package org.simantics.diagram.svg.export;

import java.awt.Shape;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.HashMap;
import java.util.Map;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.apache.batik.svggen.SVGGeneratorContext;
import org.apache.batik.svggen.SVGShape;
import org.simantics.db.common.utils.Logger;
import org.simantics.scenegraph.utils.SVGPassthruShape;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.xml.sax.SAXException;

public class SVGShapeWithPassthruSupport extends SVGShape {
	private DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
	
	public SVGShapeWithPassthruSupport(SVGGeneratorContext generatorCtx) {
		super(generatorCtx);
		dbf.setValidating(false);
		dbf.setExpandEntityReferences(false);
		try {
			dbf.setFeature("http://xml.org/sax/features/namespaces", false);
			dbf.setFeature("http://xml.org/sax/features/validation", false);
			dbf.setFeature("http://apache.org/xml/features/nonvalidating/load-dtd-grammar", false);
			dbf.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", false);
		} catch (ParserConfigurationException e) {
			Logger.defaultLogError(e);
		}
	}

	public Element toSVG(Shape shape) {
		if (shape instanceof SVGPassthruShape) {
			String source = ((SVGPassthruShape) shape).getSource();
			
			try {
				
				Document owner = generatorContext.getDOMFactory();

				@SuppressWarnings("unchecked")
				Map<String, String> defsMap = (Map<String, String>)owner.getUserData("defs-map");
				if (defsMap == null) {
					defsMap = new HashMap<String, String>();
					owner.setUserData("defs-map", defsMap, null);
				}
				
				synchronized (defsMap) {
					String symbolId = defsMap.get(source);
					if (symbolId == null) {
						symbolId = "S" + defsMap.size();
						defsMap.put(source, symbolId);
						
						DocumentBuilder db = dbf.newDocumentBuilder();
						
						Document doc = db.parse(new ByteArrayInputStream(source.getBytes("UTF-8")));
						Node node = doc.getDocumentElement();
						Node localNode = owner.importNode(node, true);

						if (localNode instanceof Element) {
							Element g = generatorContext.getDOMFactory().createElementNS(SVG_NAMESPACE_URI, SVG_G_TAG);
							Element e = (Element)localNode;
							e.setAttribute("id", symbolId);
							g.appendChild(localNode);
							return g;
						} else {
							return null;
						}
					} else {
						Element element = owner.createElement("use");
						element.setAttribute("xlink:href", "#" + symbolId);
						return element;
					}
				}
			} catch (UnsupportedEncodingException e) {
				Logger.defaultLogError(e);
				return null;
			} catch (IOException e) {
				Logger.defaultLogError(e);
				return null;
			} catch (ParserConfigurationException e) {
				Logger.defaultLogError(e);
				return null;
			} catch (SAXException e) {
				Logger.defaultLogError(e);
				return null;
			}
		} else {
			return super.toSVG(shape);
		}
		
	}
	
}