/*******************************************************************************
 * Copyright (c) 2007, 2010 Association for Decentralized Information Management
 * in Industry THTH ry.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     VTT Technical Research Centre of Finland - initial API and implementation
 *******************************************************************************/
package org.simantics.document;

import java.io.File;
import java.io.IOException;
import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.simantics.Simantics;
import org.simantics.databoard.Bindings;
import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.common.request.PossibleIndexRoot;
import org.simantics.db.exception.DatabaseException;
import org.simantics.image2.ontology.ImageResource;
import org.simantics.utils.FileUtils;


public class DocumentDialect {
    
    final Pattern imagePattern = Pattern.compile("\\[\\[Image(?::([^\\]]+))?\\]\\]");

	final static public DocumentDialect INSTANCE = new DocumentDialect();

	public String transform(ReadGraph graph, Resource res, String options) {
		
		try {
			
			String[] parts = options.split("\\|");
			if(parts.length > 0) {
				
				String uri = parts[0];
				Resource indexRoot = graph.syncRequest(new PossibleIndexRoot(res));
				if(indexRoot == null) return null;
				String rootURI = graph.getURI(indexRoot);
				uri = uri.replace("root:/", rootURI);
				// (Apros #12268) For easier image linking, allow users to
				// write white space as ' ' in the wiki-style image links.
				uri = uri.replace(" ", "%20");
				Resource image = graph.getPossibleResource(uri);
				if(image == null) return null;
				byte[] bytes = graph.getValue(image, Bindings.BYTE_ARRAY);
				MessageDigest md;
				md = MessageDigest.getInstance("MD5");
				md.update(bytes);
				BigInteger number = new BigInteger(1, md.digest());
				String digest = number.toString(16);
				File dir = Simantics.getTemporaryDirectory("documentImages");
				dir.mkdirs();
				
				ImageResource IMAGE = ImageResource.getInstance(graph);
				
				String extension;
				if(graph.isInstanceOf(image, IMAGE.PngImage)) extension = ".png";
				else if(graph.isInstanceOf(image, IMAGE.JpegImage)) extension = ".jpg";
				else return null;
				
				File f = new File(dir, digest + extension);
				if(!f.exists())
					FileUtils.writeFile(f, bytes);
				StringBuilder sb = new StringBuilder();
				sb.append("[[File: " + f.toURI());
				for(int i=1;i<parts.length;i++) {
					sb.append("|");
					sb.append(parts[i]);
				}
				sb.append("]]");
				return sb.toString();
			}
			
		} catch (DatabaseException e) {
		} catch (NoSuchAlgorithmException e) {
		} catch (IOException e) {
		}
		
		return null;
		
	}

	public String apply(ReadGraph graph, Resource res, String markup) throws DatabaseException {

		StringBuffer sb = new StringBuffer();
		Matcher matcher = imagePattern.matcher(markup);
		while(matcher.find()) {
			matcher.appendReplacement(sb, "");
			String options = matcher.group(1);
			String match = transform(graph, res, options);
			if(match != null) sb.append(match);
			else sb.append("[[Image:" + options + "]]");
		}
		matcher.appendTail(sb);
		return sb.toString();

	}
	
}