// PathVisio,
// a tool for data visualization and analysis using Biological Pathways
// Copyright 2006-2011 BiGCaT Bioinformatics
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
package org.pathvisio.core.util;

import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import org.bridgedb.DataSource;
import org.pathvisio.core.data.XrefWithSymbol;
import org.pathvisio.core.debug.Logger;
import org.xml.sax.Attributes;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;

/**
 * This sax handler can be used to quickly parse pathway information from
 * a gpml file
 */
public class PathwayParser extends DefaultHandler
{
	/** exception occuring during parsing of pathway, most likely because
	 * the input file is not properly formatted */
	public static class ParseException extends Exception
	{

		public ParseException (Exception e)
		{
			super (e);
		}
	}

	String name;
	private List<XrefWithSymbol> genes;

	public PathwayParser()
	{
		name = "";
		genes = new ArrayList<XrefWithSymbol>();
	}

	public PathwayParser(File f, XMLReader xmlReader) throws ParseException
	{
		this();
		xmlReader.setContentHandler(this);
		xmlReader.setEntityResolver(this);

		try
		{
			xmlReader.parse(new InputSource (new FileReader(f)));
		}
		catch (IOException e)
		{
			throw new ParseException (e);
		}
		catch (SAXException e)
		{
			throw new ParseException (e);
			// ignore pathways that generate an exception (return empty list)
		}
	}

	public List<XrefWithSymbol> getGenes() { return genes; }

	public String getName() { return name; }

	DataSource currentDs = null;
	String currentSymbol = null;
	String currentId = null;

	public void startElement(String uri, String localName, String qName, Attributes attributes)
			throws SAXException
	{
		if(localName.equals("DataNode"))
		{
			currentId = null;
			currentDs = null;
			currentSymbol = attributes.getValue("TextLabel");
		}
		else if(localName.equals("Pathway"))
		{
			name = attributes.getValue("Name");
		}
		else if(localName.equals("Xref"))
		{
			String sysName = attributes.getValue("Database");
			assert (sysName != null);
			currentDs = DataSource.getByFullName (sysName);
			currentId = attributes.getValue("ID");
			assert (currentId != null);

			XrefWithSymbol currentGene = new XrefWithSymbol (
					currentId, currentDs, currentSymbol);
			if(!genes.contains(currentGene)) //Don't add duplicate genes
				genes.add(currentGene);
			currentGene = null;
		}
	}

	public void error(SAXParseException e)
	{
		Logger.log.error("Error while parsing xml document", e);
	}

	public void fatalError(SAXParseException e) throws SAXParseException
	{
		Logger.log.error("Fatal error while parsing xml document", e);
		throw new SAXParseException("Fatal error, parsing of this document aborted", null);
	}

	public void warning(SAXParseException e)
	{
		Logger.log.error("Warning while parsing xml document", e);
	}
}