/*
 *  eXist Open Source Native XML Database
 *  Copyright (C) 2001-09 The eXist Project
 *  http://exist-db.org
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public License
 *  as published by the Free Software Foundation; either version 2
 *  of the License, or (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 *  $Id$
 */
package org.exist.xquery.functions.util;

import java.io.IOException;
import java.io.StringWriter;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.net.URL;

import org.exist.dom.QName;

import org.exist.xquery.BasicFunction;
import org.exist.xquery.Cardinality;
import org.exist.xquery.FunctionSignature;
import org.exist.xquery.XPathException;
import org.exist.xquery.XQueryContext;
import org.exist.xquery.value.FunctionParameterSequenceType;
import org.exist.xquery.value.FunctionReturnSequenceType;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.SequenceType;
import org.exist.xquery.value.StringValue;
import org.exist.xquery.value.Type;

/**
 * @author Pierrick Brihaye
 * @author Dizzzz
 * @author Andrzej Taramina
 *
 * DEPRECATED.  Moved to the file extension module.  See file:read.  This class will eventually be deleted
 */
public class FileRead extends BasicFunction {
	
	public final static FunctionSignature deprecated[] = {
		new FunctionSignature(
			new QName("file-read", UtilModule.NAMESPACE_URI, UtilModule.PREFIX),
			"Read the contents of a file as a string.",
			new SequenceType[] {				
				new FunctionParameterSequenceType("url", Type.ITEM, Cardinality.EXACTLY_ONE, "The URL of the file to read")
				},				
				new FunctionReturnSequenceType(Type.STRING, Cardinality.ZERO_OR_ONE, "the contents of the file"),
			"Moved to the file extension module.  See file:read() in the file extension module"
			),
		new FunctionSignature(
			new QName("file-read", UtilModule.NAMESPACE_URI, UtilModule.PREFIX),
			"Read the contents of a file as a string.",
			new SequenceType[] {
				new FunctionParameterSequenceType("url", Type.ITEM, Cardinality.EXACTLY_ONE, "The URL of the file to read"),
				new FunctionParameterSequenceType("encoding", Type.STRING, Cardinality.EXACTLY_ONE, "The encoding of the file")
				},
			new FunctionReturnSequenceType(Type.STRING, Cardinality.ZERO_OR_ONE, "the contents of the file"),
			"Moved to the file extension module.  See file:read() in the file extension module"
			)
		};
	
	/**
	 * @param context
	 * @param signature
	 */
	public FileRead( XQueryContext context, FunctionSignature signature ) 
	{
		super( context, signature );
	}
	
	/* (non-Javadoc)
	 * @see org.exist.xquery.BasicFunction#eval(org.exist.xquery.value.Sequence[], org.exist.xquery.value.Sequence)
	 */
	public Sequence eval( Sequence[] args, Sequence contextSequence ) throws XPathException 
	{
		String arg = args[0].itemAt(0).getStringValue();
		StringWriter sw;
		
		try {
			URL url = new URL( arg );
			InputStreamReader reader;
			
			if( args.length > 1 ) {			
				reader = new InputStreamReader( url.openStream(), arg = args[1].itemAt(0).getStringValue() );
			} else {
				reader = new InputStreamReader( url.openStream() );
			}
			
			sw = new StringWriter();
			char[] buf = new char[1024];
			int len;
			while( ( len = reader.read( buf ) ) > 0 ) {
				sw.write( buf, 0, len) ;
			}
			reader.close();
			sw.close();
		} 
		
		catch( MalformedURLException e ) {
			throw( new XPathException( this, e.getMessage() ) );
		} 
		
		catch( IOException e ) {
			throw( new XPathException( this, e.getMessage() ) );	
		}
		
		//TODO : return an *Item* built with sw.toString()
		
		return( new StringValue( sw.toString() ) );
	}
}