package com.ronsoft.books.nio.channels;

import java.nio.ByteBuffer;
import java.nio.MappedByteBuffer;
import java.nio.CharBuffer;
import java.nio.channels.FileChannel;
import java.nio.channels.FileChannel.MapMode;
import java.nio.channels.Channels;
import java.nio.channels.GatheringByteChannel;
import java.nio.channels.SocketChannel;
import java.nio.channels.ServerSocketChannel;
import java.nio.charset.Charset;
import java.util.regex.Pattern;
import java.util.regex.Matcher;
import java.net.InetSocketAddress;
import java.net.URLConnection;
import java.io.FileInputStream;
import java.io.FileOutputStream;

/**
 * Simple-minded HTTP server using MappedByteBuffers.
 * This example will be expanded significantly
 *
 * Created: April 2002
 * @author Ron Hitchens (ron@ronsoft.com)
 * @version $Id: HttpServer.java,v 1.2 2002/05/16 01:45:48 ron Exp $
 */
public class HttpServer
{
	private static final int DEFAULT_PORT = 8880;
	private static final String DEFAULT_ROOT_DIR = ".";

	private static final String LINE_SEP = "\r\n";
	private static final String HTTP_HDR =
		"HTTP/1.0 200 OK" + LINE_SEP +
		"Server: Ronsoft Sample Server" + LINE_SEP +
		"Content-Type: text/plain" + LINE_SEP;

	private ByteBuffer staticHdr =
		ByteBuffer.wrap (HTTP_HDR.getBytes());

	private Charset utf8 = Charset.forName ("UTF-8");
	private Pattern space = Pattern.compile ("\\s+");
	//private Matcher spaceMatch = space.matcher ("");

	private String rootDir = DEFAULT_ROOT_DIR;

	// ---------------------------------------------------------

	public static void main (String [] argv)
		throws Exception
	{
		int port = DEFAULT_PORT;

		if (argv.length != 0) {
			port = Integer.parseInt (argv [0]);
		}

		HttpServer server = new HttpServer();

		System.out.println ("Starting server on port " + port);
		server.runServer (port);
	}

	public void runServer (int port)
		throws Exception
	{
		ServerSocketChannel ssc = ServerSocketChannel.open();
		ByteBuffer temp = ByteBuffer.allocate (1024 * 10);
		ssc.socket().bind (new InetSocketAddress (port));

		while (true) {
			SocketChannel socket = ssc.accept();

			temp.clear();
			socket.read (temp);

			temp.flip();
			CharBuffer cb = utf8.decode (temp);

System.out.println ("cb = " + cb);
			String [] tokens = space.split (cb, 3);

			String filename = rootDir + tokens [1];

			FileInputStream fis = new FileInputStream (filename);
			FileChannel fc = fis.getChannel();

			sendFile (fc, socket,
				URLConnection.guessContentTypeFromName (filename));

			fc.close();
			fis.close();
			socket.close();
		}
	}

	public void sendFile (FileChannel file, GatheringByteChannel out,
		String contentType)
		throws Exception
	{
		MappedByteBuffer fileData = file.map (MapMode.READ_ONLY,
			0, file.size());

		sendBuffer (fileData, out, contentType);
	}

	private CharBuffer cbtemp = CharBuffer.allocate (1024);
	private ByteBuffer dynHdr = ByteBuffer.allocate (1024);

	private void sendBuffer (ByteBuffer data,
		GatheringByteChannel channel, String contentType)
		throws Exception
	{
		ByteBuffer [] buffers = { staticHdr, dynHdr, data };

		staticHdr.rewind();

		cbtemp.clear();
		cbtemp.put ("Content-Length: " + data.limit());
		cbtemp.put (LINE_SEP);
		cbtemp.put ("Content-Type: ");
		cbtemp.put (contentType);
		cbtemp.put (LINE_SEP);
		cbtemp.put (LINE_SEP);
		cbtemp.flip();

		buffers [1] = utf8.encode (cbtemp);

		while (channel.write (buffers) != 0) {
			// nothing
		}
	}
}