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/*
 * The contents of this file are subject to the Mozilla Public 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
 * https://www.mozilla.org/en-US/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
 * License for the specific language governing rights and limitations
 * under the License.
 *
 * The Original Code is "Simplenlg".
 *
 * The Initial Developer of the Original Code is Ehud Reiter, Albert Gatt and Dave Westwater.
 * Portions created by Ehud Reiter, Albert Gatt and Dave Westwater are Copyright (C) 2010-11 The University of Aberdeen. All Rights Reserved.
 *
 * Contributor(s): Ehud Reiter, Albert Gatt, Dave Westwater, Roman Kutlak, Margaret Mitchell, and Saad Mahamood.
 */
package simplenlg.server;

import java.io.*;
import java.net.Socket;

import simplenlg.xmlrealiser.XMLRealiser;
import simplenlg.xmlrealiser.XMLRealiserException;

/**
 * This class handles one realisation request.
 *
 * @author Roman Kutlak
 * 		
 * 		The object will parse the xml from the client socket and return
 * 		a surface realisation of the xml structure.
 * 		

 * 		If an exception occurs, the request attempts to inform the client
 * 		by sending a string that starts with "Exception: " and continues
 * 		with the message of the exception. Sending the error might fail
 * 		(for example, if the client disconnected).
 * 		
 * 		The program implements the "standard" socket protocol:
 * 		each message is preceded with an integer indicating the
 * 		length of the message (int is 4 bytes).
 */
public class RealisationRequest implements Runnable {

	Socket socket;

	static boolean DEBUG = SimpleServer.DEBUG;

	public RealisationRequest(Socket s) {
		this.socket = s;
	}

	public void run() {
		if(null == socket)
			return;

		DataInputStream input = null;
		DataOutputStream output = null;

		if(DEBUG) {
			System.out.println("Client connected from " + socket.getRemoteSocketAddress());
		}

		try {
			input = new DataInputStream(socket.getInputStream());
			output = new DataOutputStream(socket.getOutputStream());

			// read the message length
			int msgLen = input.readInt();

			// create a buffer
			byte[] data = new byte[msgLen];
			// read the entire message (blocks until complete)
			input.readFully(data);

			if(data.length < 1) {
				throw new Exception("Client did not send data.");
			}

			// now convert the raw bytes to utf-8
			String tmp = new String(data, "UTF-8");
			StringReader reader = new StringReader(tmp);

			// get the realisation
			String result = doRealisation(reader).trim();

			// convert the string to raw bytes
			byte[] tmp2 = result.getBytes("UTF-8");

			// write the length
			output.writeInt(tmp2.length);
			// write the data
			output.write(tmp2);

			if(DEBUG) {
				String text = "The following realisation was sent to client:";
				System.out.println(text + "\n\t" + result);
			}

		} catch(Exception e) {
			e.printStackTrace();
			try {
				// attempt to send the error message to the client
				byte[] tmp = ("Exception: " + e.getMessage()).getBytes("UTF-8");
				output.writeInt(tmp.length);
				output.write(tmp);
			} catch(IOException e1) {
			}
		} catch(XMLRealiserException e) {
			e.printStackTrace();
			try {
				// attempt to send the error message to the client
				byte[] tmp = ("Exception: " + e.getMessage()).getBytes("UTF-8");
				output.writeInt(tmp.length);
				output.write(tmp);
			} catch(IOException e1) {
			}
		} finally {
			try {
				socket.close();
				socket = null;
			} catch(IOException e) {
				System.err.println("Could not close client socket!");
			}
		}
	}

	protected String doRealisation(Reader inputReader) throws XMLRealiserException {
		simplenlg.xmlrealiser.wrapper.RequestType request = XMLRealiser.getRequest(inputReader);
		String output = XMLRealiser.realise(request.getDocument());
		return output;
	}
}