package org.openslx.taskmanager.network;

import java.nio.charset.StandardCharsets;

import org.apache.log4j.Logger;
import org.openslx.taskmanager.api.TaskStatus;
import org.openslx.taskmanager.main.Taskmanager;

import com.google.gson.Gson;

public class RequestParser
{
	private static final Logger log = Logger.getLogger( RequestParser.class );

	/**
	 * Our very own gson instance (for serializing replies)
	 */
	private static final Gson sendGson = new Gson();

	/**
	 * Handle the given unparsed request.
	 * 
	 * @param source source of the request, where the reply will be send to (if any)
	 * @param payload Packet data received from network, already converted to a string
	 */
	public static byte[] handle( String payload )
	{
		String[] parts = payload.split( " *, *", 3 );
		// Message format is "<message id>, <command>, <command payload/argument>"
		if ( parts.length != 3 ) {
			log.debug( "Could not split message" );
			return null;
		}
		// Look at parts[1], if it's "status" it's a request for the task
		// with the ID given in parts[2]
		if ( parts[1].equals( "status" ) ) {
			TaskStatus status = Taskmanager.getTaskStatus( parts[2] );
			return serialize( parts[0], status );
		}
		// Now check if parts[1] is "release"
		if ( parts[1].equals( "release" ) ) {
			Taskmanager.releaseTask( parts[2] );
			return null;
		}
		// Anything else in parts[0] will be treated as a fresh task invocation, so let's
		// pass it on to the task manager.
		TaskStatus status = Taskmanager.submitTask( parts[1], parts[2] );
		return serialize( parts[0], status );
	}

	private static byte[] serialize( String messageId, TaskStatus status )
	{
		String data;
		try {
			synchronized ( sendGson ) {
				data = sendGson.toJson( status );
			}
		} catch ( Throwable e ) {
			log.warn( "Could not serialize reply with TaskStatus " + status.getStatusObjectClassName() );
			log.warn( e.toString() );
			return null;
		}
		return ( messageId + ',' + data ).getBytes( StandardCharsets.UTF_8 );
	}

}