package geniusweb.partiesserver;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.fasterxml.jackson.databind.ObjectMapper;

import geniusweb.partiesserver.repository.RunningPartiesRepo;
import geniusweb.serverobjects.ServerInfo;

/**
 * Servlet implementation to get general info from the server.
 */
public class Info extends HttpServlet {

	private final static RunningPartiesRepo repo = RunningPartiesRepo
			.instance();
	private final static ObjectMapper jackson = new ObjectMapper();

	/**
	 * see
	 * {@link HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)}.
	 * Returns to the http caller
	 * <ul>
	 * <li>URL with websocket address to contact the now running agent.
	 * <li>SC_NOT_FOUND (404) if attempt is made to access non-running party.
	 * <li>SC_SERVICE_UNAVAILABLE (503) if there are no free slots to run the
	 * party.
	 * <li>SC_EXPECTATION_FAILED (417) if something else goes wrong during
	 * instantiating the party (then see logs for more details)
	 * </ul>
	 */
	@Override
	protected void doGet(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {
		response.getWriter().append(jackson.writeValueAsString(
				new ServerInfo(repo.availableSlots(), repo.maximumSlots())));
	}
}