package geniusweb.runserver;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.SocketException;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.logging.Level;

import javax.websocket.ClientEndpoint;
import javax.websocket.CloseReason;
import javax.websocket.ContainerProvider;
import javax.websocket.DeploymentException;
import javax.websocket.OnClose;
import javax.websocket.OnError;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.WebSocketContainer;

import com.fasterxml.jackson.databind.ObjectMapper;

import geniusweb.actions.Action;
import geniusweb.actions.PartyId;
import geniusweb.party.inform.Inform;
import geniusweb.protocol.partyconnection.ConnectionWithParty;
import geniusweb.references.Reference;
import tudelft.utilities.listener.DefaultListenable;
import tudelft.utilities.logging.ReportToLogger;
import tudelft.utilities.logging.Reporter;

/**
 * A websocket based {@link ConnectionWithParty}. Must be public so that it can
 * be accessed as ClientEndpoint by apache tomcat
 */
@ClientEndpoint
public class PartyConnection extends DefaultListenable<Action>
		implements ConnectionWithParty {
	private final static ObjectMapper jackson = new ObjectMapper();
	private final Reporter log;

	private final Reference reference;

	private WebSocketContainer container;
	private Session session = null;
	private URI partyuri;
	private Throwable error = null;

	/**
	 * Constructor that uses default {@link Reporter}
	 * 
	 * @param reference the address to to a http GET to get a websocket to a new
	 *                  running party.
	 */
	public PartyConnection(Reference reference) {
		this(reference, new ReportToLogger("runserver"));
	}

	/**
	 * 
	 * @param reference the address to to a http GET to get a websocket to a new
	 *                  running party.
	 * @param reporter  the {@link Reporter} used for logging important
	 *                  events/issues
	 * @throws IOException if the party does not start properly.
	 */
	public PartyConnection(Reference reference, Reporter reporter) {
		this.reference = reference;
		this.log = reporter;

	}

	public PartyConnection init() throws IOException {
		log.log(Level.INFO, "Trying to start up party " + reference);
		URI partyuri = startParty(reference);

		container = ContainerProvider.getWebSocketContainer();
		log.log(Level.INFO,
				"Trying to make websocket connection to running party "
						+ partyuri);
		try {
			container.connectToServer(this, partyuri);
		} catch (DeploymentException e) {
			throw new IOException(
					"Failed to connect with running party at " + partyuri, e);
		}
		log.log(Level.INFO, "Created websocket connection at  " + partyuri);
		return this;
	}

	/**
	 * 
	 * @param reference the address to to a http GET to get a websocket to a new
	 *                  running party.
	 * @return URI of websocket behind which is a running party
	 * @throws IOException if party did not start correctly
	 */
	private URI startParty(Reference reference) throws IOException {
		HttpURLConnection conn = (HttpURLConnection) reference.getURI().toURL()
				.openConnection();
		// if this throws, the IOException seems to contain the "retry later"
		// message
		// already
		conn.setRequestMethod("GET"); // TODO timeout
		BufferedReader rd;
		try {
			rd = new BufferedReader(
					new InputStreamReader(conn.getInputStream()));
		} catch (IOException e) {
			// read the detail message from the error stream
			rd = new BufferedReader(
					new InputStreamReader(conn.getErrorStream()));
			throw new IOException(rd.readLine(), e);
		}
		String partysocketaddress = rd.readLine();
		log.log(Level.INFO, "startparty returned " + partysocketaddress);
		if (conn.getResponseCode() != HttpURLConnection.HTTP_OK) {
			throw new IOException(
					"Something went wrong connecting to the party:"
							+ conn.getResponseCode());
		}
		try {
			this.partyuri = new URI(partysocketaddress);
		} catch (URISyntaxException e1) {
			throw new IOException("Failed to start party at " + reference, e1);
		}
		return partyuri;
	}

	/************* implements {@link ConnectionWithParty} ***************/
	@Override
	public void send(Inform info) throws IOException {
		if (session == null)
			return;
		session.getBasicRemote().sendText(jackson.writeValueAsString(info));
	}

	@Override
	public Reference getReference() {
		return this.reference;
	}

	@Override
	public PartyId getParty() {
		String name = partyuri.getPath();
		return new PartyId(name.substring(name.lastIndexOf('/') + 1));
	}

	@Override
	public void close() {
		log.log(Level.INFO, "Party close called");
		setError(new SocketException("socket is closed"));
		try {
			session.close();
			this.session = null;
		} catch (IOException e) {
			log.log(Level.SEVERE, "failed to close websocket", e);
		}
	}

	/************* implements ClientEndpoint ***************/

	@OnOpen
	public void onOpen(Session session) {
		log.log(Level.INFO, "Party is being connected: " + session);
		this.session = session;
	}

	@OnClose
	public void onClose(Session userSession, CloseReason reason) {
		log.log(Level.INFO, "closing websocket " + reference + ":" + reason);
		setError(new SocketException("socket has been closed"));

	}

	@OnMessage
	public void processMessage(String message) {
		try {
			Action act = jackson.readValue(message, Action.class);
			notifyChange(act);
		} catch (IOException e) {
			log.log(Level.WARNING,
					"received bad message from client " + reference, e);
			setError(e);
			close();
		}
	}

	@OnError
	public void processError(Throwable t) {
		log.log(Level.SEVERE, "Something went wrong internally!", t);
		setError(t);
	}

	@Override
	public URI getRemoteURI() {
		return partyuri;
	}

	@Override
	public Throwable getError() {
		return error;
	}

	/**
	 * Sets the connection to final error state and report null to listeners.
	 * Only the first error is reported, the rest is ignored.
	 * 
	 * @param err the error that occurred.
	 */
	private void setError(Throwable err) {
		boolean isSet = false;
		synchronized (this) {
			if (this.error == null) {
				this.error = err;
				isSet = true;
			}
		}
		if (isSet) {
			notifyChange(null);
		}
	}

}