package org.lcdproc.lcdjava;

import java.io.BufferedReader;

import java.io.IOException;

import java.util.concurrent.Semaphore;

import java.util.regex.Matcher;

import java.util.regex.Pattern;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

/**

* Thread that listens for data on the LCD socket.

*/

class LCDSocketPoller extends Thread {

private final Logger _log = LoggerFactory.getLogger(LCDSocketPoller.class);

/**

* The Pattern that matches ignore/listen events.

*/

private static final Pattern IGNORE_STATUS = Pattern.compile(

"(ignore|listen)\\s+(\\d+).*");

/**

* The Pattern that matches menu events.

*/

private static final Pattern MENU_STATUS = Pattern.compile(

"menuevent\\s+(\\w+)\\s+(\\w+)\\s*(.*)");

/**

* The Reader to read data from.

*/

private final BufferedReader _in;

/**

* The last line of data received.

* <p>Will be null if no data was received.

*/

private String _lastLine;

/**

* The listener to notify of listen/ignore events.

*/

private final LCDListener _listener;

private Semaphore hello;

/**

* Public constructor.

*

* @param in the BufferedReader that will receive data from the server.

* @param listener the LCDListener that gets notified of screens being

* listened to or ignored.

*/

LCDSocketPoller(BufferedReader in, LCDListener listener, Semaphore hello) throws IOException {

_in = in;

_listener = listener;

this.hello = hello;

}

@Override

public void run() {

try {

String line;

while ((line = _in.readLine()) != null) {

if (line.startsWith(LCD.RESPONSE_ERROR)) {

_log.warn("Got a response of " + line +

" from server");

}

Matcher listenIgnore = IGNORE_STATUS.matcher(line);

Matcher menuEvent = MENU_STATUS.matcher(line);

if (listenIgnore.matches()) {

boolean listen = (LCD.RESPONSE_LISTEN.equals(listenIgnore.group(1)));

int screenId = Integer.parseInt(listenIgnore.group(2));

_listener.setListenStatus(screenId, listen);

} else if (menuEvent.matches()) {

_listener.menuAction(menuEvent.group(2), menuEvent.group(1), menuEvent.group(3));

}

synchronized (this) {

_lastLine = line;

}

hello.release();

}

} catch (IOException e) {

throw new LCDException(e);

}

_log.debug("Terminating");

}

/**

* Get the last line received <i>non-blocking</i>.

* <p>Calling this clears the last line received.

*

* @return the last line received.

*/

synchronized String getLastLine() {

String ret = _lastLine;

_lastLine = null;

return ret;

}

}