package cz.cuni.amis.pogamut.ut2004.tournament.botexecution;
   
   import java.io.File;
   import java.io.IOException;
   import java.util.logging.Level;
   import java.util.logging.Logger;
   
   import cz.cuni.amis.pogamut.ut2004.utils.PogamutUT2004Property;
   import cz.cuni.amis.utils.StreamSink;
  import cz.cuni.amis.utils.exception.PogamutException;
  import cz.cuni.amis.utils.exception.PogamutIOException;
  import cz.cuni.amis.utils.flag.Flag;
  import cz.cuni.amis.utils.flag.FlagListener;
  import cz.cuni.amis.utils.flag.ImmutableFlag;
  
  /**
   * Class that wrapps the execution of the bot from the jar defined by {@link UT2004BotExecutionConfig}.
   * <p><p>
   * The class is not suitable for inheritance ... better copy-paste and adjust for yourself.
   * 
   * @author Jimmy
   */
  public class UT2004BotExecution {
  	
  	protected UT2004BotExecutionConfig config;
  	
  	/**
  	 * Flag whether the bot is running, we're synchronizing access to this class on this flag.
  	 * <p><p>
  	 * Set to TRUE ONLY IN {@link UT2004BotExecution#start()} and back to FALSE ONLY IN {@link UT2004BotExecution#shutdown(boolean)}.
  	 * Do not alter the flag from anywhere else!
  	 */
  	protected Flag<Boolean> running = new Flag<Boolean>(false);
  	
  	/**
  	 * When {@link UT2004BotExecution#start()}ed it contains the bot process.
  	 */
  	protected Process botProcess = null;
  	
  	/**
  	 * Sink for the STDOUT of the bot, it may be redirected to {@link UT2004BotExecution#log}.
  	 */
  	protected StreamSink streamSinkOutput = null;
  	
  	/**
  	 * Sink for the STDERR of the bot, it may be redirected to {@link UT2004BotExecution#log}.
  	 */
  	protected StreamSink streamSinkError = null;
  
  	/**
  	 * Log used by the object, specified during the construction.
  	 */
  	protected Logger log;
  
  	/**
  	 * @param config bot execution configuration (contains path to jar to run)
  	 * @param log log to be used (stdout/stderr of the bot will be redirected there as well with {@link Level#INFO})
  	 */
  	public UT2004BotExecution(UT2004BotExecutionConfig config, Logger log) {
  		this.log = log;
  		this.config = config;
  	}
  		
  	/**
  	 * Task that will kill the BOT process when user forgets to do so before the JVM is killed.
       */
      protected Runnable shutDownHook = new Runnable(){
  
          @Override
          public void run() {
              if (botProcess != null) botProcess.destroy();
          }
      };
      
      protected Thread shutDownHookThread;
      
      /**
       * Task that is waiting for the end of the bot process to switch {@link UT2004BotExecution#running} back to false
       * and shutdown all other utility threads (like sink).
       */
      protected Runnable waitForEnd = new Runnable() {
  
  		@Override
  		public void run() {
  			try {
  				botProcess.waitFor();
  				// BOT PROCESS HAS STOPPED WHEN THE JVM REACHES HERE
  			} catch (InterruptedException e) {
  				// we've been interrupted!
  				synchronized(running) {
  					if (!running.getFlag()) {
  						// okey we're not running, screw it...
  						return;
  					}
  				}
  				// hups, we're still running, warn the user!
  				if (log != null && log.isLoggable(Level.WARNING)) {
  					log.warning("Interrupted while waiting for the botProcess(" + config.getBotId().getToken() + ") to end!");
  				}
 				
 			} finally {
 				// perform clean-up
 				synchronized(running) {
 					if (!running.getFlag()) {
 						// okey we're not running, somebody has already shutdown, screw it...
 						return;
 					}
 					if (waitForEndThread == Thread.currentThread()) {
 						// we're still in the middle of the same execution... (shut down only if it is the same bot execution)
 						shutdown(true);
 					}
 				}
 			}
 		}
     };
     
     protected Thread waitForEndThread;
 	
     /**
      * Start the bot process. Throws {@link PogamutIOException} if it fails to start the JVM.
      * <p><p>
      * It is wise to observe the state of the {@link UT2004BotExecution#getRunning()} flag to obtain the state of the process
      * (whether the process is running or is dead). Usage of {@link FlagListener} is advised, see {@link ImmutableFlag#addListener(FlagListener)}.
      * 
      * @param host GB2004 host
      * @param port GB2004 bot port
      */
 	public void start(String host, int port) throws PogamutIOException {
 		synchronized(running) {
 			if (running.getFlag()) {
 				throw new PogamutException("Could not start the bot again, it is already running! stop() it first!", log, this);
 			}
 			
 			if (log != null && log.isLoggable(Level.WARNING)) {
 				log.warning("Starting bot: " + config);
 			}
 			
 			if (!config.isBotJarExist()) {
 				throw new PogamutException("Could not start the bot according to config " + config + " as the bot jar does not exist at specified place " + config.getJarFile().getAbsolutePath() + "!", this);
 			}
 			
 			String javaHome = System.getProperty("JAVA_HOME");
 			
 			boolean linux = System.getProperty("os.name").toLowerCase().contains("linux");
 			
 				
 			
 			String command = 
 					(javaHome == null 
 						? (linux ? "java" : "java.exe")
 						: javaHome + (linux ? "/bin/java" : "\\bin\\java.exe"));
 			
 			String fullCommand = command + " \"-D" + PogamutUT2004Property.POGAMUT_UT2004_BOT_HOST.getKey() + "=" + host + "\""
 							             + " \"-D" + PogamutUT2004Property.POGAMUT_UT2004_BOT_PORT.getKey() + "=" + port + "\""
 							             + " -jar \"" + config.getJarFile().getAbsolutePath() + "\"";
 			
 			if (log != null && log.isLoggable(Level.INFO)) {
 				log.info("Executing command: " + fullCommand);
 			}
 			
 			ProcessBuilder procBuilder = 
 				new ProcessBuilder(
 						command, 
 						"-D" + PogamutUT2004Property.POGAMUT_UT2004_BOT_HOST.getKey() + "=" + host,
 						"-D" + PogamutUT2004Property.POGAMUT_UT2004_BOT_PORT.getKey() + "=" + port,
 						"-jar", 
 						config.getJarFile().getAbsolutePath()						
 				);				            
 	        procBuilder.directory(new File(config.getJarFile().getParent()));
 	        
 	        try {
 	        	botProcess = procBuilder.start();
 	        } catch (IOException e) {
 	        	// failed to start the process
 	        	if (log != null && log.isLoggable(Level.SEVERE)) {
 	        		log.severe("Could not start the bot: " + e.getMessage());
 	        	}
 	        	botProcess = null;
 	        	throw new PogamutIOException("Failed to start the botProcess(" + config.getBotId().getToken() + "). IOException: " + e.getMessage(), e, this);
 	        }
 	        
 	        // INITIALIZE ALL THREADS
 	        if (config.isRedirectStdErr()) {
 	        	streamSinkError = new StreamSink(config.getBotId().getToken()+"-StdErrSink", botProcess.getErrorStream(), log, config.getBotId().getToken()+"-StdErr");
 	        } else {
 	        	streamSinkError = new StreamSink(config.getBotId().getToken()+"-StdErrSink", botProcess.getErrorStream());
 	        }
 	        streamSinkError.start();
 	        if (config.isRedirectStdOut()) {
 	        	streamSinkOutput = new StreamSink(config.getBotId().getToken()+"-StdOutSink", botProcess.getInputStream(), log, config.getBotId().getToken()+"-StdOut");
 	        } else {
 	        	streamSinkOutput = new StreamSink(config.getBotId().getToken()+"-StdOutSink", botProcess.getInputStream());
 	        }
 	        streamSinkOutput.start();
 	        shutDownHookThread = new Thread(shutDownHook, config.getBotId().getToken()+"-JVMShutdownHook");
 	        Runtime.getRuntime().addShutdownHook(shutDownHookThread);
 	        waitForEndThread = new Thread(waitForEnd, config.getBotId().getToken()+"-WaitForProcessEnd");
 	        running.setFlag(true);    // we're ONLINE!
 	        waitForEndThread.start(); // execute the thread that will wait for the end of the process to switch 'running' back to false
 		}
 	}
 	
 	/**
 	 * Shutdowns the process and cleans-up everything, preparing the object to be {@link UT2004BotExecution#start()}ed again.
 	 * @param waitForEndThread whether we're being called from the {@link UT2004BotExecution#waitForEnd} thread.
 	 */
 	protected void shutdown(boolean waitForEndThread) {
 		synchronized(running) {
 			if (!running.getFlag()) {
 				// we're not running, screw it!
 				return;
 			}
 			
 			if (log != null && log.isLoggable(Level.WARNING)) {
 				log.warning("Shutting down botProcess(" + config.getBotId().getToken() + ")!");
 			}
 
 			if (log != null && log.isLoggable(Level.WARNING)) {
 				log.warning("... destroying botProcess(" + config.getBotId().getToken() + ").");
 			}
 			if (botProcess != null) {
 				try {
 					botProcess.destroy();
 				} catch (Exception e) {
 				}
 			}
 			botProcess = null;
 			
 			if (log != null && log.isLoggable(Level.WARNING)) {
 				log.warning("... destroying streamSinkError(" + config.getBotId().getToken() + ").");
 			}
 			try {
 				if (streamSinkError != null) streamSinkError.interrupt();
 			} catch (Exception e) {
 			}
 			streamSinkError = null;
 			
 			if (log != null && log.isLoggable(Level.WARNING)) {
 				log.warning("... destroying streamSinkOutput(" + config.getBotId().getToken() + ").");
 			}
 			try {
 				if (streamSinkOutput != null) streamSinkOutput.interrupt();
 			} catch (Exception e) {
 			}
 			streamSinkOutput = null;
 			
 			if (log != null && log.isLoggable(Level.WARNING)) {
 				log.warning("... destroying waitForEnd(" + config.getBotId().getToken() + ").");
 			}
 			if (!waitForEndThread) {
 				try {
 					if (this.waitForEndThread != null) this.waitForEndThread.interrupt();
 				} catch (Exception e) {
 				}
 			}
 			this.waitForEndThread = null;
 			
 			if (log != null && log.isLoggable(Level.WARNING)) {
 				log.warning("... removing shutDownHook(" + config.getBotId().getToken() + ").");
 			}
 			if (shutDownHookThread != null) {
 				try {
 					Runtime.getRuntime().removeShutdownHook(shutDownHookThread);
 				} catch (Exception e) {
 				}	
 			}
 			shutDownHookThread = null;
 			
 			if (log != null && log.isLoggable(Level.WARNING)) {
 				log.warning("... setting running-flag(" + config.getBotId().getToken() + ") to FALSE.");
 			}
 			running.setFlag(false);
 			
 			if (log != null && log.isLoggable(Level.WARNING)) {
 				log.warning("Shutdown(" + config.getBotId().getToken() + ") finished.");
 			}
 		}
 	}
 	
 	/**
 	 * Shuts down the bot process (if it is running, otherwise does nothing).
 	 */
 	public void stop() {
 		shutdown(false);
 	}
     
     /**
      * Process of the bot (non-null if started).
      * @return
      */
     public Process getBotProcess() {
         return botProcess;
     }
 	
     /**
      * Flag of the state of the bot process. True == process is running (has been started using {@link UT2004BotExecution#start()}), 
      * False == process was not started or has been already terminated, either by itself or via {@link UT2004BotExecution#stop()}.
      * @return
      */
 	public ImmutableFlag<Boolean> getRunning() {
 		return running.getImmutable();
 	}
 	
 	/**
 	 * Flag of the state of the bot process. True == process is running (has been started using {@link UT2004BotExecution#start()}), 
      * False == process was not started or has been already terminated, either by itself or via {@link UT2004BotExecution#stop()}.
 	 * @return
 	 */
 	public boolean isRunning() {
 		return running.getFlag();
 	}
 	
 }