package cz.cuni.amis.utils;
   
   import java.io.BufferedReader;
   import java.io.IOException;
   import java.io.InputStream;
   import java.io.InputStreamReader;
   import java.util.logging.Level;
   import java.util.logging.Logger;
   
  /**
   * Reads content of the stream and discards it.
   * <p><p>
   * Optionally it may log the content of the stream to some logger (i.e., redirects the output of the stream to some log).
   */
  public class StreamSink extends Thread {
  
      protected InputStream os = null;
  	protected Logger log;
  	protected String logId;
  	protected Level logLevel = Level.INFO;
  
  	/**
  	 * Constructs the sink to silently discard all contents of 'os'.
  	 * @param name name of the sink thread
  	 * @param os stream to be sunk
  	 */
      public StreamSink(String name, InputStream os) {
      	this(name, os, null);
      }
      
      /**
       * Constructs the sink to redirect all output from 'os' into 'log' (used log level is {@link Level#INFO}) as default. May
       * be changed by {@link StreamSink#setLogLevel(Level)}.
       * May 
       * @param name name of the sink thread
       * @param os
       * @param log
       */
      public StreamSink(String name, InputStream os, Logger log) {
      	this(name, os, log, null);
      }
      
      /**
       * Constructs the sink to redirect all output from 'os' into 'log' (used log level is {@link Level#INFO}) as default. May
       * be changed by {@link StreamSink#setLogLevel(Level)}. Additionally all messages from the 'os' will be prefixed with 'logId+" "'.
       * 
       * @param name name of the sink thread
       * @param os
       * @param log
       * @param logId
       */
      public StreamSink(String name, InputStream os, Logger log, String logId) {
      	super(name);
          this.log = log;
          this.logId = logId;
          this.os = os;
      }
      
      public Level getLogLevel() {
  		return logLevel;
  	}
  
  	public StreamSink setLogLevel(Level logLevel) {
  		NullCheck.check(logLevel, "logLevel");
  		this.logLevel = logLevel;
  		return this;
  	}
  	
  	public Logger getLog() {
  		return log;
  	}
  	
  	protected StreamSink setLog(Logger log) {
  		this.log = log;
  		return this;
  	}
  
  	public String getLogId() {
  		return logId;
  	}
  
  	protected StreamSink setLogId(String logId) {
  		this.logId = logId;
  		return this;
  	}
  	
  	protected void handleInput(String str) {
          if (log != null && log.isLoggable(Level.INFO)) {
          	if (logId != null) {
          		log.info(logId + " " + str);
          	} else {
          		log.info(str);
          	}
          }
      }
  
      @Override
      public void run() {
          BufferedReader stdInput = new BufferedReader(new InputStreamReader(os));
 
         String s = null;
         try {
             while ((s = stdInput.readLine()) != null) {
                 handleInput(s);
             }
             os.close();
         } catch (IOException ex) {
             // the process has been closed so reading the line has failed, 
             // don't worry about it
         }
     }
 }