package cz.cuni.amis.utils;
   
   import java.io.BufferedReader;
   import java.io.File;
   import java.io.FileReader;
   import java.io.FileWriter;
   import java.io.IOException;
   import java.io.PrintWriter;
   import java.util.regex.Pattern;
  
  /**
   * Simple way how to filter your log files...
   */
  public class LogFilter {
  	
  	private File source;
  	private File destination;
  	private Pattern[] accept;
  	private Pattern[] remove;
  
  
  
  	/**
  	 * Opens 'source', writes to 'destination'.
  	 * <p><p>
  	 * Every single line from 'source' is matched against 'accept'. If some pattern matches the line, it goes to 'destination'.<p>
  	 * If not, it is matched against 'remove'. If some pattern matches the line, it is discarded.<p>
  	 * If no pattern matches, the line goes to 'destination'.
  	 * 
  	 * @param source
  	 * @param destination
  	 * @param accept
  	 * @param remove
  	 */
  	public LogFilter(File source, File destination, Pattern[] accept, Pattern[] remove) {
  		this.source = source;
  		this.destination = destination;
  		this.accept = accept;
  		this.remove = remove;
  	}
  
  	public void filter() throws IOException {
  		FileReader fileReader = new FileReader(source);
  		try {
  			BufferedReader reader = new BufferedReader(fileReader);
  			FileWriter fileWriter = new FileWriter(destination);
  			try {
  				PrintWriter writer = new PrintWriter(fileWriter);
  				
  				System.out.println("-= Log filtering =-");
  				System.out.println("Source: " + source.getAbsolutePath());
  				System.out.println("Destin: " + destination.getAbsolutePath());				
  				
  				int lineCount = 0;
  				while (reader.ready()) {
  					boolean next = false;
  					
  					System.out.print(".");
  					++lineCount;
  					if (lineCount % 100 == 0) System.out.println();
  					
  					String line = reader.readLine();
  					
  					for (Pattern a : this.accept) {
  						if (a.matcher(line).find()) {
  							writer.println(line);
  							next = true;
  							break;
  						}
  					}
  					if (next) continue;
  					
  					for (Pattern r : this.remove) {
  						if (r.matcher(line).find()) {						
  							next = true;
  							break;
  						}
  					}
  					if (next) continue;
  										
  					writer.println(line);					
  				}
  				System.out.println();
  				System.out.println("FINISHED");
  			} finally {
  				fileWriter.close();
  			}
  		} finally {
  			fileReader.close();
  		}
  		
  		
  	}
  	
  }