/*
    * JBoss, Home of Professional Open Source.
    * Copyright 2013, Red Hat Middleware LLC, and individual contributors
    * as indicated by the @author tags. See the copyright.txt file in the
    * distribution for a full listing of individual contributors.
    *
    * This is free software; you can redistribute it and/or modify it
    * under the terms of the GNU Lesser General Public License as
    * published by the Free Software Foundation; either version 2.1 of
   * the License, or (at your option) any later version.
   *
   * This software is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this software; if not, write to the Free
   * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
   * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
   */
  package org.redhat.vmtruckloader.util;
  
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.FileNotFoundException;
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.io.OutputStreamWriter;
  import java.io.Reader;
  import java.io.Writer;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Scanner;
  
  /**
   * 
   * @author Romain Pelisse - romain@redhat.com
   *
   */
  public final class FileUtils {
  
  	private final static String DEFAULT_FILE_ENCODING = "UTF-8";
  	
  	private FileUtils() {}
  	
  	public static Reader constructReaderFromClasspathResource(final String filename) {
  		try {
  			return new InputStreamReader(FileUtils.getClassLoader().getResourceAsStream(filename));
  		} catch ( Exception e) {
  			final String errorMssg = "Can't read file " + filename + " from classloader.";
  			throw new IllegalStateException(errorMssg,e);
  		}		
  	}
  	
  	private static ClassLoader getClassLoader() {
  		return Thread.currentThread().getContextClassLoader();
  	}
  
  	public static String getFileEncoding() {
          String fileEncoding = System.getProperty("file.encoding");
          if ( fileEncoding == null || "".equals(fileEncoding))
           	fileEncoding = DEFAULT_FILE_ENCODING;       	// Fallback to UTF-8 default encoding
          return fileEncoding;
  	}
  
  	public static boolean exists(String filename) {
  		return new File(filename).exists();
  	}
  
      public static void write(String filename, String text) {
          String fileEncoding = FileUtils.getFileEncoding();
          Writer out = null;
          try {
          	out = new OutputStreamWriter(new FileOutputStream(filename), fileEncoding);
              out.write(text);
              out.flush();
  			if (out != null )
  				out.close();
          } catch (IOException e) {
  			throw new IllegalStateException(e);
  		}
      }
      
      public static String read(String fileName) {
          String fileEncoding = getFileEncoding();
          StringBuilder text = new StringBuilder();
  
          Scanner scanner = null;
          try {
              scanner = new Scanner(new FileInputStream(fileName), fileEncoding);
              while (scanner.hasNextLine()) {
                  text.append(scanner.nextLine());
              }
          } catch (FileNotFoundException e) {
          	throw new IllegalStateException(e);
  		} finally {
          	if ( scanner != null )
         		scanner.close();
         }
         return text.toString();
     }
 	
 
     public static List<String> readLineByLine(File file) {
     	if ( file == null )
     		throw new IllegalArgumentException("Provided was file object was 'null'");
     	if ( ! file.exists())
     		throw new IllegalArgumentException("File " + file.getAbsolutePath() + " does not exist");
     	if ( ! file.canRead() )
     		throw new IllegalArgumentException("File " + file.getAbsolutePath() + " can't be read");
 
     	return readLineByLine(file.getAbsoluteFile().toString());
     }
 
     public static List<String> readLineByLine(String fileName) {
         String fileEncoding = getFileEncoding();        
         List<String> lines = new ArrayList<String>();
         Scanner scanner = null;
         try {
             scanner = new Scanner(new FileInputStream(fileName), fileEncoding);
             while (scanner.hasNextLine()) {
             	lines.add(scanner.nextLine());
             }
         } catch (FileNotFoundException e) {
         	throw new IllegalStateException(e);
 		} finally {
         	if ( scanner != null )
         		scanner.close();
         }
         return lines;
     }
 
     
 	public static void delete(String outputFilename) {
 		final File file = new File(outputFilename);
 		if ( file.exists() && file.canWrite() && file.isFile() ) file.delete();
 	}
 }