/*
 * Copyright (C) The Apache Software Foundation. All rights reserved.
 *
 * This software is published under the terms of the Apache Software
 * License version 1.1, a copy of which has been included with this
 * distribution in the LICENSE.txt file.  */

package org.apache.log4j;

import java.io.IOException;
import java.io.Writer;
import java.io.FileOutputStream;
import java.io.BufferedWriter;

import org.apache.log4j.spi.ErrorCode;
import org.apache.log4j.helpers.QuietWriter;
import org.apache.log4j.helpers.LogLog;

// Contibutors: Jens Uwe Pipka 
//              Ben Sandee

/**
 *  FileAppender appends log events to a file.
 *
 *  
Support for java.io.Writer and console appending
 *  has been deprecated and then removed. See the replacement
 *  solutions: {@link WriterAppender} and {@link ConsoleAppender}.
 *
 * @author Ceki Gülcü 
 * */
public class FileAppender extends WriterAppender {

  /** Append to or truncate the file? The default value for this
      variable is true, meaning that by default a
      FileAppender will append to an existing file and
      not truncate it.

      
This option is meaningful only if the FileAppender opens the
      file.
  */
  protected boolean fileAppend = true;

  /**
     The name of the log file. */
  protected String fileName = null;

  /**
     Do we do bufferedIO? */
  protected boolean bufferedIO = false;

  /**
     How big should the IO buffer be? Default is 8K. */
  protected int bufferSize = 8*1024;


  /**
     The default constructor does not do anything.
  */
  public
  FileAppender() {
  }

  /**
    Instantiate a FileAppender and open the file
    designated by filename. The opened filename will
    become the output destination for this appender.

    
If the append parameter is true, the file will be
    appended to. Otherwise, the file designated by
    filename will be truncated before being opened.

    
If the bufferedIO parameter is true,
    then buffered IO will be used to write to the output file.

  */
  public
  FileAppender(Layout layout, String filename, boolean append, boolean bufferedIO,
	       int bufferSize) throws IOException {
    this.layout = layout;
    this.setFile(filename, append, bufferedIO, bufferSize);
  }

  /**
    Instantiate a FileAppender and open the file designated by
    filename. The opened filename will become the output
    destination for this appender.

    
If the append parameter is true, the file will be
    appended to. Otherwise, the file designated by
    filename will be truncated before being opened.
  */
  public
  FileAppender(Layout layout, String filename, boolean append)
                                                             throws IOException {
    this.layout = layout;
    this.setFile(filename, append, false, bufferSize);
  }

  /**
     Instantiate a FileAppender and open the file designated by
    filename. The opened filename will become the output
    destination for this appender.

    
The file will be appended to.  */
  public
  FileAppender(Layout layout, String filename) throws IOException {
    this(layout, filename, true);
  }

  /**
     The File property takes a string value which should be the
     name of the file to append to.

     
Note that the special values
     "System.out" or "System.err" are no longer honored.

     
Note: Actual opening of the file is made when {@link
     #activateOptions} is called, not when the options are set.  */
  public void setFile(String file) {
    // Trim spaces from both ends. The users probably does not want
    // trailing spaces in file names.
    String val = file.trim();
    fileName = val;
  }

  /**
      Returns the value of the Append option.
   */
  public
  boolean getAppend() {
    return fileAppend;
  }


  /** Returns the value of the File option. */
  public
  String getFile() {
    return fileName;
  }

  /**
     If the value of File is not null, then {@link
     #setFile} is called with the values of File  and
     Append properties.

     @since 0.8.1 */
  public
  void activateOptions() {
    if(fileName != null) {
      try {
	setFile(fileName, fileAppend, bufferedIO, bufferSize);
      }
      catch(java.io.IOException e) {
	errorHandler.error("setFile("+fileName+","+fileAppend+") call failed.",
			   e, ErrorCode.FILE_OPEN_FAILURE);
      }
    } else {
      //LogLog.error("File option not set for appender ["+name+"].");
      LogLog.warn("File option not set for appender ["+name+"].");
      LogLog.warn("Are you using FileAppender instead of ConsoleAppender?");
    }
  }

 /**
     Closes the previously opened file.
  */
  protected
  void closeFile() {
    if(this.qw != null) {
      try {
	this.qw.close();
      }
      catch(java.io.IOException e) {
	// Exceptionally, it does not make sense to delegate to an
	// ErrorHandler. Since a closed appender is basically dead.
	LogLog.error("Could not close " + qw, e);
      }
    }
  }

  /**
     Get the value of the BufferedIO option.

     
BufferedIO will significatnly increase performance on heavily
     loaded systems.

  */
  public
  boolean getBufferedIO() {
    return this.bufferedIO;
  }


  /**
     Get the size of the IO buffer.
  */
  public
  int getBufferSize() {
    return this.bufferSize;
  }



  /**
     The Append option takes a boolean value. It is set to
     true by default. If true, then File
     will be opened in append mode by {@link #setFile setFile} (see
     above). Otherwise, {@link #setFile setFile} will open
     File in truncate mode.

     
Note: Actual opening of the file is made when {@link
     #activateOptions} is called, not when the options are set.
   */
  public
  void setAppend(boolean flag) {
    fileAppend = flag;
  }

  /**
     The BufferedIO option takes a boolean value. It is set to
     false by default. If true, then File
     will be opened and the resulting {@link java.io.Writer} wrapped
     around a {@link BufferedWriter}.

     BufferedIO will significatnly increase performance on heavily
     loaded systems.

  */
  public
  void setBufferedIO(boolean bufferedIO) {
    this.bufferedIO = bufferedIO;
    if(bufferedIO) {
      immediateFlush = false;
    }
  }


  /**
     Set the size of the IO buffer.
  */
  public
  void setBufferSize(int bufferSize) {
    this.bufferSize = bufferSize;
  }

  /**
    
Sets and opens the file where the log output will
    go. The specified file must be writable.

    
If there was already an opened file, then the previous file
    is closed first.

    
Do not use this method directly. To configure a FileAppender
    or one of its subclasses, set its properties one by one and then
    call activateOptions.

    @param fileName The path to the log file.
    @param append   If true will append to fileName. Otherwise will
        truncate fileName.  */
  public
  synchronized
  void setFile(String fileName, boolean append, boolean bufferedIO, int bufferSize)
                                                            throws IOException {
    LogLog.debug("setFile called: "+fileName+", "+append);

    // It does not make sense to have immediate flush and bufferedIO.
    if(bufferedIO) {
      setImmediateFlush(false);
    }

    reset();
    Writer fw = createWriter(new FileOutputStream(fileName, append));
    if(bufferedIO) {
      fw = new BufferedWriter(fw, bufferSize);
    }
    this.setQWForFiles(fw);
    this.fileName = fileName;
    this.fileAppend = append;
    this.bufferedIO = bufferedIO;
    this.bufferSize = bufferSize;
    writeHeader();
    LogLog.debug("setFile ended");
  }


  /**
     Sets the quiet writer being used.

     This method is overriden by {@link RollingFileAppender}.
   */
  protected
  void setQWForFiles(Writer writer) {
     this.qw = new QuietWriter(writer, errorHandler);
  }


  /**
     Close any previously opened file and call the parent's
     reset.  */
  protected
  void reset() {
    closeFile();
    this.fileName = null;
    super.reset();
  }
}