package org.apache.maven.plugins.assembly.utils;
   
   /*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  
  import java.io.BufferedReader;
  import java.io.BufferedWriter;
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.InputStreamReader;
  import java.io.OutputStreamWriter;
  import java.io.RandomAccessFile;
  
  import org.apache.maven.plugins.assembly.format.AssemblyFormattingException;
  
  /**
   * Line Ending class which contains convenience methods to change line endings.
   */
  public final class LineEndingsUtils
  {
  
      private LineEndingsUtils()
      {
          // prevent creations of instances.
      }
  
      /**
       * Converts the line endings of a file, writing a new file. The encoding of reading and writing can be specified.
       *
       * @param source      The source file, not null
       * @param dest        The destination file, not null
       * @param lineEndings This is the result of the getLineEndingChars(..) method in this utility class; the actual
       *                    line-ending characters, not null.
       * @param atEndOfFile The end-of-file line ending, if true then the resulting file will have a new line at the end
       *                    even if the input didn't have one, if false then the resulting file will have no new line at
       *                    the end even if the input did have one, null to determine whether to have a new line at the
       *                    end of the file based on the input file
       * @param encoding    The encoding to use, null for platform encoding
       * @throws IOException .
       */
      public static void convertLineEndings( final File source, File dest, LineEndings lineEndings,
                                             final Boolean atEndOfFile, String encoding )
          throws IOException
      {
          // MASSEMBLY-637, MASSEMBLY-96
          // find characters at the end of the file
          // needed to preserve the last line ending
          // only check for LF (as CRLF also ends in LF)
          String eofChars = "";
          if ( atEndOfFile == null )
          {
              if ( source.length() >= 1 )
              {
                  try ( RandomAccessFile raf = new RandomAccessFile( source, "r" ) )
                  {
                      raf.seek( source.length() - 1 );
                      byte last = raf.readByte();
                      if ( last == '\n' )
                      {
                          eofChars = lineEndings.getLineEndingCharacters();
                      }
                  }
              }
          }
          else if ( atEndOfFile )
          {
              eofChars = lineEndings.getLineEndingCharacters();
          }
  
          try ( BufferedReader in = getBufferedReader( source, encoding );
                BufferedWriter out = getBufferedWriter( dest, encoding ) )
          {
              String line = in.readLine();
              while ( line != null )
              {
                  out.write( line );
                  line = in.readLine();
                  if ( line != null )
                  {
                      out.write( lineEndings.getLineEndingCharacters() );
                 }
                 else
                 {
                     out.write( eofChars );
                 }
             }
         }
     }
 
     private static BufferedReader getBufferedReader( File source, String encoding ) throws IOException
     {
         if ( encoding == null )
         {
             // platform encoding
             return new BufferedReader( new InputStreamReader( new FileInputStream( source ) ) );
         }
         else
         {
             // MASSEMBLY-371
             return new BufferedReader( new InputStreamReader( new FileInputStream( source ), encoding ) );
         }
     }
 
     private static BufferedWriter getBufferedWriter( File dest, String encoding ) throws IOException
     {
         if ( encoding == null )
         {
             // platform encoding
             return new BufferedWriter( new OutputStreamWriter( new FileOutputStream( dest ) ) );
         }
         else
         {
             // MASSEMBLY-371
             return new BufferedWriter( new OutputStreamWriter( new FileOutputStream( dest ), encoding ) );
         }
     }
 
     /**
      * Converts the line endings of a file, writing a new file. The encoding of reading and writing can be specified.
      *
      * @param in          The source reader
      * @param lineEndings This is the result of the getLineEndingChars(..) method in this utility class; the actual
      *                    line-ending characters, not null.
      * @return an input stream that enforces a specifi line ending style
      */
     @SuppressWarnings( "resource" )
     public static InputStream lineEndingConverter( InputStream in, LineEndings lineEndings )
         throws IOException
     {
         return lineEndings.isNewLine()
             ? new LinuxLineFeedInputStream( in, false )
             : lineEndings.isCrLF() ? new WindowsLineFeedInputStream( in, false ) : in;
     }
 
     public static LineEndings getLineEnding( /* nullable */ String lineEnding )
         throws AssemblyFormattingException
     {
         LineEndings result = LineEndings.keep;
         if ( lineEnding != null )
         {
             try
             {
                 result = LineEndings.valueOf( lineEnding );
             }
             catch ( IllegalArgumentException e )
             {
                 throw new AssemblyFormattingException( "Illegal lineEnding specified: '" + lineEnding + "'", e );
             }
         }
         return result;
     }
 
     /**
      * Returns the appopriate line ending characters for the specified style
      *
      * @param lineEnding The name of the line ending style,
      *                   see org.apache.maven.plugin.assembly.utils.LineEndings#valueOf
      * @return The proper line ending characters
      * @throws AssemblyFormattingException
      */
     public static String getLineEndingCharacters( /* nullable */ String lineEnding )
         throws AssemblyFormattingException
     {
         String value = lineEnding;
 
         if ( lineEnding != null )
         {
             try
             {
                 value = LineEndings.valueOf( lineEnding ).getLineEndingCharacters();
             }
             catch ( IllegalArgumentException e )
             {
                 throw new AssemblyFormattingException( "Illegal lineEnding specified: '" + lineEnding + "'", e );
             }
         }
 
         return value;
     }
 
 }