package org.apache.maven.shared.filtering;
   
   /*
    * 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 org.codehaus.plexus.interpolation.InterpolationException;
  import org.codehaus.plexus.interpolation.Interpolator;
  import org.codehaus.plexus.interpolation.RecursionInterceptor;
  import org.codehaus.plexus.interpolation.SimpleRecursionInterceptor;
  
  import java.io.BufferedReader;
  import java.io.FilterReader;
  import java.io.IOException;
  import java.io.Reader;
  
  /**
   * A FilterReader implementation, that works with Interpolator interface instead of it's own interpolation
   * implementation. This implementation is heavily based on org.codehaus.plexus.util.InterpolationFilterReader.
   *
   * @author cstamas
   * @author Olivier Lamy
   *
   * @since 1.0
   */
  public class InterpolatorFilterReaderLineEnding
      extends FilterReader
  {
  
      /**
       * Interpolator used to interpolate
       */
      private Interpolator interpolator;
  
      private RecursionInterceptor recursionInterceptor;
  
      /**
       * replacement text from a token
       */
      private String replaceData = null;
  
      /**
       * Index into replacement data
       */
      private int replaceIndex = 0;
  
      /**
       * Default begin token.
       */
      public static final String DEFAULT_BEGIN_TOKEN = "${";
  
      /**
       * Default end token.
       */
      public static final String DEFAULT_END_TOKEN = "}";
  
      private String beginToken;
  
      private String endToken;
  
      /**
       * true by default to preserve backward comp
       */
      private boolean interpolateWithPrefixPattern = true;
  
      private String escapeString;
  
      private boolean useEscape = false;
  
      /**
       * if true escapeString will be preserved \{foo} -> \{foo}
       */
      private boolean preserveEscapeString = false;
  
      private boolean supportMultiLineFiltering;
  
      /**
       * must always be bigger than escape string plus delimiters, but doesn't need to be exact
       */
      private int markLength = 16;
  
      private boolean eof = false;
  
      /**
      * @param in                        reader to use
      * @param interpolator              interpolator instance to use
      * @param beginToken                start token to use
      * @param endToken                  end token to use
      * @param supportMultiLineFiltering If multi line filtering is allowed
      */
     public InterpolatorFilterReaderLineEnding( Reader in, Interpolator interpolator, String beginToken, String endToken,
                                                boolean supportMultiLineFiltering )
     {
         this( in, interpolator, beginToken, endToken, new SimpleRecursionInterceptor(), supportMultiLineFiltering );
     }
 
     /**
      * @param in                        reader to use
      * @param interpolator              interpolator instance to use
      * @param beginToken                start token to use
      * @param endToken                  end token to use
      * @param ri                        The {@link RecursionInterceptor} to use to prevent recursive expressions.
      * @param supportMultiLineFiltering If multi line filtering is allowed
      */
     private InterpolatorFilterReaderLineEnding( Reader in, Interpolator interpolator, String beginToken,
                                                 String endToken, RecursionInterceptor ri,
                                                 boolean supportMultiLineFiltering )
     {
         // wrap our own buffer, so we can use mark/reset safely.
         super( new BufferedReader( in ) );
 
         this.interpolator = interpolator;
 
         this.beginToken = beginToken;
 
         this.endToken = endToken;
 
         recursionInterceptor = ri;
 
         this.supportMultiLineFiltering = supportMultiLineFiltering;
 
         calculateMarkLength();
 
     }
 
     /**
      * Skips characters. This method will block until some characters are available, an I/O error occurs, or the end of
      * the stream is reached.
      *
      * @param n The number of characters to skip
      * @return the number of characters actually skipped
      * @throws IllegalArgumentException If <code>n</code> is negative.
      * @throws IOException              If an I/O error occurs
      */
     public long skip( long n )
         throws IOException
     {
         if ( n < 0L )
         {
             throw new IllegalArgumentException( "skip value is negative" );
         }
 
         for ( long i = 0; i < n; i++ )
         {
             if ( read() == -1 )
             {
                 return i;
             }
         }
         return n;
     }
 
     /**
      * Reads characters into a portion of an array. This method will block until some input is available, an I/O error
      * occurs, or the end of the stream is reached.
      *
      * @param cbuf Destination buffer to write characters to. Must not be <code>null</code>.
      * @param off  Offset at which to start storing characters.
      * @param len  Maximum number of characters to read.
      * @return the number of characters read, or -1 if the end of the stream has been reached
      * @throws IOException If an I/O error occurs
      */
     public int read( char cbuf[], int off, int len )
         throws IOException
     {
         for ( int i = 0; i < len; i++ )
         {
             int ch = read();
             if ( ch == -1 )
             {
                 if ( i == 0 )
                 {
                     return -1;
                 }
                 else
                 {
                     return i;
                 }
             }
             cbuf[off + i] = (char) ch;
         }
         return len;
     }
 
     /**
      * Returns the next character in the filtered stream, replacing tokens from the original stream.
      *
      * @return the next character in the resulting stream, or -1 if the end of the resulting stream has been reached
      * @throws IOException if the underlying stream throws an IOException during reading
      */
     public int read()
         throws IOException
     {
         if ( replaceIndex > 0 )
         {
             return replaceData.charAt( replaceData.length() - ( replaceIndex-- ) );
         }
         if ( eof )
         {
             return -1;
         }
 
         in.mark( markLength );
 
         int ch = in.read();
         if ( ( ch == -1 ) || ( ch == '\n' && !supportMultiLineFiltering ) )
         {
             return ch;
         }
 
         boolean inEscape = ( useEscape && ch == escapeString.charAt( 0 ) );
 
         StringBuffer key = new StringBuffer();
 
         // have we found an escape string?
         if ( inEscape )
         {
             for ( int i = 0; i < escapeString.length(); i++ )
             {
                 key.append( (char) ch );
 
                 if ( ch != escapeString.charAt( i ) || ch == -1 || ( ch == '\n' && !supportMultiLineFiltering ) )
                 {
                     // mismatch, EOF or EOL, no escape string here
                     in.reset();
                     inEscape = false;
                     key.setLength( 0 );
                     break;
                 }
 
                 ch = in.read();
 
             }
 
         }
 
         // have we found a delimiter?
         boolean foundToken = false;
         for ( int i = 0; i < beginToken.length(); i++ )
         {
             if ( ch != beginToken.charAt( i ) || ch == -1 || ( ch == '\n' && !supportMultiLineFiltering ) )
             {
                 // mismatch, EOF or EOL, no match
                 break;
             }
 
             if ( i == beginToken.length() - 1 )
             {
 
                 foundToken = true;
 
             }
 
             ch = in.read();
 
         }
 
         in.reset();
         in.skip( key.length() );
         ch = in.read();
 
         // escape means no luck, prevent parsing of the escaped character, and return
         if ( inEscape )
         {
 
             if ( beginToken != null )
             {
                 if ( !preserveEscapeString )
                 {
                     key.setLength( 0 );
                 }
             }
 
             key.append( (char) ch );
 
             replaceData = key.toString();
             replaceIndex = key.length();
 
             return read();
 
         }
 
         // no match means no luck, reset and return
         if ( !foundToken )
         {
 
             in.reset();
             return in.read();
 
         }
 
         // we're committed, find the end token, EOL or EOF
 
         key.append( beginToken );
         in.reset();
         in.skip( beginToken.length() );
         ch = in.read();
 
         int endTokenSize = endToken.length();
         int end = endTokenSize;
         do
         {
             if ( ch == -1 )
             {
                 break;
             }
             else if ( ch == '\n' && !supportMultiLineFiltering )
             {
                 // EOL
                 key.append( (char) ch );
                 break;
             }
 
             key.append( (char) ch );
 
             if ( ch == this.endToken.charAt( endTokenSize - end ) )
             {
                 end--;
                 if ( end == 0 )
                 {
                     break;
                 }
             }
             else
             {
                 end = endTokenSize;
             }
 
             ch = in.read();
         }
         while ( true );
 
         // found endtoken? interpolate our key resolved above
         String value = null;
         if ( end == 0 )
         {
             try
             {
                 if ( interpolateWithPrefixPattern )
                 {
                     value = interpolator.interpolate( key.toString(), "", recursionInterceptor );
                 }
                 else
                 {
                     value = interpolator.interpolate( key.toString(), recursionInterceptor );
                 }
             }
             catch ( InterpolationException e )
             {
                 IllegalArgumentException error = new IllegalArgumentException( e.getMessage() );
                 error.initCause( e );
 
                 throw error;
             }
         }
 
         // write away the value if present, otherwise the key unmodified
         if ( value != null )
         {
             replaceData = value;
             replaceIndex = value.length();
         }
         else
         {
             replaceData = key.toString();
             replaceIndex = key.length();
         }
 
         if ( ch == -1 )
         {
             eof = true;
         }
         return read();
 
     }
 
     public boolean isInterpolateWithPrefixPattern()
     {
         return interpolateWithPrefixPattern;
     }
 
     public void setInterpolateWithPrefixPattern( boolean interpolateWithPrefixPattern )
     {
         this.interpolateWithPrefixPattern = interpolateWithPrefixPattern;
     }
 
     public String getEscapeString()
     {
         return escapeString;
     }
 
     public void setEscapeString( String escapeString )
     {
         // TODO NPE if escapeString is null ?
         if ( escapeString != null && escapeString.length() >= 1 )
         {
             this.escapeString = escapeString;
             this.useEscape = escapeString != null && escapeString.length() >= 1;
             calculateMarkLength();
         }
     }
 
     public boolean isPreserveEscapeString()
     {
         return preserveEscapeString;
     }
 
     public void setPreserveEscapeString( boolean preserveEscapeString )
     {
         this.preserveEscapeString = preserveEscapeString;
     }
 
     public RecursionInterceptor getRecursionInterceptor()
     {
         return recursionInterceptor;
     }
 
     public InterpolatorFilterReaderLineEnding setRecursionInterceptor( RecursionInterceptor recursionInterceptor )
     {
         this.recursionInterceptor = recursionInterceptor;
         return this;
     }
 
     private void calculateMarkLength()
     {
         markLength = 16;
 
         if ( escapeString != null )
         {
             markLength += escapeString.length();
         }
 
         if ( beginToken != null )
         {
             markLength += beginToken.length();
         }
 
         if ( endToken != null )
         {
             markLength += endToken.length();
         }
 
     }
 
 }