/*
 * $Header: /home/cvs/jakarta-commons-sandbox/cli/src/java/org/apache/commons/cli/CommandLine.java,v 1.4 2002/06/06 22:32:37 bayard Exp $
 * $Revision: 1.4 $
 * $Date: 2002/06/06 22:32:37 $
 *
 * ====================================================================
 *
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 1999-2001 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Commons", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache"
 *    nor may "Apache" appear in their names without prior written
 *    permission of the Apache Group.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */

package org.apache.commons.cli;

import java.io.PrintWriter;
import java.util.Iterator;
import java.util.List;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;

/** 
 * A formatter of help messages for the current command line options
 *
 * @author Slawek Zachcial
 * @author John Keyes (jbjk at mac.com)
 **/
public class HelpFormatter
{
   // --------------------------------------------------------------- Constants

   public static final int DEFAULT_WIDTH              = 80;
   public static final int DEFAULT_LEFT_PAD           = 1;
   public static final int DEFAULT_DESC_PAD           = 3;
   public static final String DEFAULT_SYNTAX_PREFIX   = "usage: ";
   public static final String DEFAULT_OPT_PREFIX      = "-";
   public static final String DEFAULT_LONG_OPT_PREFIX = "--";
   public static final String DEFAULT_ARG_NAME        = "arg";

   // ------------------------------------------------------------------ Static

   // -------------------------------------------------------------- Attributes

   public int defaultWidth;
   public int defaultLeftPad;
   public int defaultDescPad;
   public String defaultSyntaxPrefix;
   public String defaultNewLine;
   public String defaultOptPrefix;
   public String defaultLongOptPrefix;
   public String defaultArgName;

   // ------------------------------------------------------------ Constructors
   public HelpFormatter()
   {
      defaultWidth = DEFAULT_WIDTH;
      defaultLeftPad = DEFAULT_LEFT_PAD;
      defaultDescPad = DEFAULT_DESC_PAD;
      defaultSyntaxPrefix = DEFAULT_SYNTAX_PREFIX;
      defaultNewLine = System.getProperty("line.separator");
      defaultOptPrefix = DEFAULT_OPT_PREFIX;
      defaultLongOptPrefix = DEFAULT_LONG_OPT_PREFIX;
      defaultArgName = DEFAULT_ARG_NAME;
   }

   // ------------------------------------------------------------------ Public

   public void printHelp( String cmdLineSyntax,
                          Options options )
   {
      printHelp( defaultWidth, cmdLineSyntax, null, options, null );
   }

   public void printHelp( String cmdLineSyntax,
                          String header,
                          Options options,
                          String footer )
   {
      printHelp(defaultWidth, cmdLineSyntax, header, options, footer);
   }

   public void printHelp( int width,
                          String cmdLineSyntax,
                          String header,
                          Options options,
                          String footer )
   {
      PrintWriter pw = new PrintWriter(System.out);
      printHelp( pw, width, cmdLineSyntax, header,
                 options, defaultLeftPad, defaultDescPad, footer );
      pw.flush();
   }

   public void printHelp( PrintWriter pw,
                          int width,
                          String cmdLineSyntax,
                          String header,
                          Options options,
                          int leftPad,
                          int descPad,
                          String footer )
      throws IllegalArgumentException
   {
      if ( cmdLineSyntax == null || cmdLineSyntax.length() == 0 )
      {
         throw new IllegalArgumentException("cmdLineSyntax not provided");
      }

      printUsage( pw, width, cmdLineSyntax );
      if ( header != null && header.trim().length() > 0 )
      {
         printWrapped( pw, width, header );
      }
      printOptions( pw, width, options, leftPad, descPad );
      if ( footer != null && footer.trim().length() > 0 )
      {
         printWrapped( pw, width, footer );
      }
   }

   public void printUsage( PrintWriter pw, int width, String cmdLineSyntax )
   {
      int argPos = cmdLineSyntax.indexOf(' ') + 1;
      printWrapped(pw, width, defaultSyntaxPrefix.length() + argPos,
                   defaultSyntaxPrefix + cmdLineSyntax);
   }

   public void printOptions( PrintWriter pw, int width, Options options, int leftPad, int descPad )
   {
      StringBuffer sb = new StringBuffer();
      renderOptions(sb, width, options, leftPad, descPad);
      pw.println(sb.toString());
   }

   public void printWrapped( PrintWriter pw, int width, String text )
   {
      printWrapped(pw, width, 0, text);
   }

   public void printWrapped( PrintWriter pw, int width, int nextLineTabStop, String text )
   {
      StringBuffer sb = new StringBuffer(text.length());
      renderWrappedText(sb, width, nextLineTabStop, text);
      pw.println(sb.toString());
   }

   // --------------------------------------------------------------- Protected

   protected StringBuffer renderOptions( StringBuffer sb,
                                         int width,
                                         Options options,
                                         int leftPad,
                                         int descPad )
   {
      final String lpad = createPadding(leftPad);
      final String dpad = createPadding(descPad);

      //first create list containing only <lpad>-a,--aaa where -a is opt and --aaa is
      //long opt; in parallel look for the longest opt string
      //this list will be then used to sort options ascending
      int max = 0;
      StringBuffer optBuf;
      List prefixList = new ArrayList();
      Option option;
      for ( Iterator i = options.getOptions().iterator(); i.hasNext(); )
      {
         option = (Option) i.next();
         optBuf = new StringBuffer(8);
         optBuf.append(lpad).append(defaultOptPrefix).append(option.getOpt());
         if ( option.hasLongOpt() )
         {
            optBuf.append(',').append(defaultLongOptPrefix).append(option.getLongOpt());
         }
         if ( option.hasArg() )
         {
            //FIXME - should have a way to specify arg name per option
            optBuf.append(' ').append(defaultArgName);
         }
         prefixList.add(optBuf);
         max = optBuf.length() > max ? optBuf.length() : max;
      }

      //right pad the prefixes
      for ( Iterator i = prefixList.iterator(); i.hasNext(); )
      {
         optBuf = (StringBuffer) i.next();
         if ( optBuf.length() < max )
         {
            optBuf.append(createPadding(max-optBuf.length()));
         }
         optBuf.append(dpad);
      }

      //sort this list ascending
      Collections.sort(prefixList, new StringBufferComparator());

      //finally render options
      int nextLineTabStop = max + descPad;
      String opt;
      int optOffset = leftPad + defaultOptPrefix.length();

      for ( Iterator i = prefixList.iterator(); i.hasNext(); )
      {
         optBuf = (StringBuffer) i.next();
         opt = optBuf.toString();
         if( opt.indexOf( ',' ) != -1 ) {
             opt = opt.substring( optOffset, opt.indexOf( ',', optOffset ) );
         }
         else {
             opt = opt.substring( optOffset, opt.indexOf( ' ', optOffset ) );
         }
         option = options.getOption( "-" + opt );

         renderWrappedText(sb, width, nextLineTabStop,
                           optBuf.append(option.getDescription()).toString());
         if ( i.hasNext() )
         {
            sb.append(defaultNewLine);
         }
      }

      return sb;
   }

   protected StringBuffer renderWrappedText( StringBuffer sb,
                                             int width,
                                             int nextLineTabStop,
                                             String text )
   {
      int pos = findWrapPos( text, width, 0);
      if ( pos == -1 )
      {
         sb.append(rtrim(text));
         return sb;
      }
      else
      {
         sb.append(rtrim(text.substring(0, pos))).append(defaultNewLine);
      }

      //all following lines must be padded with nextLineTabStop space characters
      final String padding = createPadding(nextLineTabStop);

      while ( true )
      {
         text = padding + text.substring(pos).trim();
         pos = findWrapPos( text, width, nextLineTabStop );
         if ( pos == -1 )
         {
            sb.append(text);
            return sb;
         }

         sb.append(rtrim(text.substring(0, pos))).append(defaultNewLine);
      }

   }

   /**
    * Finds the next text wrap position after <code>startPos</code> for the text
    * in <code>sb</code> with the column width <code>width</code>.
    * The wrap point is the last postion before startPos+width having a whitespace
    * character (space, \n, \r).
    *
    * @param sb text to be analyzed
    * @param width width of the wrapped text
    * @param startPos position from which to start the lookup whitespace character
    * @return postion on which the text must be wrapped or -1 if the wrap position is at the end
    *         of the text
    */
   protected int findWrapPos( String text, int width, int startPos )
   {
      int pos = -1;
      // the line ends before the max wrap pos or a new line char found
      if ( ((pos = text.indexOf('\n', startPos)) != -1 && pos <= width)  ||
           ((pos = text.indexOf('\t', startPos)) != -1 && pos <= width) )
      {
         return pos;
      }
      else if ( (startPos + width) >= text.length() )
      {
         return -1;
      }

      //look for the last whitespace character before startPos+width
      pos = startPos + width;
      char c;
      while ( pos >= startPos && (c = text.charAt(pos)) != ' ' && c != '\n' && c != '\r' )
      {
         --pos;
      }
      //if we found it - just return
      if ( pos > startPos )
      {
         return pos;
      }
      else
      {
         //must look for the first whitespace chearacter after startPos + width
         pos = startPos + width;
         while ( pos <= text.length() && (c = text.charAt(pos)) != ' ' && c != '\n' && c != '\r' )
         {
            ++pos;
         }
         return pos == text.length() ? -1 : pos;
      }
   }

   protected String createPadding(int len)
   {
      StringBuffer sb = new StringBuffer(len);
      for ( int i = 0; i < len; ++i )
      {
         sb.append(' ');
      }
      return sb.toString();
   }

   protected String rtrim( String s )
   {
      if ( s == null || s.length() == 0 )
      {
         return s;
      }

      int pos = s.length();
      while ( pos >= 0 && Character.isWhitespace(s.charAt(pos-1)) )
      {
         --pos;
      }
      return s.substring(0, pos);
   }

   // ------------------------------------------------------- Package protected
   
   // ----------------------------------------------------------------- Private
   
   // ----------------------------------------------------------- Inner classes

   private static class StringBufferComparator
   implements Comparator
   {
      public int compare( Object o1, Object o2 )
      {
         return ((StringBuffer) o1).toString().compareTo(((StringBuffer) o2).toString());
      }
   }
}