/*
 * $Header: /mnt/cvs/XEMELIOS/src/core/java/org/apache/commons/cli/PosixParser.java,v 1.1 2008/09/23 12:47:44 chm Exp $
 * $Revision: 1.1 $
 * $Date: 2008/09/23 12:47:44 $
 *
 * ====================================================================
 *
 * 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"
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 *
 * 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
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 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 * 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.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;

/**
 * The class PosixParser provides an implementation of the 
 * {@link Parser#flatten(Options,String[],boolean) flatten} method.
 *
 * @author John Keyes (john at integralsource.com)
 * @see Parser
 * @version $Revision: 1.1 $
 */
public class PosixParser extends Parser {

    /** holder for flattened tokens */
    private ArrayList tokens = new ArrayList();
    /** specifies if bursting should continue */
    private boolean eatTheRest;
    /** holder for the current option */
    private Option currentOption;
    /** the command line Options */
    private Options options;

    /**
     * <p>Resets the members to their original state i.e. remove
     * all of <code>tokens</code> entries, set <code>eatTheRest</code>
     * to false and set <code>currentOption</code> to null.</p>
     */
    private void init() {
        eatTheRest = false;
        tokens.clear();
        currentOption = null;
    }

    /**
     * <p>An implementation of {@link Parser}'s abstract
     * {@link Parser#flatten(Options,String[],boolean) flatten} method.</p>
     *
     * <p>The following are the rules used by this flatten method.
     * <ol>
     *  <li>if <code>stopAtNonOption</code> is <b>true</b> then do not
     *  burst anymore of <code>arguments</code> entries, just add each
     *  successive entry without further processing.  Otherwise, ignore
     *  <code>stopAtNonOption</code>.</li>
     *  <li>if the current <code>arguments</code> entry is "<b>--</b>"
     *  just add the entry to the list of processed tokens</li>
     *  <li>if the current <code>arguments</code> entry is "<b>-</b>"
     *  just add the entry to the list of processed tokens</li>
     *  <li>if the current <code>arguments</code> entry is two characters
     *  in length and the first character is "<b>-</b>" then check if this
     *  is a valid {@link Option} id.  If it is a valid id, then add the
     *  entry to the list of processed tokens and set the current {@link Option}
     *  member.  If it is not a valid id and <code>stopAtNonOption</code>
     *  is true, then the remaining entries are copied to the list of 
     *  processed tokens.  Otherwise, the current entry is ignored.</li>
     *  <li>if the current <code>arguments</code> entry is more than two
     *  characters in length and the first character is "<b>-</b>" then
     *  we need to burst the entry to determine its constituents.  For more
     *  information on the bursting algorithm see 
     *  {@link PosixParser#burstToken( String, boolean) burstToken}.</li>
     *  <li>if the current <code>arguments</code> entry is not handled 
     *  by any of the previous rules, then the entry is added to the list
     *  of processed tokens.</li>
     * </ol>
     * </p>
     *
     * @param options The command line {@link Options}
     * @param arguments The command line arguments to be parsed
     * @param stopAtNonOption Specifies whether to stop flattening
     * when an non option is found.
     * @return The flattened <code>arguments</code> String array.
     */
    protected String[] flatten( Options options, 
                                String[] arguments, 
                                boolean stopAtNonOption )
    {
        init();
        this.options = options;

        // an iterator for the command line tokens
        Iterator iter = Arrays.asList( arguments ).iterator();
        String token = null;
        
        // process each command line token
        while ( iter.hasNext() ) {

            // get the next command line token
            token = (String) iter.next();

            // handle SPECIAL TOKEN
            if( token.startsWith( "--" ) ) {
                if( token.indexOf( '=' ) != -1 ) {
                    tokens.add( token.substring( 0, token.indexOf( '=' ) ) );
                    tokens.add( token.substring( token.indexOf( '=' ) + 1,
                                                 token.length() ) );
                }
                else {
                    tokens.add( token );
                }	
            }
            // single hyphen
            else if( "-".equals( token ) ) {
                processSingleHyphen( token );
            }
            else if( token.startsWith( "-" ) ) {
                int tokenLength = token.length();
                if( tokenLength == 2 ) {
                    processOptionToken( token, stopAtNonOption );
                }
                // requires bursting
                else {
                    burstToken( token, stopAtNonOption );
                }
            }
            else {
                if( stopAtNonOption ) {
                    process( token );
                }
                else {
                    tokens.add( token );
                }
            }

            gobble( iter );
        }

        return (String[])tokens.toArray( new String[] {} );
    }

    /**
     * <p>Adds the remaining tokens to the processed tokens list.</p>
     *
     * @param iter An iterator over the remaining tokens
     */
    private void gobble( Iterator iter ) {
        if( eatTheRest ) {
            while( iter.hasNext() ) {
                tokens.add( iter.next() );
            }
        }
    }

    /**
     * <p>If there is a current option and it can have an argument
     * value then add the token to the processed tokens list and 
     * set the current option to null.</p>
     * <p>If there is a current option and it can have argument
     * values then add the token to the processed tokens list.</p>
     * <p>If there is not a current option add the special token
     * "<b>--</b>" and the current <code>value</code> to the processed
     * tokens list.  The add all the remaining <code>argument</code>
     * values to the processed tokens list.</p>
     *
     * @param value The current token
     */
    private void process( String value ) {
        if( currentOption != null && currentOption.hasArg() ) {
            if( currentOption.hasArg() ) {
                tokens.add( value );
                currentOption = null;
            }
            else if (currentOption.hasArgs() ) {
                tokens.add( value );
            }
        }
        else {
            eatTheRest = true;
            tokens.add( "--" );
            tokens.add( value );
        }
    }

    /**
     * <p>If it is a hyphen then add the hyphen directly to
     * the processed tokens list.</p>
     *
     * @param hyphen The hyphen token
     */
    private void processSingleHyphen( String hyphen ) {
        tokens.add( hyphen );
    }

    /**
     * <p>If an {@link Option} exists for <code>token</code> then
     * set the current option and add the token to the processed 
     * list.</p>
     * <p>If an {@link Option} does not exist and <code>stopAtNonOption</code>
     * is set then ignore the current token and add the remaining tokens
     * to the processed tokens list directly.</p>
     *
     * @param token The current option token
     * @param stopAtNonOption Specifies whether flattening should halt
     * at the first non option.
     */
    private void processOptionToken( String token, boolean stopAtNonOption ) {
        if( this.options.hasOption( token ) ) {
            currentOption = this.options.getOption( token );
            tokens.add( token );
        }
        else if( stopAtNonOption ) {
            eatTheRest = true;
        }
    }

    /**
     * <p>Breaks <code>token</code> into its constituent parts
     * using the following algorithm.
     * <ul>
     *  <li>ignore the first character ("<b>-</b>" )</li>
     *  <li>foreach remaining character check if an {@link Option}
     *  exists with that id.</li>
     *  <li>if an {@link Option} does exist then add that character
     *  prepended with "<b>-</b>" to the list of processed tokens.</li>
     *  <li>if the {@link Option} can have an argument value and there 
     *  are remaining characters in the token then add the remaining 
     *  characters as a token to the list of processed tokens.</li>
     *  <li>if an {@link Option} does <b>NOT</b> exist <b>AND</b> 
     *  <code>stopAtNonOption</code> <b>IS</b> set then add the special token
     *  "<b>--</b>" followed by the remaining characters and also 
     *  the remaining tokens directly to the processed tokens list.</li>
     *  <li>if an {@link Option} does <b>NOT</b> exist <b>AND</b>
     *  <code>stopAtNonOption</code> <b>IS NOT</b> set then add that
     *  character prepended with "<b>-</b>".</li>
     * </ul>
     * </p>
     */
    protected void burstToken( String token, boolean stopAtNonOption ) {
        int tokenLength = token.length();

        for( int i = 1; i < tokenLength; i++) {
            String ch = String.valueOf( token.charAt( i ) );
            boolean hasOption = options.hasOption( ch );

            if( hasOption ) {
                tokens.add( "-" + ch );
                currentOption = options.getOption( ch );
                if( currentOption.hasArg() && token.length()!=i+1 ) {
                    tokens.add( token.substring( i+1 ) );
                    break;
                }
            }
            else if( stopAtNonOption ) {
                process( token.substring( i ) );
            }
            else {
                tokens.add( "-" + ch );
            }
        }
    }
}
