/*

     dsh-commandline  Command line parser based on typed arguments.

     Copyright (c) 2004-2014 held jointly by the individual authors.

     This library is free software; you can redistribute it and/or modify it

     under the terms of the GNU Lesser General Public License as published

     by the Free Software Foundation; either version 3 of the License, or (at

     your option) any later version.

     This library is distributed in the hope that it will be useful, but WITHOUT

     ANY WARRANTY; with out even the implied warranty of MERCHANTABILITY or

     FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public

     License for more details.

     You should have received a copy of the GNU Lesser General Public License

     along with this library;  if not, write to the Free Software Foundation,

     Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA.

     > http://www.fsf.org/licensing/licenses/lgpl.html

     > http://www.opensource.org/licenses/lgpl-license.php

 */

 package org.dishevelled.commandline.argument;

 import org.dishevelled.commandline.Argument;

 import org.dishevelled.commandline.CommandLine;

 /**

  * Abstract implementation of Argument.

  *

  * @param <E> argument type

  * @author  Michael Heuer

  */

 public abstract class AbstractArgument<E>

     implements Argument<E>

 {

     /** Short name. */

     private final String shortName;

     /** Long name. */

     private final String longName;

     /** Description. */

     private final String description;

     /** Is required. */

     private final boolean required;

     /** Value. */

     private E value;

     /** True if this argument was found. */

     private boolean found;

     /**

      * Create a new abstract argument.

      *

      * @param shortName short argument name

      * @param longName long argument name

      * @param description argument description

      * @param required <code>true</code> if this argument is required

      */

     protected AbstractArgument(final String shortName,

                                final String longName,

                                final String description,

                                final boolean required)

     {

         this.shortName = shortName;

         this.longName = longName;

         this.description = description;

         this.required = required;

         this.found = false;

     }

     /** {@inheritDoc} */

     public final void visit(final String current, final CommandLine commandLine)

         throws Exception

     {

         if (isArgumentString(current))

         {

             found = true;

             return;

         }

         if (isValueString(current))

         {

             if (commandLine.hasPrevious())

             {

                 commandLine.previous();

                 if (commandLine.hasPrevious())

                 {

                     String previous = commandLine.previous();

                     if (isArgumentString(previous))

                     {

                         value = convert(current);

                     }

                     commandLine.next();

                 }

                 commandLine.next();

             }

         }

     }

     /**

      * Return true if the specified string is an argument name.

      *

      * @param s string

      * @return true if the specified string is an argument name

      */

     protected boolean isArgumentString(final String s)

     {

         return ("-" + getShortName()).equals(s)

             || ("--" + getLongName()).equals(s);

     }

     /**

      * Return true if the specified string is a value.

      *

      * @param s string

      * @return true if the specified string is a value

      */

     protected boolean isValueString(final String s)

     {

         if (s.startsWith("-"))

         {

             char next = s.charAt(1);

             if (Character.isDigit(next))

             {

                 // allow negative numbers

                 return true;

             }

             return false;

         }

         return true;

     }

     /**

      * Convert the specified string value into an instance

      * of class <code>E</code>.

      *

      * @param s string value

      * @return an instance of class <code>E</code> converted

      *    from the specified string value

      * @throws Exception if an error occurs

      */

     protected abstract E convert(final String s)

         throws Exception;

     /** {@inheritDoc} */

     public final String getShortName()

     {

         return shortName;

     }

     /** {@inheritDoc} */

     public final String getLongName()

     {

         return longName;

     }

     /** {@inheritDoc} */

     public final String getDescription()

     {

         return description;

     }

     /** {@inheritDoc} */

     public final boolean isRequired()

     {

         return required;

     }

     /** {@inheritDoc} */

     public final boolean wasFound()

     {

         return found;

     }

     /** {@inheritDoc} */

     public final E getValue()

     {

         return value;

     }

     /** {@inheritDoc} */

     public final E getValue(final E defaultValue)

     {

         return found ? value : defaultValue;

     }

     /** {@inheritDoc} */

     public final boolean equals(final Object o)

     {

         return super.equals(o);

     }

     /** {@inheritDoc} */

     public final int hashCode()

     {

         return super.hashCode();

     }

 }