// NAnt - A .NET build tool
// Copyright (C) 2001-2003 Gerry Shaw
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
//
// Arjen Poutsma (poutsma@yahoo.com)

using System;
using System.Collections;
using System.Text.RegularExpressions;
using SourceForge.NAnt;
using SourceForge.NAnt.Attributes;

namespace SourceForge.NAnt.Tasks {
    /// <summary>
    /// Sets project properties based on the evaluatuion of a regular expression.
    /// </summary>
    /// <remarks>
    /// The &quot;pattern&quot; attribute must contain one or more 
    /// <a href="http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpgenref/html/cpcongroupingconstructs.asp">named grouping constructs</a>, 
    /// which represents the names of the properties to be set.
    /// These named grouping constructs can be enclosed by angle brackets (?&lt;name&gt;) or single quotes (?'name').
    /// <note>In the build file, use the XML element <![CDATA[&lt;]]> to specify &lt;, and <![CDATA[&gt;]]> to specify &gt;.</note>
    /// <note>The named grouping construct must not contain any punctuation and it cannot begin with a number.</note>
    /// </remarks>
    /// <example>
    /// <para>Find the last word in the given string and stores it property lastword.</para>
    /// <code>
    /// <![CDATA[
    /// <regex pattern="(?'lastword'\w+)$" input="This is a test sentence"/>
    /// <echo message="${lastword}"/>
    ///  ]]>
    /// </code>
    /// <para>Splits the full filename and extension of a filename.</para>
    /// <code>
    /// <![CDATA[
    /// <regex pattern="^(?'filename'.*)\.(?'extension'\w+)$" input="d:\Temp\SomeDir\SomeDir\bla.xml"/>
    ///  ]]>
    /// </code>
    /// </example>
    [TaskName("regex")]
    public class RegexTask : Task {
        private string _pattern = null;
        private string _input = null;

        /// <summary>Represents the regular expression to be evalued.</summary>
        /// <value>Represents the regular expression to be evalued.</value>
        /// <remarks>
        /// The pattern must contain one or more named constructs, which may 
        /// not contain any punctuation and cannot begin with a number.
        /// </remarks>
        [TaskAttribute("pattern", Required=true)]
        public string Pattern {
            get { return _pattern;}
            set { _pattern = value; }
        }

        /// <summary>Represents the input for the regular expression.</summary>
        /// <value>Represents the input for the regular expression.</value>
        [TaskAttribute("input", Required=true)]
        public string Input {
            get { return _input;}
            set { _input = value; }
        }


        /// <summary>
        /// Executes the task.
        /// </summary>
        protected override void ExecuteTask() {
            Regex regex = new Regex(_pattern);
            Match match = regex.Match(_input);

            // we start the iteration at 1, since the collection of groups 
            // always starts with a group which matches the entire input and is named '0'
            // this group is of no interest to us
            for (int i=1; i < match.Groups.Count; i++) {
                string groupName = regex.GroupNameFromNumber(i);

                //Log.WriteLine("Group:{0} Value:{1}", groupName, match.Groups[groupName].Value);
                Properties [ groupName ] = match.Groups[groupName].Value;
            }
        }
    }
}