using System;
using System.Text.RegularExpressions;

namespace SharpCifs.Util.Sharpen
{
    internal class Matcher
    {
        private int _current;
        private MatchCollection _matches;
        private Regex _regex;
        private string _str;

        internal Matcher(Regex regex, string str)
        {
            this._regex = regex;
            this._str = str;
        }

        public int End()
        {
            if ((_matches == null) || (_current >= _matches.Count))
            {
                throw new InvalidOperationException();
            }
            return (_matches[_current].Index + _matches[_current].Length);
        }

        public bool Find()
        {
            if (_matches == null)
            {
                _matches = _regex.Matches(_str);
                _current = 0;
            }
            return (_current < _matches.Count);
        }

        public bool Find(int index)
        {
            _matches = _regex.Matches(_str, index);
            _current = 0;
            return (_matches.Count > 0);
        }

        public string Group(int n)
        {
            if ((_matches == null) || (_current >= _matches.Count))
            {
                throw new InvalidOperationException();
            }
            Group grp = _matches[_current].Groups[n];
            return grp.Success ? grp.Value : null;
        }

        public bool Matches()
        {
            _matches = null;
            return Find();
        }

        public string ReplaceFirst(string txt)
        {
            return _regex.Replace(_str, txt, 1);
        }

        public Matcher Reset(CharSequence str)
        {
            return Reset(str.ToString());
        }

        public Matcher Reset(string str)
        {
            _matches = null;
            this._str = str;
            return this;
        }

        public int Start()
        {
            if ((_matches == null) || (_current >= _matches.Count))
            {
                throw new InvalidOperationException();
            }
            return _matches[_current].Index;
        }
    }
}