//-----------------------------------------------------------------------
// -----------------------------------------------------------------------
// file="Node.Char"
// Project: StgSharp
// AuthorGroup: Nitload Space
// Copyright (c) Nitload Space. All rights reserved.
//     
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
//     
// -----------------------------------------------------------------------
// -----------------------------------------------------------------------
using StgSharp.State;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text;
using System.Threading.Tasks;

namespace StgSharp.RegularAnalysis
{ 
    internal class RegularExpressionEpsilonNode : RegularStateNode
    {
    }


    internal class RegularExpressionCharNode : RegularStateNode
    {

        private char _char;

        public RegularExpressionCharNode(char c)
        {
            _char = c;
        }

        public override NodeType Type => NodeType.CHAR;

        public override bool IsValidateFrom(RegularStateNode former, RegularContext context)
        {
            int pos = context.Position;
            char c = context.CurrentCharSpan[pos + 1];
            return  c == _char;
        }

    }

    internal class RegularExpressionCharsetNode : RegularStateNode
    {

        private bool _isNegated;
        private HashSet<char> _charset;

        public RegularExpressionCharsetNode(IEnumerable<char> charset, bool isNegated = false)
        {
            _charset = new(charset);
            _isNegated = isNegated;
        }

        public RegularExpressionCharsetNode(ReadOnlySpan<char> charset, bool isNegated = false)
        {
            _charset = new(charset.Length);
            _isNegated = isNegated;
        }

        public override NodeType Type => NodeType.CHARSET;

        public override bool IsValidateFrom(RegularStateNode former, RegularContext context)
        {
            int pos = context.Position;
            char c = context.CurrentCharSpan[pos + 1];
            bool contains = _charset.Contains(c);
            return _isNegated ? !contains : contains;
        }

    }
}