// Copyright (c) 2007 Omer Rauchwerger (a.k.a rauchy) (omer@rauchy.net)
// All rights reserved.
//
// This file is part of Regionerate.
// 
// 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 3 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, see <http://www.gnu.org/licenses/>.

using System.Collections;
using System.Collections.Generic;
using Rauchy.Regionerate.Domain.Entities;

namespace Rauchy.Regionerate.Shared.Components
{
    public static class CodeFilter
    {
        #region Methods (1)

        public static IEnumerable<T> Only<T>( IList<Code> codeCollection ) where T : Code
        {
            return new OnlyFilter<T>( codeCollection );
        }

        #endregion

        #region Nested Classes (1)

        private class OnlyFilter<T> : IEnumerable<T> where T : Code
        {
            private readonly IList<Code> _codeCollection;

            public OnlyFilter( IList<Code> codeCollection )
            {
                _codeCollection = codeCollection;
            }

            public IEnumerator<T> GetEnumerator()
            {
                foreach ( Code code in _codeCollection )
                {
                    T t = code as T;
                    if ( t != null )
                    {
                        yield return t;
                    }
                }
            }

            IEnumerator IEnumerable.GetEnumerator()
            {
                return GetEnumerator();
            }
        }

        #endregion
    }
}