// OrderedSequence.cs
//
// Authors:
//    Alejandro Serrano "Serras" (trupill@yahoo.es)
//    Marek Safar  <marek.safar@gmail.com>
//    Jb Evain  <jbevain@novell.com>
//
// Copyright (C) 2007 Novell, Inc (http://www.novell.com)
//
// 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.

// Needed for NET30

#if !NET_4_6
using System.Collections.Generic;

namespace System.Linq.Reimplement
{
    internal class OrderedSequence<TElement, TKey> : OrderedEnumerable<TElement>
    {
        private readonly IComparer<TKey> _comparer;
        private readonly SortDirection _direction;
        private readonly OrderedEnumerable<TElement> _parent;
        private readonly Func<TElement, TKey> _selector;

        internal OrderedSequence(IEnumerable<TElement> source, Func<TElement, TKey> keySelector, IComparer<TKey> comparer, SortDirection direction)
            : base(source)
        {
            _selector = keySelector;
            _comparer = comparer ?? Comparer<TKey>.Default;
            _direction = direction;
        }

        internal OrderedSequence(OrderedEnumerable<TElement> parent, IEnumerable<TElement> source, Func<TElement, TKey> keySelector, IComparer<TKey> comparer, SortDirection direction)
            : this(source, keySelector, comparer, direction)
        {
            _parent = parent;
        }

        public override SortContext<TElement> CreateContext(SortContext<TElement> current)
        {
            SortContext<TElement> context = new SortSequenceContext<TElement, TKey>(_selector, _comparer, _direction, current);

            if (_parent != null)
            {
                return _parent.CreateContext(context);
            }

            return context;
        }

        protected override IEnumerable<TElement> Sort(IEnumerable<TElement> source)
        {
            return QuickSort<TElement>.Sort(source, CreateContext(null));
        }
    }
}
#endif