using System;

using System.Collections.Generic;

using System.Linq;

​

namespace ConsoleApp17

{

    public class Program

    {

        private readonly OrderModeRetriever _orderModeRetriever;

​

        public Program(OrderModeRetriever orderModeRetriever)

        {

            _orderModeRetriever = orderModeRetriever;

        }

​

        private List<Grouping> _groupings = new List<Grouping>();

​

        private Dictionary<Grouping, List<Item>> _initialOrderStateMap;

        private OrderByScoreMode _orderByMode = OrderByScoreMode.Unordered;

​

        public void OnOrderByScore()

        {

            MemorizeInitialOrderState();

            ToggleOrderByMode();

            ApplyOrderByModeToItems();

​

            void MemorizeInitialOrderState()

            {

                if (_initialOrderStateMap == null)

                {

                    _initialOrderStateMap = new Dictionary<Grouping, List<Item>>();

                    foreach (var grouping in _groupings)

                    {

                        _initialOrderStateMap.Add(grouping, grouping.Items);

                    }

                }

            }

​

            void ToggleOrderByMode()

            {

                _orderModeRetriever.GetNext(_orderByMode);

            }

​

            void ApplyOrderByModeToItems()

            {

                foreach (var grouping in _groupings)

                {

                    OrderItemsInGroupingByMode(grouping, _orderByMode);

                }

            }

​

            void OrderItemsInGroupingByMode(Grouping grouping, OrderByScoreMode orderByMode)

            {

                switch (orderByMode)

                {

                    case OrderByScoreMode.Ascending: 

                        grouping.Items = grouping.Items.OrderBy(x => x.Score).ToList();

                        break;

                    case OrderByScoreMode.Descending: 

                        grouping.Items = grouping.Items.OrderByDescending(x => x.Score).ToList();

                        break;

                    case OrderByScoreMode.Unordered: 

                        grouping.Items = _initialOrderStateMap[grouping];

                        break;

                }

            }

        }

    }

​

    public class OrderModeRetriever

    {

        public OrderByScoreMode GetNext(OrderByScoreMode orderByMode)

        {

            switch (orderByMode)

            {

                case OrderByScoreMode.Ascending: return OrderByScoreMode.Descending;

                case OrderByScoreMode.Descending: return OrderByScoreMode.Unordered;

                case OrderByScoreMode.Unordered: return OrderByScoreMode.Ascending;

                default: return OrderByScoreMode.Unordered;

            }

        }

    } 

​

    public enum OrderByScoreMode

    {

        Ascending,

        Descending,

        Unordered

    }

​

    internal class Grouping

    {

        public List<Item> Items { get; set; }

    }

​

    internal class Item

    {

        public double Score { get; set; }

    }

}

​