using System;

namespace Clones
{
    public class CloneVersionSystem : ICloneVersionSystem
    {
        System.Collections.Generic.List<CloneNigga> cloneNigs = new System.Collections.Generic.List<CloneNigga> { new CloneNigga() };

        public string Execute(string nigga)
        {
            nigga = ':' + nigga;
            if (nigga.Contains(":learn"))
            {
                string[] crutch = nigga.Split(' ');
                var crutch2 = int.Parse(crutch[1]) - 1;
                cloneNigs[crutch2].programKnown.next = new Deck<int>(int.Parse(crutch[2]), cloneNigs[crutch2].programKnown, true);
                cloneNigs[crutch2].programKnown = cloneNigs[crutch2].programKnown.next;
            }
            if (nigga.Contains(":rollback"))
            {
                string[] crutch = nigga.Split(' ');
                var crutch2 = int.Parse(crutch[1]) - 1;
                cloneNigs[crutch2].programKnown = cloneNigs[crutch2].programKnown.previous;
            }
            if (nigga.Contains(":relearn"))
            {
                string[] crutch = nigga.Split(' ');
                var crutch2 = int.Parse(crutch[1]) - 1;
                cloneNigs[crutch2].programKnown = cloneNigs[crutch2].programKnown.next;
            }
            if (nigga.Contains(":clone"))
            {
                string[] crutch = nigga.Split(' ');
                var crutch2 = int.Parse(crutch[1]) - 1; ;
                cloneNigs.Add(cloneNigs[crutch2].Clone());
            }
            if (nigga.Contains(":check"))
            {
                string[] crutch = nigga.Split(' ');
                var crutch2 = int.Parse(crutch[1]) - 1;
                if (cloneNigs[crutch2].programKnown.previous != null)
                {
                    return cloneNigs[crutch2].programKnown.Value.ToString();
                }
                else
                {
                    return "basic";
                }
            }
            return null;
        }
    }

    public class CloneNigga
    {
        public Deck<int> programKnown = new Deck<int>();

        public CloneNigga Clone()
        {
            return new CloneNigga { programKnown = this.programKnown };
        }
    }

    public class Deck<T>
    {
        public Deck<T> previous = null;
        public Deck<T> next = null;

        public T Value
        {
            get; set;
        }

        public Deck()
        {

        }

        public Deck(T value)
        {
            this.Value = value;
        }

        public Deck(T value, Deck<T> nigga, bool what = true)
        {
            this.Value = value;
            if (what)
                previous = nigga;
            else
                next = nigga;
        }
    }
}