namespace TestPooling.DirtyList {
  using System;
  using System.Collections.Generic;
  using System.Linq;

  /// <summary>
  ///     While Push's stacks are generally treated as genuine stacks---that is, inclassions take their arguments from the
  ///     tops of
  ///     the stacks and push their results onto the tops of the stacks---a few inclassions (like YANK and SHOVE) do allow
  ///     direct access
  ///     to "deep" stack elements by means of integer indices. To this extent the stacks can be used as general, random
  ///     access memory
  ///     classures. This is one of the features that ensures the Turing-completeness of Push (another being the arbitrary
  ///     name/value
  ///     bindings supported by the NAME data type and DEFINE methods; see below).
  /// </summary>
  /// <typeparam name="T">The item type of the collection.</typeparam>
  public class PushStack3<T> {
    private const string Delimiter = " ";

    private readonly LinkedList<T> data;

    public PushStack3() {
      data = new LinkedList<T>();
      IsEnabled = true;
    }

    public bool IsEnabled { get; set; }

    public T Top
    {
      get
      {
        return data.Last.Value;
      }
    }

    public T TopOrDefault
    {
      get
      {
        return Count > 0 ? Top : default(T);
      }
    }

    public T Bottom
    {
      get
      {
        return data.First.Value;
      }
    }

    public T BottomOrDefault
    {
      get
      {
        return Count > 0 ? Bottom : default(T);
      }
    }

    public int Count
    {
      get
      {
        return data.Count;
      }
    }

    public bool IsEmpty
    {
      get
      {
        return Count == 0;
      }
    }

    public bool IsReadOnly
    {
      get
      {
        return false;
      }
    }

    public void Add(T item) {
      Push(item);
    }

    public void Clear() {
      data.Clear();
    }

    public bool Contains(T item) {
      return data.Contains(item);
    }

    public void CopyTo(T[] array, int arrayIndex) {
      data.CopyTo(array, arrayIndex);
    }

    public IEnumerator<T> GetEnumerator() {
      return data.GetEnumerator();
    }

    public T ElementAt(int index) {
      return data.ElementAt(index);
    }

    public T ReverseElementAt(int offset) {
      return ElementAt(Count - 1 - offset);
    }

    public void SetTop(T value) {
      data.Last.Value = value;
    }

    private LinkedListNode<T> GetByIndex(int index) {
      var current = data.First;
      for (var i = 0; i <= index; i++) {
        current = current.Next;
      }

      return current;
    }

    public T this[int key]
    {
      get
      {
        return ElementAt(key);
      }
      set
      {
        GetByIndex(key).Value = value;
      }
    }

    public void Swap(int count) {
      var topValue = Top;
      var current = data.Last;
      var bottomIndex = Count - count;


      for (var i = Count - 1; i > bottomIndex; i--) {
        current.Value = current.Previous.Value;
        current = current.Previous;
      }

      data.Last.Value = topValue;
    }

    public void Yank(int index) {
      if (index == Count - 1) return;

      var item = GetByIndex(index);
      data.Remove(item);
      data.AddLast(item);
    }

    public T Pop() {
      var value = Top;
      data.RemoveLast();

      return value;
    }

    public T[] Pop(int count) {
      var items = new T[count];

      for (var i = 0; i < count; i++) {
        items[count - i] = Top;
        data.RemoveLast();
      }

      return items;
    }

    public T Peek() {
      return Top;
    }

    public T[] Peek(int count) {
      var items = new T[count];
      var current = data.Last;

      for (var i = 0; i < count; i++) {
        items[count - i] = current.Value;
        current = current.Previous;
      }

      return items;
    }

    public void Push(T item) {
      if (!IsEnabled) return;

      data.AddLast(item);
    }

    public void Push(T item1, T item2) {
      if (!IsEnabled) return;

      data.AddLast(item1);
      data.AddLast(item2);
    }

    public void Push(T item1, T item2, T item3) {
      if (!IsEnabled) return;

      data.AddLast(item1);
      data.AddLast(item2);
      data.AddLast(item3);
    }

    public void Push(T item1, T item2, T item3, T item4) {
      if (!IsEnabled) return;

      data.AddLast(item1);
      data.AddLast(item2);
      data.AddLast(item3);
      data.AddLast(item4);
    }

    public void PushResult(int count, Func<T[], T> templateFunc) {
      if (!IsEnabled) return;

      Push(templateFunc(Pop(count)));
    }

    public void PushRange(IReadOnlyList<T> items) {
      if (!IsEnabled) return;

      for (var i = 0; i < items.Count; i++) data.AddLast(items[i]);
    }

    public void Insert(int index, T value) {
      if (!IsEnabled) return;

      var node = GetByIndex(index);
      data.AddBefore(node, value);
    }

    public bool Remove(T item) {
      return data.Remove(item);
    }

    public void RemoveTop() {
      data.RemoveLast();
    }

    public void Remove(int count) {
      for (var i = 0; i < count; i++) data.RemoveLast();
    }

    public void RemoveAt(int index) {
      var node = GetByIndex(index);

      data.Remove(node);
    }

    public void RemoveAt(int index, int count) {

      var node = GetByIndex(index);

      for (var i = 0; i < count; i++) {
        data.Remove(node);
        node = node.Next;
      }
    }

    public bool TryPop(out T item) {
      if (Count > 0) {
        item = Pop();
        return true;
      }
      item = default(T);
      return false;
    }

    public override string ToString() {
      var data = this.data as IEnumerable<T>;
      return string.Join(Delimiter, data.Reverse());
    }
  }
}