using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp14
{
    class Program
    {
        static void Main(string[] args)
        {
            ArrayEnumerator enumerator = new ArrayEnumerator("Test1", "Test2", "Test3", "Test4");
            while (enumerator.MoveNext())
            {
                Console.WriteLine(enumerator.Current);
            }
            LinkedList ll1 = new LinkedList();
            ll1.Add(1);
            ll1.Add(3);
            ll1.Add(4);
            ll1.Add(5);
            foreach (Node a in ll1)
            {
                Console.WriteLine(a.Data);
            }
            Console.ReadKey();
        }
    }




    class LinkedList : IEnumerable<int>
    {
        private Node _root;
        public int Count { get; private set; }

        public void Add(int value)
        {
            Node curNode = _root;

            if (curNode != null)
            {
                while (curNode.Next != null)
                {
                    curNode = curNode.Next;
                }
                curNode.Next = new Node(value, null);
            }
            else
            {
                _root = new Node(value, null);
            }
        }

        public void Remove(int value)
        {
            Node curNode = _root;

            if (curNode.Data == value)
            {
                curNode = curNode.Next;
            }
            else
            {
                Node removeNode = SearchNode(value);
                if (removeNode.Next != null)
                {
                    removeNode.Next = removeNode.Next.Next;
                }
                else
                {
                    Console.WriteLine("Такого элемента нет");
                }

            }
        }

        public void Balblabla()
        {
            Node currentNode = _root;
            currentNode = currentNode.Next;
        }

        public void RemoveAt(int index)
        {
            int count = 0;
            Node currentNode = _root;
            Node prevNode = currentNode;
            while (count <= index)
            {
                if (count == index)
                {
                    prevNode.Next = currentNode.Next;
                    currentNode = null;
                }
                else
                {
                    prevNode = currentNode;
                    currentNode = currentNode.Next;
                }
                count++;
            }
        }

        public void Reverse()
        {
            Node curNode = _root, nextNodes = null;
            while (curNode != null)
            {
                Node stor = curNode.Next;
                curNode.Next = nextNodes;
                nextNodes = curNode;
                curNode = stor;
            }
            _root = nextNodes;
        }

        public bool Contains(int value)
        {
            Node currentNode = _root;
            while (currentNode.Data != value)
            {
                currentNode = currentNode.Next;
                if (currentNode.Next == null)
                {
                    break;
                }
            }
            if (currentNode.Data == value)
            {
                Console.WriteLine(true);
                return true;
            }
            else
            {
                Console.WriteLine(false);
                return false;
            }
        }

        private Node SearchNode(int value)
        {
            Node curNode = _root;
            while (curNode.Next != null)
            {
                if (curNode.Next.Data != value)
                {
                    curNode = curNode.Next;
                }
                else
                {
                    return curNode;
                }
            }
            return curNode;
        }

        public void Show()
        {
            Node currentNode = _root;
            while (currentNode != null)
            {
                Console.Write(currentNode.Data + " ");
                currentNode = currentNode.Next;
            }
        }


        public LinkedListEnumerator GetEnumerator()
        {
            return new LinkedListEnumerator(_root);
        }

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

        IEnumerator<int> IEnumerable<int>.GetEnumerator()
        {
            return GetEnumerator();
        }
    }


    class LinkedListEnumerator : IEnumerator<int>
    {
        bool isFirst = true;
        Node current;
        Node front;
        public LinkedListEnumerator(Node root)
        {
            current = root;
            front = root;
        }

        public object Current
        {
            get
            {
                return current;
            }
        }

        int IEnumerator<int>.Current
        {
            get
            {
                return current.Data;
            }
        }

        public void Dispose()
        {

        }

        public bool MoveNext()
        {
            if (current == front && isFirst)
            {
                isFirst = false;
                return true;
            }
            if (current.Next != null)
            {
                current = current.Next;
                return true;
            }
            else
            {
                return false;
            }
        }

        public void Reset()
        {
            current = front;
        }
    }

    class ArrayEnumerator : IEnumerator<string>
    {
        public string Current => _data[_currentElement];
        object IEnumerator.Current => Current;

        private string[] _data;
        private int _currentElement = -1;

        public ArrayEnumerator(params string[] data)
        {
            _data = data;
        }

        public void Dispose()
        {
            throw new NotImplementedException();
        }

        public bool MoveNext()
        {
            return !(++_currentElement >= _data.Length);
        }

        public void Reset()
        {
            _currentElement = -1;
        }
    }

    class Node
    {
        public Node Next;
        public int Data;

        public Node(int data, Node next)
        {
            Next = next;
            Data = data;
        }
    }
}