using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Security.Cryptography.X509Certificates;

namespace ConsoleApp1
{
    public delegate void sa(Item item);

    public static class Manager
    {
        public static void Decrease(Item item)
        {
            item.Price /= 2;
        }
    }
    public class Item
    {
        public event sa Decrease;
        public  int ID { get; set; }
        public  string Name { get; set; }
        public  int Price { get; set; }

        public override string ToString()
        {
            return $"id - {ID}   name - {Name} price - {Price}";
        }

        public override int GetHashCode()
        {
            return ID;
        }
    }

    public  class Shop:IEnumerable
    {
        public static Queue<Item> Items{get;private set; }

        public Shop()
        {
            Items=new Queue<Item>();
        }

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

        public void Add(Item item)
        {
            Items = this + item;
        }

        public void Remove()
        {
            Items= this - Items.Last();
        }

        public IEnumerator GetEnumerator()
        {
            var enumerator = Items.GetEnumerator();
            return enumerator;
        }


        public static Queue<Item> operator +(Shop shop, Item item)
        {
            var newQueue = Items;
            newQueue.Enqueue(item);
            return newQueue;
        }

        public static Queue<Item> operator -(Shop shop, Item item)
        {
            var newQueue=Items;
            newQueue.Dequeue();
            return newQueue;
        }
    }
    public class Program
    {
        static void Main(string[] args)
        {
            var firstItem = new Item() {ID = 1, Name = "item1", Price = 10};
            var secondItem = new Item() { ID = 2, Name = "item2", Price = 5 };
            var thirdItem = new Item() { ID = 3, Name = "item3", Price = 15 };
            var fourthItem = new Item() { ID = 4, Name = "item4", Price = 13 };
            var fifthItem = new Item() { ID = 5, Name = "item5", Price = 26 };
            var shop=new Shop();
            shop.Add(firstItem);
            shop.Add(secondItem);
            shop.Add(thirdItem);
            shop.Add(fourthItem);
            shop.Add(fifthItem);
            foreach (var item in shop)
            {
                Console.WriteLine(item.ToString());
            }
        }
    }


}