[NR-CORE] Json shop system.

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using common;
using common.resources;
using log4net;
using Newtonsoft.Json;
using wServer.realm.terrain;

namespace wServer.realm.entities.vendors
{
    public class ShopItem : ISellableItem
    {
        public ushort ItemId { get; private set; }
        public int Price { get; }
        public int Count { get; }
        public string Name { get; }

        public ShopItem(string name, ushort price, int count = -1)
        {
            ItemId = ushort.MaxValue;
            Price = price;
            Count = count;
            Name = name;
        }

        public void SetItem(ushort item)
        {
            if (ItemId != ushort.MaxValue)
                throw new AccessViolationException("Can't change item after it has been set.");

            ItemId = item;
        }
    }
    
    internal static class MerchantLists
    {
        private static readonly ILog Log = LogManager.GetLogger(typeof(MerchantLists));
        
        public static readonly Dictionary<TileRegion, Tuple<List<ISellableItem>, CurrencyType, /*
            Req*/int>> Shops = new Dictionary<TileRegion, Tuple<List<ISellableItem>, CurrencyType, int>>();
        
        public static void Init(RealmManager manager)
        {
            var json = JsonConvert.DeserializeObject<List<ShopSettings>>(File.ReadAllText("shop.json"));

            foreach (var item in json)
            {
                var list = new List<ISellableItem>();
                var currency = (CurrencyType)Enum.Parse(typeof(CurrencyType), item.Currency);
                var region = (TileRegion)Enum.Parse(typeof(TileRegion), item.ShopId);

                list.Add(new ShopItem(item.Item, item.Price));
                Shops.Add(region, new Tuple<List<ISellableItem>, CurrencyType, int>(list, currency, item.Price));
            }

            foreach (var shop in Shops)
                foreach (var shopItem in shop.Value.Item1.OfType<ShopItem>())
                {
                    ushort id;
                    if (!manager.Resources.GameData.IdToObjectType.TryGetValue(shopItem.Name, out id))
                        Log.WarnFormat("Item name: {0}, not found.", shopItem.Name);
                    else
                        shopItem.SetItem(id);
                }
        }
        public partial class ShopSettings
        {
            public string Currency { get; set; }
            public string Item { get; set; }
            public ushort Price { get; set; }
            [JsonProperty("Shop_Id")]
            public string ShopId { get; set; }
        }
    }
}

[
    {
        "Currency": "Fame",
        "Item": "Sword of Acclaim",
        "Price": 100,
        "Shop_Id": "Store_1"
    },
    {
        "Currency": "Fame",
        "Item": "Demon Blade",
        "Price": 100,
        "Shop_Id": "Store_2"
    }
]

[
    {
        "StoreId": "Store_1",
        {
            "Item": "Sword of Acclaim", "Currency": "Fame", "Price": 500,
            "Item": "Archon Sword", "Currency": "Fame", "Price": 100
        }
    },
    {
        "StoreId": "Store_2",
        {
            "Item": "Potion of Defense", "Currency": "Gold", "Price": 50,
            "Item": "Potion of Wisdom", "Currency": "Gold", "Price": 15
        }
    }
]