namespace Kit.Helpers.Repository
{
    using System.Collections.Generic;
    using Microsoft.AspNetCore.Http;

    public interface IDictionaryCacheProvider
    {
        void SetByKey<TKey, TValue>(string cacheKey, TKey key, TValue value);
        TValue GetByKey<TKey, TValue>(string cacheKey, TKey key);
        TValue GetByKey<TKey, TValue>(string cacheKey, TKey key, TValue defaultValue);
    }

    public static class HttpDictionaryCacheHelper
    {
        public static bool IsConfigured => _isConfigured;
        public static IDictionaryCacheProvider Instance => _instance;

        private static bool _isConfigured = false;
        private static IDictionaryCacheProvider _instance;

        public static void Configure(IDictionaryCacheProvider instance)
        {
            _instance = instance;
            _isConfigured = _instance != null;
        }
    }

    public class HttpDictionaryCacheProvider : IDictionaryCacheProvider
    {
        public static HttpDictionaryCacheProvider Instance { get; } = new HttpDictionaryCacheProvider();
        public static void InitHelpers() => HttpDictionaryCacheHelper.Configure(Instance);
        private HttpDictionaryCacheProvider() { }
        private IDictionary<TKey, TValue> GetOrCreateDictionary<TKey, TValue>(string cacheKey)
        {
            HttpContext httpContext = HttpContextCore.Current;
            if (httpContext == null) return null;
            var cacheDictionary = httpContext.Items.ContainsKey(cacheKey) ? (Dictionary<TKey, TValue>)httpContext.Items[cacheKey] : null;

            if (cacheDictionary == null)
            {
                cacheDictionary = new Dictionary<TKey, TValue>();
                httpContext.Items[cacheKey] = cacheDictionary;
            }
            return cacheDictionary;
        }

        public void SetByKey<TKey, TValue>(string cacheKey, TKey key, TValue value) => GetOrCreateDictionary<TKey, TValue>(cacheKey).SetByKey(key, value);
        public TValue GetByKey<TKey, TValue>(string cacheKey, TKey key) => GetOrCreateDictionary<TKey, TValue>(cacheKey).GetByKey(key);
        public TValue GetByKey<TKey, TValue>(string cacheKey, TKey key, TValue defaultValue) => GetOrCreateDictionary<TKey, TValue>(cacheKey).GetByKey(key, defaultValue);

    }
}