using System;
using Microsoft.Extensions.Logging;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.Caching.Memory;
using Microsoft.Extensions.Options;
using NBitcoin;
using NBXplorer.Models;

namespace BTCPayServer.Services
{
    public class TransactionCacheProvider
    {
        IOptions<MemoryCacheOptions> _Options;
        public TransactionCacheProvider(IOptions<MemoryCacheOptions> options)
        {
            _Options = options;
        }

        ConcurrentDictionary<string, TransactionCache> _TransactionCaches = new ConcurrentDictionary<string, TransactionCache>();
        public TransactionCache GetTransactionCache(BTCPayNetwork network)
        {
            if (network == null)
                throw new ArgumentNullException(nameof(network));
            return _TransactionCaches.GetOrAdd(network.CryptoCode, c => new TransactionCache(_Options, network));
        }
    }
    public class TransactionCache : IDisposable
    {
        //IOptions<MemoryCacheOptions> _Options;
        public TransactionCache(IOptions<MemoryCacheOptions> options, BTCPayNetwork network)
        {
            //if (network == null)
            //    throw new ArgumentNullException(nameof(network));
            //_Options = options;
            //_MemoryCache = new MemoryCache(_Options);
            //Network = network;
        }

        //uint256 _LastHash;
        //int _ConfOffset;
        //IMemoryCache _MemoryCache;
        
        public void NewBlock(uint256 newHash, uint256 previousHash)
        {
            //if (_LastHash != previousHash)
            //{
            //    var old = _MemoryCache;
            //    _ConfOffset = 0;
            //    _MemoryCache = new MemoryCache(_Options);
            //    Thread.MemoryBarrier();
            //    old.Dispose();
            //}
            //else
            //    _ConfOffset++;
            //_LastHash = newHash;
        }

        public TimeSpan CacheSpan { get; private set; } = TimeSpan.FromMinutes(60);

        public BTCPayNetwork Network { get; private set; }

        public void AddToCache(TransactionResult tx)
        {
            //Logging.Logs.PayServer.LogInformation($"ADD CACHE: {tx.Transaction.GetHash()} ({tx.Confirmations} conf)");
            //_MemoryCache.Set(tx.Transaction.GetHash(), tx, DateTimeOffset.UtcNow + CacheSpan);
        }


        public TransactionResult GetTransaction(uint256 txId)
        {
            //var ok = _MemoryCache.TryGetValue(txId.ToString(), out object tx);
            //Logging.Logs.PayServer.LogInformation($"GET CACHE: {txId} ({ok} plus {_ConfOffset})");

            //var result = tx as TransactionResult;
            //var confOffset = _ConfOffset;
            //if (result != null && result.Confirmations > 0 && confOffset > 0)
            //{
            //    var serializer = new NBXplorer.Serializer(Network.NBitcoinNetwork);
            //    result = serializer.ToObject<TransactionResult>(serializer.ToString(result));
            //    result.Confirmations += confOffset;
            //    result.Height += confOffset;
            //}
            //return result;
            return null; // Does not work correctly yet
        }

        public void Dispose()
        {
            //_MemoryCache.Dispose();
        }
    }
}