public ExchangeService(ILoggerFactory loggerFactory,
ApplicationDbContext db,
IConfiguration configuration,
IRateCache rateCache,
IMemoryCache cache,
ICryptoProviderService cryptoProviderService,
IGraftWalletService wallet)
{
_settings = configuration
.GetSection("PaymentService")
.Get <PaymentServiceConfiguration>();
_logger = loggerFactory.CreateLogger(nameof(ExchangeService));
_db = db;
_rateCache = rateCache;
_cache = cache;
_cryptoProviderService = cryptoProviderService;
_wallet = wallet;
}
internal static void Recalc(Exchange exchange, PaymentServiceConfiguration settings)
{
decimal sellRate = exchange.SellToUsdRate;
decimal graftRate = exchange.GraftToUsdRate;
decimal sellAmount = 0;
decimal graftAmount = 0;
decimal buyerAmount = 0;
decimal feeAmount = 0;
decimal fee = settings.ExchangeBrokerFee;
sellAmount = exchange.ReceivedAmount;
graftAmount = sellAmount * sellRate / graftRate;
feeAmount = graftAmount * fee;
buyerAmount = graftAmount - feeAmount;
exchange.SellAmount = sellAmount;
exchange.BuyAmount = buyerAmount;
exchange.ExchangeBrokerFee = feeAmount;
exchange.Log($"Recalcalated amounts: {exchange.SellAmount} {exchange.SellCurrency} to {exchange.BuyAmount} {exchange.BuyCurrency}");
}
internal static async Task <Exchange> Create(BrokerExchangeParams model,
IRateCache rateCache, PaymentServiceConfiguration settings)
{
var log = new List <EventItem>
{
new EventItem($"Started exchange calculation")
};
log.Add(new EventItem($"Requesting {model.SellCurrency} rate..."));
decimal sellRate = await rateCache.GetRateToUsd(model.SellCurrency);
log.Add(new EventItem($"Received {model.SellCurrency} rate: {sellRate} USD"));
log.Add(new EventItem($"Requesting GRFT rate..."));
decimal graftRate = await rateCache.GetRateToUsd("GRFT");
log.Add(new EventItem($"Received GRFT rate: {graftRate} USD"));
decimal sellAmount = 0;
decimal graftAmount = 0;
decimal buyerAmount = 0;
decimal feeAmount = 0;
decimal fee = settings.ExchangeBrokerFee;
if (!string.IsNullOrWhiteSpace(model.FiatCurrency))
{
if (model.SellFiatAmount > 0)
{
sellAmount = model.SellFiatAmount / sellRate;
graftAmount = model.SellFiatAmount / graftRate;
feeAmount = graftAmount * fee;
buyerAmount = graftAmount - feeAmount;
}
else
{
buyerAmount = model.BuyFiatAmount / graftRate;
graftAmount = buyerAmount / (1 - fee);
feeAmount = graftAmount - buyerAmount;
sellAmount = graftAmount * graftRate / sellRate;
}
}
else
{
if (model.SellAmount > 0)
{
sellAmount = model.SellAmount;
graftAmount = sellAmount * sellRate / graftRate;
feeAmount = graftAmount * fee;
buyerAmount = graftAmount - feeAmount;
}
else
{
buyerAmount = model.BuyAmount;
graftAmount = buyerAmount / (1 - fee);
feeAmount = graftAmount - buyerAmount;
sellAmount = graftAmount * graftRate / sellRate;
}
}
var exchange = new Exchange
{
ExchangeId = Guid.NewGuid().ToString(),
CreatedAt = DateTime.UtcNow,
Status = PaymentStatus.Waiting,
SellAmount = sellAmount,
SellCurrency = model.SellCurrency,
BuyAmount = buyerAmount,
BuyCurrency = model.BuyCurrency,
SellToUsdRate = sellRate,
GraftToUsdRate = graftRate,
ExchangeBrokerFee = feeAmount,
BuyerWallet = model.WalletAddress,
BuyerTransactionStatus = GraftTransactionStatus.New
};
exchange.ProcessingEvents = log;
log.Add(new EventItem($"Created exchange: {exchange.SellAmount} {exchange.SellCurrency} to {exchange.BuyAmount} {exchange.BuyCurrency}"));
log.Add(new EventItem($"Exchange Broker fee of {fee*100}% is {exchange.ExchangeBrokerFee} GRFT"));
return(exchange);
}
