Gemini: implemented OnGetMarketSymbolsMetadataAsync()

Gemini is a stupid exchange which doesn't provide this info through their api so had to hardcode it...

Author: vslee

ExchangeSharp/API/Exchanges/Gemini/ExchangeGeminiAPI.cs

@@ -91,7 +91,68 @@ protected override async Task<IEnumerable<string>> OnGetMarketSymbolsAsync()
             return await MakeJsonRequestAsync<string[]>("/symbols");
         }
 
-        protected override async Task<ExchangeTicker> OnGetTickerAsync(string marketSymbol)
+		protected override async Task<IEnumerable<ExchangeMarket>> OnGetMarketSymbolsMetadataAsync()
+		{
+			List<ExchangeMarket> hardcodedSymbols = new List<ExchangeMarket>()
+			{
+				new ExchangeMarket() { IsActive = true,
+					MarketSymbol = "btcusd", BaseCurrency = "BTC", QuoteCurrency = "USD",
+					MinTradeSize = 0.00001M, QuantityStepSize = 0.00000001M, PriceStepSize = 0.01M},
+				new ExchangeMarket() { IsActive = true,
+					MarketSymbol = "ethusd", BaseCurrency = "ETH", QuoteCurrency = "USD",
+					MinTradeSize = 0.001M, QuantityStepSize = 0.000001M, PriceStepSize = 0.01M},
+				new ExchangeMarket() { IsActive = true,
+					MarketSymbol = "ethbtc", BaseCurrency = "ETH", QuoteCurrency = "BTC",
+					MinTradeSize = 0.001M, QuantityStepSize = 0.000001M, PriceStepSize = 0.00001M},
+				new ExchangeMarket() { IsActive = true,
+					MarketSymbol = "zecusd", BaseCurrency = "ZEC", QuoteCurrency = "USD",
+					MinTradeSize = 0.001M, QuantityStepSize = 0.000001M, PriceStepSize = 0.01M},
+				new ExchangeMarket() { IsActive = true,
+					MarketSymbol = "zecbtc", BaseCurrency = "ZEC", QuoteCurrency = "BTC",
+					MinTradeSize = 0.001M, QuantityStepSize = 0.000001M, PriceStepSize = 0.00001M},
+				new ExchangeMarket() { IsActive = true,
+					MarketSymbol = "zeceth", BaseCurrency = "ZEC", QuoteCurrency = "ETH",
+					MinTradeSize = 0.001M, QuantityStepSize = 0.000001M, PriceStepSize = 0.0001M},
+				new ExchangeMarket() { IsActive = true,
+					MarketSymbol = "zecbch", BaseCurrency = "ZEC", QuoteCurrency = "BCH",
+					MinTradeSize = 0.001M, QuantityStepSize = 0.000001M, PriceStepSize = 0.0001M},
+				new ExchangeMarket() { IsActive = true,
+					MarketSymbol = "zecltc", BaseCurrency = "ZEC", QuoteCurrency = "LTC",
+					MinTradeSize = 0.001M, QuantityStepSize = 0.000001M, PriceStepSize = 0.001M},
+				new ExchangeMarket() { IsActive = true,
+					MarketSymbol = "bchusd", BaseCurrency = "BCH", QuoteCurrency = "USD",
+					MinTradeSize = 0.001M, QuantityStepSize = 0.000001M, PriceStepSize = 0.01M},
+				new ExchangeMarket() { IsActive = true,
+					MarketSymbol = "bchbtc", BaseCurrency = "BCH", QuoteCurrency = "BTC",
+					MinTradeSize = 0.001M, QuantityStepSize = 0.000001M, PriceStepSize = 0.00001M},
+				new ExchangeMarket() { IsActive = true,
+					MarketSymbol = "bcheth", BaseCurrency = "BCH", QuoteCurrency = "ETH",
+					MinTradeSize = 0.001M, QuantityStepSize = 0.000001M, PriceStepSize = 0.0001M},
+				new ExchangeMarket() { IsActive = true,
+					MarketSymbol = "ltcusd", BaseCurrency = "LTC", QuoteCurrency = "USD",
+					MinTradeSize = 0.01M, QuantityStepSize = 0.00001M, PriceStepSize = 0.01M},
+				new ExchangeMarket() { IsActive = true,
+					MarketSymbol = "ltcbtc", BaseCurrency = "LTC", QuoteCurrency = "BTC",
+					MinTradeSize = 0.01M, QuantityStepSize = 0.00001M, PriceStepSize = 0.00001M},
+				new ExchangeMarket() { IsActive = true,
+					MarketSymbol = "ltceth", BaseCurrency = "LTC", QuoteCurrency = "ETH",
+					MinTradeSize = 0.01M, QuantityStepSize = 0.00001M, PriceStepSize = 0.0001M},
+				new ExchangeMarket() { IsActive = true,
+					MarketSymbol = "ltcbch", BaseCurrency = "LTC", QuoteCurrency = "BCH",
+					MinTradeSize = 0.01M, QuantityStepSize = 0.00001M, PriceStepSize = 0.0001M},
+			};
+			// + check to make sure no symbols are missing
+			var apiSymbols = await GetMarketSymbolsAsync();
+			foreach (var apiSymbol in apiSymbols)
+				if (!hardcodedSymbols.Select(m => m.MarketSymbol).Contains(apiSymbol))
+					throw new Exception("hardcoded symbols out of date, please send a PR on GitHub to update.");
+			foreach (var hardcodedSymbol in hardcodedSymbols)
+				if (!apiSymbols.Contains(hardcodedSymbol.MarketSymbol))
+					throw new Exception("hardcoded symbols out of date, please send a PR on GitHub to update.");
+			return hardcodedSymbols;
+		}
+
+		protected override async Task<ExchangeTicker> OnGetTickerAsync(string marketSymbol)
         {
             JToken obj = await MakeJsonRequestAsync<JToken>("/pubticker/" + marketSymbol);
             if (obj == null || obj.Count() == 0)