BTSE: Filter no liquidity pairs (#1182)

* BTSE: Filter no liquidity pairs

* thrasher: update commentary

---------

Co-authored-by: Ryan O'Hara-Reid <ryan.oharareid@thrasher.io>

exchanges/btse/btse_types.go

@@ -55,6 +55,8 @@ type MarketSummary []struct {
 	MaxRiskLimit        int      `json:"maxRiskLimit"`
 	AvailableSettlement []string `json:"availableSettlement"`
 	Futures             bool     `json:"futures"`
+	IsMarketOpenToSpot  bool     `json:"isMarketOpenToSpot"`
+	IsMarketOpentoOTC   bool     `json:"isMarketOpenToOtc"`
 }
 
 // OHLCV holds Open, High Low, Close, Volume data for set symbol

exchanges/btse/btse_wrapper.go

@@ -248,7 +248,15 @@ func (b *BTSE) FetchTradablePairs(ctx context.Context, a asset.Item) (currency.P
 	}
 	pairs := make([]currency.Pair, 0, len(m))
 	for x := range m {
-		if !m[x].Active {
+		if !m[x].Active ||
+			// BTSE returns 0 for both highest bid and lowest ask if there is
+			// no order book data, so we skip those pairs. There is no way to
+			// take or provide liquidity for these pairs.
+
+			// TODO: Add support for an OTC asset as this eliminates many valid
+			// tradable pairs which are active, OTC only and available on the
+			// front-end.
+			(m[x].LowestAsk == 0 && m[x].HighestBid == 0) {
 			continue
 		}
 		var pair currency.Pair