Offline worst case trade fees (#274)

* Really basic getSimulated fee function everywhere

* Worst case fees for all exchanges

* Adds tests, fixes comment spacing. Adds wrapper logic. Makes test api key var name consistent. Removes some okcoin ETT tests

* Removes redundant functions

* linting issues. Fixes introduces huobi issues

* More linting

* Stops trying to hide ETT problems, uses iota

* Skips ETT tests for now

exchanges/bitfinex/bitfinex.go

@@ -1086,6 +1086,8 @@ func (b *Bitfinex) GetFee(feeBuilder *exchange.FeeBuilder) (float64, error) {
 		fee = getInternationalBankDepositFee(feeBuilder.Amount)
 	case exchange.InternationalBankWithdrawalFee:
 		fee = getInternationalBankWithdrawalFee(feeBuilder.Amount)
+	case exchange.OfflineTradeFee:
+		fee = getOfflineTradeFee(feeBuilder.PurchasePrice, feeBuilder.Amount)
 	}
 	if fee < 0 {
 		fee = 0
@@ -1093,6 +1095,12 @@ func (b *Bitfinex) GetFee(feeBuilder *exchange.FeeBuilder) (float64, error) {
 	return fee, nil
 }
 
+// getOfflineTradeFee calculates the worst case-scenario trading fee
+// does not require an API request, requires manual updating
+func getOfflineTradeFee(price, amount float64) float64 {
+	return 0.001 * price * amount
+}
+
 // GetCryptocurrencyWithdrawalFee returns an estimate of fee based on type of transaction
 func (b *Bitfinex) GetCryptocurrencyWithdrawalFee(c currency.Code, accountFees AccountFees) (fee float64, err error) {
 	switch result := accountFees.Withdraw[c.String()].(type) {

exchanges/bitfinex/bitfinex_test.go

@@ -14,8 +14,8 @@ import (
 
 // Please supply your own keys here to do better tests
 const (
-	testAPIKey              = ""
-	testAPISecret           = ""
+	apiKey                  = ""
+	apiSecret               = ""
 	canManipulateRealOrders = false
 )
 
@@ -30,8 +30,8 @@ func TestSetup(t *testing.T) {
 		t.Error("Test Failed - Bitfinex Setup() init error")
 	}
 	b.Setup(&bfxConfig)
-	b.APIKey = testAPIKey
-	b.APISecret = testAPISecret
+	b.APIKey = apiKey
+	b.APISecret = apiSecret
 	if !b.Enabled || b.AuthenticatedAPISupport || b.RESTPollingDelay != time.Duration(10) ||
 		b.Verbose || b.Websocket.IsEnabled() || len(b.BaseCurrencies) < 1 ||
 		len(b.AvailablePairs) < 1 || len(b.EnabledPairs) < 1 {
@@ -619,12 +619,27 @@ func setFeeBuilder() *exchange.FeeBuilder {
 	}
 }
 
+// TestGetFeeByTypeOfflineTradeFee logic test
+func TestGetFeeByTypeOfflineTradeFee(t *testing.T) {
+	var feeBuilder = setFeeBuilder()
+	b.GetFeeByType(feeBuilder)
+	if apiKey == "" || apiSecret == "" {
+		if feeBuilder.FeeType != exchange.OfflineTradeFee {
+			t.Errorf("Expected %v, received %v", exchange.OfflineTradeFee, feeBuilder.FeeType)
+		}
+	} else {
+		if feeBuilder.FeeType != exchange.CryptocurrencyTradeFee {
+			t.Errorf("Expected %v, received %v", exchange.CryptocurrencyTradeFee, feeBuilder.FeeType)
+		}
+	}
+}
+
 func TestGetFee(t *testing.T) {
 	b.SetDefaults()
 	TestSetup(t)
 	var feeBuilder = setFeeBuilder()
 
-	if testAPIKey != "" || testAPISecret != "" {
+	if apiKey != "" || apiSecret != "" {
 		// CryptocurrencyTradeFee Basic
 		if resp, err := b.GetFee(feeBuilder); resp != float64(0.002) || err != nil {
 			t.Error(err)

exchanges/bitfinex/bitfinex_wrapper.go

@@ -329,6 +329,10 @@ func (b *Bitfinex) GetWebsocket() (*exchange.Websocket, error) {
 
 // GetFeeByType returns an estimate of fee based on type of transaction
 func (b *Bitfinex) GetFeeByType(feeBuilder *exchange.FeeBuilder) (float64, error) {
+	if (b.APIKey == "" || b.APISecret == "") && // Todo check connection status
+		feeBuilder.FeeType == exchange.CryptocurrencyTradeFee {
+		feeBuilder.FeeType = exchange.OfflineTradeFee
+	}
 	return b.GetFee(feeBuilder)
 }