Calculating each exchange's fees (#188)

* Adds some constants for fee types
Adds some fee calculation in an attempt to be generic
Adds fee stuff to Bittrex
Adds fee stuff to bitstamp

* Fixes bitstamp fee calculation

* Tests
Tests all scenarios for GetFeeByType

* Adds method to wrapper
Adds err to response
Checks for err

* Adds support for Bittrex fees

* Adds maker/taker dynamic to fees
Updates tests
Adds bitmex fee support
Removes unused switch case scenarios to not waste space

* Adds bithumb support for fee calculation

* Adds Bitfinex fee support
Adds list of currencies as const strings
Sets up bitflyer

* Fixes arguments

* Greatly expands symbols
Adds Binance fee calculation support
Cleans up previous exchanges

* Fixes errors for fee calculations

* Adds ANX fee support

* Adds btcc fee support
Adds alphapoint fee wrapper support
Renames method to match "enum"
Uses symbols in tests, not inline strings

* Adds support for BTCMarkets fee calculation
Adds new method to retrieve fee amount from BTCMarkets
Adds new fee type struct: FeeBuilder
Updates ANX and BTCMarkets to use new FeeBuilder type struct
Standardises the tests to run when it comes to fee calculation

* Migrates all existing exchange fee to use new feebuilder type struct
Uses standard testing model

* Fixes unit tests

* Updates maker taker fees in test config

* Removes parallel from fee testing

* Removes more parallel from tests

* Adds coinbasepro fee support

* Adds Coinut fee support

* Adds Exmo fee support
Adds maker fee support to coinut
Introduces a type for fees and bank transfers to prevent random strings being used

* Adds partial bitflyer support
Moves bitflyer to feeBuilder struct

* Adds gateio fee support

* Adds Gemini fee support

* Adds hitbtc fee support

* Adds huobi fee support

* Adds HuobiHadax fee support

* Adds itbit fee support

* Adds partial kraken fee support with trading fees

* Finishes basic Kraken fee support

* Adds basic LakeBTC fee support

* Adds basic liqui fee support

* Adds localbitcoins fee support.......

* Adds basic okcoin fee support

* Adds simple OKEX fee support
Adds many new currency symbols
Fixes liqui's fees

* Adds poloniex fee support

* Adds fee support for Yobit

* Adds WEX fee support

* Adds ZB fee support

* Removes bad reference

* Improves accuracy of variable name

* trading fee method names are now consistent

(cherry picked from commit 21c82e8b90cae590cfd73d365d7be39e1a00e973)

* Fixes rebasing issues

* Fixes issues from rebase
Removes "IsTaker" as IsMaker bool can imply taker
Updates tests to actually work.

* Adds a zero to the test

* Fixes bitfinex api endpoints and fixes fee calculations

* Updates btcmarkets trading fee calculation

* Verifies tests with apis for all exchanges except coinbasepro, itbit and bitflyer
Removes taker fee test as taker is default

* Removes redundant all exchange wrapper error checks due to the error checks being redundant

* Addresses review comments:
- Renames variables
- Changes how functions return data
- Fixes typo

exchanges/wex/wex.go

@@ -11,6 +11,7 @@ import (
 
 	"github.com/thrasher-/gocryptotrader/common"
 	"github.com/thrasher-/gocryptotrader/config"
+	"github.com/thrasher-/gocryptotrader/currency/symbol"
 	exchange "github.com/thrasher-/gocryptotrader/exchanges"
 	"github.com/thrasher-/gocryptotrader/exchanges/request"
 	"github.com/thrasher-/gocryptotrader/exchanges/ticker"
@@ -127,11 +128,6 @@ func (w *WEX) GetTradablePairs() ([]string, error) {
 	return currencies, nil
 }
 
-// GetFee returns the exchange fee
-func (w *WEX) GetFee() float64 {
-	return w.Fee
-}
-
 // GetInfo returns the WEX info
 func (w *WEX) GetInfo() (Info, error) {
 	resp := Info{}
@@ -399,3 +395,60 @@ func (w *WEX) SendAuthenticatedHTTPRequest(method string, values url.Values, res
 		true,
 		w.Verbose)
 }
+
+// GetFee returns an estimate of fee based on type of transaction
+func (w *WEX) GetFee(feeBuilder exchange.FeeBuilder) (float64, error) {
+	var fee float64
+	switch feeBuilder.FeeType {
+	case exchange.CryptocurrencyTradeFee:
+		info, err := w.GetInfo()
+		if err != nil {
+			return 0, err
+		}
+		currency := feeBuilder.FirstCurrency + feeBuilder.Delimiter + feeBuilder.SecondCurrency
+		fee = calculateTradingFee(info, currency, feeBuilder.PurchasePrice, feeBuilder.Amount)
+	case exchange.CryptocurrencyWithdrawalFee:
+		fee = getWithdrawalFee(feeBuilder.FirstCurrency)
+	case exchange.InternationalBankDepositFee:
+		fee = getInternationalBankDepositFee(feeBuilder.CurrencyItem, feeBuilder.Amount, feeBuilder.BankTransactionType)
+	}
+	if fee < 0 {
+		fee = 0
+	}
+
+	return fee, nil
+}
+
+func calculateTradingFee(info Info, currency string, purchasePrice, amount float64) (fee float64) {
+	fee = info.Pairs[common.StringToLower(currency)].Fee
+	return (fee / 100) * amount * purchasePrice
+}
+
+func getWithdrawalFee(currency string) float64 {
+	return WithdrawalFees[currency]
+}
+
+func getInternationalBankDepositFee(currency string, amount float64, bankTransactionType exchange.InternationalBankTransactionType) float64 {
+	var fee float64
+
+	switch bankTransactionType {
+	case exchange.WireTransfer:
+		fallthrough
+	case exchange.WesternUnion:
+		switch currency {
+		case symbol.USD:
+			fee = 0.065 * amount
+		}
+	case exchange.MoneyGram:
+		switch currency {
+		case symbol.USD:
+			fee = 0.065 * amount
+		}
+	case exchange.Contact:
+		switch currency {
+		case symbol.USD:
+			fee = 0.065 * amount
+		}
+	}
+	return fee
+}

exchanges/wex/wex_test.go

@@ -4,6 +4,8 @@ import (
 	"testing"
 
 	"github.com/thrasher-/gocryptotrader/config"
+	"github.com/thrasher-/gocryptotrader/currency/symbol"
+	exchange "github.com/thrasher-/gocryptotrader/exchanges"
 )
 
 var w WEX
@@ -40,13 +42,6 @@ func TestGetTradablePairs(t *testing.T) {
 	}
 }
 
-func TestGetFee(t *testing.T) {
-	t.Parallel()
-	if w.GetFee() != 0.2 {
-		t.Error("Test Failed - GetFee() error")
-	}
-}
-
 func TestGetInfo(t *testing.T) {
 	t.Parallel()
 	_, err := w.GetInfo()
@@ -166,3 +161,96 @@ func TestRedeemCoupon(t *testing.T) {
 		t.Error("Test Failed - RedeemCoupon() error", err)
 	}
 }
+
+func setFeeBuilder() exchange.FeeBuilder {
+	return exchange.FeeBuilder{
+		Amount:         1,
+		Delimiter:      "_",
+		FeeType:        exchange.CryptocurrencyTradeFee,
+		FirstCurrency:  symbol.LTC,
+		SecondCurrency: symbol.BTC,
+		IsMaker:        false,
+		PurchasePrice:       1,
+		CurrencyItem:        symbol.USD,
+		BankTransactionType: exchange.WireTransfer,
+	}
+}
+
+func TestGetFee(t *testing.T) {
+	w.SetDefaults()
+	TestSetup(t)
+	var feeBuilder = setFeeBuilder()
+
+	// CryptocurrencyTradeFee Basic
+	if resp, err := w.GetFee(feeBuilder); resp != float64(0.002) || err != nil {
+		t.Error(err)
+		t.Errorf("Test Failed - GetFee() error. Expected: %f, Recieved: %f", float64(0.002), resp)
+	}
+
+	// CryptocurrencyTradeFee High quantity
+	feeBuilder = setFeeBuilder()
+	feeBuilder.Amount = 1000
+	feeBuilder.PurchasePrice = 1000
+	if resp, err := w.GetFee(feeBuilder); resp != float64(2000) || err != nil {
+		t.Errorf("Test Failed - GetFee() error. Expected: %f, Recieved: %f", float64(2000), resp)
+		t.Error(err)
+	}
+
+
+	// CryptocurrencyTradeFee IsMaker
+	feeBuilder = setFeeBuilder()
+	feeBuilder.IsMaker = true
+	if resp, err := w.GetFee(feeBuilder); resp != float64(0.002) || err != nil {
+		t.Errorf("Test Failed - GetFee() error. Expected: %f, Recieved: %f", float64(0.002), resp)
+		t.Error(err)
+	}
+
+	// CryptocurrencyTradeFee Negative purchase price
+	feeBuilder = setFeeBuilder()
+	feeBuilder.PurchasePrice = -1000
+	if resp, err := w.GetFee(feeBuilder); resp != float64(0) || err != nil {
+		t.Errorf("Test Failed - GetFee() error. Expected: %f, Recieved: %f", float64(0), resp)
+		t.Error(err)
+	}
+	// CryptocurrencyWithdrawalFee Basic
+	feeBuilder = setFeeBuilder()
+	feeBuilder.FeeType = exchange.CryptocurrencyWithdrawalFee
+	if resp, err := w.GetFee(feeBuilder); resp != float64(0.001) || err != nil {
+		t.Errorf("Test Failed - GetFee() error. Expected: %f, Recieved: %f", float64(0.001), resp)
+		t.Error(err)
+	}
+
+	// CryptocurrencyWithdrawalFee Invalid currency
+	feeBuilder = setFeeBuilder()
+	feeBuilder.FirstCurrency = "hello"
+	feeBuilder.FeeType = exchange.CryptocurrencyWithdrawalFee
+	if resp, err := w.GetFee(feeBuilder); resp != float64(0) || err != nil {
+		t.Errorf("Test Failed - GetFee() error. Expected: %f, Recieved: %f", float64(0), resp)
+		t.Error(err)
+	}
+
+	// CyptocurrencyDepositFee Basic
+	feeBuilder = setFeeBuilder()
+	feeBuilder.FeeType = exchange.CyptocurrencyDepositFee
+	if resp, err := w.GetFee(feeBuilder); resp != float64(0) || err != nil {
+		t.Errorf("Test Failed - GetFee() error. Expected: %f, Recieved: %f", float64(0), resp)
+		t.Error(err)
+	}
+
+	// InternationalBankDepositFee Basic
+	feeBuilder = setFeeBuilder()
+	feeBuilder.FeeType = exchange.InternationalBankDepositFee
+	if resp, err := w.GetFee(feeBuilder); resp != float64(0.065) || err != nil {
+		t.Errorf("Test Failed - GetFee() error. Expected: %f, Recieved: %f", float64(0.065), resp)
+		t.Error(err)
+	}
+
+	// InternationalBankWithdrawalFee Basic
+	feeBuilder = setFeeBuilder()
+	feeBuilder.FeeType = exchange.InternationalBankWithdrawalFee
+	feeBuilder.CurrencyItem = symbol.USD
+	if resp, err := w.GetFee(feeBuilder); resp != float64(0) || err != nil {
+		t.Errorf("Test Failed - GetFee() error. Expected: %f, Recieved: %f", float64(0), resp)
+		t.Error(err)
+	}
+}

exchanges/wex/wex_types.go

@@ -1,5 +1,7 @@
 package wex
 
+import "github.com/thrasher-/gocryptotrader/currency/symbol"
+
 // Response is a generic struct used for exchange API request result
 type Response struct {
 	Return  interface{} `json:"return"`
@@ -152,3 +154,19 @@ type RedeemCoupon struct {
 	TransID        int64   `json:"transID"`
 	Error          string  `json:"error"`
 }
+
+// WithdrawalFees the large list of predefined withdrawal fees
+// Prone to change, using highest value
+var WithdrawalFees = map[string]float64{
+	symbol.BTC:  0.0004,
+	symbol.LTC:  0.001,
+	symbol.NMC:  0.1,
+	symbol.NVC:  0.1,
+	symbol.PPC:  0.1,
+	symbol.DSH:  0.001,
+	symbol.ETH:  0.003,
+	symbol.BCH:  0.001,
+	symbol.ZEC:  0.001,
+	symbol.USDT: 10,
+	symbol.XMR:  0.01,
+}

exchanges/wex/wex_wrapper.go

@@ -211,3 +211,8 @@ func (w *WEX) WithdrawFiatExchangeFundsToInternationalBank(currency pair.Currenc
 func (w *WEX) GetWebsocket() (*exchange.Websocket, error) {
 	return nil, errors.New("not yet implemented")
 }
+
+// GetFeeByType returns an estimate of fee based on type of transaction
+func (w *WEX) GetFeeByType(feeBuilder exchange.FeeBuilder) (float64, error) {
+	return w.GetFee(feeBuilder)
+}