pkg/types: refactor exchange name

pkg/types/exchange.go

@@ -15,30 +15,6 @@ const DateFormat = "2006-01-02"
 
 type ExchangeName string
 
-func (n *ExchangeName) Value() (driver.Value, error) {
-	return n.String(), nil
-}
-
-func (n *ExchangeName) UnmarshalJSON(data []byte) error {
-	var s string
-	if err := json.Unmarshal(data, &s); err != nil {
-		return err
-	}
-
-	switch s {
-	case "binance", "bitget", "bybit", "max", "okex", "kucoin":
-		*n = ExchangeName(s)
-		return nil
-
-	}
-
-	return fmt.Errorf("unknown or unsupported exchange name: %s, valid names are: binance, bitget, bybit, max, okex, kucoin", s)
-}
-
-func (n ExchangeName) String() string {
-	return string(n)
-}
-
 const (
 	ExchangeMax      ExchangeName = "max"
 	ExchangeBinance  ExchangeName = "binance"
@@ -59,15 +35,43 @@ var SupportedExchanges = []ExchangeName{
 	// note: we are not using "backtest"
 }
 
-func ValidExchangeName(a string) (ExchangeName, error) {
-	aa := strings.ToLower(a)
-	for _, n := range SupportedExchanges {
-		if string(n) == aa {
-			return n, nil
-		}
+func (n *ExchangeName) Value() (driver.Value, error) {
+	return n.String(), nil
+}
+
+func (n *ExchangeName) UnmarshalJSON(data []byte) error {
+	var s string
+	if err := json.Unmarshal(data, &s); err != nil {
+		return err
 	}
 
-	return "", fmt.Errorf("invalid exchange name: %s", a)
+	*n = ExchangeName(s)
+	if !n.IsValid() {
+		return fmt.Errorf("%s is an invalid exchange name", s)
+	}
+
+	return nil
+}
+
+func (n ExchangeName) IsValid() bool {
+	switch n {
+	case ExchangeBinance, ExchangeBitget, ExchangeBybit, ExchangeMax, ExchangeOKEx, ExchangeKucoin:
+		return true
+	}
+	return false
+}
+
+func (n ExchangeName) String() string {
+	return string(n)
+}
+
+func ValidExchangeName(a string) (ExchangeName, error) {
+	exName := ExchangeName(strings.ToLower(a))
+	if !exName.IsValid() {
+		return "", fmt.Errorf("invalid exchange name: %s", a)
+	}
+
+	return exName, nil
 }
 
 type ExchangeMinimal interface {