Update project structure and build process

libwallet/newop/exchange_rates.go

@@ -0,0 +1,39 @@
+package newop
+
+import (
+	"github.com/muun/libwallet"
+	"github.com/shopspring/decimal"
+)
+
+// ExchangeRateWindow holds a map of exchange rates from BTC to every currency we handle
+type ExchangeRateWindow struct {
+	WindowId int
+	rates    map[string]float64
+}
+
+func (w *ExchangeRateWindow) AddRate(currency string, rate float64) {
+	if w.rates == nil {
+		w.rates = make(map[string]float64)
+	}
+	w.rates[currency] = rate
+}
+
+func (w *ExchangeRateWindow) Rate(currency string) float64 {
+	return w.rates[currency]
+}
+
+func (s *ExchangeRateWindow) Currencies() *libwallet.StringList {
+	var currencies []string
+	for key := range s.rates {
+		currencies = append(currencies, key)
+	}
+	return libwallet.NewStringListWithElements(currencies)
+}
+
+func (w *ExchangeRateWindow) convert(amount *MonetaryAmount, currency string) *MonetaryAmount {
+	fromRate := decimal.NewFromFloat(w.Rate(amount.Currency))
+	toRate := decimal.NewFromFloat(w.Rate(currency))
+	value := amount.Value.Div(fromRate).Mul(toRate)
+
+	return &MonetaryAmount{Value: value, Currency: currency}
+}