service backend

api/fx/oracle/internal/service/oracle/math.go

@@ -0,0 +1,67 @@
+package oracle
+
+import (
+	"math/big"
+	"strings"
+	"time"
+
+	"github.com/tech/sendico/fx/storage/model"
+	"github.com/tech/sendico/pkg/decimal"
+	"github.com/tech/sendico/pkg/merrors"
+	fxv1 "github.com/tech/sendico/pkg/proto/common/fx/v1"
+)
+
+// Convenience aliases to pkg/decimal for backward compatibility
+var (
+	ratFromString = decimal.RatFromString
+	mulRat        = decimal.MulRat
+	divRat        = decimal.DivRat
+	formatRat     = decimal.FormatRat
+)
+
+// roundRatToScale wraps pkg/decimal.RoundRatToScale with model RoundingMode conversion
+func roundRatToScale(value *big.Rat, scale uint32, mode model.RoundingMode) (*big.Rat, error) {
+	return decimal.RoundRatToScale(value, scale, convertRoundingMode(mode))
+}
+
+// convertRoundingMode converts fx/storage model.RoundingMode to pkg/decimal.RoundingMode
+func convertRoundingMode(mode model.RoundingMode) decimal.RoundingMode {
+	switch mode {
+	case model.RoundingModeHalfEven:
+		return decimal.RoundingModeHalfEven
+	case model.RoundingModeHalfUp:
+		return decimal.RoundingModeHalfUp
+	case model.RoundingModeDown:
+		return decimal.RoundingModeDown
+	case model.RoundingModeUnspecified:
+		return decimal.RoundingModeUnspecified
+	default:
+		return decimal.RoundingModeHalfEven
+	}
+}
+
+func priceFromRate(rate *model.RateSnapshot, side fxv1.Side) (*big.Rat, error) {
+	var priceStr string
+	switch side {
+	case fxv1.Side_BUY_BASE_SELL_QUOTE:
+		priceStr = rate.Ask
+	case fxv1.Side_SELL_BASE_BUY_QUOTE:
+		priceStr = rate.Bid
+	default:
+		priceStr = ""
+	}
+
+	if strings.TrimSpace(priceStr) == "" {
+		priceStr = rate.Mid
+	}
+
+	if strings.TrimSpace(priceStr) == "" {
+		return nil, merrors.InvalidArgument("oracle: rate snapshot missing price")
+	}
+
+	return ratFromString(priceStr)
+}
+
+func timeFromUnixMilli(ms int64) time.Time {
+	return time.Unix(0, ms*int64(time.Millisecond))
+}