crossover

backend-go/internal/wei/converter.go

@@ -0,0 +1,100 @@
+package wei
+
+import (
+	"fmt"
+	"math/big"
+	"strings"
+)
+
+var weiPerEth = new(big.Int).Exp(big.NewInt(10), big.NewInt(18), nil)
+
+// ToEth converts a Wei string to a float64 ETH value.
+// Use for display only — not for precision-sensitive comparisons.
+func ToEth(weiString string) (float64, error) {
+	if weiString == "" || weiString == "0" {
+		return 0, nil
+	}
+
+	w, ok := new(big.Int).SetString(weiString, 10)
+	if !ok {
+		return 0, fmt.Errorf("invalid Wei value: %s", weiString)
+	}
+
+	wf := new(big.Float).SetInt(w)
+	ef := new(big.Float).SetInt(weiPerEth)
+	result, _ := new(big.Float).Quo(wf, ef).Float64()
+	return result, nil
+}
+
+// FromEth converts an ETH float64 to a Wei string.
+// Handles decimal precision by splitting on the decimal point.
+func FromEth(eth float64) (string, error) {
+	if eth == 0 {
+		return "0", nil
+	}
+
+	s := fmt.Sprintf("%.18f", eth)
+	parts := strings.SplitN(s, ".", 2)
+	whole := parts[0]
+	decimal := ""
+	if len(parts) == 2 {
+		decimal = parts[1]
+	}
+
+	// Pad or trim decimal to exactly 18 digits
+	if len(decimal) < 18 {
+		decimal = decimal + strings.Repeat("0", 18-len(decimal))
+	} else {
+		decimal = decimal[:18]
+	}
+
+	wholeBig, ok := new(big.Int).SetString(whole, 10)
+	if !ok {
+		return "", fmt.Errorf("invalid ETH value: %f", eth)
+	}
+	decimalBig, ok := new(big.Int).SetString(decimal, 10)
+	if !ok {
+		return "", fmt.Errorf("invalid ETH decimal: %s", decimal)
+	}
+
+	result := new(big.Int).Mul(wholeBig, weiPerEth)
+	result.Add(result, decimalBig)
+	return result.String(), nil
+}
+
+func Compare(weiA, weiB string) (int, error) {
+	a, ok := new(big.Int).SetString(weiA, 10)
+	if !ok {
+		return 0, fmt.Errorf("invalid Wei value: %s", weiA)
+	}
+	b, ok := new(big.Int).SetString(weiB, 10)
+	if !ok {
+		return 0, fmt.Errorf("invalid Wei value: %s", weiB)
+	}
+	return a.Cmp(b), nil
+}
+
+func GreaterThanOrEqual(weiA, weiB string) (bool, error) {
+	cmp, err := Compare(weiA, weiB)
+	if err != nil {
+		return false, err
+	}
+	return cmp >= 0, nil
+}
+
+func LessThan(weiA, weiB string) (bool, error) {
+	cmp, err := Compare(weiA, weiB)
+	if err != nil {
+		return false, err
+	}
+	return cmp < 0, nil
+}
+
+// FormatAsEth formats a Wei string as "X.XXXX ETH".
+func FormatAsEth(weiString string, decimals int) (string, error) {
+	eth, err := ToEth(weiString)
+	if err != nil {
+		return "", err
+	}
+	return fmt.Sprintf("%.*f ETH", decimals, eth), nil
+}