fixed fee direction

api/gateway/aurora/internal/service/provider/mask.go

@@ -0,0 +1,21 @@
+package provider
+
+import "strings"
+
+// MaskPAN redacts a primary account number by keeping the first 6 and last 4 digits.
+func MaskPAN(pan string) string {
+	p := strings.TrimSpace(pan)
+	if len(p) <= 4 {
+		return strings.Repeat("*", len(p))
+	}
+
+	if len(p) <= 10 {
+		return p[:2] + strings.Repeat("*", len(p)-4) + p[len(p)-2:]
+	}
+
+	maskLen := len(p) - 10
+	if maskLen < 0 {
+		maskLen = 0
+	}
+	return p[:6] + strings.Repeat("*", maskLen) + p[len(p)-4:]
+}