优化结构

internal/integration/payment/wechat_v2.go

@@ -3,8 +3,10 @@ package payment
 import (
 	"bytes"
 	"context"
+	"crypto/rand"
 	"crypto/tls"
 	"crypto/x509"
+	"encoding/hex"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -570,7 +572,15 @@ func paymentHTTPClient(c map[string]any) (*http.Client, error) {
 	return &http.Client{Timeout: 20 * time.Second, Transport: &http.Transport{TLSClientConfig: &tls.Config{Certificates: []tls.Certificate{cert}, RootCAs: pool, MinVersion: tls.VersionTLS12}}}, nil
 }
 
-func nonce() string { return fmt.Sprintf("%d", time.Now().UnixNano()) }
+// nonce returns a compact request token. Clock-only values can collide when
+// several payment requests are prepared in the same scheduler tick.
+func nonce() string {
+	var raw [8]byte
+	if _, err := rand.Read(raw[:]); err == nil {
+		return hex.EncodeToString(raw[:])
+	}
+	return fmt.Sprintf("%d", time.Now().UnixNano())
+}
 func stringOr(extra map[string]any, key, fallback string) string {
 	if value, ok := extra[key].(string); ok {
 		return value