improved logging + autotests

api/gateway/mntx/internal/service/monetix/signature.go

@@ -0,0 +1,112 @@
+package monetix
+
+import (
+	"bytes"
+	"crypto/hmac"
+	"crypto/sha512"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"sort"
+	"strconv"
+	"strings"
+)
+
+func signPayload(payload any, secret string) (string, error) {
+	canonical, err := signaturePayloadString(payload)
+	if err != nil {
+		return "", err
+	}
+
+	mac := hmac.New(sha512.New, []byte(secret))
+	if _, err := mac.Write([]byte(canonical)); err != nil {
+		return "", err
+	}
+	return base64.StdEncoding.EncodeToString(mac.Sum(nil)), nil
+}
+
+// SignPayload exposes signature calculation for callback verification.
+func SignPayload(payload any, secret string) (string, error) {
+	return signPayload(payload, secret)
+}
+
+func signaturePayloadString(payload any) (string, error) {
+	data, err := json.Marshal(payload)
+	if err != nil {
+		return "", err
+	}
+
+	var root any
+	decoder := json.NewDecoder(bytes.NewReader(data))
+	decoder.UseNumber()
+	if err := decoder.Decode(&root); err != nil {
+		return "", err
+	}
+
+	lines := make([]string, 0)
+	collectSignatureLines(nil, root, &lines)
+	sort.Strings(lines)
+
+	return strings.Join(lines, ";"), nil
+}
+
+func collectSignatureLines(path []string, value any, lines *[]string) {
+	switch v := value.(type) {
+	case map[string]any:
+		for key, child := range v {
+			if strings.EqualFold(key, "signature") {
+				continue
+			}
+			collectSignatureLines(append(path, key), child, lines)
+		}
+	case []any:
+		if len(v) == 0 {
+			return
+		}
+		for idx, child := range v {
+			collectSignatureLines(append(path, strconv.Itoa(idx)), child, lines)
+		}
+	default:
+		line := formatSignatureLine(path, v)
+		if line != "" {
+			*lines = append(*lines, line)
+		}
+	}
+}
+
+func formatSignatureLine(path []string, value any) string {
+	if len(path) == 0 {
+		return ""
+	}
+	val := signatureValueString(value)
+	segments := append(append([]string{}, path...), val)
+	return strings.Join(segments, ":")
+}
+
+func signatureValueString(value any) string {
+	switch v := value.(type) {
+	case nil:
+		return "null"
+	case string:
+		return v
+	case json.Number:
+		return v.String()
+	case bool:
+		if v {
+			return "1"
+		}
+		return "0"
+	case float64:
+		return strconv.FormatFloat(v, 'f', -1, 64)
+	case float32:
+		return strconv.FormatFloat(float64(v), 'f', -1, 32)
+	case int:
+		return strconv.Itoa(v)
+	case int8, int16, int32, int64:
+		return fmt.Sprint(v)
+	case uint, uint8, uint16, uint32, uint64:
+		return fmt.Sprint(v)
+	default:
+		return fmt.Sprint(v)
+	}
+}