Organize backend into product executable and shared Go modules

backend/product/verification/store/idempotency.go

@@ -0,0 +1,84 @@
+package verification
+
+import (
+	"context"
+	"errors"
+	verificationmodel "git.sendico.io/tech/sxchnge/product/verification/model"
+	"strings"
+
+	mutil "git.sendico.io/tech/sxchnge/shared/database/query"
+	"git.sendico.io/tech/sxchnge/shared/database/repository"
+	"git.sendico.io/tech/sxchnge/shared/database/repository/builder"
+	"git.sendico.io/tech/sxchnge/shared/errors"
+	"go.mongodb.org/mongo-driver/v2/bson"
+)
+
+func normalizedIdempotencyKey(value *string) (string, bool) {
+	if value == nil {
+		return "", false
+	}
+	key := strings.TrimSpace(*value)
+	if key == "" {
+		return "", false
+	}
+	return key, true
+}
+
+func syntheticIdempotencyKey() string {
+	return "auto:" + bson.NewObjectID().Hex()
+}
+
+func idempotencyContextFilter(
+	request *Request,
+	idempotencyKey string,
+) builder.Query {
+	return repository.Query().And(
+		repository.Filter("accountRef", request.AccountRef),
+		repository.Filter("purpose", request.Purpose),
+		repository.Filter("target", request.Target),
+		repository.Filter("idempotencyKey", idempotencyKey),
+	)
+}
+
+func idempotencySeed(request *Request, idempotencyKey string) string {
+	return strings.Join([]string{
+		request.AccountRef.Hex(),
+		string(request.Purpose),
+		request.Target,
+		request.ContextRef,
+		request.Kind,
+		idempotencyKey,
+	}, "|")
+}
+
+func (db *verificationDB) lookupIdempotencyReplay(ctx context.Context, request *Request, idempotencyKey string) (*verificationmodel.VerificationToken, bool, error) {
+	tokens, err := mutil.GetObjects[verificationmodel.VerificationToken](
+		ctx,
+		db.Logger,
+		idempotencyContextFilter(request, idempotencyKey),
+		nil,
+		db.Repository,
+	)
+	switch {
+	case err == nil:
+	case errors.Is(err, merrors.ErrNoData):
+		return nil, false, nil
+	default:
+		return nil, false, err
+	}
+
+	var replayed *verificationmodel.VerificationToken
+	for i := range tokens {
+		existingContextRef := strings.TrimSpace(tokens[i].ContextRef)
+		// The lookup intentionally ignores contextRef. A reused idempotency key
+		// in another context is a client conflict, not a replay.
+		if existingContextRef != request.ContextRef {
+			return nil, false, ErrorIdempotencyConflict()
+		}
+		if replayed == nil {
+			token := tokens[i]
+			replayed = &token
+		}
+	}
+	return replayed, replayed != nil, nil
+}