feat: backend service

backend/internal/geo/declared_country.go

@@ -0,0 +1,43 @@
+package geo
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	"galaxy/backend/internal/postgres/jet/backend/table"
+
+	"github.com/go-jet/jet/v2/postgres"
+	"github.com/google/uuid"
+)
+
+// SetDeclaredCountryAtRegistration writes the geoip-derived country to
+// `accounts.declared_country` for userID, and only when the column is
+// currently NULL. The semantics match PLAN.md §5.8: declared_country is
+// captured at first registration and never updated thereafter, so
+// repeated calls on the same account are no-ops.
+//
+// The geoip lookup itself is best-effort: a missing or invalid country
+// returns nil (no UPDATE executed) and never blocks the auth flow. Errors
+// from the database UPDATE itself surface to the caller so the auth
+// service can decide whether to log or escalate.
+func (s *Service) SetDeclaredCountryAtRegistration(ctx context.Context, userID uuid.UUID, sourceIP string) error {
+	if s == nil {
+		return errors.New("geo: nil service")
+	}
+	country := s.LookupCountry(sourceIP)
+	if country == "" {
+		return nil
+	}
+	stmt := table.Accounts.UPDATE(table.Accounts.DeclaredCountry, table.Accounts.UpdatedAt).
+		SET(postgres.String(country), postgres.NOW()).
+		WHERE(
+			table.Accounts.UserID.EQ(postgres.UUID(userID)).
+				AND(table.Accounts.DeclaredCountry.IS_NULL()).
+				AND(table.Accounts.DeletedAt.IS_NULL()),
+		)
+	if _, err := stmt.ExecContext(ctx, s.db); err != nil {
+		return fmt.Errorf("geo: set declared_country for %s: %w", userID, err)
+	}
+	return nil
+}