/// Création comptes staff (gestionnaire / admin) — ticket #161.
bool canCreateStaffAccounts(String? role) {
  final r = (role ?? '').trim().toLowerCase();
  return r == 'administrateur' || r == 'super_admin';
}

/// Droits d’affichage poubelle — tickets #154 / #160.
bool canDeleteMetier(String? role) {
  final r = (role ?? '').trim().toLowerCase();
  return r == 'gestionnaire' ||
      r == 'administrateur' ||
      r == 'super_admin';
}

bool canDeleteGestionnaire(String? role) {
  final r = (role ?? '').trim().toLowerCase();
  return r == 'administrateur' || r == 'super_admin';
}

bool canDeleteAdministrateur({
  required String? currentRole,
  required String? currentUserId,
  required String targetUserId,
  required String targetRole,
  required int adminCount,
}) {
  final me = (currentRole ?? '').trim().toLowerCase();
  if (me != 'administrateur' && me != 'super_admin') return false;
  if (targetUserId.trim().isEmpty) return false;
  if (currentUserId != null &&
      currentUserId.trim() == targetUserId.trim()) {
    return false;
  }
  final target = targetRole.trim().toLowerCase();
  if (target == 'super_admin') return false;
  if (adminCount <= 1 && me != 'super_admin') return false;
  return true;
}

String? adminDeleteBlockedReason({
  required String? currentRole,
  required String? currentUserId,
  required String targetUserId,
  required String targetRole,
  required int adminCount,
}) {
  if (currentUserId != null &&
      currentUserId.trim() == targetUserId.trim()) {
    return 'Vous ne pouvez pas supprimer votre propre compte.';
  }
  if (targetRole.trim().toLowerCase() == 'super_admin') {
    return 'Le super administrateur ne peut pas être supprimé.';
  }
  if (adminCount <= 1 &&
      (currentRole ?? '').trim().toLowerCase() != 'super_admin') {
    return 'Seul un super administrateur peut supprimer le dernier administrateur.';
  }
  return null;
}