type ResolveIframeAssistantIdInput = {
  selectedAgentId: string | null;
  threadMetadataAgentId: string | null;
  preferDefaultAssistant?: boolean;
};

function normalizeAgentId(agentId: string | null | undefined): string | undefined {
  const trimmed = agentId?.trim();
  return trimmed ? trimmed : undefined;
}

export function resolveIframeAssistantId({
  selectedAgentId,
  threadMetadataAgentId,
  preferDefaultAssistant = false,
}: ResolveIframeAssistantIdInput): string | undefined {
  if (preferDefaultAssistant) {
    return normalizeAgentId(selectedAgentId);
  }
  return (
    normalizeAgentId(selectedAgentId) ??
    normalizeAgentId(threadMetadataAgentId)
  );
}