src/media-understanding/output-extract.ts

export function extractLastJsonObject(raw: string): unknown {
  const trimmed = raw.trim();
  const start = trimmed.lastIndexOf("{");
  if (start === -1) {
    return null;
  }
  const slice = trimmed.slice(start);
  try {
    return JSON.parse(slice);
  } catch {
    return null;
  }
}

export function extractGeminiResponse(raw: string): string | null {
  const payload = extractLastJsonObject(raw);
  if (!payload || typeof payload !== "object") {
    return null;
  }
  const response = (payload as { response?: unknown }).response;
  if (typeof response !== "string") {
    return null;
  }
  const trimmed = response.trim();
  return trimmed || null;
}