function extensionName(config) {
  return String(config?.name ?? '').trim();
}

async function readJson(response) {
  const text = await response.text();
  if (!response.ok) {
    throw new Error(text || `upstream ${response.status}`);
  }
  return text ? JSON.parse(text) : null;
}

export function sessionStdioExtensionNames(extensions) {
  return [
    ...new Set(
      (extensions ?? [])
        .filter((extension) => String(extension?.type ?? '').trim() === 'stdio')
        .map(extensionName)
        .filter(Boolean),
    ),
  ].sort();
}

export async function cancelSessionActiveRequest(apiFetch, sessionId, requestId) {
  const normalizedSessionId = String(sessionId ?? '').trim();
  const normalizedRequestId = String(requestId ?? '').trim();
  if (!normalizedSessionId || !normalizedRequestId) {
    return { cancelled: false, skipped: true };
  }

  const response = await apiFetch(
    `/sessions/${encodeURIComponent(normalizedSessionId)}/cancel`,
    {
      method: 'POST',
      body: JSON.stringify({ request_id: normalizedRequestId }),
    },
  );
  const text = await response.text();
  if (
    !response.ok
    && ![404, 409, 410].includes(Number(response.status))
    && !/(?:not found|no active|already (?:finished|cancelled))/i.test(text)
  ) {
    throw new Error(text || `upstream ${response.status}`);
  }
  return {
    cancelled: response.ok,
    skipped: !response.ok,
  };
}

/**
 * Stop per-session stdio MCP children while preserving the Goose conversation.
 * Session reconciliation restores the required extensions before the next turn.
 */
export async function quiesceSessionStdioExtensions(apiFetch, sessionId) {
  const normalizedSessionId = String(sessionId ?? '').trim();
  if (!normalizedSessionId) return { removed: [], skipped: true };

  const payload = await readJson(
    await apiFetch(`/sessions/${encodeURIComponent(normalizedSessionId)}/extensions`),
  );
  const names = sessionStdioExtensionNames(payload?.extensions);
  const removed = [];
  for (const name of names) {
    await readJson(
      await apiFetch('/agent/remove_extension', {
        method: 'POST',
        body: JSON.stringify({
          session_id: normalizedSessionId,
          name,
        }),
      }),
    );
    removed.push(name);
  }
  return { removed, skipped: names.length === 0 };
}