const fetchWithCustomHeader: typeof fetch = async (url, init) => {
      const headers = new Headers(init?.headers);
      if (this.config.jwt) {
        headers.set('Authorization', `Bearer ${this.config.jwt}`);
      }
      headers.set('X-Redpanda-Stream-Tokens', 'true');

      const newInit = { ...init, headers };

      return fetch(url, newInit);
    };

    const client = await createA2AClientWithFallback(this.modelId, { fetchImpl: fetchWithCustomHeader });

async function createA2AClientWithFallback(agentUrl: string, options: A2AClientOptions): Promise<A2AClient> {
  const urls = getAgentCardUrls({ agentUrl });
  const errors: Error[] = [];

  for (let i = 0; i < urls.length; i++) {
    const url = urls[i];
    const isLastUrl = i === urls.length - 1;

    try {
      const client = await A2AClient.fromCardUrl(url, options);
      return client;
    } catch (error) {
      errors.push(error as Error);
      console.log(`Failed to fetch agent card from ${url}, ${isLastUrl ? 'no more URLs to try' : 'trying next URL...'}`);
      // Continue to next URL if not the last one
      if (isLastUrl) {
        break;
      }
    }
  }

export function getAgentCardUrls({ agentUrl }: { agentUrl: string }): string[] {
  // Normalize URL by removing trailing slash
  const normalizedUrl = agentUrl.endsWith('/') ? agentUrl.slice(0, -1) : agentUrl;

  // If the URL already points to a specific file, use it as-is
  const isFullPath =
    normalizedUrl.includes('agent-card.json') ||
    normalizedUrl.includes('agent.json') ||
    normalizedUrl.includes('well-known');

  if (isFullPath) {
    return [normalizedUrl];
  }

  // Try agent-card.json first, fall back to agent.json
  return [`${normalizedUrl}/.well-known/agent-card.json`, `${normalizedUrl}/.well-known/agent.json`];
}