type AssistantToolResult = {
  content: string;
  data?: unknown;
};

export function readToolError(result: AssistantToolResult): string | null {
  if (result.data && typeof result.data === "object" && result.data !== null && "error" in (result.data as Record<string, unknown>)) {
    const error = (result.data as Record<string, unknown>).error;
    return typeof error === "string" ? error : null;
  }

  try {
    const parsed = JSON.parse(result.content) as unknown;
    if (parsed && typeof parsed === "object" && "error" in (parsed as Record<string, unknown>)) {
      const error = (parsed as Record<string, unknown>).error;
      return typeof error === "string" ? error : null;
    }
  } catch {
    // tool content may be plain text
  }

  return null;
}

export function readToolSuccessMessage(result: AssistantToolResult): string | null {
  if (result.data && typeof result.data === "object" && result.data !== null) {
    const data = result.data as Record<string, unknown>;
    if (typeof data.message === "string" && data.message.trim().length > 0) return data.message;
    if (typeof data.description === "string" && data.description.trim().length > 0) return data.description;
  }

  try {
    const parsed = JSON.parse(result.content) as unknown;
    if (parsed && typeof parsed === "object") {
      const content = parsed as Record<string, unknown>;
      if (typeof content.message === "string" && content.message.trim().length > 0) return content.message;
      if (typeof content.description === "string" && content.description.trim().length > 0) return content.description;
    }
  } catch {
    // tool content may be plain text
  }

  return typeof result.content === "string" && result.content.trim().length > 0
    ? result.content
    : null;
}