const MAX_RAW_LEN = 8000;

export interface KavenegarNormalized {
  httpLikeStatus?: number;
  message?: string;
  raw: string;
}

export function safeJsonStringify(value: unknown): string {
  try {
    const s = JSON.stringify(value);
    return s.length > MAX_RAW_LEN
      ? `${s.slice(0, MAX_RAW_LEN)}...[truncated]`
      : s;
  } catch {
    return String(value);
  }
}

/**
 * Kavenegar REST responses use `{ return: { status, message }, ... }`.
 * Transport failures may yield non-JSON strings or malformed bodies.
 */
export function normalizeKavenegarBody(body: unknown): KavenegarNormalized {
  if (typeof body === "string") {
    try {
      return normalizeKavenegarBody(JSON.parse(body) as unknown);
    } catch {
      const raw =
        body.length > MAX_RAW_LEN
          ? `${body.slice(0, MAX_RAW_LEN)}...[truncated]`
          : body;
      return { raw };
    }
  }

  let httpLikeStatus: number | undefined;
  let message: string | undefined;

  if (body && typeof body === "object" && !Array.isArray(body)) {
    const ret = (body as { return?: { status?: unknown; message?: unknown } })
      .return;
    if (ret && typeof ret === "object") {
      if (typeof ret.status === "number" && Number.isFinite(ret.status)) {
        httpLikeStatus = ret.status;
      }
      if (typeof ret.message === "string") {
        message = ret.message;
      }
    }
  }

  return {
    httpLikeStatus,
    message,
    raw: safeJsonStringify(body),
  };
}

/** Kavenegar uses `return.status === 200` for a successful API call. */
export function isKavenegarSuccess(body: unknown): boolean {
  return normalizeKavenegarBody(body).httpLikeStatus === 200;
}

/** The nest client sometimes rejects with a JSON string `{ "error": "..." }`. */
export function unwrapKavenegarTransportError(err: unknown): unknown {
  if (typeof err === "string") {
    try {
      return JSON.parse(err) as unknown;
    } catch {
      return { transportMessage: err };
    }
  }
  if (err instanceof Error) {
    return { name: err.name, message: err.message };
  }
  return err;
}