/** Extract a readable message from googleapis / Gaxios errors. */
export function extractYouTubeErrorMessage(err: unknown): string {
  if (!err || typeof err !== "object") {
    return typeof err === "string" ? err : "Unknown YouTube error";
  }

  const anyErr = err as {
    message?: string;
    errors?: Array<{ message?: string; reason?: string }>;
    response?: {
      data?: {
        error?: {
          message?: string;
          errors?: Array<{ message?: string; reason?: string }>;
        };
      };
    };
  };

  const nested =
    anyErr.response?.data?.error?.errors?.[0]?.message ||
    anyErr.response?.data?.error?.message ||
    anyErr.errors?.[0]?.message;

  if (nested?.trim()) return nested.trim();
  if (anyErr.message?.trim()) return anyErr.message.trim();
  return "Unknown YouTube error";
}

export function isYouTubeUploadLimitError(message: string) {
  const lower = message.toLowerCase();
  return (
    lower.includes("exceeded the number of videos") ||
    lower.includes("uploadLimitExceeded") ||
    lower.includes("upload limit") ||
    (lower.includes("quota") && lower.includes("exceeded") && lower.includes("youtube"))
  );
}

export const YOUTUBE_UPLOAD_LIMIT_USER_MESSAGE =
  "YouTube upload limit reached: this Google/YouTube account has exceeded the number of videos " +
  "it may upload right now. This is YouTube's own daily limit, not your Songs2YT plan quota. " +
  "Try again later (often after 24 hours) or use a different YouTube channel.";

/** User-facing message for the dashboard (distinct from Songs2YT plan quota). */
export function formatYouTubeErrorForUser(err: unknown): string {
  const raw = extractYouTubeErrorMessage(err);
  if (isYouTubeUploadLimitError(raw)) return YOUTUBE_UPLOAD_LIMIT_USER_MESSAGE;
  return raw;
}

/** Normalize a stored job-item error string for display in the UI. */
export function displayJobItemError(message: string | null | undefined): string | null {
  if (!message?.trim()) return null;
  if (isYouTubeUploadLimitError(message)) return YOUTUBE_UPLOAD_LIMIT_USER_MESSAGE;
  return message.trim();
}