const LEGACY_ICON_FILENAME_PATTERN = /^[a-z0-9][a-z0-9._-]*\.svg$/i;
const CLOUDINARY_SPORT_ICON_PATH_PATTERN = /\/image\/upload\/(?:v\d+\/)?sports-icons\/[^/?#]+\.svg(?:[?#].*)?$/i;

export function resolveSportIconUrl(iconUrl: string | null | undefined): string | null {
  if (!iconUrl) return null;
  if (/^(https?:|data:|\/)/.test(iconUrl)) return iconUrl;
  return `/sports-icons/${iconUrl}`;
}

export function isCloudinarySportIconUrl(iconUrl: string): boolean {
  try {
    const url = new URL(iconUrl);
    return url.protocol === "https:" &&
      url.hostname.endsWith("res.cloudinary.com") &&
      CLOUDINARY_SPORT_ICON_PATH_PATTERN.test(`${url.pathname}${url.search}${url.hash}`);
  } catch {
    return false;
  }
}

export function isLegacySportIconFilename(iconUrl: string): boolean {
  return LEGACY_ICON_FILENAME_PATTERN.test(iconUrl) && !iconUrl.includes("/");
}

export function parseSportIconUrlInput(value: unknown): string | null | undefined {
  if (typeof value !== "string" || !value.trim()) return null;

  const iconUrl = value.trim();
  if (isCloudinarySportIconUrl(iconUrl) || isLegacySportIconFilename(iconUrl)) {
    return iconUrl;
  }

  return undefined;
}