const HOST_RE =
  /^[a-z0-9](?:[a-z0-9-]{0,61}[a-z0-9])?(?:\.[a-z0-9](?:[a-z0-9-]{0,61}[a-z0-9])?)+$/;

export const PARKED_DNS_PROVIDERS = ['arvan', 'cloudflare'] as const;
export type ParkedDnsProvider = (typeof PARKED_DNS_PROVIDERS)[number];

export type ParkedAlias = {
  host: string;
  dns: ParkedDnsProvider;
};

/** Strip protocol, path, trailing dot, and leading www. */
export function normalizeParkedHost(raw: string): string {
  let host = raw.trim().toLowerCase();
  host = host.replace(/^https?:\/\//, '');
  host = host.split('/')[0] ?? host;
  host = host.split(':')[0] ?? host;
  host = host.replace(/\.$/, '');
  host = host.replace(/^www\./, '');
  return host;
}

export function isValidParkedHost(host: string): boolean {
  return HOST_RE.test(host) && !host.endsWith('.local');
}

export function isParkedDnsProvider(value: unknown): value is ParkedDnsProvider {
  return value === 'arvan' || value === 'cloudflare';
}

export function parseParkedDnsMap(raw: unknown): Record<string, ParkedDnsProvider> {
  if (!raw || typeof raw !== 'object' || Array.isArray(raw)) return {};
  const out: Record<string, ParkedDnsProvider> = {};
  for (const [key, value] of Object.entries(raw as Record<string, unknown>)) {
    const host = normalizeParkedHost(key);
    if (host && isParkedDnsProvider(value)) out[host] = value;
  }
  return out;
}

export function uniqueParkedAliases(
  raw: Array<{ host?: string; dns?: string } | string>,
): ParkedAlias[] {
  const seen = new Set<string>();
  const out: ParkedAlias[] = [];
  for (const item of raw) {
    const host = normalizeParkedHost(typeof item === 'string' ? item : (item.host ?? ''));
    if (!host || seen.has(host)) continue;
    seen.add(host);
    const dnsRaw = typeof item === 'string' ? 'arvan' : item.dns;
    out.push({
      host,
      dns: isParkedDnsProvider(dnsRaw) ? dnsRaw : 'arvan',
    });
  }
  return out;
}

export function uniqueParkedHosts(raw: string[]): string[] {
  return uniqueParkedAliases(raw).map((item) => item.host);
}