import { SPECIAL_GROUP_KEY_PATTERN } from '../common/special-group-key';

export const WEBSITE_STATIC_IMAGE_CATALOG_PATH = '/meshkee/static-image-slots';

export type WebsiteStaticImageCatalogSlot = {
  key: string;
  label: string;
  kind: 'single' | 'list';
  pageKey: string;
  aspectRatio: string | null;
  recommendedWidth: number | null;
  itemCount: number | null;
};

const ASPECT_RATIO_PATTERN = /^[0-9]{1,3}:[0-9]{1,3}$/;

function asRecord(value: unknown): Record<string, unknown> | null {
  return value && typeof value === 'object' && !Array.isArray(value)
    ? (value as Record<string, unknown>)
    : null;
}

function readString(value: unknown): string {
  return typeof value === 'string' ? value.trim() : '';
}

function readOptionalInt(value: unknown, min: number, max: number): number | null {
  if (value == null || value === '') return null;
  const parsed = typeof value === 'number' ? value : Number(value);
  if (!Number.isInteger(parsed) || parsed < min || parsed > max) return null;
  return parsed;
}

export function parseWebsiteStaticImageCatalog(
  payload: unknown,
): WebsiteStaticImageCatalogSlot[] {
  const root = asRecord(payload);
  const rawSlots = Array.isArray(root?.slots) ? root.slots : Array.isArray(payload) ? payload : null;
  if (!rawSlots) {
    throw new Error('Slot catalog must be { slots: [...] }');
  }

  const slots: WebsiteStaticImageCatalogSlot[] = [];
  const seen = new Set<string>();

  for (const entry of rawSlots) {
    const row = asRecord(entry);
    if (!row) continue;

    const key = readString(row.key);
    if (!key || !SPECIAL_GROUP_KEY_PATTERN.test(key) || seen.has(key)) continue;

    const kind = readString(row.kind) === 'single' ? 'single' : 'list';
    const label = readString(row.label) || key;
    const pageKey = readString(row.pageKey) || 'home';
    if (!SPECIAL_GROUP_KEY_PATTERN.test(pageKey)) continue;

    const aspectRatioRaw = readString(row.aspectRatio);
    const aspectRatio =
      aspectRatioRaw && ASPECT_RATIO_PATTERN.test(aspectRatioRaw) ? aspectRatioRaw : null;

    const itemCount =
      kind === 'single' ? 1 : readOptionalInt(row.itemCount, 1, 24);

    seen.add(key);
    slots.push({
      key,
      label: label.slice(0, 255),
      kind,
      pageKey,
      aspectRatio,
      recommendedWidth: readOptionalInt(row.recommendedWidth, 1, 8000),
      itemCount,
    });
  }

  if (slots.length === 0) {
    throw new Error('Slot catalog did not contain any valid slots');
  }

  return slots;
}

export function websiteCatalogUrls(hosts: string[]): string[] {
  const uniqueHosts = [...new Set(hosts.map((host) => host.toLowerCase().trim()).filter(Boolean))];
  const urls: string[] = [];

  for (const host of uniqueHosts) {
    const bare = host.replace(/^www\./, '');
    const variants = [bare, `www.${bare}`];
    for (const candidate of variants) {
      urls.push(`https://${candidate}${WEBSITE_STATIC_IMAGE_CATALOG_PATH}`);
      urls.push(`http://${candidate}${WEBSITE_STATIC_IMAGE_CATALOG_PATH}`);
      urls.push(`https://${candidate}${WEBSITE_STATIC_IMAGE_CATALOG_PATH}.json`);
    }
  }

  return [...new Set(urls)];
}