import type { CheerioAPI } from 'cheerio';

interface LazyOptions {
  readonly skip: number;
}

const DEFAULT_OPTIONS: LazyOptions = {
  skip: 1,
};

export function applyLazyLoading(
  document: CheerioAPI,
  options: LazyOptions = DEFAULT_OPTIONS,
): void {
  const { skip } = options;
  let index = 0;
  document('img').each((_i, element) => {
    const img = document(element);
    if (img.attr('loading')) {
      return;
    }

    index += 1;
    if (index <= skip) {
      return;
    }

    img.attr('loading', 'lazy');
    if (!img.attr('fetchpriority')) {
      img.attr('fetchpriority', 'low');
    }
  });
}