import { parseQuery } from 'utils/parse-query';
import { THEMES, MAX_SHOWN_ROOT_COMMENTS } from './constants';

function parseNumber(value: unknown) {
  if (typeof value !== 'string') {
    return undefined;
  }

  const parsed = +value;

  return isNaN(parsed) ? undefined : parsed;
}

function includes<T extends U, U>(coll: ReadonlyArray<T>, el: U): el is T {
  return coll.includes(el as T);
}

export const rawParams = parseQuery();
export const maxShownComments = parseNumber(rawParams.max_shown_comments) ?? MAX_SHOWN_ROOT_COMMENTS;
export const isEmailSubscription = rawParams.show_email_subscription !== 'false';
export const isRssSubscription =
  rawParams.show_rss_subscription === undefined || rawParams.show_rss_subscription !== 'false';
export const theme = (rawParams.theme = includes(THEMES, rawParams.theme) ? rawParams.theme : THEMES[0]);
export const siteId = rawParams.site_id || 'remark';
export const pageTitle = rawParams.page_title;
export const url = rawParams.url;
export const token = rawParams.token;
export const locale = rawParams.locale || 'en';