/* eslint-disable ember/no-observers */
import { inject as service } from '@ember/service';
import { isArray } from '@ember/array';
import Helper from '@ember/component/helper';
import { observer } from '@ember/object';

const exact = (a, b) => a === b;
const startsWith = (a, b) => a.indexOf(b) === 0;

export default Helper.extend({
  router: service(),

  onRouteChange: observer('router.currentURL', 'router.currentRouteName', function () {
    this.recompute();
  }),

  compute([routeName, model], { isExact }) {
    const router = this.router;
    const currentRoute = router.get('currentRouteName');
    let currentURL = router.get('currentURL');
    // if we have any query params we want to discard them
    currentURL = currentURL.split('?')[0];
    const comparator = isExact ? exact : startsWith;
    if (!currentRoute) {
      return false;
    }
    if (isArray(routeName)) {
      return routeName.some((name) => comparator(currentRoute, name));
    } else if (model) {
      // slice off the rootURL from the generated route
      return comparator(currentURL, router.urlFor(routeName, model).slice(router.rootURL.length - 1));
    } else {
      return comparator(currentRoute, routeName);
    }
  },
});