import { Injectable } from '@angular/core';
import { CanActivate, ActivatedRouteSnapshot, RouterStateSnapshot, Router, ActivatedRoute } from '@angular/router';
import { PublicationService } from '../services/publication-service/publication.service';

@Injectable()
export class QueryGuard implements CanActivate {

	constructor(
		private pubService: PublicationService,
		private router: Router,
		public activatedRoute: ActivatedRoute
	) {}

	/**
	 *  Check that the necessary query parameters are present and that they have the correct value.
	 *  If the parameters needs to be modified, we do so in the guard before navigating, and then redirect to the correct URL.
	 */
	canActivate(route: ActivatedRouteSnapshot, state: RouterStateSnapshot) {
		const paramsObj = Object.assign({}, route.queryParams);
		let modified = false;

		const pubId = this.pubService.getPublicationId();
		const siteLanguage = this.pubService.getLanguage();

		// default * search to get all results
		if (!('q' in paramsObj) || paramsObj.q.trim() === '' ) {
			paramsObj['q'] = '*';
			modified = true;
		}

		// Check if searcher is set. If not, check if on brand site and add prefix if so.
		if (!('searcher' in paramsObj)) {
			paramsObj['searcher'] = 'all';
			modified = true;
		}

		if (!('site' in paramsObj) || paramsObj.site !== pubId) {
			paramsObj['site'] = pubId;
			modified = true;
		}
		if (!('language' in paramsObj) || paramsObj.language !== siteLanguage) {
			paramsObj['language'] = siteLanguage;
			modified = true;
		}

		// If we had to modify query params, navigate to new url. replaceUrl to replace previous wrong params in browser history.
		if (modified) {
			const url = state.url.split('?')[0];

			this.router.navigate([url], {
				queryParams: paramsObj,
				replaceUrl: true
			});
			return false;
		}
		else { return true; }
	}
}