import { Events, Routes, Selectors, Store } from '@storefront/flux-capacitor';
import { core, BaseService } from '../core/service';
import UrlBeautifier from '../core/url-beautifier';
import StoreFront from '../storefront';
import Utils from './urlUtils';

export const STORAGE_KEY: string = 'gb-previous-search-terms';

@core
class SearchService extends BaseService<SearchService.Options> {
  constructor(app: StoreFront, opts: SearchService.Options) {
    super(app, opts);

    this.app.flux.on(Events.SEARCH_CHANGED, this.pushState, this);
    this.app.flux.on(Events.SEARCH_URL_UPDATED, this.fetchProducts, this);
  }

  init() {
    // no-op
  }

  /**
   * Stores the current search term, sends an event to hide sayt, and
   * pushes a search route to history.
   */
  pushState() {
    this.app.flux.emit('sayt:hide');
    this.pushSearchTerm(Selectors.query(this.app.flux.store.getState()));
    this.app.flux.pushState({ route: Routes.SEARCH });
  }

  /**
   * Stores the given search term in a cookie.
   *
   * @param term The term to store.
   * @return The list of search terms stored.
   */
  pushSearchTerm(term: string): string[] {
    let previousTerms = this.getPastSearchTerms();

    if (!this.opts.storeDuplicateSearchTerms) {
      previousTerms = previousTerms.filter((pastTerm) => pastTerm !== term);
    }

    previousTerms.unshift(term);
    previousTerms.splice(this.opts.maxPastSearchTerms);

    this.app.services.cookie.set(STORAGE_KEY, previousTerms);

    return previousTerms;
  }

  /**
   * Returns an array of past search terms.
   */
  getPastSearchTerms(): string[] {
    try {
      return JSON.parse(this.app.services.cookie.get(STORAGE_KEY)).slice(0, this.opts.maxPastSearchTerms);
    } catch (e) {
      this.app.log.warn(`failed to extract previous searches from cookie ${STORAGE_KEY}`, e);
      return [];
    }
  }

  /**
   * Fetches products based on the values in the given state.
   *
   * @param urlState The current history state.
   */
  fetchProducts(urlState: Store.History) {
    const state = this.app.flux.store.getState();
    const request = Utils.searchStateToRequest(<UrlBeautifier.SearchUrlState>urlState.request, state);
    const newState = Utils.mergeSearchState(state, <UrlBeautifier.SearchUrlState>urlState.request);

    this.app.flux.refreshState(newState);
    this.app.flux.store.dispatch(this.app.flux.actions.fetchProductsWhenHydrated({ request }));
  }
}

namespace SearchService {
  export interface Options {
    maxPastSearchTerms?: number;
    storeDuplicateSearchTerms?: boolean;
  }
}

export default SearchService;