import { each, map, difference, union } from 'lodash';

import { http } from '../services';

export const favoriteStore = {
  state: {
    songs: [],
    length: 0,
    fmtLength: '',
  },

  /**
   * All songs favorite'd by the current user.
   *
   * @return {Array.<Object>}
   */
  get all() {
    return this.state.songs;
  },

  /**
   * Set all favorite'd songs.
   *
   * @param  {Array.<Object>} value
   */
  set all(value) {
    this.state.songs = value;
  },

  /**
   * Toggle like/unlike a song.
   * A request to the server will be made.
   *
   * @param {Object}   song
   */
  toggleOne(song) {
    // Don't wait for the HTTP response to update the status, just toggle right away.
    // This may cause a minor problem if the request fails somehow, but do we care?
    song.liked = !song.liked;
    song.liked ? this.add(song) : this.remove(song);

    return new Promise((resolve, reject) => {
      http.post('interaction/like', { song: song.id }, r => resolve(r), r => reject(r));
    });
  },

  /**
   * Add a song/songs into the store.
   *
   * @param {Array.<Object>|Object} songs
   */
  add(songs) {
    this.all = union(this.all, [].concat(songs));
  },

  /**
   * Remove a song/songs from the store.
   *
   * @param {Array.<Object>|Object} songs
   */
  remove(songs) {
    this.all = difference(this.all, [].concat(songs));
  },

  /**
   * Remove all favorites.
   */
  clear() {
    this.all = [];
  },

  /**
   * Like a bunch of songs.
   *
   * @param {Array.<Object>}  songs
   */
  like(songs) {
    // Don't wait for the HTTP response to update the status, just set them to Liked right away.
    // This may cause a minor problem if the request fails somehow, but do we care?
    each(songs, song => song.liked = true);
    this.add(songs);

    return new Promise((resolve, reject) => {
      http.post('interaction/batch/like', { songs: map(songs, 'id') }, r => resolve(r), r => reject(r));
    });
  },

  /**
   * Unlike a bunch of songs.
   *
   * @param {Array.<Object>}  songs
   */
  unlike(songs) {
    each(songs, song => song.liked = false);
    this.remove(songs);

    return new Promise((resolve, reject) => {
      http.post('interaction/batch/unlike', { songs: map(songs, 'id') }, r => resolve(r), r => reject(r));
    });
  },
};