import { head, last, each, includes, union, difference, map, shuffle as _shuffle, first } from 'lodash';

export const queueStore = {
  state: {
    songs: [],
    current: null,
  },

  init() {
    // We don't have anything to do here yet.
    // How about another song then?
    //
    // LITTLE WING
    // -- by Jimi Fucking Hendrix
    //
    // Well she's walking
    // Through the clouds
    // With a circus mind
    // That's running wild
    // Butterflies and zebras and moonbeams and fairytales
    // That's all she ever thinks about
    // Riding with the wind
    //
    // When I'm sad
    // She comes to me
    // With a thousand smiles
    // She gives to me free
    // It's alright she said
    // It's alright
    // Take anything you want from me
    // Anything...
  },

  /**
   * Get all queued songs.
   *
   * @return {Array.<Object>}
   */
  get all() {
    return this.state.songs;
  },

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

  /**
   * The first song in the queue.
   *
   * @return {?Object}
   */
  get first() {
    return head(this.all);
  },

  /**
   * The last song in the queue.
   *
   * @return {?Object}
   */
  get last() {
    return last(this.all);
  },

  /**
   * Determine if the queue contains a song.
   *
   * @param  {Object} song
   *
   * @return {Boolean}
   */
  contains(song) {
    return includes(this.all, song);
  },

  /**
   * Add a list of songs to the end of the current queue,
   * or replace the current queue as a whole if `replace` is true.
   *
   * @param {Object|Array.<Object>}   songs   The song, or an array of songs
   * @param {Boolean}         replace Whether to replace the current queue
   * @param {Boolean}         toTop   Whether to prepend or append to the queue
   */
  queue(songs, replace = false, toTop = false) {
    songs = [].concat(songs);

    if (replace) {
      this.all = songs;
    } else {
      this.all = toTop ? union(songs, this.all) : union(this.all, songs);
    }
  },

  /**
   * Queue song(s) to after the current song.
   *
   * @param  {Array.<Object>|Object} songs
   */
  queueAfterCurrent(songs) {
    songs = [].concat(songs);

    if (!this.current || !this.all.length) {
      return this.queue(songs);
    }

    // First we unqueue the songs to make sure there are no duplicates.
    this.unqueue(songs);

    const head = this.all.splice(0, this.indexOf(this.current) + 1);
    this.all = head.concat(songs, this.all);
  },

  /**
   * Unqueue a song, or several songs at once.
   *
   * @param  {Object|String|Array.<Object>} songs The song(s) to unqueue
   */
  unqueue(songs) {
    this.all = difference(this.all, [].concat(songs));
  },

  /**
   * Move some songs to after a target.
   *
   * @param  {Array.<Object>} songs  Songs to move
   * @param  {Object}     target The target song object
   */
  move(songs, target) {
    const $targetIndex = this.indexOf(target);

    each(songs, song => {
      this.all.splice(this.indexOf(song), 1);
      this.all.splice($targetIndex, 0, song);
    });
  },

  /**
   * Clear the current queue.
   */
  clear() {
    this.all = [];
    this.current = null;
  },

  /**
   * Get index of a song in the queue.
   *
   * @param  {Object} song
   *
   * @return {?Integer}
   */
  indexOf(song) {
    return this.all.indexOf(song);
  },

  /**
   * The next song in queue.
   *
   * @return {?Object}
   */
  get next() {
    if (!this.current) {
      return first(this.all);
    }

    const idx = map(this.all, 'id').indexOf(this.current.id) + 1;

    return idx >= this.all.length ? null : this.all[idx];
  },

  /**
   * The previous song in queue.
   *
   * @return {?Object}
   */
  get previous() {
    if (!this.current) {
      return last(this.all);
    }

    const idx = map(this.all, 'id').indexOf(this.current.id) - 1;

    return idx < 0 ? null : this.all[idx];
  },

  /**
   * The current song.
   *
   * @return {Object}
   */
  get current() {
    return this.state.current;
  },

  /**
   * Set a song as the current queued song.
   *
   * @param  {Object} song
   *
   * @return {Object} The queued song.
   */
  set current(song) {
    return this.state.current = song;
  },

  /**
   * Shuffle the queue.
   *
   * @return {Array.<Object>} The shuffled array of song objects
   */
  shuffle() {
    return this.all = _shuffle(this.all);
  },
};