/*eslint camelcase: ["error", {properties: "never"}]*/

import Vue from 'vue'
import { reduce, each, union, difference, take, filter, orderBy } from 'lodash'

import stub from '@/stubs/album'
import { artistStore } from '.'

export const albumStore = {
  stub,
  cache: [],

  state: {
    albums: [stub]
  },

  /**
   * Init the store.
   *
   * @param  {Array.<Object>} albums The array of album objects
   */
  init (albums) {
    // Traverse through the artists array and add their albums into our master album list.
    this.all = albums
    each(this.all, album => this.setupAlbum(album))
  },

  setupAlbum (album) {
    const artist = artistStore.byId(album.artist_id)
    artist.albums = union(artist.albums, [album])

    Vue.set(album, 'artist', artist)
    Vue.set(album, 'info', null)
    Vue.set(album, 'songs', [])
    Vue.set(album, 'playCount', 0)

    this.cache[album.id] = album

    return album
  },

  /**
   * Get all albums in the store.
   *
   * @return {Array.<Object>}
   */
  get all () {
    return this.state.albums
  },

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

  byId (id) {
    return this.cache[id]
  },

  /**
   * Add new album/albums into the current collection.
   *
   * @param  {Array.<Object>|Object} albums
   */
  add (albums) {
    albums = [].concat(albums)
    each(albums, album => {
      this.setupAlbum(album, album.artist)
      album.playCount = reduce(album.songs, (count, song) => count + song.playCount, 0)
    })

    this.all = union(this.all, albums)
  },

  purify () {
    this.compact()
  },

  /**
   * Remove empty albums from the store.
   */
  compact () {
    const emptyAlbums = filter(this.all, album => album.songs.length === 0)
    if (!emptyAlbums.length) {
      return
    }

    this.all = difference(this.all, emptyAlbums)
    each(emptyAlbums, album => delete this.cache[album.id])
  },

  /**
   * Get top n most-played albums.
   *
   * @param  {Number} n
   *
   * @return {Array.<Object>}
   */
  getMostPlayed (n = 6) {
    // Only non-unknown albums with actually play count are applicable.
    const applicable = filter(this.all, album => album.playCount && album.id !== 1)
    return take(orderBy(applicable, 'playCount', 'desc'), n)
  },

  /**
   * Get n most recently added albums.
   *
   * @param  {Number} n
   *
   * @return {Array.<Object>}
   */
  getRecentlyAdded (n = 6) {
    const applicable = filter(this.all, album => album.id !== 1)
    return take(orderBy(applicable, 'created_at', 'desc'), n)
  }
}