text: 'use strict';
  
  const Collector = require('./interfaces/Collector');
  const Collection = require('../util/Collection');
  const { Events } = require('../util/Constants');
  
  /**
   * @typedef {CollectorOptions} ReactionCollectorOptions
   * @property {number} max The maximum total amount of reactions to collect
   * @property {number} maxEmojis The maximum number of emojis to collect
   * @property {number} maxUsers The maximum number of users to react
   */
  
  /**
   * Collects reactions on messages.
   * Will automatically stop if the message (`'messageDelete'`),
   * channel (`'channelDelete'`), or guild (`'guildDelete'`) are deleted.
   * @extends {Collector}
   */
  class ReactionCollector extends Collector {
    /**
     * @param {Message} message The message upon which to collect reactions
     * @param {CollectorFilter} filter The filter to apply to this collector
     * @param {ReactionCollectorOptions} [options={}] The options to apply to this collector
     */
    constructor(message, filter, options = {}) {
      super(message.client, filter, options);
  
      /**
       * The message upon which to collect reactions
       * @type {Message}
       */
      this.message = message;
  
      /**
       * The users which have reacted to this message
       * @type {Collection}
       */
      this.users = new Collection();
  
      /**
       * The total number of reactions collected
       * @type {number}
       */
      this.total = 0;
  
      this.empty = this.empty.bind(this);
      this._handleChannelDeletion = this._handleChannelDeletion.bind(this);
      this._handleGuildDeletion = this._handleGuildDeletion.bind(this);
      this._handleMessageDeletion = this._handleMessageDeletion.bind(this);
  
      if (this.client.getMaxListeners() !== 0) this.client.setMaxListeners(this.client.getMaxListeners() + 1);
      this.client.on(Events.MESSAGE_REACTION_ADD, this.handleCollect);
      this.client.on(Events.MESSAGE_REACTION_REMOVE, this.handleDispose);
      this.client.on(Events.MESSAGE_REACTION_REMOVE_ALL, this.empty);
      this.client.on(Events.MESSAGE_DELETE, this._handleMessageDeletion);
      this.client.on(Events.CHANNEL_DELETE, this._handleChannelDeletion);
      this.client.on(Events.GUILD_DELETE, this._handleGuildDeletion);
  
      this.once('end', () => {
        this.client.removeListener(Events.MESSAGE_REACTION_ADD, this.handleCollect);
        this.client.removeListener(Events.MESSAGE_REACTION_REMOVE, this.handleDispose);
        this.client.removeListener(Events.MESSAGE_REACTION_REMOVE_ALL, this.empty);
        this.client.removeListener(Events.MESSAGE_DELETE, this._handleMessageDeletion);
        this.client.removeListener(Events.CHANNEL_DELETE, this._handleChannelDeletion);
        this.client.removeListener(Events.GUILD_DELETE, this._handleGuildDeletion);
        if (this.client.getMaxListeners() !== 0) this.client.setMaxListeners(this.client.getMaxListeners() - 1);
      });
  
      this.on('collect', (reaction, user) => {
        this.total++;
        this.users.set(user.id, user);
      });
  
      this.on('remove', (reaction, user) => {
        this.total--;
        if (!this.collected.some(r => r.users.has(user.id))) this.users.delete(user.id);
      });
    }
  
    /**
     * Handles an incoming reaction for possible collection.
     * @param {MessageReaction} reaction The reaction to possibly collect
     * @returns {?Snowflake|string}
     * @private
     */
    collect(reaction) {
      /**
       * Emitted whenever a reaction is collected.
       * @event ReactionCollector#collect
       * @param {MessageReaction} reaction The reaction that was collected
       * @param {User} user The user that added the reaction
       */
      if (reaction.message.id !== this.message.id) return null;
      return ReactionCollector.key(reaction);
    }
  
    /**
     * Handles a reaction deletion for possible disposal.
     * @param {MessageReaction} reaction The reaction to possibly dispose of
     * @param {User} user The user that removed the reaction
     * @returns {?Snowflake|string}
     */
    dispose(reaction, user) {
      /**
       * Emitted whenever a reaction is disposed of.
       * @event ReactionCollector#dispose
       * @param {MessageReaction} reaction The reaction that was disposed of
       * @param {User} user The user that removed the reaction
       */
      if (reaction.message.id !== this.message.id) return null;
  
      /**
       * Emitted whenever a reaction is removed from a message. Will emit on all reaction removals,
       * as opposed to {@link Collector#dispose} which will only be emitted when the entire reaction
       * is removed.
       * @event ReactionCollector#remove
       * @param {MessageReaction} reaction The reaction that was removed
       * @param {User} user The user that removed the reaction
       */
      if (this.collected.has(ReactionCollector.key(reaction)) &&
          this.users.has(user.id)) {
        this.emit('remove', reaction, user);
      }
      return reaction.count ? null : ReactionCollector.key(reaction);
    }
  
    /**
     * Empties this reaction collector.
     */
    empty() {
      this.total = 0;
      this.collected.clear();
      this.users.clear();
      this.checkEnd();
    }
  
    endReason() {
      if (this.options.max && this.total >= this.options.max) return 'limit';
      if (this.options.maxEmojis && this.collected.size >= this.options.maxEmojis) return 'emojiLimit';
      if (this.options.maxUsers && this.users.size >= this.options.maxUsers) return 'userLimit';
      return null;
    }
  
    /**
     * Handles checking if the message has been deleted, and if so, stops the collector with the reason 'messageDelete'.
     * @private
     * @param {Message} message The message that was deleted
     * @returns {void}
     */
    _handleMessageDeletion(message) {
      if (message.id === this.message.id) {
        this.stop('messageDelete');
      }
    }
  
    /**
     * Handles checking if the channel has been deleted, and if so, stops the collector with the reason 'channelDelete'.
     * @private
     * @param {GuildChannel} channel The channel that was deleted
     * @returns {void}
     */
    _handleChannelDeletion(channel) {
      if (channel.id === this.message.channel.id) {
        this.stop('channelDelete');
      }
    }
  
    /**
     * Handles checking if the guild has been deleted, and if so, stops the collector with the reason 'guildDelete'.
     * @private
     * @param {Guild} guild The guild that was deleted
     * @returns {void}
     */
    _handleGuildDeletion(guild) {
      if (this.message.guild && guild.id === this.message.guild.id) {
        this.stop('guildDelete');
      }
    }
  
    /**
     * Gets the collector key for a reaction.
     * @param {MessageReaction} reaction The message reaction to get the key for
     * @returns {Snowflake|string}
     */
    static key(reaction) {
      return reaction.emoji.id || reaction.emoji.name;
    }
  }
  
  module.exports = ReactionCollector;
  