const { Manager } = require('./manager')
const { GuildAction } = require('./guild_action')
const { Track } = require('./track')
const { youtube_instance } = require("./youtube")

/**
 * The {@link Manager} that manage resources. Its main goal is to search resources and get their metadata.<br />
 * Note that it only works for YouTube videos for now.
 * @extends Manager
 */
class ResourceManager extends Manager {
  #awaiting_answers

  constructor() {
    super(...arguments)
    this.#awaiting_answers = []
  }

  /**
   * Performs a research, depending on the search terms it's been asked for
   * @param {string|string[]} query The search terms
   * @returns {Track[]} An array of objects representing the search results.
   */
  async get_search_results(query) {
    if (query instanceof Array)
      query = query.join(' ')
    return await youtube_instance.search_track(query)
  }

  /**
   * Do a research and send the search results back to the Discord channel it's been asked for
   * @param {GuildAction}
   */
  async search({ message, params }) {
    const tracks = await this.get_search_results(params)
    if (tracks.length === 0) {
      message.channel.send(':warning: Something went wrong. Please try again')
    } else {
      const text_res = tracks
            .slice(0, 10)
            .map((track, i) => (i + 1) + ' ' + track)
            .join('\n')
      const input_manager = this.get_manager('input')
      // TODO: 2000 chars limit
      // TODO: find a better syntaxic coloration than js
      const own_message = await message.channel.send('```js\n' + text_res + '```')
      const trigger = {
        pattern: /^\d+/,
        target: 'resource',
        action: 'search_confirm',
        ttl: 300,
        user_shared: false,
        repeat: 1,
        on_expire: function() {
          own_message.react('🛑')
        }
      }
      this.#awaiting_answers.push({
        trigger: trigger,
        search_results: tracks,
        from: message.member.id
      })
      input_manager.add_trigger(trigger)
    }
  }

  /**
   * Choose a track given its id in a search result. Note that this only works right after a call to the {@link ResourceManager#search} action.
   * @param {GuildAction}
   */
  async search_confirm({ message, params }) {
    // TODO: update this so that it can be more relient on the Trigger received
    const id = parseInt(message.content)
    const answer = this.#awaiting_answers
          .filter(a => a.from === message.member.id)
          .slice(-1)[0]
    if (answer === undefined) {
      message.channel.send(':warning: Something went wrong. That\'s not supposed to happen...')
    } else if (answer.search_results[id - 1] === undefined) {
      message.channel.send(':warning: Please choose a number between 1 and ' + answer.search_results.length)
    } else {
      // TODO: calling the add method is a bit ugly, we can probably do better...
      const action = new GuildAction({ message, params: [answer.search_results[id - 1].get_url()] })
      this.get_manager('player').add(action)
      message.react('👌')
    }
  }

  /**
   * Given the url of a song, get its metadata.
   * @param {string} url
   * @returns {Track}
   */
  async get_metadata(url) {
    return youtube_instance.get_metadata(url)
  }
}

module.exports = { ResourceManager }