(function () {
  'use strict'
  window.GOVUK = window.GOVUK || {}
  var GOVUK = window.GOVUK || {}

  var YoutubeLinkEnhancement = function ($element) {
    this.$element = $element
  }

  YoutubeLinkEnhancement.prototype.init = function () {
    if (!this.campaignCookiesAllowed()) {
      return
    }

    var $youtubeLinks = this.$element.querySelectorAll('a[href*="youtube.com"], a[href*="youtu.be"]')

    if ($youtubeLinks.length > 0) {
      YoutubeLinkEnhancement.insertApiScript()
    }

    for (var i = 0; i < $youtubeLinks.length; ++i) {
      var $link = $youtubeLinks[i]
      var href = $link.getAttribute('href')
      var hasTracking = $link.hasAttribute('data-youtube-player-analytics')
      var options = {
        link: $link
      }

      if (hasTracking) {
        options.tracking = {
          hasTracking: hasTracking,
          category: $link.getAttribute('data-youtube-player-analytics-category')
        }
      }

      if (href.indexOf('/live_stream') >= 0) {
        var channelId = YoutubeLinkEnhancement.parseLivestream(href)

        if (!this.hasDisabledEmbed($link) && channelId) {
          options.channel = channelId
          this.setupVideo(options)
        }
      } else {
        var videoId = YoutubeLinkEnhancement.parseVideoId(href)
        if (!this.hasDisabledEmbed($link) && videoId) {
          options.videoId = videoId
          this.setupVideo(options)
        }
      }
    }
  }

  YoutubeLinkEnhancement.prototype.hasDisabledEmbed = function ($link) {
    return $link.getAttribute('data-youtube-player') === 'off'
  }

  YoutubeLinkEnhancement.prototype.setupVideo = function (options) {
    var elementId = YoutubeLinkEnhancement.nextId()
    var $link = options.link

    var id = options.videoId ? options.videoId : options.channel

    var parentPara = $link.parentNode
    var parentContainer = parentPara.parentNode

    var youtubeVideoContainer = document.createElement('div')
    youtubeVideoContainer.className += 'gem-c-govspeak__youtube-video'
    youtubeVideoContainer.innerHTML = '<span id="' + elementId + '" data-video-id="' + id + '"></span>'

    options.title = $link.textContent

    parentContainer.replaceChild(youtubeVideoContainer, parentPara)
    this.insertVideo(elementId, options)
  }

  YoutubeLinkEnhancement.prototype.insertVideo = function (elementId, options) {
    var channelId = ''
    var videoId = ''

    if (options.channel) {
      channelId = options.channel
      videoId = 'live_stream'
    } else {
      videoId = options.videoId
    }

    var videoInsert = function () {
      new window.YT.Player(elementId, { // eslint-disable-line no-new
        videoId: videoId,
        host: 'https://www.youtube-nocookie.com',
        playerVars: {
          // enables the player to be controlled via IFrame or JavaScript Player API calls
          enablejsapi: 1,
          origin: window.location.origin,
          // don't show related videos
          rel: 0,
          // disable option to allow single key shortcuts due to (WCAG SC 2.1.4)
          // https://www.w3.org/WAI/WCAG21/quickref/#character-key-shortcuts
          disablekb: 1,
          // prevent the YouTube logo from displaying in the control bar
          modestbranding: 1,
          // To support live_stream videos
          channel: channelId
        },
        events: {
          onReady: function (event) {
            // update iframe title attribute once video is ready
            var videoTitle = options.title
            event.target.f.title = videoTitle + ' (video)'
          },
          onStateChange: function (event) {
            var eventData = event.data
            var eventTarget = event.target
            var states = {
              /* eslint-disable quote-props */
              '-1': 'VideoUnstarted',
              '0': 'VideoEnded',
              '1': 'VideoPlaying',
              '2': 'VideoPaused',
              '3': 'VideoBuffering',
              '5': 'VideoCued'
              /* eslint-enable */
            }
            if (states[eventData] && options.tracking && options.tracking.hasTracking &&
                window.GOVUK.analytics && window.GOVUK.analytics.trackEvent) {
              var tracking = {
                category: options.tracking.category,
                action: states[eventData],
                label: { transport: 'beacon', label: eventTarget.getVideoData && eventTarget.getVideoData().title }
              }

              window.GOVUK.analytics.trackEvent(tracking.category, tracking.action, tracking.label)
            }
          }
        }
      })
    }

    videoInsert = videoInsert.bind(this)

    if (YoutubeLinkEnhancement.playerApiReady) {
      videoInsert.call()
    } else {
      YoutubeLinkEnhancement.queuedInserts.push(videoInsert)
    }
  }

  YoutubeLinkEnhancement.prototype.campaignCookiesAllowed = function () {
    var cookiePolicy = window.GOVUK.getConsentCookie()
    return cookiePolicy !== null ? cookiePolicy.campaigns : true
  }

  YoutubeLinkEnhancement.nextId = function () {
    this.embedCount = this.embedCount || 0
    this.embedCount += 1
    return 'youtube-' + this.embedCount
  }

  YoutubeLinkEnhancement.insertApiScript = function () {
    if (this.apiScriptInserted) {
      return
    }

    var tag = document.createElement('script')
    tag.src = 'https://www.youtube.com/player_api'
    var firstScriptTag = document.getElementsByTagName('script')[0]
    firstScriptTag.parentNode.insertBefore(tag, firstScriptTag)
    this.apiScriptInserted = true
  }

  YoutubeLinkEnhancement.parseLivestream = function (url) {
    var matches = url.match(/channel=([^&]*)/)

    if (matches) {
      return matches[1]
    }
  }

  // This is a public class method so it can be used outside of this embed to
  // check that user input for videos will be supported in govspeak
  YoutubeLinkEnhancement.parseVideoId = function (url) {
    var parts

    if (url.indexOf('youtube.com') > -1) {
      var params = {}
      parts = url.split('?')
      if (parts.length === 1) {
        return
      }
      parts = parts[1].split('&')
      for (var i = 0; i < parts.length; i++) {
        var part = parts[i].split('=')
        params[part[0]] = part[1]
      }
      return params.v
    } else if (url.indexOf('youtu.be') > -1) {
      parts = url.split('/')
      return parts.pop()
    }
  }

  YoutubeLinkEnhancement.apiScriptInserted = false
  YoutubeLinkEnhancement.playerApiReady = false
  // an array of functions to be called once the Youtube Player API is ready
  YoutubeLinkEnhancement.queuedInserts = []

  window.onYouTubePlayerAPIReady = function () {
    YoutubeLinkEnhancement.playerApiReady = true
    for (var i = 0; i < YoutubeLinkEnhancement.queuedInserts.length; i++) {
      YoutubeLinkEnhancement.queuedInserts[i].call()
    }
  }

  GOVUK.GovspeakYoutubeLinkEnhancement = YoutubeLinkEnhancement
})()