jwplayer_percent_tracking.coffee

class @VideoProgressTracker
  constructor: (@video) ->
    @played_five_seconds = 0
    @checkpoints = [0, 25, 50, 75, 95]

  track: ->
    @played_five_seconds += 1
    @triggerCheckpoints(500 * @played_five_seconds / @duration)

  start: ->
    @duration ?= @video.getDuration()
    clearInterval(@interval)
    @setUpdateInterval()

  pause: ->
    clearInterval(@interval)

  setUpdateInterval: ->
    callback = => @track()
    @interval = setInterval callback, 5000

  triggerCheckpoints: (current_percent) ->
    if current_percent >= @checkpoints[0]
      completed_percent = @checkpoints.shift()
      $.post(gon.record_video_progress_path, { lesson_id: gon.lesson_id, percent: completed_percent })

video.coffee

jwplayer("video").setup
  events:
    onPlay: (e) ->
      video_tracker.start()

    onPause: (e) ->
      video_tracker.pause()

@.video_tracker = new VideoProgressTracker(jwplayer("video"))