_ = require('underscore')
Backbone = require('backbone')


class Queue
  constructor: ->
    _.extend(@, Backbone.Events)
    @queue = []

  dequeue: =>
    if @queue.length
      callback() for callback in @queue
      @queue.length = 0

  whenCondition: (condition, callback)->
    isTrue = if typeof condition is 'function' then condition() else condition

    if isTrue
      callback()
    else
      @queue.push(callback)

  whenAvailable: (callback)=> @whenCondition(@available, callback)
  whenReady: (callback)=> @whenCondition(@ready, callback)
  whenLoaded: (callback)=> @whenCondition(@loaded, callback)

module.exports = Queue