codecombat/app/views/play/level/WebSurfaceView.coffee

CocoView = require 'views/core/CocoView'
template = require 'templates/play/level/web-surface-view'

module.exports = class WebSurfaceView extends CocoView
  id: 'web-surface-view'
  template: template

  subscriptions:
    'tome:html-updated': 'onHTMLUpdated'

  initialize: (options) ->
    @goals = (goal for goal in options.goalManager?.goals ? [] when goal.html)
    # Consider https://www.npmjs.com/package/css-select to do this on virtualDom instead of in iframe on concreteDOM
    super(options)

  afterRender: ->
    super()
    @iframe = @$('iframe')[0]
    $(@iframe).on 'load', (e) =>
      window.addEventListener 'message', @onIframeMessage
      @iframeLoaded = true
      @onIframeLoaded?()
      @onIframeLoaded = null

  # TODO: make clicking Run actually trigger a 'create' update here (for resetting scripts)
        
  onHTMLUpdated: (e) ->
    unless @iframeLoaded
      return @onIframeLoaded = => @onHTMLUpdated e unless @destroyed
    dom = htmlparser2.parseDOM e.html, {}
    body = _.find(dom, name: 'body') ? {name: 'body', attribs: null, children: dom}
    html = _.find(dom, name: 'html') ? {name: 'html', attribs: null, children: [body]}
    # TODO: pull out the actual scripts, styles, and body/elements they are doing so we can merge them with our initial structure on the other side
    { virtualDom, styles, scripts } = @extractStylesAndScripts(@dekuify html)
    messageType = if e.create or not @virtualDom then 'create' else 'update'
    @iframe.contentWindow.postMessage {type: messageType, dom: virtualDom, styles, scripts, goals: @goals}, '*'
    @virtualDom = virtualDom

  dekuify: (elem) ->
    return elem.data if elem.type is 'text'
    return null if elem.type is 'comment'  # TODO: figure out how to make a comment in virtual dom
    elem.attribs = _.omit elem.attribs, (val, attr) -> attr.indexOf('<') > -1 # Deku chokes on `<thing <p></p>`
    unless elem.name
      console.log("Failed to dekuify", elem)
      return elem.type
    deku.element(elem.name, elem.attribs, (@dekuify(c) for c in elem.children ? []))
  
  extractStylesAndScripts: (dekuTree) ->
    recurse = (dekuTree) ->
      #base case
      if dekuTree.type is '#text'
        return { virtualDom: dekuTree, styles: [], scripts: [] }
      if dekuTree.type is 'style'
        return { styles: [dekuTree], scripts: [] }
      if dekuTree.type is 'script'
        return { styles: [], scripts: [dekuTree] }
      # recurse over children
      childStyles = []
      childScripts = []
      dekuTree.children?.forEach (dekuChild, index) =>
        { virtualDom, styles, scripts } = recurse(dekuChild)
        dekuTree.children[index] = virtualDom
        childStyles = childStyles.concat(styles)
        childScripts = childScripts.concat(scripts)
      dekuTree.children = _.filter dekuTree.children # Remove the nodes we extracted
      return { virtualDom: dekuTree, scripts: childScripts, styles: childStyles }
    
    { virtualDom, scripts, styles } = recurse(dekuTree)
    wrappedStyles = deku.element('head', {}, styles)
    wrappedScripts = deku.element('head', {}, scripts)
    return { virtualDom, scripts: wrappedScripts, styles: wrappedStyles }
    
  combineNodes: (type, nodes) ->
    if _.any(nodes, (node) -> node.type isnt type)
      throw new Error("Can't combine nodes of different types. (Got #{nodes.map (n) -> n.type})")
    children = nodes.map((n) -> n.children).reduce(((a,b) -> a.concat(b)), [])
    if _.isEmpty(children)
      deku.element(type, {})
    else
      deku.element(type, {}, children)

  onIframeMessage: (event) =>
    origin = event.origin or event.originalEvent.origin
    unless origin is window.location.origin
      return console.log 'Ignoring message from bad origin:', origin
    unless event.source is @iframe.contentWindow
      return console.log 'Ignoring message from somewhere other than our iframe:', event.source
    switch event.data.type
      when 'goals-updated'
        Backbone.Mediator.publish 'god:new-html-goal-states', goalStates: event.data.goalStates, overallStatus: event.data.overallStatus
      when 'error'
        # NOTE: The line number in this is relative to the script tag, not the user code. The offset is added in SpellView.
        Backbone.Mediator.publish 'web-dev:error', _.pick(event.data, ['message', 'line', 'column', 'url'])
      else
        console.warn 'Unknown message type', event.data.type, 'for message', event, 'from origin', origin

  destroy: ->
    window.removeEventListener 'message', @onIframeMessage
    super()