KDObject           = require './Object'
KDNotificationView = require 'notifications/NotificationView'

module.exports = class KDRouter extends KDObject

  {history} = window

  listenerKey = 'ಠ_ಠ'

  @registerStaticEmitter()

  createObjectRef =(obj)->
    return unless obj?.bongo_? and obj.getId?
    constructorName   : obj.bongo_?.constructorName
    id                : obj.getId()

  revive =(objRef, callback)->
    unless objRef?.constructorName? and objRef.id? then callback null
    else KD.remote.cacheable objRef.constructorName, objRef.id, callback

  constructor:(routes)->

    super()

    @tree          = {} # this is the tree for quick lookups
    @routes        = {} # this is the flat namespace containing all routes
    @visitedRoutes = []
    @addRoutes routes  if routes

    KD.utils.defer => KDRouter.emit 'RouterIsReady', this


  listen:->
    # this handles the case that the url is an "old-style" hash fragment hack.
    if location.hash.length
      hashFragment = location.hash.substr 1
      @userRoute = hashFragment
      @utils.defer => @handleRoute hashFragment,
        shouldPushState   : yes
        replaceState      : yes
    @startListening()

  popState:(event)->
    revive event.state, (err, state)=>
      return KD.showError err  if err
      @handleRoute "#{location.pathname}#{location.search}",
        shouldPushState   : no
        state             : state

  clear:(route = '/', replaceState = yes)->
    delete @userRoute # TODO: i hope deleting the userRoute here doesn't break anything... C.T.
    @handleRoute route, {replaceState}

  back:-> if @visitedRoutes.length <= 1 then @clear() else history.back()

  startListening:->
    return no  if @isListening # make this action idempotent
    @isListening = yes
    # we need to add a listener to the window's popstate event:
    window.addEventListener 'popstate', @bound "popState"
    return yes

  stopListening:->
    return no  unless @isListening # make this action idempotent
    @isListening = no
    # we need to remove the listener from the window's popstate event:
    window.removeEventListener 'popstate', @bound "popState"
    return yes

  @handleNotFound =(route)->
    console.trace()
    log "The route #{ Encoder.XSSEncode route } was not found!"

  getCurrentPath:-> @currentPath

  handleNotFound:(route)->
    message =
      if /<|>/.test route
      then "Invalid route!"
      else"404 Not found! #{ Encoder.XSSEncode route }"

    delete @userRoute
    @clear()
    log "The route #{route} was not found!"
    new KDNotificationView title: message

  routeWithoutEdgeAtIndex =(route, i)->
    "/#{route.slice(0, i).concat(route.slice i + 1).join '/'}"

  addRoute:(route, listener)->

    @routes[route] = listener
    node = @tree
    route = route.split '/'
    route.shift() # first edge is garbage like '' or '#!'
    for edge, i in route
      last = edge.length - 1
      if '?' is edge.charAt last # then this is an "optional edge".
        # recursively alias this route without this optional edge:
        @addRoute routeWithoutEdgeAtIndex(route, i), listener
        edge = edge.substr 0, last # get rid of the "?" from the route
      if /^:/.test edge
        node[':'] or= name: edge.substr 1
        node = node[':']
      else
        node[edge] or= {}
        node = node[edge]
    node[listenerKey] or= []
    node[listenerKey].push listener  unless listener in node[listenerKey]

  addRoutes:(routes)->
    @addRoute route, listener  for own route, listener of routes

  handleRoute:(userRoute, options={})->
    userRoute = userRoute.slice 1  if (userRoute.indexOf '!') is 0
    @visitedRoutes.push userRoute  if @visitedRoutes.last isnt userRoute

    [frags, query...] = (userRoute ? @getDefaultRoute?() ? '/').split '?'

    query = @utils.parseQuery query.join '&'

    {shouldPushState, replaceState, state, suppressListeners} = options
    shouldPushState ?= yes

    objRef = createObjectRef state

    node = @tree
    params = {}

    frags = frags.split '/'
    frags.shift() # first edge is garbage like '' or '#!'

    frags = frags.filter Boolean

    path = "/#{frags.join '/'}"

    qs = @utils.stringifyQuery query
    path += "?#{qs}"  if qs.length

    notFound = no
    for edge in frags
      if node[edge]
        node = node[edge]
      else
        param = node[':']
        if param?
          params[param.name] = edge
          node = param
        else notFound = yes

    if not suppressListeners and shouldPushState and not replaceState and path is @currentPath
      @emit 'AlreadyHere', path, { params, frags }
      return

    @handleNotFound frags.join '/'  if notFound

    @currentPath = path

    if shouldPushState
      method = if replaceState then 'replaceState' else 'pushState'
      history[method] objRef, path, path

    routeInfo = {params, query}
    @emit 'RouteInfoHandled', {params, query, path}

    unless suppressListeners
      listeners = node[listenerKey]
      if listeners?.length
        listener.call this, routeInfo, state, path  for listener in listeners

    return this

  handleQuery:(query)->
    query = @utils.stringifyQuery query  unless 'string' is typeof query
    return  unless query.length
    nextRoute = "#{@currentPath}?#{query}"
    @handleRoute nextRoute