immutable-state-machine.ls

# *-state-maker :: (model) -> {render, cleanup}
# state-maker s are modules and can be defined in different modules
# render :: (all-state-makers, callback) -> void 
# all-state-makers is an object, it's useful for explicitly specifying which states are accessible from this render function.

second = (_, b) -> b

init-state-maker = (_) ->
  <- second ->
  {
    render: ({sub-method-state-maker}, callback) -> 
      {visit-id, sub-method} <- $.get '/visits'
      callback null, (sub-method-state-maker {visit-id, sub-method})
    cleanup: (callback) -> callback null
  }

sub-method-state-maker = (model:{visit-id, sub-method, error}) ->
  is-pin = sub-method.type == 'pin'
  is-mo = sub-method.type == 'mo'
    
  $parent = \.state.sub-method

  <- second ->
  {
    render: ({pin-method-state-maker, sub-method-state-maker}, callback) -> 
      $ \body .add-class \state-sub-method
      if is-mo
        $parent .find \.sub-method.mo .show! 
      else if is-pin
        $parent .find \.sub-method.pin .show! 
      else
        $parent .find \.sub-method.normal .show!


      if error is not null
        switch error
        | 'msisdin-submission' => $ \.msisdin-submission.error .show!
        | otherwise => console.error 'Unknown Error'
      else
        $ \.error .hide!


      subscribe = ->
        switch
        | is-pin => 
          {succeed, submission-id} <- $.get '/submit'
          callback <| if succeed then (pin-state-maker {visit-id, submission-id, retries: 0}) else sub-method-state-maker model <<< error: 'msisdin-submission'
        | otherwise =>
          window.location.href = sub-method.url
          callback <| congrats-state-maker {visit-id, sub-method}
      
      $parent .find \.subscribe .on \click, subscribe

    cleanup: (callback) ->
      $parent 
        ..find \.error .hide!
        ..find \.sub-method .hide!
        ..hide!
      $ \body .remove-class \state-sub-method
      callback null
  }

pin-method-state-maker = (model:{visit-id, submission-id, retries, error}) ->
  $parent = $ \.state-pin
  <- second -> 
  {
    render: ({pin-method-state-maker, sub-method-state-maker, congrats-state-maker}, callback) ->
      $ \body .add-class \state-pin
      if error is not null
        $ \.error .show!

      submit-pin = ->
        {succeed, mo:{short-code, keyword}?, subscriber-id, service-url} <- $.get '/submit-pin'
        callback null, do ->
          if succeed
            congrats-state-maker {visit-id, subscriber-id, service-url} 
          else
            if retries > 2 and mo is not null
              sub-method-state-maker {visit-id, sub-method: {type: 'mo', short-code, keyword}}
            else
              pin-method-state-maker model <<< retries: retries + 1, error: 'invalid-pin'
      
      $parent.find \.submit .on \click, -> submit-pin

    cleanup: (next-state, callback) ->
      $parent
        ..find \.error .hide
        ..hide!
      $ \body .remove-class \state-pin

      callback null
  }



all-state-makers = {
  init-state-maker
  sub-method-state-maker
  pin-method-state-maker
}

next = (prev-state:{cleanup}?, current-state:{render}) ->
  _ <- cleanup current-state 
  _, next-state <- render all-state-makers
  next current-state, next-state


next null, (init-state-maker {cleanup: -> it null})