/* -----------------------------------------------------------------------------
Copyright 2021,2023 Kevin P. Barry

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
----------------------------------------------------------------------------- */

// Author: Kevin P. Barry [ta0kira@gmail.com]

$ModuleOnly$

@value interface StateMachine {
  transition () -> (optional StateMachine)
}

@value interface StateTransition<#l, #s|> {
  immutable

  runWith (#l, #s) -> (optional StateTransition<#l, #s>)
}

@value interface StatePredicate<#l, #s|> {
  immutable

  test (#l, #s) -> (Bool)
}

concrete Run {
  @category then<#l, #s>
  (optional StateTransition<#l, #s>, optional StateTransition<#l, #s>) ->
  (optional StateTransition<#l, #s>)

  @category ifElse<#l, #s>
  (StatePredicate<#l, #s> test:,
   optional StateTransition<#l, #s> doIf:,
   optional StateTransition<#l, #s> doElse:) ->
  (StateTransition<#l, #s>)
}

concrete LabeledStateMachine<#l, #s> {
  #l immutable

  @category new<#l, #s>
    #l immutable
  (#l, #s, optional StateTransition<#l, #s>) -> (StateMachine)
}

concrete StateExecutor {
  @category multiplexStates (DefaultOrder<StateMachine>, Generator<Float>) -> ()
}