module test

import StdMisc
import iTasks
import Data.Either
import StdEnv
import Data.Func

Start w = flip doTasks w $
	updateInformation () [] 42
	>>* [OnAction (Action "Continue") (always (return 43))]

(>>*) infixl 1// :: !(Task a) ![TaskCont a (Task b)] -> Task b | iTask a & iTask b
(>>*) task steps :== step task (const Nothing) steps

step :: !(Task a) ((Maybe a) -> Maybe b) [TaskCont a (Task b)] -> Task b | iTask a & iTask b
step lhs lhsValFun conts
	= parallel
		[(Embedded, \stl->lhs @? \v->case v of
			NoValue = Value (Left Nothing) False
			(Value v s) = Value (Left (Just v)) s
		)]
		(map stepCont conts)
		@? stepVal lhsValFun
where
	stepVal :: ((Maybe a) -> Maybe b) (TaskValue [(Int, TaskValue (Either (Maybe a) b))]) -> TaskValue b
	stepVal tfun NoValue = NoValue
	stepVal tfun (Value [(_, x):_] _) = case x of
		//Not yet stepped:
		Value (Left l) s = case tfun l of
			Nothing = NoValue
			Just v = Value v False
		//Stepped but no value
		NoValue = NoValue
		Value (Right r) s = Value r s
	stepVal _ _ = abort "cannot happen"

	stepCont :: (TaskCont a (Task b)) -> TaskCont
		[(Int, TaskValue (Either (Maybe a) b))]
		(ParallelTaskType, ParallelTask (Either (Maybe a) b))
	stepCont (OnValue f) = OnValue (transform f)
	stepCont (OnAction a f) = OnAction a (transform f)
	
	transform f v
		# v = case v of
			Value [(_, v)] _ = case v of
				NoValue = NoValue
				Value (Left (Just v)) s = Value v s
				Value _ = NoValue
			NoValue = NoValue
		= case f v of
			Nothing = Nothing
			Just t = Just (Embedded, \stl->
				get (sdsFocus {onlyIndex=Nothing,onlyTaskId=Nothing,onlySelf=False,includeValue=False,includeProgress=False,includeAttributes=False} stl)
				removeTask taskId stl
				>-| t @ Right)

//	stepCont (OnException f) = OnException \e->(Embedded, \stl->e f @ Right)
//	stepCont (OnAllExceptions b) = OnAllExceptions b