module Handler.Utils.Workflow.Restriction
  ( checkWorkflowRestriction
  ) where

import Import

import Utils.Workflow

import qualified Data.Set as Set
import qualified Data.Map as Map


checkWorkflowRestriction :: Maybe IdWorkflowState
                         -> PredDNF WorkflowGraphRestriction
                         -> Bool
checkWorkflowRestriction mHistory dnf = maybe False (ofoldr1 (||)) . fromNullable $ map evalConj dnf'
  where
    evalConj = maybe True (ofoldr1 (&&)) . fromNullable . map evalPred
    evalPred PLVariable{ plVar = WorkflowGraphRestrictionPayloadFilled{..} } = wgrPayloadFilled `Set.member`    filledPayloads
    evalPred PLNegated{  plVar = WorkflowGraphRestrictionPayloadFilled{..} } = wgrPayloadFilled `Set.notMember` filledPayloads
    evalPred PLVariable{ plVar = WorkflowGraphRestrictionPreviousNode{..}  } = maybe False (wgrPreviousNode ==) cState
    evalPred PLNegated{  plVar = WorkflowGraphRestrictionPreviousNode{..}  } = maybe True  (wgrPreviousNode /=) cState
    evalPred PLVariable{ plVar = WorkflowGraphRestrictionInitial           } = is    _Nothing mHistory
    evalPred PLNegated{  plVar = WorkflowGraphRestrictionInitial           } = isn't _Nothing mHistory
    dnf' = map (Set.toList . toNullable) . Set.toList $ dnfTerms dnf

    filledPayloads | Just history <- mHistory = Map.keysSet . Map.filter (not . Set.null) $ workflowStateCurrentPayloads history
                   | otherwise = Set.empty
    cState = wpTo . last <$> mHistory