{-# LANGUAGE GADTs #-}
{-# LANGUAGE StandaloneDeriving #-}

-- | Evaluation of a Nomyx expression
module Nomyx.Core.Engine.Evaluation where

import           Control.Category            hiding (id)
import           Control.Lens
import           Control.Monad
import           Control.Monad.Except
import           Control.Monad.State
import           Data.List
import           Data.Maybe
import           Data.Time
import           Data.Typeable
import qualified Imprevu.Evaluation as Imp
import           Imprevu.Evaluation hiding (runEvalError, events)
import           Imprevu
import           Nomyx.Language
import           Nomyx.Core.Engine.Utils
import           Nomyx.Core.Engine.Types     hiding (_vRuleNumber)
import           Prelude                     hiding (log, (.))
import           System.Random


-- * Evaluation

-- | evaluate an effecful expression.
evalNomex :: Nomex a -> Evaluate a
evalNomex (NewVar v a)            = evNewVar v a
evalNomex (DelVar v)              = evDelVar v
evalNomex (WriteVar v val)        = evWriteVar v val
evalNomex (OnEvent ev h)          = evOnEvent ev h
evalNomex (DelEvent en)           = evDelEvent en
evalNomex (SendMessage m d)       = evSendMessage m d
evalNomex (NewOutput pn s)        = evNewOutput pn s
evalNomex (UpdateOutput on s)     = evUpdateOutput on s
evalNomex (DelOutput on)          = evDelOutput on
evalNomex (ProposeRule rule)      = evProposeRule rule
evalNomex (ActivateRule rule)     = evActivateRule rule
evalNomex (RejectRule rule)       = evRejectRule rule
evalNomex (AddRule rule)          = evAddRule rule
evalNomex (ModifyRule m rule)     = evModifyRule m rule
evalNomex (SetPlayerName pn n)    = evChangeName pn n
evalNomex (DelPlayer pn)          = evDelPlayer pn
evalNomex (SetVictory ps)         = evSetVictory ps
--evalNomex (LiftEffect e)          = liftEval $ evalNomex e
evalNomex (ThrowError s)          = throwError s
evalNomex (CatchError n h)        = catchError (evalNomex n) (evalNomex . h)
evalNomex (Return a)              = return a
evalNomex (Bind ex f)             = evalNomex ex >>= \e -> evalNomex (f e)
evalNomex (GetRandomNumber r)     = evGetRandomNumber r

-- | evaluate an effectless expression.
evalNomex (ReadVar v)     = evReadVar v
evalNomex (GetOutput on)  = evGetOutput on
evalNomex  GetRules       = use (evalEnv . eGame . rules)
evalNomex  GetPlayers     = use (evalEnv . eGame . players)
evalNomex  GetEvents      = use (evalEnv . eGame . events) >>= return . (map _erEventInfo)
evalNomex  SelfRuleNumber = use (evalEnv . eRuleNumber)
evalNomex (GetCurrentTime)= use (evalEnv . eGame . currentTime)
evalNomex (Simu sim ev)   = evSimu sim ev


evNewVar :: (Typeable a, Show a) => VarName -> a -> Evaluate (Maybe (V a))
evNewVar name def = do
   (vars, rn) <- accessGame variables
   case find ((== name) . view vName) vars of
      Nothing -> do
         modifyGame variables (Var rn name def : )
         return $ Just (V name)
      Just _ -> return Nothing

evDelVar :: V a -> Evaluate Bool
evDelVar (V name) = do
   (vars, _) <- accessGame variables
   case find ((== name) . view vName) vars of
      Nothing -> return False
      Just _ -> do
         modifyGame variables $ filter ((/= name) . view vName)
         return True

evWriteVar :: (Typeable a, Show a) => V a -> a -> Evaluate Bool
evWriteVar (V name) val = do
   (vars, _) <- accessGame variables
   case find (\(Var _ myName _) -> myName == name) vars of
      Nothing -> return False
      Just (Var rn myName _) -> do
         modifyGame variables $ replaceWith ((== name) . view vName) (Var rn myName val)
         return True

evOnEvent :: (Typeable e, Show e) => Event e -> ((EventNumber, e) -> Nomex ()) -> Evaluate EventNumber
evOnEvent ev h = do
   (evs, rn) <- accessGame events
   let en = head $ [1..] \\ (map (_eventNumber . _erEventInfo) evs)
   modifyGame events (\eis -> (RuleEventInfo rn (EventInfo en ev h SActive [])) : eis)
   return en

evSendMessage :: (Typeable a, Show a) => Msg a -> a -> Evaluate ()
evSendMessage m = triggerEvent (Signal m)

evProposeRule :: RuleInfo -> Evaluate Bool
evProposeRule rule = do
   (rs, _) <- accessGame rules
   case find (\r -> (rule ^. rNumber) == (r ^. rNumber)) rs of
      Nothing -> do
         modifyGame rules (rule:)
         triggerEvent (Signal Proposed) rule
         return True
      Just _ -> return False

--Sets the rule status to Active and execute it if possible
evActivateRule :: RuleNumber -> Evaluate Bool
evActivateRule rn = do
   (rs, by) <- accessGame rules --bug here
   case find (\r -> _rNumber r == rn && _rStatus r /= Active) rs of
      Nothing -> return False
      Just r -> do
         putGame rules $ replaceWith ((== rn) . view rNumber) r{_rStatus = Active, _rAssessedBy = Just by} rs
         --execute the rule, using its own number: so events and outputs will have its number.
         withRN (_rNumber r) $ evalNomex (_rRule r)
         triggerEvent (Signal Activated) r
         return True

--replace temporarily the rule number used for evaluation
withEvent' :: EventInfo -> Evaluate a -> Evaluate a
withEvent' (EventInfo en _ _ _ _) eval = do
   (evs, _) <- accessGame events
   let rn = _erRuleNumber $ fromJust $ find (\(RuleEventInfo _ (EventInfo en2 _ _ evst _)) -> en == en2) evs
   oldRn <- use (evalEnv . eRuleNumber)
   evalEnv . eRuleNumber .= rn
   a <- eval
   evalEnv . eRuleNumber .= oldRn
   return a

evRejectRule :: RuleNumber -> Evaluate Bool
evRejectRule rn = do
   (rs, by) <- accessGame rules
   case find (\r -> _rNumber r == rn && _rStatus r /= Reject) rs of
      Nothing -> return False
      Just r -> do
         delVarsRule rn
         delEventsRule rn
         delOutputsRule rn
         delVictoryRule rn
         putGame rules $ replaceWith ((== rn) . view rNumber) r{_rStatus = Reject, _rAssessedBy = Just by} rs
         triggerEvent (Signal Rejected) r
         return True

evAddRule :: RuleInfo -> Evaluate Bool
evAddRule rule = do
   (rs, _) <- accessGame rules
   case find (\a -> (rule ^. rNumber) == (a ^. rNumber)) rs of
      Nothing -> do
         modifyGame rules (rule:)
         triggerEvent (Signal Added) rule
         return True
      Just _ -> return False


evModifyRule :: RuleNumber -> RuleInfo -> Evaluate Bool
evModifyRule rn rule = do
   (rs, _) <- accessGame rules
   let newRules = replaceWith ((== rn) . view rNumber) rule rs
   case find ((== rn) . view rNumber) rs of
      Nothing -> return False
      Just r ->  do
         putGame rules newRules
         triggerEvent (Signal Modified) r
         return True

evDelPlayer :: PlayerNumber -> Evaluate Bool
evDelPlayer pn = do
   g <- use (evalEnv . eGame)
   case find ((== pn) . view playerNumber) (_players g) of
      Nothing -> do
         return False
      Just pid -> do
         modifyGame players $ filter (\a -> a ^. playerNumber /= pn)
         triggerEvent (Signal Leave) pid
         return True

evChangeName :: PlayerNumber -> PlayerName -> Evaluate Bool
evChangeName pn name = do
   pls <- use (evalEnv . eGame . players)
   case find ((== pn) . view playerNumber) pls of
      Nothing -> return False
      Just pid -> do
         putGame players $ replaceWith ((== pn) . view playerNumber) (pid {_playerName = name}) pls
         return True

evDelEvent :: EventNumber -> Evaluate Bool
evDelEvent en = do
   evs <- use (evalEnv . eGame . events)
   case find ((== en) . view (erEventInfo . eventNumber)) evs of
      Nothing -> return False
      Just eh -> case (_evStatus $ _erEventInfo eh) of
         SActive -> do
            let evs' = replaceWith ((== en) . view (erEventInfo . eventNumber))  (erEventInfo . evStatus .~ SDeleted $ eh) evs
            putGame events evs'
            return True
         SDeleted -> return False

evTriggerTime :: UTCTime -> Evaluate ()
evTriggerTime t = triggerEvent (Signal t) t

evNewOutput :: Maybe PlayerNumber -> Nomex String -> Evaluate OutputNumber
evNewOutput pn s = do
   (ops, rn) <- accessGame outputs
   let on = head $ [1..] \\ (map _outputNumber ops)
   modifyGame outputs (Output on rn pn s SActive : )
   return on

evGetOutput :: OutputNumber -> Evaluate (Maybe String)
evGetOutput on = do
   ops <- use (evalEnv . eGame . outputs)
   case find (\(Output myOn _ _ _ s) -> myOn == on && s == SActive) ops of
      Nothing -> return Nothing
      Just (Output _ _ _ o _) -> do
         out <- evalNomex o
         return $ Just out

evUpdateOutput :: OutputNumber -> Nomex String -> Evaluate Bool
evUpdateOutput on s = do
   (ops, _) <- accessGame outputs
   case find (\(Output myOn _ _ _ st) -> myOn == on && st == SActive) ops of
      Nothing -> return False
      Just (Output _ rn pn _ _) -> do
         modifyGame outputs $ replaceWith ((== on) . view outputNumber) (Output on rn pn s SActive)
         return True

evDelOutput :: OutputNumber -> Evaluate Bool
evDelOutput on = do
   ops <- use (evalEnv . eGame . outputs)
   case find ((== on) . view outputNumber) ops of
      Nothing -> return False
      Just o -> case _oStatus o of
         SActive -> do
            putGame outputs $ replaceWith ((== on) . view outputNumber) o{_oStatus = SDeleted} ops
            return True
         SDeleted -> return False

evSetVictory :: Nomex [PlayerNumber] -> Evaluate ()
evSetVictory ps = do
   rn <- use (evalEnv . eRuleNumber)
   putGame victory (Just $ VictoryInfo rn ps)
   triggerEvent (Signal Victory) (VictoryInfo rn ps)

evReadVar :: (Typeable a, Show a) => V a -> Evaluate (Maybe a)
evReadVar (V name) = do
   vars <- use (evalEnv . eGame . variables)
   let var = find ((== name) . view vName) vars
   case var of
      Nothing -> return Nothing
      Just (Var _ _ val) -> case cast val of
          Just v -> return $ Just v
          Nothing -> return Nothing

evGetRandomNumber :: Random a => (a, a) -> Evaluate a
evGetRandomNumber r = do
   g <- use (evalEnv . eGame . randomGen)
   let (a, g') = randomR r g
   putGame randomGen g'
   return a

--TODO should we also give a rule number to simulate the Nomex with?
-- currently we use the simulating rule number
evSimu :: Nomex a -> Nomex Bool -> Evaluate Bool
evSimu sim ev = undefined--do
   --rn <- use (evalEnv . eRuleNumber)
   --let s = runEvalError rn Nothing (evalNomex sim)
   --g <- use (evalEnv . eGame)
   --let g' = execState s g
   --return $ runEvaluate' g' rn (evalNomex ev)

-- * misc

getVictorious :: Game -> [PlayerNumber]
getVictorious g = case _victory g of
   Nothing -> []
   Just (VictoryInfo rn v) -> runEvaluate' g rn (evalNomex v)

evalOutput :: Game -> Output -> String
evalOutput g (Output _ rn _ o _) = runEvaluate' g rn (evalNomex o)

allOutputs :: Game -> [String]
allOutputs g = map (evalOutput g) (_outputs g)

getTimeEvents :: UTCTime -> Game -> [UTCTime]
getTimeEvents t g = join $ maybeToList $ Imp.runEvaluate (Imp.getTimeEvents t) (defaultEvalEnv 0 g)


--delete all variables of a rule
delVarsRule :: RuleNumber -> Evaluate ()
delVarsRule rn = void $ (evalEnv . eGame . variables) %= filter ((/= rn) . view vRuleNumber)

--delete all events of a rule
delEventsRule :: RuleNumber -> Evaluate ()
delEventsRule rn = do
   evs <- use (evalEnv . eGame . events)
   let toDelete = filter ((== rn) . view (erRuleNumber)) evs
   mapM_ (evDelEvent . _eventNumber . _erEventInfo) toDelete

--delete all outputs of a rule
delOutputsRule :: RuleNumber -> Evaluate ()
delOutputsRule rn = do
   os <- use (evalEnv . eGame . outputs)
   let toDelete = filter ((== rn) . view oRuleNumber) os
   mapM_ (evDelOutput . _outputNumber) toDelete

--delete victory of a rule
delVictoryRule :: RuleNumber -> Evaluate ()
delVictoryRule rn = do
   vic <- use (evalEnv . eGame . victory)
   when (isJust vic && _vRuleNumber (fromJust vic) == rn) $ (evalEnv . eGame . victory) .= Nothing

--extract the game state from an Evaluate
--knowing the rule number performing the evaluation (0 if by the system)
--and the player number to whom display errors (set to Nothing for all players)
runEvalError :: RuleNumber -> Maybe PlayerNumber -> Evaluate a -> State Game (Maybe a)
runEvalError rn mpn eva = do
  g <- get
  let (a, (EvalEnv (EvalState g' _) _)) = runState (Imp.runEvalError eva) (defaultEvalEnv rn g)
  put g'
  return a

defaultEvalEnv :: RuleNumber -> Game -> EvalEnvN Nomex EvalState
defaultEvalEnv rn g = EvalEnv (EvalState g rn) defaultEvalConf

--TODO: to check. how to map the events correctly?
defaultEvalConf :: EvalConfN Nomex EvalState
defaultEvalConf = EvalConf getEventsNomex setEventsNomex evalNomex errorNomex withEvent' where
   getEventsNomex s = map _erEventInfo (_events $ _eGame s)
   setEventsNomex eis s = (eGame . events) .~ (getreis (_events $ _eGame s) eis) $ s where
     getreis reis eis = if (length reis /= length eis) then error "setEvents" else zipWith (\rei ei -> rei {_erEventInfo = ei}) reis eis

runSystemEval :: PlayerNumber -> Evaluate a -> State Game (Maybe a)
runSystemEval pn = runEvalError 0 (Just pn)

runSystemEval' :: Evaluate a -> State Game (Maybe a)
runSystemEval' = runEvalError 0 Nothing

errorNomex :: EventNumber -> String -> Evaluate ()
errorNomex en s = do 
   tracePN 0 $ "Error: " ++ s
   log Nothing $ "Error: " ++ s ++ ", from event: " ++ (show en)

runEvaluate :: Game -> RuleNumber -> State EvalEnv a -> a
runEvaluate g rn ev = error "runEvaluate" --evalState ev (EvalEnv rn g evalNomex)

runEvaluate' :: Game -> RuleNumber -> Evaluate a -> a
runEvaluate' g rn ev = fromJust $ Imp.runEvaluate ev (defaultEvalEnv rn g) --TODO check this fromJust

-- | Show instance for Game
-- showing a game involves evaluating some parts (such as victory and outputs)
instance Show Game where
   show g@(Game gn _ rs ps vs es os _ l t _) =
      "Game Name = "      ++ show gn ++
      "\n\n Rules = "       ++ (intercalate "\n " $ map show rs) ++
      "\n\n Players = "     ++ show ps ++
      "\n\n Variables = "   ++ show vs ++
      "\n\n Events = "      ++ (intercalate "\n " $ map (displayEvent g) es) ++ "\n" ++
      "\n\n Outputs = "     ++ (intercalate "\n " $ map (displayOutput g) os) ++ "\n" ++
      "\n\n Victory = "     ++ show (getVictorious g) ++
      "\n\n currentTime = " ++ show t ++ "\n" ++
      "\n\n logs = " ++ show l ++ "\n"

displayEvent :: Game -> RuleEventInfo -> String
displayEvent g (RuleEventInfo rn ei@(EventInfo en _ _ s envi)) =
   "event num: " ++ (show en) ++
   ", rule num: " ++ (show rn) ++
   ", remaining signals: " ++ (show $ getRemainingSignals ei (EvalEnv (EvalState g 0) defaultEvalConf)) ++ --TODO: display also event result?
   ", envs: " ++ (show envi) ++
   ", status: " ++ (show s)

deriving instance Show LoggedGame

displayOutput :: Game -> Output -> String
displayOutput g o@(Output on rn mpn _ s) =
   "output num: " ++ (show on) ++
   ", rule num: " ++ (show rn) ++
   ", by pn: " ++ (show mpn) ++
   ", output: " ++ (show $ evalOutput g o) ++
   ", status: " ++ (show s)