module Handler.Exam.Register
  ( ButtonExamRegister(..)
  , postERegisterR
  ) where

import Import

import Handler.Utils
import Handler.Utils.Exam


-- Dedicated ExamRegistrationButton
data ButtonExamRegister = BtnExamRegister | BtnExamDeregister
  deriving (Enum, Eq, Ord, Bounded, Read, Show, Generic, Typeable)
instance Universe ButtonExamRegister
instance Finite ButtonExamRegister
nullaryPathPiece ''ButtonExamRegister $ camelToPathPiece' 1
embedRenderMessage ''UniWorX ''ButtonExamRegister id
instance Button UniWorX ButtonExamRegister where
  btnClasses BtnExamRegister   = [BCIsButton, BCPrimary]
  btnClasses BtnExamDeregister = [BCIsButton, BCDanger]

  btnLabel  BtnExamRegister   = [whamlet|#{iconExamRegister True} _{MsgBtnExamRegister}|]
  btnLabel  BtnExamDeregister = [whamlet|#{iconExamRegister False} _{MsgBtnExamDeregister}|]


postERegisterR :: TermId -> SchoolId -> CourseShorthand -> ExamName -> Handler Html

postERegisterR tid ssh csh examn = do
  Entity uid User{..} <- requireAuth

  Entity eId Exam{..} <- runDB $ fetchExam tid ssh csh examn

  ((btnResult, _), _) <- runFormPost buttonForm

  formResult btnResult $ \case
    BtnExamRegister -> do
      runDB $ do
        now <- liftIO getCurrentTime
        insert_ $ ExamRegistration eId uid Nothing now
        audit $ TransactionExamRegister eId uid
      addMessageIconI Success IconExamRegisterTrue $ MsgExamRegisteredSuccess examn
      redirect $ CExamR tid ssh csh examn EShowR
    BtnExamDeregister -> do
      runDB $ do
        deleteBy $ UniqueExamRegistration eId uid
        audit $ TransactionExamDeregister eId uid
      addMessageIconI Info IconExamRegisterFalse $ MsgExamDeregisteredSuccess examn
        -- yes, it's a success message, but it should be visually different from a positive success, since most will just note the positive green color! See discussion on commit 5f4925a4
      redirect $ CExamR tid ssh csh examn EShowR

  invalidArgs ["Register/Deregister button required"]