module Handler.Submission.Download
  ( getSubDownloadR
  , getSubArchiveR
  , getCorrectionsDownloadR
  ) where

import Import

import Handler.Utils
import Handler.Utils.Submission

import qualified Data.Set as Set

import qualified Database.Esqueleto as E

import qualified Data.Conduit.Combinators as Conduit


getSubDownloadR :: TermId -> SchoolId -> CourseShorthand -> SheetName -> CryptoFileNameSubmission -> SubmissionFileType -> FilePath -> Handler TypedContent
getSubDownloadR tid ssh csh shn cID (submissionFileTypeIsUpdate -> isUpdate) path = do
  (submissionID, isRating) <- runDB $ do
    submissionID <- submissionMatchesSheet tid ssh csh shn cID

    isRating <- (== Just submissionID) <$> isRatingFile path

    when (isUpdate || isRating) $
      guardAuthResult =<< evalAccessDB (CSubmissionR tid ssh csh shn cID CorrectionR) False

    return (submissionID, isRating)

  case isRating of
    True
      | isUpdate -> maybe notFound sendThisFile <=< runDB . runMaybeT $ 
          lift . ratingFile cID =<< MaybeT (getRating submissionID)
      | otherwise -> notFound
    False -> do
      let results = (.| Conduit.map entityVal) . E.selectSource . E.from $ \sf -> do
            E.where_ $ sf E.^. SubmissionFileSubmission E.==. E.val submissionID
                 E.&&. sf E.^. SubmissionFileTitle E.==. E.val path
                 E.&&. E.not_ (sf E.^. SubmissionFileIsDeletion)
                 E.&&. sf E.^. SubmissionFileIsUpdate E.==. E.val isUpdate
                 -- E.&&. E.not_ (E.isNothing $ f E.^. FileContent) -- This is fine, we just return 204
            return sf

      serveOneFile results

getSubArchiveR :: TermId -> SchoolId -> CourseShorthand -> SheetName -> CryptoFileNameSubmission -> SubmissionFileType -> Handler TypedContent
getSubArchiveR tid ssh csh shn cID sfType = do
  when (sfType == SubmissionCorrected) $
    guardAuthResult =<< evalAccess (CSubmissionR tid ssh csh shn cID CorrectionR) False

  sfType' <- ap getMessageRender $ pure sfType
  archiveName <- fmap (flip addExtension (unpack extensionZip) . unpack) . ap getMessageRender . pure $ MsgSubmissionTypeArchiveName tid ssh csh shn cID sfType'

  let source = do
        submissionID <- lift $ submissionMatchesSheet tid ssh csh shn cID
        rating <- lift $ getRating submissionID

        case sfType of
          SubmissionOriginal -> (.| Conduit.map (Left . entityVal)) . E.selectSource . E.from $ \sf -> do
            E.where_ $ sf E.^. SubmissionFileSubmission E.==. E.val submissionID
                 E.&&. sf E.^. SubmissionFileIsUpdate E.==. E.val False
            return sf
          _other -> E.selectSource (E.from $ submissionFileQuery submissionID) .| Conduit.map (Left . entityVal)

        when (sfType == SubmissionCorrected) $
          maybe (return ()) (yieldM . fmap Right . ratingFile cID) rating

  serveSomeFiles' archiveName source


getCorrectionsDownloadR :: Handler TypedContent
getCorrectionsDownloadR = do -- download all assigned and open submissions
  uid <- requireAuthId
  subs <- runDB $ selectKeysList
            [ SubmissionRatingBy   ==. Just uid
            , SubmissionRatingTime ==. Nothing
            ] []
  when (null subs) $ do
    addMessageI Info MsgNoOpenSubmissions
    redirect CorrectionsR
  submissionMultiArchive SubmissionDownloadAnonymous $ Set.fromList subs