ebook-manager/src/Database/Channel.hs

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2018-08-05 23:13:49 +03:00
{-# Language TypeApplications #-}
{-# Language DataKinds #-}
module Database.Channel
( userChannels
, insertChannel
, Channel(..) )
where
import ClassyPrelude
import Database.Schema
import Database
import Database.Selda
userChannels :: (MonadMask m, MonadIO m) => Username -> SeldaT m [Channel]
userChannels username = fromRels <$> query q
where
q = do
userId :*: _ :*: username' :*: _ <- select (gen users)
channel@(_ :*: _ :*: owner) <- select (gen channels)
restrict (owner .== userId)
restrict (username' .== literal username)
return channel
insertChannel :: (MonadMask m, MonadIO m) => Username -> Text -> SeldaT m ()
insertChannel username channel = do
mUserId <- listToMaybe <$> getUser
void $ forM mUserId $ \userId ->
insertUnless (gen channels) (doesNotExist userId) [ def :*: channel :*: userId ]
where
doesNotExist userId (_ :*: channel' :*: userId') = channel' .== literal channel .&& userId' .== literal userId
getUser = query $ do
userId :*: _ :*: user :*: _ <- select (gen users)
restrict (user .== literal username)
return userId