118 lines
4.3 KiB
Haskell
118 lines
4.3 KiB
Haskell
{-# Language TypeApplications #-}
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{-# Language TypeOperators #-}
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{-# Language DataKinds #-}
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{-# Language DuplicateRecordFields #-}
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module Database.Book
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( def
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, insertBook
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, getBook
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, bookExists
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, updateBook
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, isBookOwner
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, setContent
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, InsertBook(..)
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, UpdateBook(..)
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, usersBooks
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, Book(..)
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, HashDigest(..)
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, BookID) where
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import ClassyPrelude
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import Database.Schema (books, users, Username, Book(..), BookID(..), UserID, HashDigest(..))
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import Database
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import Database.Selda
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import Database.Selda.Generic
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import Database.Tag (attachTag)
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usersBooks :: (MonadSelda m, MonadMask m, MonadIO m) => Username -> m [Book]
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usersBooks username = fromRels <$> query q
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where
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q = do
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userId :*: _ :*: username' :*: _ <- select (gen users)
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book@(_ :*: digest :*: _ :*: _ :*: _ :*: owner) <- select (gen books)
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restrict (username' .== literal username)
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restrict (userId .== owner)
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restrict (not_ (isNull digest))
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return book
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getBook :: (MonadSelda m, MonadMask m, MonadIO m) => BookID -> Username -> m (Maybe Book)
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getBook identifier owner = listToMaybe . fromRels <$> query q
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where
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q = do
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_ :*: bookId <- bookOwner' identifier owner
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book@(bookId' :*: _) <- select (gen books)
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restrict (bookId .== bookId')
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return book
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data InsertBook = InsertBook { contentType :: Text
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, title :: Maybe Text
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, description :: Maybe Text
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, owner :: Username }
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-- Always inserts
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insertBook :: (MonadSelda m, MonadMask m, MonadIO m) => InsertBook -> m (Maybe BookID)
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insertBook InsertBook{..} = do
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mUserId <- query $ do
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userId :*: _ :*: username' :*: _ <- select (gen users)
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restrict (username' .== literal owner)
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return userId
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forM (listToMaybe mUserId) $ \userId -> do
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let book = Book{owner=userId,identifier=def,contentHash=Nothing,..}
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BookID . fromRowId <$> insertGenWithPK books [book]
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data UpdateBook = UpdateBook { identifier :: BookID
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, contentType :: Text
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, title :: Maybe Text
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, description :: Maybe Text
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, owner :: Username
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, tags :: [Text]}
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bookExists :: (MonadSelda m, MonadMask m, MonadIO m) => BookID -> m Bool
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bookExists identifier = not . null <$> query q
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where
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q = do
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(bookId :*: _) <- select (gen books)
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restrict (bookId .== literal identifier)
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return bookId
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isBookOwner :: (MonadSelda m, MonadIO m, MonadThrow m) => BookID -> Username -> m Bool
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isBookOwner identifier username = not . null <$> query (bookOwner' identifier username)
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bookOwner' :: BookID -> Username -> Query s (Col s UserID :*: Col s BookID)
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bookOwner' identifier username = do
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userId :*: _ :*: username' :*: _ <- select (gen users)
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bookId :*: _ :*: _ :*: _ :*: _ :*: bookOwner <- select (gen books)
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restrict (userId .== bookOwner)
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restrict (username' .== literal username)
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restrict (bookId .== literal identifier)
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return (userId :*: bookId)
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updateBook :: (MonadSelda m, MonadMask m, MonadIO m) => UpdateBook -> m (Maybe UpdateBook)
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updateBook book@UpdateBook{..} = do
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connectChannels
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connectTags
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updateBook'
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where
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connectTags = mapM_ (attachTag owner identifier) tags
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connectChannels = return ()
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updateBook' = do
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mUserId <- query (bookOwner' identifier owner)
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forM (listToMaybe mUserId) $ \_userId -> do
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update_ (gen books) predicate (\b -> b `with` [ pContentType := literal contentType
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, pTitle := literal title
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, pDescription := literal description ])
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return book
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_ :*: _ :*: pContentType :*: pTitle :*: pDescription :*: _ = selectors (gen books)
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predicate (bookId :*: _) = bookId .== literal identifier
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setContent :: (MonadSelda m, MonadMask m, MonadIO m) => BookID -> Username -> HashDigest -> m ()
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setContent identifier owner digest = do
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mOwner <- query (bookOwner' identifier owner)
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void $ forM (listToMaybe mOwner) $ \_ ->
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update_ (gen books) predicate (\b -> b `with` [ pHash := literal (Just digest)])
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where
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_ :*: pHash :*: _ = selectors (gen books)
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predicate (bookId :*: _) = bookId .== literal identifier
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