69 lines
2.5 KiB
Haskell
69 lines
2.5 KiB
Haskell
{-# Language TypeApplications #-}
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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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, updateBook
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, InsertBook(..)
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, UpdateBook(..)
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, usersBooks
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, Book(..)
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, BookID) where
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import ClassyPrelude
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import Database.Schema
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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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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@(_ :*: _ :*: _ :*: _ :*: _ :*: owner) <- select (gen books)
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restrict (username' .== literal username)
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restrict (userId .== owner)
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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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updateBook :: (MonadSelda m, MonadMask m, MonadIO m) => UpdateBook -> m (Maybe UpdateBook)
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updateBook book@UpdateBook{..} = do
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mUserId <- query $ 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 owner)
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restrict (bookId .== literal identifier)
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return userId
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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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where
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_ :*: _ :*: pContentType :*: pTitle :*: pDescription :*: _ = selectors (gen books)
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predicate (bookId :*: _) = bookId .== literal identifier
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