{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE RankNTypes #-}

module Network.GRPC.HighLevel.Generated where

import Network.GRPC.HighLevel.Server
import Network.GRPC.LowLevel.Call

-- | Used at the kind level as a parameter to service definitions
--   generated by the grpc compiler, with the effect of having the
--   field types reduce to the appropriate types for the method types.
data GRPCImpl = ServerImpl | ClientImpl

-- | GHC does not let us partially apply a type family. However, we
--   can define a type to use as an 'interpreter', and then use this
--   'interpreter' type fully applied to get the same effect.
type family MkHandler (impl :: GRPCImpl) (methodType :: GRPCMethodType) i o

type instance MkHandler 'ServerImpl 'Normal          i o = ServerHandler       i o
type instance MkHandler 'ServerImpl 'ClientStreaming i o = ServerReaderHandler i o
type instance MkHandler 'ServerImpl 'ServerStreaming i o = ServerWriterHandler i o
type instance MkHandler 'ServerImpl 'BiDiStreaming   i o = ServerRWHandler     i o