{-# LANGUAGE OverloadedRecordDot #-}
{-# LANGUAGE TypeFamilies #-}

module Yore.Servant (GetSendfile, Sendfile (..)) where

import Network.HTTP.Types (ResponseHeaders, status200)
import Network.Wai (responseFile)
import Servant (HasServer (..))
import Servant.Server.Internal.Delayed (runAction)
import Servant.Server.Internal.RouteResult (RouteResult (..))
import Servant.Server.Internal.Router (Router' (..))

-- | Servant route type that responds with a file using @sendfile@.
data GetSendfile

data Sendfile = Sendfile
  { headers :: ResponseHeaders
  -- ^ The headers to send along with the file, e.g. @content-type@ or cache information.
  , path :: FilePath
  -- ^ The file to respond with.
  }
  deriving (Show)

instance HasServer GetSendfile context where
  type ServerT GetSendfile m = m Sendfile

  hoistServerWithContext _ _ nt = nt

  route _ _ action = RawRouter $ \env request respond ->
    runAction action env request respond $ \sendfile ->
      Route $ responseFile status200 sendfile.headers sendfile.path Nothing