{-# LANGUAGE DataKinds           #-}
{-# LANGUAGE DeriveAnyClass      #-}
{-# LANGUAGE DeriveGeneric       #-}
{-# LANGUAGE KindSignatures      #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TypeApplications    #-}
{-# LANGUAGE TypeFamilies        #-}
{-# LANGUAGE TypeOperators       #-}

module Server (loadConfig, Config(..), RemoteRef(..), State, JobStatus(..),
                    setJobStatus) where

import           CheckDir             (DirResult)
import           Control.Concurrent   (MVar, modifyMVar_)
import           Data.Aeson           (FromJSON, ToJSON, eitherDecode)
import qualified Data.ByteString.Lazy as LB
import           Data.Map             (Map)
import qualified Data.Map             as M
import           Data.Text            (Text)
import           GHC.Generics         (Generic)
import           LintConfig           (LintConfig')

-- | a reference in a remote git repository
data RemoteRef = RemoteRef
  { repourl :: Text
  , reporef :: Text
  } deriving (Generic, FromJSON, Eq, Ord)

type family ConfigRes (b :: Bool) a where
  ConfigRes True a = a
  ConfigRes False a = FilePath

-- | the server's configuration
data Config l = Config
  { tmpdir     :: FilePath
  -- ^ dir to clone git things in
  , port       :: Int
  -- ^ port to bind to
  , entrypoint :: FilePath
  , lintconfig :: ConfigRes l LintConfig'
  }

data JobStatus =
  Pending | Linted DirResult | Failed Text
  deriving (Generic, ToJSON)

type State = Map RemoteRef JobStatus


loadConfig :: Config False -> IO (Config True)
loadConfig config = do
  loaded <- LB.readFile (lintconfig config) >>= \res ->
      case eitherDecode res :: Either String LintConfig' of
        Left err   -> error $ "config file invalid: " <> err
        Right file -> pure file
  pure $ config { lintconfig = loaded }


setJobStatus :: MVar State -> RemoteRef -> JobStatus -> IO ()
setJobStatus mvar ref status = modifyMVar_ mvar $ \state ->
  pure $ M.insert ref status state