{-# LANGUAGE DataKinds        #-}
{-# LANGUAGE DeriveAnyClass   #-}
{-# LANGUAGE DeriveGeneric    #-}
{-# LANGUAGE LambdaCase       #-}
{-# LANGUAGE TypeApplications #-}

module Git (App, submitImpl) where

import           Bindings.Cli.Git       (gitProc)
import           CheckDir               (DirResult, recursiveCheckDir)
import           Cli.Extras             (CliT, ProcessFailure, Severity (..),
                                         callProcessAndLogOutput)
import           Control.Monad.Extra    (ifM)
import           Control.Monad.IO.Class (liftIO)
import           Data.Text              (Text)
import qualified Data.Text              as T
import qualified Data.UUID              as UUID
import qualified Data.UUID.V4           as UUID
import           Servant
import           Serverconfig
import           System.Directory       (doesDirectoryExist)
import           System.FilePath        ((</>))


-- | this servant app can run cli programs!
type App = CliT ProcessFailure Handler

-- | annoying (and afaik unused), but has to be here for type system reasons
instance MonadFail Handler where
  fail _ = throwError $ err500

-- | someone submitted a map; lint it (synchronously for now)
submitImpl :: Config True -> RemoteRef -> App DirResult
submitImpl config ref = do
  ifM (liftIO $ doesDirectoryExist gitdir)
    (callProcessAndLogOutput (Debug, Error) gitfetch)
    (callProcessAndLogOutput (Debug, Error) gitclone)
  checkPath config gitdir (reporef ref)
  where gitclone = gitProc gitdir -- TODO: these calls fail for dumb http, add some fallback!
          [ "clone", T.unpack $ repourl ref, "--bare", "--depth", "1", "-b", T.unpack (reporef ref)]
        gitfetch = gitProc gitdir
          [ "fetch", "origin", T.unpack (reporef ref), "--depth", "1" ]
        gitdir = tmpdir config </> hashedname
        hashedname = fmap escapeSlash . T.unpack . repourl $ ref
        escapeSlash = \case
          '/' -> '-'
          a   -> a

checkPath :: Config True -> FilePath -> Text -> App DirResult
checkPath config gitdir ref = do
  rand <- liftIO $ UUID.nextRandom
  let workdir = "/tmp" </> ("worktree-" <> UUID.toString rand)
  callProcessAndLogOutput (Debug, Error)
    $ gitProc gitdir [ "worktree", "add", workdir ]
  callProcessAndLogOutput (Debug, Error)
    $ gitProc workdir [ "checkout", T.unpack ref ]
  res <- liftIO $ recursiveCheckDir (lintconfig config) gitdir (entrypoint config)
  callProcessAndLogOutput (Debug, Error)
    $ gitProc gitdir [ "worktree", "remove", "-f", "-f", workdir ]
  pure res