module Vere.Pier where

import ClassyPrelude

import Vere.Pier.Types

import qualified Vere.Log  as Log
import qualified Vere.Serf as Serf

import Vere.Serf (EventId, Serf)


--------------------------------------------------------------------------------

ioDrivers = [] :: [IODriver]


--------------------------------------------------------------------------------

-- This is called to make a freshly booted pier. It assigns an identity to an
-- event log and takes a chill pill.
boot :: ByteString -> FilePath -> LogIdentity
     -> IO (Serf, EventLog, EventId, Mug)
boot pill top id = do
  let logPath = top <> "/log"

  log <- Log.open logPath

  Log.writeIdent log id

  serf   <- Serf.startSerfProcess top
  (e, m) <- Serf.bootSerf serf id pill

  pure (serf, log, e, m)


{-
    What we really want to do is write the log identity and then do
    normal startup, but writeIdent requires a full log state
    including input/output queues.
-}
resume :: FilePath -> IO (Serf, EventLog, EventId, Mug)
resume top = do
  log    <- Log.open (top <> "/.urb/log")
  ident  <- Log.readIdent log
  lastEv <- Log.latestEventNumber log
  serf   <- Serf.startSerfProcess top
  (e, m) <- Serf.replay serf ident lastEv (Log.readEvents log)

  pure (serf, log, e, m)


-- Run Pier --------------------------------------------------------------------

{-
/* _pier_work_save(): tell worker to save checkpoint.
*/
static void
_pier_work_save(u3_pier* pir_u)
{
  u3_controller* god_u = pir_u->god_u;
  u3_disk* log_u = pir_u->log_u;
  u3_save* sav_u = pir_u->sav_u;

  c3_assert( god_u->dun_d == sav_u->req_d );
  c3_assert( log_u->com_d >= god_u->dun_d );

  {
    u3_noun mat = u3ke_jam(u3nc(c3__save, u3i_chubs(1, &god_u->dun_d)));
    u3_newt_write(&god_u->inn_u, mat, 0);

    //  XX wait on some report of success before updating?
    //
    sav_u->dun_d = sav_u->req_d;
  }

  //  if we're gracefully shutting down, do so now
  //
  if ( u3_psat_done == pir_u->sat_e ) {
    _pier_exit_done(pir_u);
  }
}
-}



{-
performCommonPierStartup :: Serf.Serf
                         -> TQueue Ovum
                         -> TQueue (Writ [Eff])
                         -> TQueue (Writ [Eff])
                         -> LogState
                         -> IO Pier
performCommonPierStartup serf computeQ persistQ releaseQ logState = do
  for ioDrivers $ \x -> do
    bootMessage <- bornEvent x
    atomically $ writeTQueue computeQ bootMessage

  driverThreads <- for ioDrivers $ \x -> do
    startDriver x (writeTQueue computeQ)

  -- TODO: Don't do a bunch of extra work; we send all events to all drivers
  portingThread <- async $ do
    forever $ do
      r <- atomically (readTQueue releaseQ)
      for_ driverThreads $ \(_, k) ->
        for_ (payload r) $ \eff ->
          k eff

  Serf.workerThread serf (readTQueue computeQ) undefined

  pure (Pier{..})
-}