-- |Description: Sync Interpreters
module Polysemy.Conc.Interpreter.Sync where

import Control.Concurrent (isEmptyMVar)
import Polysemy.Resource (Resource)

import Polysemy.Conc.Effect.Race (Race)
import Polysemy.Conc.Effect.Scoped (Scoped)
import qualified Polysemy.Conc.Effect.Sync as Sync
import Polysemy.Conc.Effect.Sync (Sync, SyncResources (SyncResources), unSyncResources)
import Polysemy.Conc.Interpreter.Scoped (runScopedAs)
import qualified Polysemy.Conc.Race as Race

-- |Interpret 'Sync' with the provided 'MVar'.
interpretSyncWith ::
  ∀ d r .
  Members [Race, Embed IO] r =>
  MVar d ->
  InterpreterFor (Sync d) r
interpretSyncWith var =
  interpret \case
    Sync.Block ->
      readMVar var
    Sync.Wait interval ->
      rightToMaybe <$> Race.timeoutAs () interval (readMVar var)
    Sync.Try ->
      tryReadMVar var
    Sync.TakeBlock ->
      takeMVar var
    Sync.TakeWait interval ->
      rightToMaybe <$> Race.timeoutAs () interval (takeMVar var)
    Sync.TakeTry ->
      tryTakeMVar var
    Sync.ReadBlock ->
      readMVar var
    Sync.ReadWait interval ->
      rightToMaybe <$> Race.timeoutAs () interval (readMVar var)
    Sync.ReadTry ->
      tryReadMVar var
    Sync.PutBlock d ->
      putMVar var d
    Sync.PutWait interval d ->
      Race.timeoutAs_ False interval (True <$ putMVar var d)
    Sync.PutTry d ->
      tryPutMVar var d
    Sync.Empty ->
      embed (isEmptyMVar var)

-- |Interpret 'Sync' with an empty 'MVar'.
interpretSync ::
  ∀ d r .
  Members [Race, Embed IO] r =>
  InterpreterFor (Sync d) r
interpretSync sem = do
  var <- newEmptyMVar
  interpretSyncWith var sem

-- |Interpret 'Sync' with an 'MVar' containing the specified value.
interpretSyncAs ::
  ∀ d r .
  Members [Race, Embed IO] r =>
  d ->
  InterpreterFor (Sync d) r
interpretSyncAs d sem = do
  var <- newMVar d
  interpretSyncWith var sem

-- |Interpret 'Sync' for locally scoped use with an empty 'MVar'.
interpretScopedSync ::
  ∀ d r .
  Members [Resource, Race, Embed IO] r =>
  InterpreterFor (Scoped (SyncResources (MVar d)) (Sync d)) r
interpretScopedSync =
  runScopedAs (SyncResources <$> newEmptyMVar) \ r -> interpretSyncWith (unSyncResources r)

-- |Interpret 'Sync' for locally scoped use with an 'MVar' containing the specified value.
interpretScopedSyncAs ::
  ∀ d r .
  Members [Resource, Race, Embed IO] r =>
  d ->
  InterpreterFor (Scoped (SyncResources (MVar d)) (Sync d)) r
interpretScopedSyncAs d =
  runScopedAs (SyncResources <$> newMVar d) \ r -> interpretSyncWith (unSyncResources r)