content: {-# LANGUAGE TemplateHaskell #-}
  
  -- This file is part of the Wire Server implementation.
  --
  -- Copyright (C) 2022 Wire Swiss GmbH <opensource@wire.com>
  --
  -- This program is free software: you can redistribute it and/or modify it under
  -- the terms of the GNU Affero General Public License as published by the Free
  -- Software Foundation, either version 3 of the License, or (at your option) any
  -- later version.
  --
  -- This program is distributed in the hope that it will be useful, but WITHOUT
  -- ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  -- FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
  -- details.
  --
  -- You should have received a copy of the GNU Affero General Public License along
  -- with this program. If not, see <https://www.gnu.org/licenses/>.
  
  module Wire.Sem.Now
    ( Now (..),
      get,
      boolTTL,
    )
  where
  
  import Data.Time.Clock
  import Imports
  import Polysemy
  import Polysemy.Check (deriveGenericK)
  import Wire.Sem.FromUTC
  
  data Now m a where
    Get :: Now m UTCTime
  
  makeSem ''Now
  deriveGenericK ''Now
  
  deriving instance Show (Now m a)
  
  -- | Check a time against 'Now', checking if it's still alive (hasn't occurred yet.)
  boolTTL ::
    forall t r a.
    (Member Now r, Ord t, FromUTC t) =>
    -- | The value to return if the TTL is expired
    a ->
    -- | The value to return if the TTL is alive
    a ->
    t -> -- The time to check
    Sem r a
  boolTTL f t time = do
    now <- fromUTCTime <$> get
    pure $ bool f t $ now <= time
  