{-# LANGUAGE DataKinds #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE ViewPatterns #-}
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE FunctionalDependencies #-}
{-# LANGUAGE UndecidableInstances #-}

-- | A client library for 'Thermoprint.API'
module Thermoprint.Client
       ( Client(..)
       , mkClient, mkClient'
       -- = Reexports
       , ServantError(..)
       , module Thermoprint.API
       , module Servant.Client
       , module Control.Monad.Except
       , module Control.Natural
       ) where

import Thermoprint.API
import Data.Map (Map)
import Data.Sequence (Seq)
import Data.Time (UTCTime)

import Servant.Client hiding (HasClient(..), mkClient)
import qualified Servant.Client as S
import Network.HTTP.Client (Manager, ManagerSettings, newManager, defaultManagerSettings)
import Servant.API
-- import Servant.Utils.Enter
import Control.Natural ((:~>)(..))
import Control.Monad.Except (ExceptT(..), runExceptT)

import Control.Monad.Reader (ReaderT, runReaderT, ask)
import Control.Monad.Catch (Exception, MonadThrow(..))
import Control.Monad.IO.Class (MonadIO(..))
import Control.Monad.Trans (lift)

import Control.Concurrent.STM.TVar (newTVarIO)

import Control.Monad
import Control.Category
import Prelude hiding (id, (.))


class Enter typ mod ret | typ mod -> ret, typ ret -> mod, mod ret -> typ where
  enter :: mod -> typ -> ret

instance Enter (m a) (m :~> n) (n a) where
  enter (NT f) = f

instance (Enter typ1 mod1 ret1, Enter typ2 mod2 ret2, mod1 ~ mod2) => Enter (typ1 :<|> typ2) mod1 (ret1 :<|> ret2) where
  enter mod (a :<|> b) = enter mod a :<|> enter mod b

instance Enter typ mod ret => Enter (r -> typ) mod (r -> ret) where
  enter mod = (enter mod .)


-- | All 'ThermoprintAPI'-functions as a record
--
-- Use like this:
--
-- > {-# LANGUAGE RecordWildCards #-}
-- > 
-- > main :: IO ()
-- > -- ^ Display a list of printers with their status
-- > main = print =<< printers
-- >   where Client{..} = mkClient' defaultManagerSettings $ Http "localhost" 3000
data Client m = Client
  { printers :: m (Map PrinterId PrinterStatus)
                -- ^ List all printers
  , jobs :: Maybe PrinterId
            -> Maybe (Range (JobId))
            -> Maybe (Range (UTCTime))
            -> m (Seq (JobId, UTCTime, JobStatus))
            -- ^ List a selection of jobs
  , jobCreate :: Maybe PrinterId -> Printout -> m JobId
                 -- ^ Send a 'Printout' to be queued
  , job :: JobId -> m Printout
           -- ^ Retrieve the contents of a job
  , jobStatus :: JobId -> m JobStatus
                 -- ^ Query a jobs status
  , jobDelete :: JobId -> m ()
                 -- ^ Delete a job from the queue (not from history or while it is being printed)
  , drafts :: m (Map DraftId (Maybe DraftTitle))
              -- ^ List all saved drafts
  , draftCreate :: Maybe DraftTitle
                -> Printout
                -> m DraftId
                -- ^ Create a new draft
  , draftReplace :: DraftId
                 -> Maybe DraftTitle
                 -> Printout
                 -> m ()
                 -- ^ Replace the contents and title of an existing draft
  , draft :: DraftId -> m (Maybe DraftTitle, Printout)
             -- ^ Retrieve the contents and title of a draft
  , draftDelete :: DraftId -> m ()
                   -- ^ Delete a draft
  , draftPrint :: DraftId -> Maybe PrinterId -> m JobId
                  -- ^ Send a draft to be printed
  }

withArgs :: (x -> a :<|> b) -> ((x -> a) :<|> (x -> b))
-- ^ Undo factoring of APIs
withArgs subAPI = (\(a :<|> _) -> a) . subAPI :<|> (\(_ :<|> b) -> b) . subAPI

mkClientS :: Monad m
          => (ClientM :~> m) -- ^ A monad functor ('Nat') used to make the api functions work in any monad which can do 'IO' and handle errors
          -> Client m
-- ^ Generate a 'Client'
mkClientS n = Client{..}
  where
    printers
      :<|> (jobs :<|> jobCreate)
      :<|> (withArgs -> job :<|> (withArgs -> jobStatus :<|> jobDelete))
      :<|> (drafts :<|> draftCreate)
      :<|> (withArgs -> draftReplace :<|> (withArgs -> draft :<|> (withArgs -> draftDelete :<|> draftPrint)))
      = enter n $ client thermoprintAPI

mkClient :: (MonadThrow m, MonadIO m) => ManagerSettings -> BaseUrl -> Client m
mkClient mSettings url = mkClientS clientNat
  where
    clientNat :: forall m. (MonadThrow m, MonadIO m) => ClientM :~> m
    clientNat = NT $ \cAct -> do
      mgr <- liftIO $ newManager mSettings
      cjar <- liftIO $ newTVarIO mempty
      either throwM return =<< liftIO (runClientM cAct . ClientEnv mgr url $ Just cjar)

mkClient' :: (MonadThrow m, MonadIO m) => BaseUrl -> Client m
-- ^ @mkClient' = mkClient defaultManagerSettings
mkClient' = mkClient defaultManagerSettings