{-# LANGUAGE RecordWildCards            #-}
{-# LANGUAGE EmptyDataDecls             #-}
{-# LANGUAGE FlexibleContexts           #-}
{-# LANGUAGE GADTs                      #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE MultiParamTypeClasses      #-}
{-# LANGUAGE OverloadedStrings          #-}
{-# LANGUAGE QuasiQuotes                #-}
{-# LANGUAGE TemplateHaskell            #-}
{-# LANGUAGE TypeFamilies               #-}
{-# LANGUAGE OverloadedStrings          #-}
{-# LANGUAGE TypeOperators              #-}

module Thermoprint.Server
       ( thermoprintServer
       , module Data.Default.Class
       , module Servant.Server.Internal.Enter
       ) where

import Data.Default.Class
import qualified Config.Dyre as Dyre

import System.IO (hPutStrLn, stderr)
import System.Exit (exitFailure)

import Control.Monad ((<=<), mapM_, liftM2)
import Prelude hiding ((.), id)
import Control.Category

import Control.Monad.Logger
import Control.Monad.Reader
import Control.Monad.Trans.Resource
import Control.Monad.Trans.Either
import Control.Monad.IO.Class

import Data.Functor.Compose

import Thermoprint.API hiding (JobId(..), DraftId(..))
import qualified Thermoprint.API as API (JobId(..), DraftId(..))
import Data.Set (Set)
import qualified Data.Set as Set
import Data.Sequence (Seq)
import qualified Data.Sequence as Seq
import Data.Sequence (Map)
import qualified Data.Sequence as Map

import qualified Network.Wai.Handler.Warp as Warp
import Network.Wai (Application)

import Servant
import Servant.Server
import Servant.Server.Internal.Enter

import Database.Persist
import Database.Persist.Sql
import Database.Persist.TH

data Config = Config { dyreError    :: Maybe String
                     , warpSettings :: Warp.Settings
                     }

instance Default Config where
  def = Config { dyreError    = Nothing
               , warpSettings = Warp.defaultSettings
               }

data HandlerInput = HandlerInput { sqlPool :: ConnectionPool
                                 }


share [mkPersist sqlSettings, mkMigrate "migrateAll"] [persistLowerCase|
Job
    printer PrinterId
    content Printout
Draft
    title DraftTitle Maybe
    content Printout
|]


thermoprintServer :: ( MonadLogger m
                     , MonadIO m
                     , MonadBaseControl IO m
                     , MonadReader ConnectionPool m
                     ) => (m :~> IO) -> Config -> IO ()
thermoprintServer io = Dyre.wrapMain $ Dyre.defaultParams
  { Dyre.projectName = "thermoprint-server"
  , Dyre.realMain    = realMain <=< handleDyreErrors
  , Dyre.showError   = (\cfg msg -> cfg { dyreError = Just msg })
  }
    where
      handleDyreErrors cfg@(Config{..})
          | Just msg <- dyreError = do
              hPutStrLn stderr msg
              exitFailure
              undefined
          | otherwise = return cfg

      realMain (Config{..}) = enter io $ do
        sqlPool <- ask
        runSqlPool (runMigrationSilent migrateAll) sqlPool >>= mapM_ $(logWarn)
        let
          handlerInput = HandlerInput
            { sqlPool = sqlPool
            }
          io' :: ReaderT HandlerInput IO :~> IO
          io' = runReaderTNat handlerInput
        liftIO . Warp.runSettings warpSettings . serve thermoprintAPI $ enter (hoistNat io') thermoprintServer'

type Handler = EitherT ServantErr (ReaderT HandlerInput IO)

(<||>) :: Monad m => m a -> m b -> m (a :<|> b)
(<||>) = liftM2 (:<|>)
infixr 9 <||>

thermoprintServer' :: ServerT ThermoprintAPI Handler
thermoprintServer' = listPrinters
                     :<|> listJobs <||> queueJob
                     :<|> getJob <||> jobStatus <||> deleteJob
                     :<|> (listDrafts :<|> addDraft)
                     :<|> updateDraft <||> getDraft <||> deleteDraft <||> printDraft


listPrinters :: Handler (Set PrinterId)
listPrinters = return Set.empty

queueJob :: Maybe PrinterId -> Printout -> Handler API.JobId
queueJob = return undefined

printerStatus :: PrinterId -> Handler PrinterStatus
printerStatus = return undefined

listJobs :: Maybe PrinterId -> Maybe API.JobId -> Maybe API.JobId -> Handler (Seq (API.JobId, JobStatus))
listJobs = return undefined

getJob :: API.JobId -> Handler Printout
getJob = return undefined

jobStatus :: API.JobId -> Handler JobStatus
jobStatus = return undefined

deleteJob :: API.JobId -> Handler ()
deleteJob = return undefined

listDrafts :: Handler (Map API.DraftId (Maybe DraftTitle))
listDrafts = return undefined

addDraft :: Maybe DraftTitle -> Printout -> Handler API.DraftId
addDraft = return undefined

updateDraft :: API.DraftId -> Maybe DraftTitle -> Printout -> Handler ()
updateDraft = return undefined

getDraft :: API.DraftId -> Handler (Maybe DraftTitle, Printout)
getDraft = return undefined

deleteDraft :: API.DraftId -> Handler ()
deleteDraft = return undefined

printDraft :: API.DraftId -> Maybe PrinterId -> Handler API.JobId
printDraft = return undefined