{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE TypeApplications  #-}

module Soostone.Handlers where

import Soostone.Types
    ( AppState(AppState, sqliteFile, stmMap), AppM, Count(..), Key )

import Data.Functor ( ($>) )
import Database.SQLite.Simple
    ( open,
      Connection,
      close,
      executeNamed,
      queryNamed,
      withImmediateTransaction,
      NamedParam((:=)) )
import Control.Monad.Catch ( finally )
import Control.Monad.Reader   ( ask )
import Control.Monad.IO.Class ( liftIO )
import qualified StmContainers.Map as SM
import GHC.Conc (atomically)


submitKeyHandler :: Key -> AppM ()
submitKeyHandler key = do
  AppState{..} <- ask
  liftIO $ atomically $ do
    SM.lookup key stmMap >>= \case
      Just v  -> SM.insert (v + 1) key stmMap
      Nothing -> SM.insert 1       key stmMap

{--
withSQLiteCon $ \con -> do
  r <- liftIO $ withImmediateTransaction con $ do
    queryNamed @Count con "SELECT count FROM keys WHERE key=:key" [":key" := key] >>= \case
      []  -> executeNamed con "INSERT INTO keys (key, count) VALUES (:key, :count)" [":key" := key, ":count" := Count 1] $> Right ()
      [c] -> executeNamed con "UPDATE keys SET count = :count WHERE key = :key" [":count" := c + 1, ":key" := key] $> Right ()
      _   -> pure $ Left "Oops"
  case r of
    Right _ -> pure ()
    Left e -> fail e -- internal error
--}


countKeyHandler :: Key -> AppM Count
countKeyHandler key = do
  AppState{..} <- ask
  liftIO $ atomically $ do
    SM.lookup key stmMap >>= \case
      Just v  -> return v
      Nothing -> return (Count 0)

withSQLiteCon :: (Connection -> AppM a) -> AppM a
withSQLiteCon action = do
  AppState{..} <- ask
  conn <- liftIO $ open sqliteFile
  action conn `finally` liftIO (close conn)