ThreeLayerCake

ThreeLayerCake.hs

{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE GeneralisedNewtypeDeriving #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE FunctionalDependencies #-}

module Bot
  ( runMeInMain
  ) where

import Control.Monad.Identity
import Control.Monad.Reader

class (Monad m, MonadReader Env m) =>
      AwaitMessage m p
  | m -> p
  where
  awaitMessage :: m p

class (Monad m, MonadReader Env m, AwaitMessage m p) =>
      ReplyToMessage m p
  | p -> m
  where
  replyToMessage :: p -> m ()

data Bot
  = VK
  | Telegram

type Token = String

type ChatId = String

type UserId = String

data TelegramConfig =
  TelegramConfig Token

data Env = Env
  { telegramConfig :: TelegramConfig
  , val2 :: Int
  }

newtype TelegramM a = TelegramM
  { unTelegramM :: ReaderT Env IO a
  } deriving (Functor, Applicative, Monad, MonadIO, MonadReader Env)

newtype VKM a = VKM
  { unVKM :: ReaderT Env IO a
  } deriving (Functor, Applicative, Monad, MonadIO, MonadReader Env)

data TelegramPayload =
  TelegramPayload ChatId
                  UserId

instance ReplyToMessage TelegramM TelegramPayload where
  replyToMessage (TelegramPayload chatId userId) = do
    (TelegramConfig token) <- asks telegramConfig
    pure ()

instance AwaitMessage TelegramM TelegramPayload where
  awaitMessage = pure $ TelegramPayload "chatId" "userId"

instance ReplyToMessage VKM VKPayload where
  replyToMessage vkString = do
    yo <- asks val2
    pure ()

instance AwaitMessage VKM VKPayload where
  awaitMessage = pure $ VKPayload "chatId" "userId"

type DifferentField = Int

type SessionId = String

data VKConfig =
  VKConfig Token
           DifferentField

data VKPayload =
  VKPayload SessionId
            ChatId

app :: (AwaitMessage m p, ReplyToMessage m p) => m ()
app = do
  msg <- awaitMessage
  replyToMessage msg

runMeInMain :: Bot -> IO ()
runMeInMain bot =
  case bot of
    Telegram -> runReaderT (unTelegramM app) env
    VK -> runReaderT (unVKM app) env
  where
    env = (Env {telegramConfig = TelegramConfig "token", val2 = 3})