{-# LANGUAGE RecordWildCards #-}
module Telegram.Bot.Simple.BotApp (
  BotApp(..),
  BotJob(..),
  WebhookConfig(..),

  startBot,
  startBot_,

  startBotAsync,
  startBotAsync_,

  startBotWebhook,
  startBotWebhook_,

  getEnvToken,
) where

import           Control.Concurrent                  (forkIO)
import           Control.Monad                       (void)
import           Data.String                         (fromString)
import           Servant.Client
import           System.Environment                  (getEnv)

import           Control.Exception                   (finally)
import           Data.Either                         (isLeft)
import           Network.Wai.Handler.Warp
import           Network.Wai.Handler.WarpTLS
import qualified Telegram.Bot.API                    as Telegram
import           Telegram.Bot.API.Webhook            (SetWebhookRequest,
                                                      deleteWebhook,
                                                      setUpWebhook, webhookApp)
import           Telegram.Bot.Simple.BotApp.Internal

-- | Start bot with asynchronous polling.
-- The result is a function that allows you to send actions
-- directly to the bot.
startBotAsync :: BotApp model action -> ClientEnv -> IO (action -> IO ())
startBotAsync bot env = do
  botEnv <- startBotEnv bot env
  fork_ $ startBotPolling bot botEnv
  return (issueAction botEnv Nothing . Just)
  where
    fork_ = void . forkIO . void . flip runClientM env

-- | Like 'startBotAsync', but ignores result.
startBotAsync_ :: BotApp model action -> ClientEnv -> IO ()
startBotAsync_ bot env = void (startBotAsync bot env)

-- | Start bot with update polling in the main thread.
startBot :: BotApp model action -> ClientEnv -> IO (Either ClientError ())
startBot bot env = do
  botEnv <- startBotEnv bot env
  runClientM (startBotPolling bot botEnv) env

-- | Like 'startBot', but ignores result.
startBot_ :: BotApp model action -> ClientEnv -> IO ()
startBot_ bot = void . startBot bot

data WebhookConfig = WebhookConfig
  { webhookConfigTlsSettings       :: TLSSettings,
    webhookConfigTlsWarpSettings   :: Settings,
    webhookConfigSetWebhookRequest :: SetWebhookRequest
  }

-- | Start bot with webhook on update in the main thread.
-- Port must be one of 443, 80, 88, 8443
-- certPath must be provided if using self signed certificate.
startBotWebhook :: BotApp model action -> WebhookConfig -> ClientEnv -> IO (Either ClientError ())
startBotWebhook bot (WebhookConfig{..}) env = do
  botEnv <- startBotEnv bot env
  res <- setUpWebhook webhookConfigSetWebhookRequest env
  if isLeft res
    then return res
    else Right <$> runTLS webhookConfigTlsSettings webhookConfigTlsWarpSettings (webhookApp bot botEnv)
  `finally`
    deleteWebhook env


-- | Like 'startBotWebhook', but ignores result.
startBotWebhook_ :: BotApp model action -> WebhookConfig -> ClientEnv -> IO ()
startBotWebhook_ bot webhookConfig = void . startBotWebhook bot webhookConfig

-- | Get a 'Telegram.Token' from environment variable.
--
-- Common use:
--
-- @
-- 'getEnvToken' "TELEGRAM_BOT_TOKEN"
-- @
getEnvToken :: String -> IO Telegram.Token
getEnvToken varName = fromString <$> getEnv varName

startBotEnv :: BotApp model action -> ClientEnv -> IO (BotEnv model action)
startBotEnv bot env = do
  botEnv <- defaultBotEnv bot env
  _jobThreadIds <- scheduleBotJobs botEnv (botJobs bot)
  _actionsThreadId <- processActionsIndefinitely bot botEnv
  return botEnv