{-# LANGUAGE DeriveDataTypeable #-}
{-# LANGUAGE ExistentialQuantification #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE TemplateHaskell #-}

module Network.IRC.Types
  ( Nick (..)
  , MsgHandlerName
  , User (..)
  , Message (..)
  , MessageDetails (..)
  , Command (..)
  , Event (..)
  , SomeEvent
  , QuitEvent(..)
  , EventResponse (..)
  , BotConfig (..)
  , BotStatus (..)
  , Bot (..)
  , IRC
  , runIRC
  , MsgHandler (..)
  , MonadMsgHandler
  , newMsgHandler
  , handleMessage
  , handleEvent
  , stopMsgHandler
  , getHelp )
where

import ClassyPrelude
import Control.Monad.Base      (MonadBase)
import Control.Monad.Reader    (ReaderT, MonadReader, runReaderT)
import Control.Monad.State     (StateT, MonadState, execStateT)
import Data.Configurator.Types (Config)
import Data.Data               (Data)
import Data.SafeCopy           (base, deriveSafeCopy)
import Data.Typeable           (cast)

import Network.IRC.Util

-- IRC related

newtype Nick = Nick { nickToText :: Text }
               deriving (Eq, Ord, Data, Typeable, Hashable)

instance Show Nick where
  show = unpack . nickToText

$(deriveSafeCopy 0 'base ''Nick)

data User = Self | User { userNick :: !Nick, userServer :: !Text }
            deriving (Show, Eq)

data Message = Message { msgTime :: !UTCTime, msgLine :: !Text, msgDetails :: MessageDetails}
               deriving (Show, Eq)

data MessageDetails =
    IdleMsg
  | NickInUseMsg
  | PingMsg      { msg       :: !Text }
  | PongMsg      { msg       :: !Text }
  | NamesMsg     { nicks     :: ![Nick] }
  | ChannelMsg   { user      :: !User, msg        :: !Text }
  | PrivMsg      { user      :: !User, msg        :: !Text }
  | ActionMsg    { user      :: !User, msg        :: !Text }
  | JoinMsg      { user      :: !User }
  | QuitMsg      { user      :: !User, msg        :: !Text }
  | PartMsg      { user      :: !User, msg        :: !Text }
  | NickMsg      { user      :: !User, newNick    :: !Nick }
  | KickMsg      { user      :: !User, kickedNick :: !Nick, msg       :: !Text }
  | ModeMsg      { user      :: !User, msgTarget  :: !Text, mode      :: !Text , modeArgs :: ![Text] }
  | OtherMsg     { msgSource :: !Text, msgCommand :: !Text, msgTarget :: !Text , msg      :: !Text }
  deriving (Show, Eq)

data Command =
    PingCmd         { rmsg  :: !Text }
  | PongCmd         { rmsg  :: !Text }
  | ChannelMsgReply { rmsg  :: !Text }
  | PrivMsgReply    { ruser :: !User, rmsg :: !Text }
  | NickCmd
  | UserCmd
  | JoinCmd
  | QuitCmd
  | NamesCmd
  deriving (Show, Eq)

-- Internal events

class (Typeable e, Show e) => Event e where
  toEvent :: e -> IO SomeEvent
  toEvent e = SomeEvent <$> pure e <*> getCurrentTime

  fromEvent :: SomeEvent -> Maybe (e, UTCTime)
  fromEvent (SomeEvent e time) = do
    ev <- cast e
    return (ev, time)

data SomeEvent = forall e. Event e => SomeEvent e UTCTime deriving (Typeable)
instance Show SomeEvent where
  show (SomeEvent e time) = formatTime defaultTimeLocale "[%F %T] " time ++ show e

data QuitEvent = QuitEvent deriving (Show, Typeable)
instance Event QuitEvent

data EventResponse =  RespNothing
                    | RespEvent SomeEvent
                    | RespMessage Message
                    | RespCommand Command
                    deriving (Show)

-- Bot

type MsgHandlerName = Text

data BotConfig = BotConfig { server         :: !Text
                           , port           :: !Int
                           , channel        :: !Text
                           , botNick        :: !Nick
                           , botTimeout     :: !Int
                           , msgHandlerInfo :: !(Map MsgHandlerName (Map Text Text))
                           , config         :: !Config }

instance Show BotConfig where
  show BotConfig { .. } = "server = "   ++ show server     ++ "\n" ++
                          "port = "     ++ show port       ++ "\n" ++
                          "channel = "  ++ show channel    ++ "\n" ++
                          "nick = "     ++ show botNick    ++ "\n" ++
                          "timeout = "  ++ show botTimeout ++ "\n" ++
                          "handlers = " ++ show (mapKeys msgHandlerInfo)

data Bot = Bot { botConfig   :: !BotConfig
               , socket      :: !Handle
               , msgHandlers :: !(Map MsgHandlerName MsgHandler) }

data BotStatus = Connected
               | Disconnected
               | Joined
               | Kicked
               | Errored
               | Idle
               | Interrupted
               | NickNotAvailable
               deriving (Show, Eq)

newtype IRC a = IRC { _runIRC :: StateT BotStatus (ReaderT Bot IO) a }
                deriving ( Functor
                         , Applicative
                         , Monad
                         , MonadIO
                         , MonadReader Bot
                         , MonadState BotStatus )

runIRC :: Bot -> BotStatus -> IRC a -> IO BotStatus
runIRC bot botStatus = flip runReaderT bot . flip execStateT botStatus . _runIRC

-- Message handlers

newtype MsgHandlerT a = MsgHandlerT { _runMsgHandler :: ReaderT BotConfig IO a }
                        deriving ( Functor
                                 , Applicative
                                 , Monad
                                 , MonadIO
                                 , MonadBase IO
                                 , MonadReader BotConfig )

class (MonadIO m, Applicative m, MonadReader BotConfig m, MonadBase IO m) => MonadMsgHandler m where
  msgHandler :: MsgHandlerT a -> m a

instance MonadMsgHandler MsgHandlerT where
  msgHandler = id

handleMessage :: MsgHandler -> BotConfig -> Message -> IO [Command]
handleMessage MsgHandler { .. } botConfig =
  flip runReaderT botConfig . _runMsgHandler . onMessage

stopMsgHandler :: MsgHandler -> BotConfig -> IO ()
stopMsgHandler MsgHandler { .. } botConfig =
  flip runReaderT botConfig . _runMsgHandler $ onStop

handleEvent :: MsgHandler -> BotConfig -> SomeEvent -> IO EventResponse
handleEvent MsgHandler { .. } botConfig =
  flip runReaderT botConfig . _runMsgHandler . onEvent

getHelp :: MsgHandler -> BotConfig -> IO (Map Text Text)
getHelp MsgHandler { .. } botConfig =
  flip runReaderT botConfig . _runMsgHandler $ onHelp

data MsgHandler = MsgHandler {
  onMessage :: !(forall m . MonadMsgHandler m => Message -> m [Command]),
  onStop    :: !(forall m . MonadMsgHandler m => m ()),
  onEvent   :: !(forall m . MonadMsgHandler m => SomeEvent -> m EventResponse),
  onHelp    :: !(forall m . MonadMsgHandler m => m (Map Text Text))
}

newMsgHandler :: MsgHandler
newMsgHandler = MsgHandler {
  onMessage = const $ return [],
  onStop    = return (),
  onEvent   = const $ return RespNothing,
  onHelp    = return mempty
}