{-# 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
  , MsgHandlerMaker (..))
where

import ClassyPrelude
import Control.Concurrent.Lifted (Chan)
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, Ord)

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

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, Ord)

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

-- Events

class (Typeable e, Show e, Eq 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, Typeable e) => SomeEvent e UTCTime deriving (Typeable)
instance Show SomeEvent where
  show (SomeEvent e time) = formatTime defaultTimeLocale "[%F %T] " time ++ show e
instance Eq SomeEvent where
  SomeEvent e1 t1 == SomeEvent e2 t2 =
    case cast e2 of
      Just e2' -> e1 == e2' && t1 == t2
      Nothing  -> False

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

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

-- Bot

type MsgHandlerName = Text

data BotConfig = BotConfig { server           :: !Text
                           , port             :: !Int
                           , channel          :: !Text
                           , botNick          :: !Nick
                           , botTimeout       :: !Int
                           , msgHandlerInfo   :: !(Map MsgHandlerName (Map Text Text))
                           , msgHandlerMakers :: ![MsgHandlerMaker]
                           , 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, Ord)

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
}

data MsgHandlerMaker = MsgHandlerMaker {
  msgHandlerName  :: !MsgHandlerName,
  msgHandlerMaker :: BotConfig -> Chan SomeEvent -> MsgHandlerName -> IO (Maybe MsgHandler)
}

instance Eq MsgHandlerMaker where
  m1 == m2 = msgHandlerName m1 == msgHandlerName m2
instance Ord MsgHandlerMaker where
  m1 `compare` m2 = msgHandlerName m1 `compare` msgHandlerName m2