{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE TemplateHaskell #-}

module Network.MoeSocks.Common where

import Control.Lens
import Control.Monad.Writer hiding (listen)
import Data.IP (IPRange, isMatchedTo)
import Data.Maybe (isJust)
import Data.Text.Lens
import Network.Socket (SockAddr(..), Socket(..), SocketType(..), Family(..))
import Network.Socket (setSocketOption, SocketOption(..))

import Network.MoeSocks.Type

import Network.MoeSocks.Helper ((-), tryIO, error_)
import Network.MoeSocks.Helper (setSocket_TCP_NOTSENT_LOWAT, getSocketWithHint)
import Prelude hiding ((-), take)


makePrisms ''IPRange

check_IP_List :: AddressType -> [IPRange] -> Bool
check_IP_List _address@(IPv4_Address _) a_IP_List =
  isJust -
    do
      _ip <- show _address  ^? _Show
      findOf (each . _IPv4Range) (isMatchedTo _ip) a_IP_List

check_IP_List _address@(IPv6_Address _) a_IP_List =
  isJust -
    do
      _ip <- show _address ^? _Show
      findOf (each . _IPv6Range) (isMatchedTo _ip) a_IP_List

check_IP_List _ _ = False

withChecked_IP_List :: AddressType -> ([IPRange], Maybe [IPRange])
                        -> IO a -> IO ()
withChecked_IP_List aAddressType (aDenyList, aAllowList) aIO =
  if check_IP_List aAddressType aDenyList
    then error_ - show aAddressType
                <> " is in the denied list"
    else
      case aAllowList of
        Nothing -> () <$ aIO
        Just _allowList ->
          if not - check_IP_List aAddressType _allowList
            then error_ - show aAddressType
                    <> " is NOT in the allowed list"
            else
              () <$ aIO

getIPLists :: Env -> ([IPRange], Maybe [IPRange])
getIPLists aEnv = (aEnv ^. denyList <> aEnv ^. forbidden_IPs, mempty)

showConnectionType :: ConnectionType -> String
showConnectionType TCP_IP_StreamConnection = "TCP_Stream"
-- showConnectionType TCP_IP_PortBinding      = "TCP_Bind  "
showConnectionType UDP_Port                = "UDP       "

showRequest :: ClientRequest -> String
showRequest _r =
                   _r ^. addressType . to show
                <> ":"
                <> _r ^. portNumber . to show

showRelay :: SockAddr -> ClientRequest -> String
showRelay aSockAddr aClientRequest =
      show aSockAddr <> " -> " <> showRequest aClientRequest

addressType_To_Family :: AddressType -> Family
addressType_To_Family (IPv4_Address _) = AF_INET
addressType_To_Family (IPv6_Address _) = AF_INET6
addressType_To_Family _                = AF_UNSPEC

_SocketType :: Prism' SocketType ConnectionType
_SocketType = prism' connectionType_To_SocketType socketType_To_connectionType
  where
    connectionType_To_SocketType :: ConnectionType -> SocketType
    connectionType_To_SocketType TCP_IP_StreamConnection = Stream
    {-connectionType_To_SocketType TCP_IP_PortBinding      = NoSocketType-}
    connectionType_To_SocketType UDP_Port                = Datagram

    socketType_To_connectionType :: SocketType -> Maybe ConnectionType
    socketType_To_connectionType Stream = Just TCP_IP_StreamConnection
    socketType_To_connectionType Datagram = Just UDP_Port
    socketType_To_connectionType _ = Nothing


initTarget :: ClientRequest -> IO (Socket, SockAddr)
initTarget _clientRequest = do
  let
      _socketType = _clientRequest ^. connectionType . re _SocketType
      _hostName   = _clientRequest ^. addressType . to show . re _Text
      _port       = _clientRequest ^. portNumber
      _family     = _clientRequest ^. addressType . to addressType_To_Family

  getSocketWithHint _family _hostName _port _socketType


setSocketConfig:: Env -> Socket -> IO ()
setSocketConfig aEnv aSocket = do
  setSocketOption aSocket NoDelay 1
  when (aEnv ^. socketOption_TCP_NOTSENT_LOWAT) - do
    tryIO "setSocket_TCP_NOTSENT_LOWAT" - setSocket_TCP_NOTSENT_LOWAT aSocket
    pure ()