{-# LANGUAGE BangPatterns #-}
{-# LANGUAGE MultiWayIf #-}
{-# LANGUAGE OverloadedLists #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE RecordWildCards #-}

module Main where

import Control.Concurrent
import qualified Data.ByteString.Base16 as BS16
import qualified Data.ByteString.Char8 as C8
import Data.IORef
import Data.List.NonEmpty (NonEmpty)
import qualified Data.List.NonEmpty as NE
import Data.X509.CertificateStore
import Network.Run.TCP
import Network.Socket
import Network.TLS hiding (is0RTTPossible)
import Network.TLS.Internal (makeCipherShowPretty)
import System.Console.GetOpt
import System.Environment
import System.Exit
import System.X509

import Client
import Common
import Imports

data Options = Options
    { optDebugLog :: Bool
    , optShow :: Bool
    , optKeyLogFile :: Maybe FilePath
    , optGroups :: [Group]
    , optValidate :: Bool
    , optVerNego :: Bool
    , optResumption :: Bool
    , opt0RTT :: Bool
    , optRetry :: Bool
    , optVersions :: [Version]
    , optALPN :: String
    , optCertFile :: Maybe FilePath
    , optKeyFile :: Maybe FilePath
    }
    deriving (Show)

defaultOptions :: Options
defaultOptions =
    Options
        { optDebugLog = False
        , optShow = False
        , optKeyLogFile = Nothing
        , optGroups = supportedGroups defaultSupported
        , optValidate = False
        , optVerNego = False
        , optResumption = False
        , opt0RTT = False
        , optRetry = False
        , optVersions = supportedVersions defaultSupported
        , optALPN = "http/1.1"
        , optCertFile = Nothing
        , optKeyFile = Nothing
        }

usage :: String
usage = "Usage: quic-client [OPTION] addr port [path]"

options :: [OptDescr (Options -> Options)]
options =
    [ Option
        ['d']
        ["debug"]
        (NoArg (\o -> o{optDebugLog = True}))
        "print debug info"
    , Option
        ['v']
        ["show-content"]
        (NoArg (\o -> o{optShow = True}))
        "print downloaded content"
    , Option
        ['l']
        ["key-log-file"]
        (ReqArg (\file o -> o{optKeyLogFile = Just file}) "<file>")
        "a file to store negotiated secrets"
    , Option
        ['g']
        ["groups"]
        (ReqArg (\gs o -> o{optGroups = readGroups gs}) "<groups>")
        "specify groups"
    , Option
        ['e']
        ["validate"]
        (NoArg (\o -> o{optValidate = True}))
        "validate server's certificate"
    , Option
        ['R']
        ["resumption"]
        (NoArg (\o -> o{optResumption = True}))
        "try session resumption"
    , Option
        ['Z']
        ["0rtt"]
        (NoArg (\o -> o{opt0RTT = True}))
        "try sending early data"
    , Option
        ['S']
        ["hello-retry"]
        (NoArg (\o -> o{optRetry = True}))
        "try client hello retry"
    , Option
        ['2']
        ["tls12"]
        (NoArg (\o -> o{optVersions = [TLS12]}))
        "use TLS 1.2"
    , Option
        ['3']
        ["tls13"]
        (NoArg (\o -> o{optVersions = [TLS13]}))
        "use TLS 1.3"
    , Option
        ['a']
        ["alpn"]
        (ReqArg (\a o -> o{optALPN = a}) "<alpn>")
        "set ALPN"
    , Option
        ['c']
        ["cert"]
        (ReqArg (\fl o -> o{optCertFile = Just fl}) "<file>")
        "certificate file"
    , Option
        ['k']
        ["key"]
        (ReqArg (\fl o -> o{optKeyFile = Just fl}) "<file>")
        "key file"
    ]

showUsageAndExit :: String -> IO a
showUsageAndExit msg = do
    putStrLn msg
    putStrLn $ usageInfo usage options
    putStrLn $ "  <groups> = " ++ intercalate "," (map fst namedGroups)
    exitFailure

clientOpts :: [String] -> IO (Options, [String])
clientOpts argv =
    case getOpt Permute options argv of
        (o, n, []) -> return (foldl (flip id) defaultOptions o, n)
        (_, _, errs) -> showUsageAndExit $ concat errs

main :: IO ()
main = do
    args <- getArgs
    (opts@Options{..}, ips) <- clientOpts args
    (host, port, paths) <- case ips of
        [] -> showUsageAndExit usage
        _ : [] -> showUsageAndExit usage
        h : p : [] -> return (h, p, ["/"])
        h : p : ps -> return (h, p, C8.pack <$> NE.fromList ps)
    when (null optGroups) $ do
        putStrLn "Error: unsupported groups"
        exitFailure
    let onCertReq = \_ -> case optCertFile of
            Just certFile -> case optKeyFile of
                Just keyFile -> do
                    Right (!cc, !priv) <- credentialLoadX509 certFile keyFile
                    return $ Just (cc, priv)
                _ -> return Nothing
            _ -> return Nothing
    ref <- newIORef []
    let debug
            | optDebugLog = putStrLn
            | otherwise = \_ -> return ()
        showContent
            | optShow = C8.putStr
            | otherwise = \_ -> return ()
        aux =
            Aux
                { auxAuthority = host
                , auxPort = port
                , auxDebugPrint = debug
                , auxShow = showContent
                , auxReadResumptionData = readIORef ref
                }
    mstore <-
        if optValidate then Just <$> getSystemCertificateStore else return Nothing
    let cparams = getClientParams opts host port (smIORef ref) mstore onCertReq
        client
            | optALPN == "dot" = clientDNS
            | otherwise = clientHTTP11
    makeCipherShowPretty
    runClient opts client cparams aux paths

runClient
    :: Options -> Cli -> ClientParams -> Aux -> NonEmpty ByteString -> IO ()
runClient opts@Options{..} client cparams aux@Aux{..} paths = do
    auxDebugPrint "------------------------"
    (info1, msd) <- runTLS opts cparams aux $ \ctx -> do
        i1 <- getInfo ctx
        when optDebugLog $ printHandshakeInfo i1
        client aux paths ctx
        msd' <- auxReadResumptionData
        return (i1, msd')
    if
        | optResumption ->
            if isResumptionPossible msd
                then do
                    let cparams2 = modifyClientParams cparams msd False
                    info2 <- runClient2 opts client cparams2 aux paths
                    if infoVersion info1 == TLS12
                        then do
                            if infoTLS12Resumption info2
                                then do
                                    putStrLn "Result: (R) TLS resumption ... OK"
                                    exitSuccess
                                else do
                                    putStrLn "Result: (R) TLS resumption ... NG"
                                    exitFailure
                        else do
                            if infoTLS13HandshakeMode info2 == Just PreSharedKey
                                then do
                                    putStrLn "Result: (R) TLS resumption ... OK"
                                    exitSuccess
                                else do
                                    putStrLn "Result: (R) TLS resumption ... NG"
                                    exitFailure
                else do
                    putStrLn "Result: (R) TLS resumption ... NG"
                    exitFailure
        | opt0RTT ->
            if is0RTTPossible info1 msd
                then do
                    let cparams2 = modifyClientParams cparams msd True
                    info2 <- runClient2 opts client cparams2 aux paths
                    if infoTLS13HandshakeMode info2 == Just RTT0
                        then do
                            putStrLn "Result: (Z) 0-RTT ... OK"
                            exitSuccess
                        else do
                            putStrLn "Result: (Z) 0-RTT ... NG"
                            exitFailure
                else do
                    putStrLn "Result: (Z) 0-RTT ... NG"
                    exitFailure
        | optRetry ->
            if infoTLS13HandshakeMode info1 == Just HelloRetryRequest
                then do
                    putStrLn "Result: (S) retry ... OK"
                    exitSuccess
                else do
                    putStrLn "Result: (S) retry ... NG"
                    exitFailure
        | otherwise -> do
            putStrLn "Result: (H) handshake ... OK"
            when (optALPN == "http/1.1") $
                putStrLn "Result: (1) HTTP/1.1 transaction ... OK"
            exitSuccess

runClient2
    :: Options
    -> Cli
    -> ClientParams
    -> Aux
    -> NonEmpty ByteString
    -> IO Information
runClient2 opts@Options{..} client cparams aux@Aux{..} paths = do
    threadDelay 100000
    auxDebugPrint "<<<< next connection >>>>"
    auxDebugPrint "------------------------"
    runTLS opts cparams aux $ \ctx -> do
        if opt0RTT
            then do
                void $ client aux paths ctx
                i <- getInfo ctx
                when optDebugLog $ printHandshakeInfo i
                return i
            else do
                i <- getInfo ctx
                when optDebugLog $ printHandshakeInfo i
                void $ client aux paths ctx
                return i

runTLS
    :: Options
    -> ClientParams
    -> Aux
    -> (Context -> IO a)
    -> IO a
runTLS Options{..} cparams Aux{..} action =
    runTCPClient auxAuthority auxPort $ \sock -> do
        ctx <- contextNew sock cparams
        when optDebugLog $
            contextHookSetLogging
                ctx
                defaultLogging
                    { loggingPacketSent = putStrLn . (">> " ++)
                    , loggingPacketRecv = putStrLn . ("<< " ++)
                    }
        handshake ctx
        r <- action ctx
        bye ctx
        return r

modifyClientParams
    :: ClientParams -> [(SessionID, SessionData)] -> Bool -> ClientParams
modifyClientParams cparams ts early =
    cparams
        { clientWantSessionResumeList = ts
        , clientUseEarlyData = early
        }

getClientParams
    :: Options
    -> HostName
    -> ServiceName
    -> SessionManager
    -> Maybe CertificateStore
    -> OnCertificateRequest
    -> ClientParams
getClientParams Options{..} serverName port sm mstore onCertReq =
    (defaultParamsClient serverName (C8.pack port))
        { clientSupported = supported
        , clientUseServerNameIndication = True
        , clientShared = shared
        , clientHooks = hooks
        , clientDebug = debug
        }
  where
    groups
        | optRetry = FFDHE8192 : optGroups
        | otherwise = optGroups
    shared =
        defaultShared
            { sharedSessionManager = sm
            , sharedCAStore = case mstore of
                Just store -> store
                Nothing -> mempty
            , sharedValidationCache = validateCache
            }
    supported =
        defaultSupported
            { supportedVersions = optVersions
            , supportedGroups = groups
            }
    hooks =
        defaultClientHooks
            { onSuggestALPN = return $ Just [C8.pack optALPN]
            , onCertificateRequest = onCertReq
            }
    validateCache
        | isJust mstore = sharedValidationCache defaultShared
        | otherwise =
            ValidationCache
                (\_ _ _ -> return ValidationCachePass)
                (\_ _ _ -> return ())
    debug =
        defaultDebugParams
            { debugKeyLogger = getLogger optKeyLogFile
            }

smIORef :: IORef [(SessionID, SessionData)] -> SessionManager
smIORef ref =
    noSessionManager
        { sessionEstablish = \sid sdata ->
            modifyIORef' ref (\xs -> (sid, sdata) : xs)
                >> printTicket sid sdata
                >> return Nothing
        }

printTicket :: SessionID -> SessionData -> IO ()
printTicket sid sdata = do
    C8.putStr $ "Ticket: " <> C8.take 16 (BS16.encode sid) <> "..., "
    putStrLn $ "0-RTT: " <> if sessionMaxEarlyDataSize sdata > 0 then "OK" else "NG"

isResumptionPossible :: [(SessionID, SessionData)] -> Bool
isResumptionPossible = not . null

is0RTTPossible :: Information -> [(SessionID, SessionData)] -> Bool
is0RTTPossible _ [] = False
is0RTTPossible info xs =
    infoVersion info == TLS13
        && any (\(_, sd) -> sessionMaxEarlyDataSize sd > 0) xs