{-# LANGUAGE LambdaCase        #-}
{-# LANGUAGE NamedFieldPuns    #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE RecordWildCards   #-}
{-# LANGUAGE ViewPatterns      #-}
module Kiki
    ( module Kiki
    , setVerifyFlag
    ) where

import qualified Codec.Encryption.OpenPGP.ASCIIArmor as ASCIIArmor
import           Codec.Encryption.OpenPGP.ASCIIArmor.Types
import           Control.Applicative
import           Control.Exception
import           Control.Monad
import qualified Crypto.Hash as C
import           Data.ASN1.BinaryEncoding
import           Data.ASN1.Encoding
import           Data.ASN1.Types
import           Data.Binary
import           Data.Bool
import           Data.Coerce
import           Data.Char
import           Data.Functor
import           Data.List
import           Data.Maybe
import           Data.OpenPGP
import           Data.OpenPGP.Util
import           Data.Ord
import qualified Data.Traversable           as T (mapM)
import           System.Directory
import           System.FilePath.Posix      as FilePath
import           System.IO
import           System.IO.Error
import           System.IO.Temp
import           System.Posix.Files
import           System.Posix.Types         (FileMode)
import           System.Posix.IO            as Posix (createPipe)
import           System.Posix.User
import           Data.ByteArray.Encoding
import qualified Data.ByteString.Char8      as S8
import qualified Data.ByteString.Lazy       as L
import qualified Data.ByteString.Lazy.Char8 as Char8
import qualified Data.Map.Strict            as Map
import           GHC.Stack
import           Network.Socket
import qualified SSHKey                     as SSH

import           CommandLine
import           DotLock
import           GnuPGAgent                 (Query (..))
-- import qualified IntMapClass as I
import           KeyRing hiding (pemFromPacket)
import           KeyDB
import           KeyRing.BuildKeyDB (gpgipv6addr, Hostnames, allNames)
import           TimeUtil

withAgent :: [PassphraseSpec] -> [PassphraseSpec]
withAgent [] = [PassphraseAgent]
withAgent ps = ps

ciphername :: SymmetricAlgorithm -> String
ciphername Unencrypted = "-"
ciphername TripleDES   = "3des"
ciphername (SymmetricAlgorithm w8) = "cipher-"++show w8
ciphername c = map toLower $ show c

cipherFromString :: String -> SymmetricAlgorithm
cipherFromString "clear"       = Unencrypted
cipherFromString "unencrypted" = Unencrypted
cipherFromString s             =
    case filter ( (== s) . ciphername) ciphers of
        x:_                  -> x
        -- _ | all isHexDigit s -> unhex s
        _                    -> error $ "known ciphers: "++unwords (map ciphername ciphers)
 {-
 where
    unhex hx = case convertFromBase Base16 (S8.pack hx) of
                Left e -> do
                    -- Useful for debugging but insecure generally ;)
                    -- putStrLn $ "convertFromBase error for input "++show hx++": "++show e
                    return Nothing
                Right bs -> return $ Just $ S8.unpack bs
-}


ciphers :: [SymmetricAlgorithm]
ciphers = takeWhile notFallback $ map toEnum $ [0..4]++[7..]
 where
    notFallback (SymmetricAlgorithm _) = False
    notFallback _                      = True

-- |
-- Regenerate /var/cache/kiki
refresh :: (FilePath -> FilePath) -> CommonArgsParsed -> IO ()
refresh root homepass = do
    let homepass' = homepass { cap_homespec = fmap root (cap_homespec homepass) }
    KikiResult r report <- runKeyRing $ minimalOp False homepass'
    let mroot = case root "" of
                    "/" -> Nothing
                    ""  -> Nothing
                    pth -> Just pth
    case r of
        KikiSuccess rt -> refreshCache rt mroot
        _              -> return () -- XXX: silent fail?

data CommonArgsParsed = CommonArgsParsed
    { cap_homespec :: Maybe String
    , cap_passfd :: Maybe InputFile
    , cap_fpstyle :: FingerprintStyle
    }

data FingerprintStyle
    = FingerprintAuto
    | Fingerprint5
 deriving (Eq,Ord,Show)

instance Read FingerprintStyle where
    readsPrec _ s = case break isSpace s of
        ("auto",t) -> [(FingerprintAuto, drop 1 t)]
        ("5",t)    -> [(Fingerprint5, drop 1 t)]
        _          -> []

streaminfo :: StreamInfo
streaminfo = StreamInfo
    { fill = KF_None
    , spill = KF_None
    , typ = KeyRingFile
    , initializer = NoCreate
    , access = AutoAccess
    , transforms = []
    }

minimalOp :: Bool -> CommonArgsParsed -> KeyRingOperation
minimalOp isHomeless cap = op
 where
    streaminfo = StreamInfo { fill = KF_None
                            , typ = KeyRingFile
                            , spill = KF_All
                            , initializer = NoCreate
                            , access = AutoAccess
                            , transforms = []
                            }
    op = KeyRingOperation
        { opFiles = if isHomeless
                        then Map.empty
                        else Map.fromList $
                            [ ( HomeSec, streaminfo { access = Sec })
                            , ( HomePub, streaminfo { access = Pub })
                            ]
        , opPassphrases = withAgent $ do pfile <- maybeToList (cap_passfd cap)
                                         return $ PassphraseSpec Nothing Nothing pfile
        , opTransforms = []
        , opHome = cap_homespec cap
        , preferredPGPVersion = 4
        }

run :: [String] -> Args (IO ()) -> IO ()
run args x =
    case runArgs (parseInvocation (uncurry fancy kikiOptions "") args) x of
        Left e   -> hPutStrLn stderr $ usageErrorMessage e
        Right io -> io

outputReport :: [(FilePath, KikiReportAction)] -> IO ()
outputReport report = do
    forM_ report $ \(fname,act) -> do
        putStrLn $ fname ++ ": " ++ reportString act

spawn :: CommonArgsParsed -> SymmetricAlgorithm -> FilePath -> IO ()
spawn cmn cipher path = do
    putStrLn "TODO: implement keygen.sh replacement.sh"

mkdirFor :: FilePath -> IO ()
mkdirFor path = do
    let dir = takeDirectory path
    createDirectoryIfMissing True dir


-- | Useful default KeyRingFile StreamInfo.
strm :: StreamInfo
strm = StreamInfo
              { typ         = KeyRingFile
              , fill        = KF_None
              , spill       = KF_All
              , access      = AutoAccess
              , initializer = NoCreate
              , transforms  = []
              }

-- | Convenience constructor for StreamInfo
buildStreamInfo :: KeyFilter -> FileType -> StreamInfo
buildStreamInfo rtyp ftyp = strm { typ = ftyp , fill = rtyp }

-- | Convenience constuctor for Streaminfo generating a tagged subkey.
peminfo :: Int       -- ^ bits
           -> String -- ^ subkey tag.
           -> StreamInfo
peminfo bits usage = StreamInfo
              { typ         = PEMFile
              , fill        = KF_None -- KF_Match usage
              , spill       = KF_Match usage
              , access      = Sec
              , initializer = Internal (GenRSA $ bits `div` 8)
              , transforms  = []
              }

importAndRefresh :: Word8 -> (FilePath -> FilePath) -> CommonArgsParsed -> SymmetricAlgorithm -> IO ()
importAndRefresh pgpver root cmn cipher = do
  let rootdir = do guard (root "x" /= "x")
                   Just $ root ""
  me <- getEffectiveUserID
  let noChrootArg = rootdir == Nothing
      bUnprivileged = (me/=0) && noChrootArg
  bool id (error "--chroot requires an argument") (rootdir==Just "") $ do
    let homespec = mplus (slash <$> rootdir <*> cap_homespec cmn)
                         (fmap (++"/root/.gnupg") rootdir)
        passfd = cap_passfd cmn
    (home,secring,pubring,mbwk) <- unconditionally $ getHomeDir homespec
    osHomeDir <- if bUnprivileged then getHomeDirectory else return "/root"

    old_umask <- setFileCreationMask 0o077 -- Keyring files need to be created with proper mask.
    gotsec <- doesFileExist secring
    (torgen,pwds) <- bool id (const $ return (Generate 0 $ GenRSA $ 1024 `div` 8, [])) gotsec $ do
        -- We have no secring.gpg (and thus no master key).
        -- Since 'runKeyRing' cannot currently cope with this situation, we will
        -- generate a master-key and very minimal secring.gpg file.
        master_un <- generateKey (GenRSA $ 4096 `div` 8 )
            <&> \k -> MappedPacket (k { is_subkey = False     -- Set as master-key.
                                      , version   = pgpver }) -- Set pgp packet version.
                                   Map.empty                 -- Packet occurs in no files.
        -- The user may desire the master key is encrypted on disk but this
        -- requires a password prompt.  In order to have a decent prompt, it'd
        -- be nice if we could display the .onion hostname for the key.
        -- Therefore, we generate the tor key early.
        tor_un <- fmap (\k -> k { version = pgpver }) $ generateKey (GenRSA $ 1024 `div` 8 )
        -- However, we'll postpone writing the tor key to the keyring and
        -- instead have the later all-in-one call to runKeyRing take care of
        -- it.  That interface does not currently provide a way to accept
        -- in-memory input, so we'll create a fifo stream for it to read the
        -- key in PEM format.
        (read_tor,write_tor) <- Posix.createPipe
        rs <- writeKeyToFile (streaminfo { typ    = PEMFile
                                         , access = Sec
                                         , spill  = KF_Match "tor"
                                         , fill   = KF_All })
                             (FileDesc write_tor)
                             tor_un
        -- -- Currently disabled: show warnings and errors from the PEM generation.
        -- outputReport $ map (first show) rs

        let ctx = InputFileContext secring pubring
        -- Here we encrypt the master-key if neccessary.  If no --passphrase-fd option
        -- was used, the user will receive prompts from gpg-agent.
        (master0,transcoder) <- do
            let main_passwds = withAgent $ do pfd <- maybeToList passfd
                                              return $ PassphraseSpec Nothing Nothing pfd
                uidentry = Map.singleton (keykey $ packet master_un)
                            $ master_un { packet = Query (packet master_un)
                                                         (torUIDFromKey tor_un)
                                                         Nothing }
            cipher's2k <- do
                IteratedSaltedS2K _ salt _ <- randomS2K SHA1
                return $ (cipher {- AES128 -}, IteratedSaltedS2K SHA1 salt (15 * 2^19))
            transcoder <- makeMemoizingDecrypter main_passwds ctx (Just master_un, uidentry)
            master <- transcoder cipher's2k master_un
            return (master,transcoder)

        -- Finally, we write-out the secring.gpg file.
        case master0 of
            KikiSuccess master -> do
                mkdirFor secring
                writeInputFileL ctx
                                HomeSec
                                $ encode $ Message [master]
                putStrLn $ "Wrote master key."
                return (FileDesc read_tor, [PassphraseMemoizer transcoder])
            er -> do
                hPutStrLn stderr ("warning: " ++ errorString er)
                hPutStrLn stderr "warning: keys will not be encrypted.";
                mkdirFor secring
                writeInputFileL ctx
                                HomeSec
                                $ encode $ Message [packet master_un]
                putStrLn $ "Wrote unencrypted master key."
                return (FileDesc read_tor, [])

    -- If the public ring does not exist, then creating an empty file is
    -- sufficient to satisfy 'runKeyRing'.  However, as we've already generated
    -- a key above, GnuPG will not like the unsynced state we are leaving these
    -- files.  It's important at this point that, 'runKeyRing' actually occurs
    -- to fix things up.
    gotpub <- doesFileExist pubring
    when (not gotpub) $ do
        mkdirFor pubring
        writeInputFileL (InputFileContext secring pubring)
                        HomePub
                        ( encode $ Message [] )

    setFileCreationMask old_umask -- We're done creating keyring files, so restore umask.

    let sshcpath = fromMaybe "" rootdir ++ osHomeDir ++ ".ssh/id_rsa"
        sshspath = fromMaybe "" rootdir ++ "/etc/ssh/ssh_host_rsa_key"
        mktorkey = ( torgen , case torgen of
                                FileDesc _ -> StreamInfo { typ = PEMFile
                                                         , fill = KF_Match "tor"
                                                         , spill = KF_Match "tor"
                                                         , access = Sec
                                                         , initializer = NoCreate
                                                         , transforms = [] }
                                _          -> strm { spill = KF_Match "tor" })
        op =
          KeyRingOperation
          { opFiles =
              Map.fromList $
                [ ( HomeSec, buildStreamInfo KF_All KeyRingFile )
                , ( HomePub, (buildStreamInfo KF_All KeyRingFile) { access = Pub } )
                , mktorkey
                , ( Generate 1 (GenRSA (2048 `div` 8)), strm { spill = KF_Match "ipsec" })
                , ( ArgFile sshcpath, (peminfo 2048 "ssh-client") )
                , ( ArgFile sshspath, (peminfo 2048 "ssh-server") )
                , ( Generate 2 (GenRSA (4096 `div` 8)), strm { spill = KF_Match "encrypt" })
                --, ( Generate 3 GenEd25519, strm { spill = KF_Match "sign" })
                --, ( Generate 4 GenCv25519, strm { spill = KF_Match "tox-id" })
                ]
          , opPassphrases = withAgent $ pwds ++ do pfd <- maybeToList passfd
                                                   return $ PassphraseSpec Nothing Nothing pfd
          , opHome = homespec
          , opTransforms = []
          , preferredPGPVersion = pgpver
          }
        nop =
          KeyRingOperation
          { opFiles = Map.fromList -- It's too late for a true no-op,
                                   -- so we'll sync the keyrings at least.
                [ ( HomeSec, buildStreamInfo KF_All KeyRingFile )
                , ( HomePub, (buildStreamInfo KF_All KeyRingFile) { access = Pub } )
                , mktorkey -- We'll also add the torkey and UID since
                           -- otherwise this will be a strange keyring.
                ]
          , opPassphrases = withAgent $ do pfd <- maybeToList passfd
                                           return $ PassphraseSpec Nothing Nothing pfd
          , opHome=homespec
          , opTransforms = []
          , preferredPGPVersion = pgpver
          }
    when bUnprivileged $ do
        hPutStrLn stderr "Insufficient privilege generating system service keys."
    -- Run the all-in-one operation that generates or imports all subkeys.
    KikiResult rt report <- runKeyRing (if bUnprivileged then nop else op)
    outputReport report
    rt <- case rt of
        BadPassphrase ->
            error "Operation requires correct passphrase. (Hint: Use --passphrase-fd=0 to input it on stdin.)"
        _ -> unconditionally $ return rt
    -- Finally, we update /var/cache/kiki.
    when (not bUnprivileged) $ refreshCache rt rootdir

data Peer =
  Peer
    { peerHostnames :: Hostnames
    , kd :: KeyData
    }
addr :: Peer -> SockAddr
addr = gpgipv6addr  . peerHostnames

newtype IpsecPeerConfig = IpsecPeerConfig Char8.ByteString
-- Installs the cert file for the peer to the filesystem, and returns an
-- ipsec.conf snippet configuring the peer and referencing the installed cert
-- file.
installIpsecPeerCertificate :: FileWriter -> Peer -> IO IpsecPeerConfig
installIpsecPeerCertificate fw p@Peer{kd} = IpsecPeerConfig <$>
    fromMaybe "" <$> do
            forM (listToMaybe ipsecs) $ \k -> do
                flip (either warn') (pemFromPacket k :: Either String String) $ \pem -> do
                    case sshs of
                        (sshkey:_) -> do
                          let theirHostname = ResolvableHostname $ sshKeyToHostname sshkey
                          write fw (peerCertPath p) pem
                          return $ strongswanPeerConfiguration p theirHostname
                        _ -> error "fuck."
  where
    warn' x = warn x >> return Char8.empty

    their_master = packet $ keyMappedPacket kd :: Packet

    -- We find all cross-certified ipsec keys for the given cross-certified onion name.
    ipsecs :: [Packet]
    ipsecs = sortOn (Down . timestamp)
             $ getSubkeys CrossSigned their_master (keySubKeys kd) "ipsec"
               -- ++ getSubkeys CrossSigned their_master (keySubKeys kd) "strongswan"

    sshs :: [Packet]
    sshs = sortOn (Down . timestamp)
             $ getSubkeys CrossSigned their_master (keySubKeys kd) "ssh-server"

ipsecPath :: String -> Char8.ByteString -> String
ipsecPath theDirName theBaseName = "ipsec.d/" ++ theDirName ++ "/" ++ Char8.unpack theBaseName

ipsecKeyPath :: MyIdentity -> FilePath
ipsecKeyPath (MyIdentity (Char8.pack . showA -> addr) _) = ipsecPath "private" (addr <> ".pem")

ipsecCertPath :: MyIdentity -> FilePath
ipsecCertPath (MyIdentity (Char8.pack . showA -> addr) _) = ipsecPath "certs" (addr <> ".pem")

peerCertPath :: Peer -> FilePath
peerCertPath = ipsecPath "certs" . coerce . peerCertificateName

makeFileWriter :: (FilePath -> FilePath) -> (IO ()) -> FileWriter
makeFileWriter p c =
  FileWriter
    { pathMaker        = p
    , fileWriterCommit = c
    , write            = write' writeFile
    , writeL           = write' L.writeFile
    , writeL077 =
        \f bs -> do
          old_umask <- setFileCreationMask 0o077
          write' L.writeFile f bs
          setFileCreationMask old_umask
    }
  where
    write' wr (p -> f) bs = do
      createDirectoryIfMissing True $ takeDirectory f
      wr f bs

data FileWriter =
  FileWriter
    { pathMaker        :: FilePath -> FilePath
    , fileWriterCommit :: IO ()
    , write            :: FilePath -> String -> IO ()
    , writeL           :: FilePath -> Char8.ByteString -> IO ()
    , writeL077        :: FilePath -> Char8.ByteString -> IO FileMode
    }

getMkPathAndCommit :: FilePath -> IO (FileWriter)
getMkPathAndCommit destdir = do
            let cachedir                    = takeDirectory destdir
                unslash ('/':xs)            = xs
                unslash xs                  = xs
                timeout                     = -1 -- TODO: set milisecond timeout on dotlock
            createDirectoryIfMissing True cachedir
            tmpdir            <- createTempDirectory cachedir (takeBaseName destdir ++ ".")
            createSymbolicLink (makeRelative cachedir tmpdir) (tmpdir ++ ".link")
            lock              <- dotlock_create destdir 0
            T.mapM (flip dotlock_take timeout) lock
            let mkpath pth                  = tmpdir </> unslash (makeRelative destdir pth)
                commit                      = do
                    oldcommit <- (Just <$> readSymbolicLink destdir)
                                    `catch` \e -> do
                                        when (not $ isDoesNotExistError e) $ warn (show e)
                                        return Nothing
                    -- Note: Files not written to are considered deleted,
                    --       otherwise call readyReadBeforeWrite on them.
                    rename (tmpdir ++ ".link") destdir
                    er        <- T.mapM dotlock_release lock
                    void $ T.mapM removeDirectoryRecursive (FilePath.combine cachedir <$> oldcommit)
            -- Present transaction is Write only (or Write-Before-Read) which is fine.
            -- If ever Read-Before-Write is required, uncomment and use:
            -- let readyReadBeforeWrite pth = do
            --    let copyIt                = do
            --          createDirectoryIfMissing True (takeDirectory (mkpath pth))
            --          copyFile (destdir </> unslash (makeRelative destdir pth) (mkpath pth)
            --    doesFileExist (mkpath pth) >>= flip when copyIt
            --    return (mkpath pth)
            return $ makeFileWriter mkpath commit

generateHostsFile :: FileWriter -> KeyRingRuntime -> IO ()
generateHostsFile fw rt      = do
    let hostspath            = pathMaker fw "hosts"
        op                   = KeyRingOperation
             { opFiles       = Map.fromList $
                [ ( HomePub, streaminfo { typ=KeyRingFile, spill=KF_All, access=Pub } )
                , ( ArgFile hostspath, streaminfo { typ=Hosts, spill=KF_None, fill=KF_All, access=Pub } )
                ]
             , opPassphrases = []
             , opHome        = Just $ takeDirectory (rtPubring rt)
             , opTransforms  = []
             , preferredPGPVersion = 4 -- Does not matter (no fill of pgp files).
             }
    KikiResult _ report <- runKeyRing op
    outputReport report

getSshKnownHosts :: Peer -> Char8.ByteString
getSshKnownHosts peer@Peer{kd} = Char8.unlines taggedblobs
  where
    their_master = packet $ keyMappedPacket kd
    sshs :: [Packet]
    sshs         = sortOn (Down . timestamp) $ getSubkeys CrossSigned their_master (keySubKeys $ kd) "ssh-server"
    blobs        = mapMaybe sshblobFromPacketL sshs
    taggedblobs  = do
      n <- allNames $ peerHostnames peer
      map ((coerce n <> " ") <>) blobs

data MyIdentity = MyIdentity {
  myGpgAddress :: SockAddr,
  myGpgKeyGrip :: String
}

installIpsecConf :: FileWriter -> MyIdentity -> [Peer] -> IO ()
installIpsecConf fw MyIdentity{myGpgAddress} cs = do
    snippets <- mapM (coerce . installIpsecPeerCertificate fw) cs
    writeL fw "ipsec.conf" . Char8.unlines
          $ [ "conn %default"
            , "  ikelifetime=60m"
            , "  keylife=20m"
            , "  rekeymargin=3m"
            , "  keyingtries=%forever"
            , "  keyexchange=ikev2"
            , "  dpddelay=10s"
            , "  dpdaction=restart"
            , "  left=%defaultroute"
            , "  leftsubnet=" <> Char8.pack (showA myGpgAddress) <> "/128"
            , "  leftauth=pubkey"
            , "  leftid=" <> Char8.pack (showA myGpgAddress)
            , "  leftsigkey=" <> Char8.pack (showA myGpgAddress) <> ".pem"
            , "  leftikeport=4500"
            , "  rightikeport=4500"
            , "  right=%any"
            , "  rightauth=pubkey"
            , "  type=tunnel"
            , "  auto=route"
            , ""
            ] ++ filter (not . Char8.null) snippets

getMyIdentity :: KeyRingRuntime -> Maybe MyIdentity
getMyIdentity rt = do
    wk <- rtWorkingKey rt
    wkaddr <- gpgipv6addr . getHostnames <$> lookupKeyData (keykey wk) (rtKeyDB rt)
    return $ MyIdentity wkaddr (show $ fingerprint wk)

refreshCache :: KeyRingRuntime -> Maybe FilePath -> IO ()
refreshCache rt rootdir = do
    fw <- getMkPathAndCommit (fromMaybe "" rootdir ++ "/var/cache/kiki/config")
    generateHostsFile fw rt
    fromMaybe (error "No working key.") $ do
    myId <- getMyIdentity rt
    Just $ do

    let exportOp = passphrases <> pemSecrets
                               <> minimalOp False
                                            (CommonArgsParsed (Just $ takeDirectory $ rtPubring rt)
                                                              Nothing
                                                              FingerprintAuto)
         where
          passphrases = mempty { opPassphrases = [PassphraseMemoizer (rtPassphrases rt)] }
          pemSecrets = mempty { opFiles = Map.fromList
            [ send "ipsec"      (ipsecKeyPath myId)    "missing ipsec key?"
            , send "ssh-client" ("root/.ssh/id_rsa")   "missing ssh-client key?"
            , send "ssh-server" ("ssh_host_rsa_key")   "missing ssh host key?"
            , send "tor"        ("tor/private_key")    "missing tor key?"
            ]
          }
          send usage path warning =
            ( ArgFile (pathMaker fw path), StreamInfo { typ = PEMFile
                                       , fill = KF_Match usage
                                       , spill = KF_None
                                       , access = Sec
                                       , initializer = WarnMissing warning
                                       , transforms = []
                                       })
    KikiResult rt' report <- runKeyRing exportOp
    outputReport report
    -- outputReport $ map (first $ resolveForReport ctx) $ filter ((/=ExportedSubkey) . snd) report
    rt'' <- rethrowKikiErrors rt'
    writePublicKeyFiles rt'' fw myId

rethrowKikiErrors :: HasCallStack => KikiCondition a -> IO a
rethrowKikiErrors BadPassphrase =
  error "Operation requires correct passphrase. (Hint: Use --passphrase-fd=0 to input it on stdin.)"
rethrowKikiErrors rt = unconditionally $ return rt

newtype UidHostname = UidHostname Char8.ByteString
newtype ResolvableHostname = ResolvableHostname Char8.ByteString

listPeers :: KeyRingRuntime -> [Peer]
listPeers rt = map (uncurry Peer) . filter notme . mapMaybe namedContact . keyData . rtKeyDB $ rt
  where
    kk = keykey (fromJust $ rtWorkingKey rt)
    notme (_,kd) = keykey (keyPacket kd) /= kk
    namedContact kd = do
      let h = getHostnames kd
      _ <- listToMaybe $ allNames h
      return (h, kd)

writePublicKeyFiles :: KeyRingRuntime -> FileWriter -> MyIdentity -> IO ()
writePublicKeyFiles rt fw myId@(MyIdentity _ grip) = do

    -- Finally, export public keys if they do not exist.
    either warn (write fw "root/.ssh/id_rsa.pub") $ show_ssh' "ssh-client" grip (rtKeyDB rt)
    either warn (write fw "ssh_host_rsa_key.pub") $ show_ssh' "ssh-server" grip (rtKeyDB rt)
    either warn (write fw $ ipsecCertPath myId) $ show_pem' "ipsec" grip (rtKeyDB rt) pemFromPacket

    let cs          = listPeers rt
        known_hosts = L.concat $ map getSshKnownHosts $ cs

    writeL fw "ssh_known_hosts" known_hosts

    installIpsecConf fw myId cs
    fileWriterCommit fw


sshKeyToHostname :: Packet -> Char8.ByteString
sshKeyToHostname sshkey = do
  case rsaKeyFromPacket sshkey of
    Just (RSAKey (MPI n) (MPI e)) -> do
        let blob = SSH.sshrsa e n
            sum = C.hashlazy blob :: C.Digest C.SHA256
        Char8.fromStrict (convertToBase Base16 sum) <> ".ssh-rsa.cryptonomic.net"
    Nothing   -> ""

peerConnectionName :: Peer -> Char8.ByteString
peerConnectionName = coerce . peerAddress

peerCertificateName :: Peer -> Char8.ByteString
peerCertificateName = (<> ".pem") . coerce . peerAddress

peerAddress :: Peer -> Char8.ByteString
peerAddress = Char8.pack . showA . addr

strongswanPeerConfiguration :: Peer -> ResolvableHostname -> Char8.ByteString
strongswanPeerConfiguration peer (ResolvableHostname rightip) = Char8.unlines
    [ "conn "          <> peerConnectionName peer
    , "  right="       <> rightip
    , "  rightsubnet=" <> peerAddress peer <> "/128"
    , "  rightauth=pubkey"
    , "  rightid="     <> peerAddress peer
    , "  rightsigkey=" <> peerCertificateName peer
    ]

-- conn hiotuxliwisbp6mi.onion
--   right=%hiotuxliwisbp6mi.onion.ipv4
--   rightsubnet=fdcc:76c8:cb34:74e6:2aa3:cb39:abc8:d403/128
--   rightauth=pubkey
--   rightid=fdcc:76c8:cb34:74e6:2aa3:cb39:abc8:d403
--   rightrsasigkey=hiotuxliwisbp6mi.onion.pem

showA :: SockAddr -> String
showA addr = if null bracket then pre else drop 1 pre
    where (pre,bracket) = break (==']') (show addr)


pemFromPacket :: Monad m => Packet -> m String
pemFromPacket k = do
    let rsa = pkcs8 . fromJust $ rsaKeyFromPacket k
        der = encodeASN1 DER (toASN1 rsa [])
        qq  = S8.unpack $ convertToBase Base64 (L.toStrict der)
    return $
        writePEM PemPublicKey qq -- ("TODO "++show keyspec)

show_pem :: String -> String -> KeyDB -> IO ()
show_pem keyspec wkgrip db = either warn putStrLn $ show_pem' keyspec wkgrip db pemFromPacket

show_pem' :: String -> String -> KeyDB -> (Packet -> Either String b) -> Either String b
show_pem' keyspec wkgrip db keyfmt = do
    let s = parseSpec wkgrip keyspec
    flip (maybe . Left $ keyspec ++ ": not found")
         (selectPublicKey s db)
         keyfmt

warn :: String -> IO ()
warn str = hPutStrLn stderr str

show_sshfp :: String -> String -> KeyDB -> IO ()
show_sshfp keyspec wkgrip db = do
    let s = parseSpec wkgrip keyspec
    case selectPublicKey s db of
        Nothing -> hPutStrLn stderr $ keyspec ++ ": not found"
        Just k  -> Char8.putStrLn $ sshKeyToHostname k

show_ssh :: String -> String -> KeyDB -> IO ()
show_ssh keyspec wkgrip db = either warn putStrLn $ show_ssh' keyspec wkgrip db

show_ssh' :: String -> String -> KeyDB -> Either String String
show_ssh' keyspec wkgrip db = do
    let s = parseSpec wkgrip keyspec
    flip (maybe . Left $ keyspec ++ ": not found")
         (selectPublicKey s db)
         $ return . sshblobFromPacket

-- |
-- interpolate %var patterns in a string.
interp :: Map.Map String String -> String -> String
interp vars raw = es >>= interp1
 where
    gs = groupBy (\_ c -> c/='%') raw
    es = dropWhile null $ gobbleEscapes ("":gs)
            where gobbleEscapes :: [String] -> [String]
                  gobbleEscapes (a:"%":b:bs) = (a++b) : gobbleEscapes bs
                  gobbleEscapes (g:gs)       = g : gobbleEscapes gs
                  gobbleEscapes []           = []
    interp1 ('%':'(':str) = fromMaybe "" (Map.lookup key vars) ++ drop 1 rest
                            where (key,rest) = break (==')') str
    interp1 plain = plain

sshblobFromPacket :: Packet -> String
sshblobFromPacket k = Char8.unpack $ fromJust $ sshblobFromPacketL k

sshblobFromPacketL :: Packet -> Maybe Char8.ByteString
sshblobFromPacketL k = do
    RSAKey (MPI n) (MPI e) <- rsaKeyFromPacket k
    return $ SSH.keyblob (n,e)

{-
replaceSshServerKeys root cmn = do
    let homepass' = cmn { cap_homespec = fmap root (cap_homespec cmn) }
        replaceSSH op = op { opFiles = files }
            where
                files = Map.adjust delssh HomeSec
                        $ Map.adjust delssh HomePub
                        $ Map.insert (ArgFile $ root "/etc/ssh/ssh_host_rsa_key") strm $ opFiles op
                strm = streaminfo { typ = PEMFile, spill = KF_Match "ssh-server", access = Sec }
                delssh strm = strm { transforms = DeleteSubkeyByUsage "ssh-server" : transforms strm
                                   , fill = KF_All }
    KikiResult r report <- runKeyRing $ minimalOp False homepass'
    case r of
        KikiSuccess rt -> Kiki.refreshCache rt $ case root "" of
                                                    "/" -> Nothing
                                                    ""  -> Nothing
                                                    pth -> Just pth
        err            -> hPutStrLn stderr $ errorString err
-}

slash :: String -> String -> String
slash "/"    ('/':xs) = '/':xs
slash ""     ('/':xs) = '/':xs
slash ""     xs       = '/':xs
slash (y:ys) xs       = y:slash ys xs

dashdashPGPVersion :: Args Word8
dashdashPGPVersion = liftA2 (\is4 is5 -> if is5 then 5 else if is4 then 4 else defaultV) (flag "-4") (flag "-5")
 where
    defaultV = 4 -- Use v4 packets by default for now.


dashdashChroot :: Args (FilePath -> FilePath)
dashdashChroot = pure (\r a -> slash r a) <*> arg "--chroot" <|> pure id

dashdashHomedir :: Args CommonArgsParsed
dashdashHomedir = CommonArgsParsed
                <$> optional (arg "--homedir")
                <*> optional (FileDesc <$> read <$> arg "--passphrase-fd")
                <*> (fromMaybe FingerprintAuto <$> optional (read <$> arg "--fingerprint"))

dashdashCipher :: Args SymmetricAlgorithm
dashdashCipher = fromMaybe CAST5 <$> optional (cipherFromString <$> arg "--cipher")

kikiOptions :: ( [(String,Int)], [String] )
kikiOptions = ( ss, ps )
 where
    ss = [("--chroot",1),("--passphrase-fd",1),("--homedir",1),("--cipher",1)]
    ps = []

verifyFile :: Bool -> CommonArgsParsed -> [FilePath] -> FilePath -> IO ()
verifyFile isHomeless cap keyrings filename = do
    let mop = minimalOp isHomeless cap
    KikiResult r report <- runKeyRing mop
                                { opFiles = opFiles mop
                                    `Map.union` Map.fromList
                                        [ (ArgFile f, strm { access = Pub }) | f <- keyrings ]
                                }
    case r of
        KikiSuccess rt -> go rt
        err            -> hPutStrLn stderr $ errorString err
 where
    go :: KeyRingRuntime -> IO ()
    go rt = do
        bs <- L.readFile filename
        case ASCIIArmor.decodeLazy bs of
            Right (ClearSigned hashes txt (Armor ArmorSignature _ sig):_) ->
                case parsePackets sig of
                    Right sigs -> do
                        let over = DataSignature lit sigs
                            lit = LiteralDataPacket
                                    { format    = error "format" :: Char -- TODO
                                    , filename  = filename
                                    , timestamp = error "timestamp" :: Word32 -- TODO
                                    , content   = txt
                                    }
                            -- TODO: Remove this take 1 after optimizing 'candidateSignerKeys'
                            tentativeTake1 xs = take 1 xs
                            keys = concatMap (candidateSignerKeys (rtKeyDB rt)) $ tentativeTake1 sigs
                            good = verify (Message keys) over
                        putStrLn $ unwords
                            [ "verifyFile:"
                            , show (length $ signatures_over good)
                            , "good of"
                            , show (length $ signatures_over over)
                            , "signatures."
                            ]
                        -- when (null (signatures_over good)) $ do
                        --    L.putStrLn txt
                    rs -> do
                        hPutStrLn stderr $ show rs
            _ -> do
                hPutStrLn stderr "Unsupported file format."

signFile :: Bool -> CommonArgsParsed -> [FilePath] -> String -> FilePath -> IO ()
signFile isHomeless cap keyrings keyid filename = do
    let mop = minimalOp isHomeless cap
    KikiResult r report <- runKeyRing mop
                                { opFiles = opFiles mop
                                    `Map.union` Map.fromList
                                        [ (ArgFile f, strm { access = Sec }) | f <- keyrings ]
                                }
    case r of
        KikiSuccess rt -> go rt
        err            -> hPutStrLn stderr $ errorString err
 where
    go :: KeyRingRuntime -> IO ()
    go rt = do
        tm <- modificationTime <$> getFileStatus filename
        bs <- L.readFile filename
        let hashed = [] -- TODO: FingerprintPacket
            unhashed = [IssuerPacket keyid]
            lit = LiteralDataPacket
                    { format = 'b' -- b:binary, t:text, u:utf8
                    , filename  = filename
                    , timestamp = fromTime tm -- seconds since Jan 1, 1970 UTC
                    , content = bs
                    }
            hash = SHA512
        case smallprGrip keyid of
            Nothing -> hPutStrLn stderr "Bad keygrip."
            Just grip -> do
                let keydata = lookupByGrip grip (rtKeyDB rt)
                case keydata of
                    [] -> hPutStrLn stderr "No matching key."
                    (k,_):_ -> rtPassphrases rt (Unencrypted,S2K 100 "") k >>= \case
                        KikiSuccess un -> do
                            mb <- pgpSign (Message [un]) (DataSignature lit []) hash keyid
                            case mb of
                                Nothing -> hPutStrLn stderr "Failed to make signature."
                                Just o -> do
                                    putStrLn $ "Using "++show (fingerprint un)++" to write " <> filename <> ".sig"
                                    let sigs = map (\sig -> sig { unhashed_subpackets = unhashed }) (signatures_over o)
                                    L.writeFile (filename <> ".sig") $ L.concat $ map encode sigs
                        err -> hPutStrLn stderr $ errorString err

parsePackets :: L.ByteString -> Either String [Packet]
parsePackets bs = case decodeOrFail bs of
                Left  (more,off,er)  -> Left er
                Right (more,off,pkt) -> do
                    if (more/=L.empty) then parsePackets more >>= \pkts -> Right (pkt : pkts)
                                       else Right [pkt]