-- Keyring.hs: OpenPGP (RFC4880) transferable keys parsing
-- Copyright © 2012-2013  Clint Adams
-- This software is released under the terms of the Expat license.
-- (See the LICENSE file).

module Data.Conduit.OpenPGP.Keyring (
   conduitToTKs
 , conduitToTKsDropping
 , sinkKeyringMap
) where

import qualified Data.ByteString as B
import Data.Conduit
import qualified Data.Conduit.List as CL
import Data.IxSet (empty, insert)

import Codec.Encryption.OpenPGP.Types
import Data.Conduit.OpenPGP.Keyring.Instances ()

data Phase = MainKey | Revs | Uids | UAts | Subs
    deriving (Eq, Ord, Show)

conduitToTKs :: MonadResource m => Conduit Pkt m TK
conduitToTKs = conduitToTKs' True

conduitToTKsDropping :: MonadResource m => Conduit Pkt m TK
conduitToTKsDropping = conduitToTKs' False

fakecmAccum :: Monad m => (a -> (Phase, Maybe TK) -> ((Phase, Maybe TK), [TK])) -> (Phase, Maybe TK) -> Conduit a m TK
fakecmAccum f =
    loop
  where
    loop accum =
        await >>= maybe (finalyield accum) go
      where
        go a = do
            let (accum', bs) = f a accum
            Prelude.mapM_ yield bs
            loop accum'
        finalyield = maybe (return ()) yield . snd

conduitToTKs' :: MonadResource m => Bool -> Conduit Pkt m TK
conduitToTKs' intolerant = fakecmAccum push (MainKey, Nothing)
    where
        push i s = case (s, i) of
                       ((MainKey, _), PublicKeyPkt pkp) -> ((Revs, Just (TK pkp Nothing [] [] [] [])), [])
                       ((MainKey, _), SecretKeyPkt pkp ska) -> ((Revs, Just (TK pkp (Just ska) [] [] [] [])), [])
                       ((Revs, Just (TK pkp Nothing revs uids uats subs)), SignaturePkt sp) -> ((Revs, Just (TK pkp Nothing (revs ++ [sp]) uids uats subs)), [])
                       ((Revs, Just (TK pkp Nothing revs _ uats subs)), UserIdPkt u) -> ((Uids, Just (TK pkp Nothing revs [(u, [])] uats subs)), [])
                       ((Uids, Just (TK pkp Nothing revs uids uats subs)), SignaturePkt sp) -> ((Uids, Just (TK pkp Nothing revs (addUidSig sp uids) uats subs)), [])
                       ((Uids, Just (TK pkp Nothing revs uids uats subs)), UserIdPkt u) -> ((Uids, Just (TK pkp Nothing revs (uids ++ [(u, [])]) uats subs)), [])
                       ((Uids, Just (TK pkp Nothing revs uids _ subs)), UserAttributePkt u) -> ((UAts, Just (TK pkp Nothing revs uids [(u, [])] subs)), [])
                       ((Uids, Just (TK pkp Nothing revs uids uats _)), PublicSubkeyPkt p) -> ((Subs, Just (TK pkp Nothing revs uids uats [(PublicSubkeyPkt p, SigVOther 0 B.empty, Nothing)])), [])
                       ((Uids, Just (TK pkp Nothing revs uids uats subs)), PublicKeyPkt p) -> ((Revs, Just (TK p Nothing [] [] [] [])), [TK pkp Nothing revs uids uats subs])
                       ((UAts, Just (TK pkp Nothing revs uids uats subs)), SignaturePkt sp) -> ((UAts, Just (TK pkp Nothing revs uids (addUAtSig sp uats) subs)), [])
                       ((UAts, Just (TK pkp Nothing revs uids uats subs)), UserAttributePkt u) -> ((UAts, Just (TK pkp Nothing revs uids (uats ++ [(u, [])]) subs)), [])
                       ((UAts, Just (TK pkp Nothing revs uids uats subs)), UserIdPkt u) -> ((Uids, Just (TK pkp Nothing revs (uids ++ [(u, [])]) uats subs)), [])
                       ((UAts, Just (TK pkp Nothing revs uids uats _)), PublicSubkeyPkt p) -> ((Subs, Just (TK pkp Nothing revs uids uats [(PublicSubkeyPkt p, SigVOther 0 B.empty, Nothing)])), [])
                       ((UAts, Just (TK pkp Nothing revs uids uats subs)), PublicKeyPkt p) -> ((Revs, Just (TK p Nothing [] [] [] [])), [TK pkp Nothing revs uids uats subs])
                       ((Subs, Just (TK pkp Nothing revs uids uats subs)), PublicSubkeyPkt p) -> ((Subs, Just (TK pkp Nothing revs uids uats (subs ++ [(PublicSubkeyPkt p, SigVOther 0 B.empty, Nothing)]))), [])
                       ((Subs, Just (TK pkp Nothing revs uids uats subs)), SignaturePkt sp) -> case sType sp of
                                                                                SubkeyBindingSig -> ((Subs, Just (TK pkp Nothing revs uids uats (setBSig sp subs))), [])
                                                                                SubkeyRevocationSig -> ((Subs, Just (TK pkp Nothing revs uids uats (setRSig sp subs))), [])
                                                                                _ -> dropOrError intolerant s $ "Unexpected subkey sig: " ++ show (fst s) ++ "/" ++ show i
                       ((Subs, Just (TK pkp Nothing revs uids uats subs)), PublicKeyPkt p) -> ((Revs, Just (TK p Nothing [] [] [] [])), [TK pkp Nothing revs uids uats subs])
                       ((Revs, Just (TK pkp mska revs uids uats subs)), SignaturePkt sp) -> ((Revs, Just (TK pkp mska (revs ++ [sp]) uids uats subs)), [])
                       ((Revs, Just (TK pkp mska revs _ uats subs)), UserIdPkt u) -> ((Uids, Just (TK pkp mska revs [(u, [])] uats subs)), [])
                       ((Uids, Just (TK pkp mska revs uids uats subs)), SignaturePkt sp) -> ((Uids, Just (TK pkp mska revs (addUidSig sp uids) uats subs)), [])
                       ((Uids, Just (TK pkp mska revs uids uats subs)), UserIdPkt u) -> ((Uids, Just (TK pkp mska revs (uids ++ [(u, [])]) uats subs)), [])
                       ((Uids, Just (TK pkp mska revs uids _ subs)), UserAttributePkt u) -> ((UAts, Just (TK pkp mska revs uids [(u, [])] subs)), [])
                       ((Uids, Just (TK pkp mska revs uids uats _)), SecretSubkeyPkt p ss) -> ((Subs, Just (TK pkp mska revs uids uats [(SecretSubkeyPkt p ss, SigVOther 0 B.empty, Nothing)])), [])
                       ((Uids, Just (TK pkp mska revs uids uats subs)), SecretKeyPkt p sk) -> ((Revs, Just (TK p (Just sk) [] [] [] [])), [TK pkp mska revs uids uats subs])
                       ((UAts, Just (TK pkp mska revs uids uats subs)), SignaturePkt sp) -> ((UAts, Just (TK pkp mska revs uids (addUAtSig sp uats) subs)), [])
                       ((UAts, Just (TK pkp mska revs uids uats subs)), UserAttributePkt u) -> ((UAts, Just (TK pkp mska revs uids (uats ++ [(u, [])]) subs)), [])
                       ((UAts, Just (TK pkp mska revs uids uats subs)), UserIdPkt u) -> ((Uids, Just (TK pkp mska revs (uids ++ [(u, [])]) uats subs)), [])
                       ((UAts, Just (TK pkp mska revs uids uats _)), SecretSubkeyPkt p ss) -> ((Subs, Just (TK pkp mska revs uids uats [(SecretSubkeyPkt p ss, SigVOther 0 B.empty, Nothing)])), [])
                       ((UAts, Just (TK pkp mska revs uids uats subs)), SecretKeyPkt p ss) -> ((Revs, Just (TK p (Just ss) [] [] [] [])), [TK pkp mska revs uids uats subs])
                       ((Subs, Just (TK pkp mska revs uids uats subs)), SecretSubkeyPkt p ss) -> ((Subs, Just (TK pkp mska revs uids uats (subs ++ [(SecretSubkeyPkt p ss, SigVOther 0 B.empty, Nothing)]))), [])
                       ((Subs, Just (TK pkp mska revs uids uats subs)), SignaturePkt sp) -> case sType sp of
                                                                                SubkeyBindingSig -> ((Subs, Just (TK pkp mska revs uids uats (setBSig sp subs))), [])
                                                                                SubkeyRevocationSig -> ((Subs, Just (TK pkp mska revs uids uats (setRSig sp subs))), [])
                                                                                _ -> dropOrError intolerant s $ "Unexpected subkey sig: " ++ show (fst s) ++ "/" ++ show i
                       ((Subs, Just (TK pkp mska revs uids uats subs)), SecretKeyPkt p sk) -> ((Revs, Just (TK p (Just sk) [] [] [] [])), [TK pkp mska revs uids uats subs])
                       ((_,_), TrustPkt _) -> (s, [])
                       _ -> dropOrError intolerant s $ "Unexpected packet: " ++ show (fst s) ++ "/" ++ show i
        addUidSig s uids = init uids ++ [(\(u, us) -> (u, us ++ [s])) (last uids)]
        addUAtSig s uats = init uats ++ [(\(u, us) -> (u, us ++ [s])) (last uats)]
        setBSig s subs = init subs ++ [(\(p, _, r) -> (p, s, r)) (last subs)]
        setRSig s subs = init subs ++ [(\(p, b, _) -> (p, b, Just s)) (last subs)]
        sType (SigV3 st _ _ _ _ _ _) = st
        sType (SigV4 st _ _ _ _ _ _) = st
        sType _ = error "This should never happen."
        dropOrError :: Bool -> (Phase, Maybe TK) -> String -> ((Phase, Maybe TK), [TK])
        dropOrError True _ e = error e
        dropOrError False s _ = (s, [])

sinkKeyringMap :: MonadResource m => Sink TK m Keyring
sinkKeyringMap = CL.fold (flip insert) empty