-- Copyright (C) 2013, 2014  Fraser Tweedale
--
-- Licensed under the Apache License, Version 2.0 (the "License");
-- you may not use this file except in compliance with the License.
-- You may obtain a copy of the License at
--
--      http://www.apache.org/licenses/LICENSE-2.0
--
-- Unless required by applicable law or agreed to in writing, software
-- distributed under the License is distributed on an "AS IS" BASIS,
-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-- See the License for the specific language governing permissions and
-- limitations under the License.

{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE TypeFamilies #-}

{-|

A JSON Web Key (JWK) is a JavaScript Object Notation (JSON) data
structure that represents a cryptographic key.  This module also
defines a JSON Web Key Set (JWK Set) JSON data structure for
representing a set of JWKs.

-}
module Crypto.JOSE.JWK
  (
    JWK(JWK)
  , jwkMaterial
  , jwkUse
  , jwkKeyOps
  , jwkAlg
  , jwkKid
  , jwkX5u
  , jwkX5c
  , jwkX5t
  , jwkX5tS256

  , JWKSet(..)

  , module Crypto.JOSE.JWA.JWK
  ) where

import Control.Applicative
import Data.Bifunctor
import Data.Maybe (catMaybes)

import Control.Lens hiding ((.=))
import Data.Aeson

import Crypto.JOSE.Classes
import qualified Crypto.JOSE.JWA.JWE.Alg as JWA.JWE
import Crypto.JOSE.JWA.JWK
import qualified Crypto.JOSE.JWA.JWS as JWA.JWS
import qualified Crypto.JOSE.TH
import qualified Crypto.JOSE.Types as Types
import qualified Crypto.JOSE.Types.Internal as Types


-- | JWK §3.3.  "alg" (Algorithm) Parameter
--
data Alg = JWSAlg JWA.JWS.Alg | JWEAlg JWA.JWE.Alg
  deriving (Eq, Show)

instance FromJSON Alg where
  parseJSON v = (JWSAlg <$> parseJSON v) <|> (JWEAlg <$> parseJSON v)

instance ToJSON Alg where
  toJSON (JWSAlg alg) = toJSON alg
  toJSON (JWEAlg alg) = toJSON alg


-- | JWK §3.3.  "key_ops" (Key Operations) Parameter
--
$(Crypto.JOSE.TH.deriveJOSEType "KeyOp"
  [ "sign", "verify", "encrypt", "decrypt"
  , "wrapKey", "unwrapKey", "deriveKey", "deriveBits"
  ])


-- | JWK §3.2.  "use" (Public Key Use) Parameter
--
$(Crypto.JOSE.TH.deriveJOSEType "KeyUse" ["sig", "enc"])


-- | JWK §3.  JSON Web Key (JWK) Format
--
data JWK = JWK
  {
    _jwkMaterial :: Crypto.JOSE.JWA.JWK.KeyMaterial
  , _jwkUse :: Maybe KeyUse
  , _jwkKeyOps :: Maybe [KeyOp]
  , _jwkAlg :: Maybe Alg
  , _jwkKid :: Maybe String
  , _jwkX5u :: Maybe Types.URI
  , _jwkX5c :: Maybe [Types.Base64X509]
  , _jwkX5t :: Maybe Types.Base64SHA1
  , _jwkX5tS256 :: Maybe Types.Base64SHA256
  }
  deriving (Eq, Show)
makeLenses ''JWK

instance FromJSON JWK where
  parseJSON = withObject "JWK" $ \o -> JWK
    <$> parseJSON (Object o)
    <*> o .:? "use"
    <*> o .:? "key_ops"
    <*> o .:? "alg"
    <*> o .:? "kid"
    <*> o .:? "x5u"
    <*> o .:? "x5c"
    <*> o .:? "x5t"
    <*> o .:? "x5t#S256"

instance ToJSON JWK where
  toJSON (JWK {..}) = object $ catMaybes
    [ fmap ("alg" .=) _jwkAlg
    , fmap ("use" .=) _jwkUse
    , fmap ("key_ops" .=) _jwkKeyOps
    , fmap ("kid" .=) _jwkKid
    , fmap ("x5u" .=) _jwkX5u
    , fmap ("x5c" .=) _jwkX5c
    , fmap ("x5t" .=) _jwkX5t
    , fmap ("x5t#S256" .=) _jwkX5tS256
    ]
    ++ Types.objectPairs (toJSON _jwkMaterial)

instance Key JWK where
  type KeyGenParam JWK = Crypto.JOSE.JWA.JWK.KeyMaterialGenParam
  type KeyContent JWK = Crypto.JOSE.JWA.JWK.KeyMaterial
  gen p = first fromKeyContent . gen p
  fromKeyContent k = JWK k z z z z z z z z where z = Nothing
  public = jwkMaterial public
  sign h k = sign h $ k ^. jwkMaterial
  verify h k = verify h $ k ^. jwkMaterial


-- | JWK §4.  JSON Web Key Set (JWK Set) Format
--
newtype JWKSet = JWKSet [JWK] deriving (Eq, Show)

instance FromJSON JWKSet where
  parseJSON = withObject "JWKSet" (\o -> JWKSet <$> o .: "keys")