Implement Sapling spends (#42)

This PR add support for Sapling spends in the communication with Zebra.

Reviewed-on: #42
Co-authored-by: Rene Vergara <rene@vergara.network>
Co-committed-by: Rene Vergara <rene@vergara.network>

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [0.5.1.0]
 
+### Added
+
+- Functionality to capture Sapling Spends
+
 ### Changed
 
 - Modified the `makeZebraCall` function to handle errors explicitly

src/ZcashHaskell/Sapling.hs

@@ -90,11 +90,13 @@ instance FromJSON RawTxResponse where
       ht <- obj .: "height"
       c <- obj .: "confirmations"
       b <- obj .: "blocktime"
+      sSpend <- obj .: "vShieldedSpend"
       case o of
-        Nothing -> pure $ RawTxResponse i h (getShieldedOutputs h) [] ht c b
+        Nothing ->
+          pure $ RawTxResponse i h sSpend (getShieldedOutputs h) [] ht c b
         Just o' -> do
           a <- o' .: "actions"
-          pure $ RawTxResponse i h (getShieldedOutputs h) a ht c b
+          pure $ RawTxResponse i h sSpend (getShieldedOutputs h) a ht c b
 
 -- | Attempts to obtain a sapling SpendingKey using a HDSeed
 genSaplingSpendingKey :: Seed -> CoinType -> Int -> Maybe SaplingSpendingKey

src/ZcashHaskell/Types.hs

@@ -207,6 +207,7 @@ instance FromJSON BlockResponse where
 data RawTxResponse = RawTxResponse
   { rt_id :: !HexString
   , rt_hex :: !HexString
+  , rt_shieldedSpends :: ![ShieldedSpend]
   , rt_shieldedOutputs :: ![BS.ByteString]
   , rt_orchardActions :: ![OrchardAction]
   , rt_blockheight :: !Integer
@@ -283,6 +284,30 @@ newtype SaplingReceiver =
 instance ToBytes SaplingReceiver where
   getBytes (SaplingReceiver s) = s
 
+-- | Type to represent a Sapling Shielded Spend as provided by the @getrawtransaction@ RPC method
+data ShieldedSpend = ShieldedSpend
+  { sp_cv :: !HexString
+  , sp_anchor :: !HexString
+  , sp_nullifier :: !HexString
+  , sp_rk :: !HexString
+  , sp_proof :: !HexString
+  , sp_auth :: !HexString
+  } deriving stock (Eq, Prelude.Show, GHC.Generic, Read)
+    deriving anyclass (SOP.Generic, SOP.HasDatatypeInfo)
+    deriving anyclass (Data.Structured.Show)
+    deriving (BorshSize, ToBorsh, FromBorsh) via AsStruct ShieldedSpend
+
+instance FromJSON ShieldedSpend where
+  parseJSON =
+    withObject "ShieldedSpend" $ \obj -> do
+      cv <- obj .: "cv"
+      anchor <- obj .: "anchor"
+      nullifier <- obj .: "nullifier"
+      rk <- obj .: "rk"
+      p <- obj .: "proof"
+      sig <- obj .: "spendAuthSig"
+      pure $ ShieldedSpend cv anchor nullifier rk p sig
+
 -- | Type to represent a Sapling Shielded Output as provided by the @getrawtransaction@ RPC method of @zcashd@.
 data ShieldedOutput = ShieldedOutput
   { s_cv :: !HexString -- ^ Value commitment to the input note