From 0e6f7503d4947e57b657e93210a2cec9737f28d9 Mon Sep 17 00:00:00 2001
From: "Rene V. Vergara" <rvergara59@protonmail.com>
Date: Tue, 5 Mar 2024 22:10:05 -0500
Subject: [PATCH] Sapling Extended Spemding Key generation from HDSedd (64 byte
 array)

---
 librustzcash-wrapper/Cargo.lock |  1 +
 librustzcash-wrapper/Cargo.toml |  1 +
 librustzcash-wrapper/src/lib.rs | 35 ++++++++++++++++++++-------------
 src/ZcashHaskell/Sapling.hs     | 15 ++++++--------
 test/Spec.hs                    | 18 ++++++++++-------
 5 files changed, 40 insertions(+), 30 deletions(-)

diff --git a/librustzcash-wrapper/Cargo.lock b/librustzcash-wrapper/Cargo.lock
index 7f59103..bc4b733 100644
--- a/librustzcash-wrapper/Cargo.lock
+++ b/librustzcash-wrapper/Cargo.lock
@@ -1314,6 +1314,7 @@ dependencies = [
  "borsh 0.10.3",
  "f4jumble",
  "haskell-ffi",
+ "nom",
  "orchard 0.7.1",
  "proc-macro2",
  "zcash_address 0.2.0",
diff --git a/librustzcash-wrapper/Cargo.toml b/librustzcash-wrapper/Cargo.toml
index 9c8f966..d7b2495 100644
--- a/librustzcash-wrapper/Cargo.toml
+++ b/librustzcash-wrapper/Cargo.toml
@@ -17,6 +17,7 @@ zcash_primitives = "0.13.0"
 zcash_client_backend = "0.10.0"
 zip32 = "0.1.0"
 proc-macro2 = "1.0.66"
+nom = "7.1.3"
 
 [features]
 capi = []
diff --git a/librustzcash-wrapper/src/lib.rs b/librustzcash-wrapper/src/lib.rs
index bfb2794..8963325 100644
--- a/librustzcash-wrapper/src/lib.rs
+++ b/librustzcash-wrapper/src/lib.rs
@@ -49,7 +49,11 @@ use zcash_address::{
     ZcashAddress
 };
 
-use zcash_client_backend::keys::{sapling, sapling::ExtendedFullViewingKey};
+use zcash_client_backend::keys::{
+    sapling, 
+    sapling::ExtendedFullViewingKey,
+    sapling::ExtendedSpendingKey};
+
 use zcash_primitives::zip32::AccountId;
 use std::slice;
 
@@ -615,24 +619,27 @@ pub extern "C" fn rust_wrapper_recover_seed(
 
 #[no_mangle]
 pub extern "C" fn rust_wrapper_sapling_spendingkey(
-    in_seed: *const u8,
-    seed_len: usize,
+    iseed: *const u8,
+    iseed_len: usize,
     coin_type: u32,
     acc_id: u32,
     out: *mut u8,
     out_len: &mut usize
     ){
-    let seed: Vec<u8> = marshall_from_haskell_var(in_seed, input_len, RW);
-    let fake_response = "It's working";
-    marshall_to_haskell_var(&fake_response.as_bytes().to_vec(), out, out_len, RW);
-
-//    let extsk  = sapling::spending_key(&seed[0..32], 
-//                                      cointype, 
-//                                      accountid);
-//    println!("SpendingKey -> {:?}", extsk);
-//    let s = extsk.to_bytes(); 
-//    let xsk : Vec<u8> =  s.iter().cloned().collect();
-//    marshall_to_haskell_var(&xsk, out, out_len, RW);
+        println!("From Rust\n=========");
+    let seed: Vec<u8> = marshall_from_haskell_var(iseed, iseed_len, RW);
+    if  ( seed.len() <= 0 ) {
+        println!("Seed error, returning a null vector...");
+        marshall_to_haskell_var(&vec![0], out, out_len, RW);
+    } else {
+        println!("Seed in rust : {:?}\n", seed);
+        println!("Coin Type -> {}\nAccount Id -> {}",coin_type,acc_id);
+        let su8 = &seed;
+        let seedu8 : &[u8] = &su8;
+        let extsk: ExtendedSpendingKey = sapling::ExtendedSpendingKey::master(&seedu8); 
+        let extsk_bytes = extsk.to_bytes().to_vec(); 
+        marshall_to_haskell_var(&extsk_bytes, out, out_len, RW);
+    }
 }
 
 #[no_mangle]
diff --git a/src/ZcashHaskell/Sapling.hs b/src/ZcashHaskell/Sapling.hs
index d32668e..c34314c 100644
--- a/src/ZcashHaskell/Sapling.hs
+++ b/src/ZcashHaskell/Sapling.hs
@@ -41,6 +41,8 @@ import ZcashHaskell.Types
   , SaplingSKeyParams(..)
   , ShieldedOutput(..)
   , decodeHexText
+  , AccountId 
+  , CoinType
   )
 import ZcashHaskell.Utils
 
@@ -88,14 +90,9 @@ instance FromJSON RawTxResponse where
         Just o' -> do
           a <- o' .: "actions"
           pure $ RawTxResponse i h (getShieldedOutputs h) a ht c b
-
+--
 -- | Attempts to obtain a sapling SpendinKey using a HDSeed, a Coin Type and an Account ID
-genSaplingSpendingKey :: BS.ByteString -> Word32 -> Word32 -> Maybe BS.ByteString
+genSaplingSpendingKey :: BS.ByteString -> Word32-> AccountId -> BS.ByteString
 genSaplingSpendingKey seed coin_type account_id = do
-  if BS.length res > 0
-    then Just res
-    else Nothing
-  where
-    res =
-      withPureBorshVarBuffer
-        (rustWrapperSaplingSpendingkey seed coin_type account_id)
+      let res = withPureBorshVarBuffer (rustWrapperSaplingSpendingkey seed (fromIntegral coin_type) (fromIntegral account_id) )
+      res
\ No newline at end of file
diff --git a/test/Spec.hs b/test/Spec.hs
index 9f85b03..abfd17c 100644
--- a/test/Spec.hs
+++ b/test/Spec.hs
@@ -57,6 +57,9 @@ import ZcashHaskell.Types
   , UnifiedAddress(..)
   , UnifiedFullViewingKey(..)
   , decodeHexText
+  , AccountId
+  , CoinType
+  , getValue
   )
 import ZcashHaskell.Utils
 
@@ -528,10 +531,11 @@ main = do
                    241, 243, 172, 178,
                    104, 81, 159, 144
                   ] :: [Word8]
-          let coin  = 1 :: Word32
-          let account = 0 :: Word32
-          let msg = genSaplingSpendingKey (word8ArrayToByteString hdseed) coin account
-          case msg of
-              Nothing -> "Bad response from genSapingSpendingKey"
-              Just msg -> fromMaybe "BadResponse" msg
-          "mm " `shouldBe` "genSaplingSpendingKey Function called."
\ No newline at end of file
+          let cointype  =  getValue TestNetCoin
+          let account = 0 :: AccountId
+          let msg = genSaplingSpendingKey (word8ArrayToByteString hdseed) cointype account
+          let msgArr = BS.unpack msg
+          if (length msgArr) == 169
+                  then True
+                  else False
+--          msgArr `shouldBe` "It's working."
\ No newline at end of file