WIP id and recover spark coin

lib/flutter_libsparkmobile.dart

@@ -88,18 +88,57 @@ abstract final class LibSpark {
     String serializedCoin, {
     required String privateKeyHex,
     required int index,
+    bool isTestNet = false,
   }) {
-    final result = _bindings.identifyCoin(
+    final result = _bindings.idAndRecoverCoin(
       serializedCoin.toNativeUtf8().cast<Char>(),
       serializedCoin.length,
       privateKeyHex.toNativeUtf8().cast<Char>(),
       index,
+      isTestNet ? 1 : 0,
     );
 
-    throw UnimplementedError(
-      "Have ffi return all the data we need for SparkCoin."
-      " This may or may not encompass all fields currently in SparkCoin.",
+    final LibSparkCoinType coinType;
+    switch (result.ref.type) {
+      case 0:
+        coinType = LibSparkCoinType.mint;
+        break;
+      case 1:
+        coinType = LibSparkCoinType.mint;
+        break;
+      default:
+        throw Exception("Unknown coin type \"${result.ref.type}\" found.");
+    }
+
+    final ret = LibSparkCoin(
+      type: coinType,
+      nonce: result.ref.nonce.toUint8List(result.ref.nonceLength),
+      address: result.ref.address.cast<Utf8>().toDartString(),
+      value: BigInt.from(result.ref.value),
+      memo: result.ref.memo.cast<Utf8>().toDartString(),
+      diversifier: BigInt.from(result.ref.diversifier),
+      encryptedDiversifier:
+          result.ref.serial.toUint8List(result.ref.encryptedDiversifierLength),
+      serial: result.ref.serial.toUint8List(result.ref.serialLength),
+      lTagHash: result.ref.lTagHash.cast<Utf8>().toDartString(),
     );
+
+    malloc.free(result.ref.address);
+    malloc.free(result.ref.memo);
+    malloc.free(result.ref.lTagHash);
+    malloc.free(result.ref.encryptedDiversifier);
+    malloc.free(result.ref.nonce);
+    malloc.free(result.ref.serial);
+    malloc.free(result);
+
+    return ret;
+  }
+}
+
+extension on Pointer<UnsignedChar> {
+  Uint8List toUint8List(int length) {
+    // TODO needs free?
+    return Uint8List.fromList(cast<Uint8>().asTypedList(length));
   }
 }
 

lib/src/flutter_libsparkmobile_bindings_generated.dart

@@ -72,6 +72,34 @@ class FlutterLibsparkmobileBindings {
       CIdentifiedCoinData Function(
           ffi.Pointer<ffi.Char>, int, ffi.Pointer<ffi.Char>, int)>();
 
+  ffi.Pointer<AggregateCoinData> idAndRecoverCoin(
+    ffi.Pointer<ffi.Char> serializedCoin,
+    int serializedCoinLength,
+    ffi.Pointer<ffi.Char> keyDataHex,
+    int index,
+    int isTestNet,
+  ) {
+    return _idAndRecoverCoin(
+      serializedCoin,
+      serializedCoinLength,
+      keyDataHex,
+      index,
+      isTestNet,
+    );
+  }
+
+  late final _idAndRecoverCoinPtr = _lookup<
+      ffi.NativeFunction<
+          ffi.Pointer<AggregateCoinData> Function(
+              ffi.Pointer<ffi.Char>,
+              ffi.Int,
+              ffi.Pointer<ffi.Char>,
+              ffi.Int,
+              ffi.Int)>>('idAndRecoverCoin');
+  late final _idAndRecoverCoin = _idAndRecoverCoinPtr.asFunction<
+      ffi.Pointer<AggregateCoinData> Function(
+          ffi.Pointer<ffi.Char>, int, ffi.Pointer<ffi.Char>, int, int)>();
+
   /// FFI-friendly wrapper for spark::createSparkMintRecipients.
   ///
   /// createSparkMintRecipients: https://github.com/firoorg/sparkmobile/blob/8bf17cd3deba6c3b0d10e89282e02936d7e71cdd/src/spark.cpp#L43
@@ -396,3 +424,36 @@ final class OutputScript extends ffi.Struct {
   @ffi.Int()
   external int length;
 }
+
+/// Aggregate data structure to handle passing spark mint/spend data across FFI
+final class AggregateCoinData extends ffi.Struct {
+  @ffi.Char()
+  external int type;
+
+  @ffi.Uint64()
+  external int diversifier;
+
+  @ffi.Uint64()
+  external int value;
+
+  external ffi.Pointer<ffi.Char> address;
+
+  external ffi.Pointer<ffi.Char> memo;
+
+  external ffi.Pointer<ffi.Char> lTagHash;
+
+  external ffi.Pointer<ffi.UnsignedChar> encryptedDiversifier;
+
+  @ffi.Int()
+  external int encryptedDiversifierLength;
+
+  external ffi.Pointer<ffi.UnsignedChar> serial;
+
+  @ffi.Int()
+  external int serialLength;
+
+  external ffi.Pointer<ffi.UnsignedChar> nonce;
+
+  @ffi.Int()
+  external int nonceLength;
+}

lib/src/models/spark_coin.dart

@@ -11,7 +11,7 @@ enum LibSparkCoinType {
 class LibSparkCoin {
   final LibSparkCoinType type;
 
-  final Uint8List? k; // TODO: proper name (not single char!!) is this nonce???
+  final Uint8List? nonce;
 
   final String? address;
 
@@ -26,11 +26,11 @@ class LibSparkCoin {
   final Uint8List? serial;
   final Uint8List? tag;
 
-  final Uint8List? lTagHash;
+  final String? lTagHash;
 
   LibSparkCoin({
     required this.type,
-    this.k,
+    this.nonce,
     this.address,
     this.value,
     this.memo,
@@ -44,7 +44,7 @@ class LibSparkCoin {
 
   LibSparkCoin copyWith({
     LibSparkCoinType? type,
-    Uint8List? k,
+    Uint8List? nonce,
     String? address,
     BigInt? value,
     String? memo,
@@ -53,11 +53,11 @@ class LibSparkCoin {
     Uint8List? encryptedDiversifier,
     Uint8List? serial,
     Uint8List? tag,
-    Uint8List? lTagHash,
+    String? lTagHash,
   }) {
     return LibSparkCoin(
       type: type ?? this.type,
-      k: k ?? this.k,
+      nonce: nonce ?? this.nonce,
       address: address ?? this.address,
       value: value ?? this.value,
       memo: memo ?? this.memo,
@@ -74,7 +74,7 @@ class LibSparkCoin {
   String toString() {
     return 'LibSparkCoin('
         ', type: $type'
-        ', k: $k'
+        ', k: $nonce'
         ', address: $address'
         ', value: $value'
         ', memo: $memo'

src/flutter_libsparkmobile.cpp

@@ -61,6 +61,63 @@ CIdentifiedCoinData identifyCoin(const char* serializedCoin, int serializedCoinL
     }
 }
 
+FFI_PLUGIN_EXPORT
+AggregateCoinData* idAndRecoverCoin(
+        const char* serializedCoin,
+        int serializedCoinLength,
+        const char* keyDataHex,
+        int index,
+        int isTestNet) {
+    try {
+        spark::Coin coin = deserializeCoin(serializedCoin, serializedCoinLength);
+
+        // Derive the incoming view key from the key data and index.
+        spark::SpendKey spendKey = createSpendKeyFromData(keyDataHex, index);
+        spark::FullViewKey fullViewKey(spendKey);
+        spark::IncomingViewKey incomingViewKey(fullViewKey);
+
+        spark::IdentifiedCoinData identifiedCoinData = coin.identify(incomingViewKey);
+
+        spark::RecoveredCoinData data = coin.recover(fullViewKey, identifiedCoinData);
+
+        spark::Address address = getAddress(incomingViewKey, identifiedCoinData.i);
+        std::string addressString = address.encode(isTestNet ? spark::ADDRESS_NETWORK_TESTNET : spark::ADDRESS_NETWORK_MAINNET);
+
+        AggregateCoinData* result = (AggregateCoinData*)malloc(sizeof(AggregateCoinData));
+
+        result->type = coin.type;
+        result->diversifier = identifiedCoinData.i;
+        result->value = identifiedCoinData.v;
+
+        result->address = (char*)malloc((addressString.length() + 1) * sizeof(char));
+        std::strcpy(result->address, addressString.c_str());
+
+        result->memo = (char*)malloc((identifiedCoinData.memo.length() + 1) * sizeof(char));
+        std::strcpy(result->memo, identifiedCoinData.memo.c_str());
+
+        uint256 lTagHash = primitives::GetLTagHash(data.T);
+        result->lTagHash = (char*)malloc((lTagHash.GetHex().length() + 1) * sizeof(char));
+        std::strcpy(result->lTagHash, lTagHash.GetHex().c_str());
+
+        result->encryptedDiversifier = (unsigned char*)malloc(identifiedCoinData.d.size() * sizeof(unsigned char));
+        result->encryptedDiversifierLength = identifiedCoinData.d.size();
+        memcpy(result->encryptedDiversifier,identifiedCoinData.d.data(),identifiedCoinData.d.size() * sizeof(unsigned char));
+
+        result->nonce = (unsigned char*)malloc(32 * sizeof(unsigned char));
+        result->nonceLength = 32;
+        identifiedCoinData.k.serialize(result->nonce);
+
+        result->serial = (unsigned char*)malloc(data.s.GetHex().length() * sizeof(unsigned char));
+        result->serialLength = data.s.GetHex().length();
+        memcpy(result->serial,data.s.GetHex().c_str(),data.s.GetHex().length() * sizeof(unsigned char));
+
+        return result;
+    } catch (const std::exception& e) {
+        std::cerr << "Exception: " << e.what() << std::endl;
+        return nullptr;
+    }
+}
+
 /*
  * FFI-friendly wrapper for spark::createSparkMintRecipients.
  *

src/flutter_libsparkmobile.h

@@ -34,6 +34,15 @@ const char* createIncomingViewKey(const char* keyData, int index);
 FFI_PLUGIN_EXPORT
 struct CIdentifiedCoinData identifyCoin(const char* serializedCoin, int serializedCoinLength, const char* keyDataHex, int index);
 
+FFI_PLUGIN_EXPORT
+struct AggregateCoinData* idAndRecoverCoin(
+        const char* serializedCoin,
+        int serializedCoinLength,
+        const char* keyDataHex,
+        int index,
+        int isTestNet
+);
+
 /*
  * FFI-friendly wrapper for spark::createSparkMintRecipients.
  *

src/structs.h

@@ -169,6 +169,41 @@ struct OutputScript {
     int length;
 };
 
+/*
+ * Aggregate data structure to handle passing spark mint/spend data across FFI
+ */
+struct AggregateCoinData {
+    char type;
+    uint64_t diversifier;
+    uint64_t value;
+      char *address;
+      char *memo;
+      char *lTagHash;
+
+    unsigned char *encryptedDiversifier;
+    int encryptedDiversifierLength;
+
+    unsigned char *serial;
+    int serialLength;
+
+    unsigned char *nonce;
+    int nonceLength;
+};
+
+
+//struct IdentifiedCoinData {
+//    uint64_t i; // diversifier
+//    std::vector<unsigned char> d; // encrypted diversifier
+//    uint64_t v; // value
+//    Scalar k; // nonce
+//    std::string memo; // memo
+//};
+//
+//struct RecoveredCoinData {
+//    Scalar s; // serial
+//    GroupElement T; // tag
+//};
+
 //#ifdef __cplusplus
 //}
 //#endif