feat: Add type secpCtx for Wallet

bdk-android/lib/src/androidTest/kotlin/org/bitcoindevkit/WalletTest.kt

@@ -6,6 +6,7 @@ import kotlin.test.assertTrue
 import kotlin.test.assertFalse
 import androidx.test.ext.junit.runners.AndroidJUnit4
 import org.junit.runner.RunWith
+import kotlin.test.assertNotNull
 
 @RunWith(AndroidJUnit4::class)
 class WalletTest {
@@ -65,4 +66,17 @@ class WalletTest {
             "Addresses should be the same"
         )
     }
+
+    @Test
+    fun getWalletSecpCtx() {
+        val wallet: Wallet = Wallet.createSingle(
+            descriptor = BIP84_DESCRIPTOR,
+            network = Network.TESTNET,
+            persister = conn
+        )
+        val secp = wallet.secpCtx()
+        val stringSpec = secp.toString()
+
+        assertNotNull(stringSpec, "SecpCtx should not be null")
+    }
 }

bdk-ffi/src/types.rs

@@ -43,6 +43,7 @@ use bdk_esplora::esplora_client::api::MerkleProof as BdkMerkleProof;
 use bdk_esplora::esplora_client::api::OutputStatus as BdkOutputStatus;
 use bdk_esplora::esplora_client::api::Tx as BdkTx;
 use bdk_esplora::esplora_client::api::TxStatus as BdkTxStatus;
+use bdk_wallet::bitcoin::secp256k1::{All, Secp256k1};
 
 pub(crate) type KeychainKind = bdk_wallet::KeychainKind;
 
@@ -1438,6 +1439,30 @@ impl From<bdk_wallet::ChangeSet> for ChangeSet {
     }
 }
 
+/// The secp256k1 engine, used to execute all signature operations.
+#[derive(Debug, uniffi::Object)]
+#[uniffi::export(Debug, Display)]
+pub struct SecpCtx {
+    pub(crate) secp: Secp256k1<All>,
+}
+
+#[uniffi::export]
+impl SecpCtx {
+    /// Create a new SecpCtx
+    #[uniffi::constructor]
+    pub fn new() -> Self {
+        SecpCtx {
+            secp: Secp256k1::new(),
+        }
+    }
+}
+
+impl Display for SecpCtx {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{:?}", self.secp)
+    }
+}
+
 /// Details about a transaction affecting the wallet (relevant and canonical).
 #[derive(uniffi::Record, Debug, Clone)]
 pub struct TxDetails {

bdk-ffi/src/wallet.rs

@@ -7,10 +7,11 @@ use crate::error::{
 use crate::store::{PersistenceType, Persister};
 use crate::types::{
     AddressInfo, Balance, BlockId, CanonicalTx, ChangeSet, EvictedTx, FullScanRequestBuilder,
-    KeychainAndIndex, KeychainKind, LocalOutput, Policy, SentAndReceivedValues, SignOptions,
-    SyncRequestBuilder, UnconfirmedTx, Update, WalletEvent, WalletKeychain,
+    KeychainAndIndex, KeychainKind, LocalOutput, Policy, SecpCtx, SentAndReceivedValues,
+    SignOptions, SyncRequestBuilder, UnconfirmedTx, Update, WalletEvent, WalletKeychain,
 };
 
+use bdk_wallet::bitcoin::secp256k1::{All, Secp256k1};
 use bdk_wallet::bitcoin::Network;
 use bdk_wallet::keys::KeyMap;
 #[allow(deprecated)]
@@ -770,6 +771,12 @@ impl Wallet {
     pub fn public_descriptor(&self, keychain: KeychainKind) -> String {
         self.get_wallet().public_descriptor(keychain).to_string()
     }
+
+    /// Return the secp256k1 context used for all signing operations.
+    pub fn secp_ctx(&self) -> Arc<SecpCtx> {
+        let secp: Secp256k1<All> = self.get_wallet().secp_ctx().clone();
+        Arc::new(SecpCtx { secp })
+    }
 }
 
 impl Wallet {