Add methods on the TxBuilder

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

@@ -15,6 +15,8 @@ class LiveWalletTest {
         val update = esploraClient.scan(wallet, 10uL, 1uL)
         wallet.applyUpdate(update)
         println("Balance: ${wallet.getBalance().total()}")
+        val balance: Balance = wallet.getBalance()
+        println("Balance: $balance")
 
         assert(wallet.getBalance().total() > 0uL)
     }

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

@@ -1,6 +1,7 @@
 package org.bitcoindevkit
 
 import kotlin.test.Test
+import kotlin.test.assertEquals
 import androidx.test.ext.junit.runners.AndroidJUnit4
 import org.junit.runner.RunWith
 import kotlin.test.assertEquals

bdk-ffi/src/bdk.udl

@@ -43,6 +43,12 @@ enum BdkError {
   "Psbt",
 };
 
+enum ChangeSpendPolicy {
+  "ChangeAllowed",
+  "OnlyChange",
+  "ChangeForbidden"
+};
+
 interface Balance {
   u64 immature();
 
@@ -95,8 +101,24 @@ interface TxBuilder {
 
   TxBuilder add_recipient(Script script, u64 amount);
 
+  TxBuilder set_recipients(sequence<ScriptAmount> script_amount);
+
+  TxBuilder add_unspendable(OutPoint unspendable);
+
+  TxBuilder add_utxo(OutPoint outpoint);
+
+  TxBuilder change_policy(ChangeSpendPolicy change_policy);
+
+  TxBuilder do_not_spend_change();
+
+  TxBuilder only_spend_change();
+
+  TxBuilder manually_selected_only();
+
   TxBuilder fee_rate(float sat_per_vbyte);
 
+  TxBuilder drain_wallet();
+
   [Throws=BdkError]
   PartiallySignedTransaction finish([ByRef] Wallet wallet);
 };
@@ -198,6 +220,15 @@ interface EsploraClient {
   Update scan(Wallet wallet, u64 stop_gap, u64 parallel_requests);
 };
 
+// ------------------------------------------------------------------------
+// bdk-ffi-defined types
+// ------------------------------------------------------------------------
+
+dictionary ScriptAmount {
+  Script script;
+  u64 amount;
+};
+
 // ------------------------------------------------------------------------
 // bdk crate - bitcoin re-exports
 // ------------------------------------------------------------------------
@@ -263,3 +294,8 @@ interface PartiallySignedTransaction {
 
   Transaction extract_tx();
 };
+
+dictionary OutPoint {
+  string txid;
+  u32 vout;
+};

bdk-ffi/src/bitcoin.rs

@@ -4,7 +4,9 @@ use bdk::bitcoin::consensus::Decodable;
 use bdk::bitcoin::network::constants::Network as BdkNetwork;
 use bdk::bitcoin::psbt::PartiallySignedTransaction as BdkPartiallySignedTransaction;
 use bdk::bitcoin::Address as BdkAddress;
+use bdk::bitcoin::OutPoint as BdkOutPoint;
 use bdk::bitcoin::Transaction as BdkTransaction;
+use bdk::bitcoin::Txid;
 use bdk::Error as BdkError;
 
 use std::io::Cursor;
@@ -283,3 +285,21 @@ impl From<BdkPartiallySignedTransaction> for PartiallySignedTransaction {
         }
     }
 }
+
+/// A reference to a transaction output.
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub struct OutPoint {
+    /// The referenced transaction's txid.
+    pub txid: String,
+    /// The index of the referenced output in its transaction's vout.
+    pub vout: u32,
+}
+
+impl From<&OutPoint> for BdkOutPoint {
+    fn from(outpoint: &OutPoint) -> Self {
+        BdkOutPoint {
+            txid: Txid::from_str(&outpoint.txid).unwrap(),
+            vout: outpoint.vout,
+        }
+    }
+}

bdk-ffi/src/lib.rs

@@ -7,6 +7,7 @@ mod wallet;
 // TODO 6: Why are these imports required?
 use crate::bitcoin::Address;
 use crate::bitcoin::Network;
+use crate::bitcoin::OutPoint;
 use crate::bitcoin::PartiallySignedTransaction;
 use crate::bitcoin::Script;
 use crate::bitcoin::Transaction;
@@ -21,6 +22,7 @@ use crate::wallet::Update;
 use crate::wallet::Wallet;
 
 use bdk::keys::bip39::WordCount;
+use bdk::wallet::tx_builder::ChangeSpendPolicy;
 use bdk::wallet::AddressIndex as BdkAddressIndex;
 use bdk::wallet::AddressInfo as BdkAddressInfo;
 use bdk::wallet::Balance as BdkBalance;
@@ -32,10 +34,10 @@ use std::sync::Arc;
 uniffi::include_scaffolding!("bdk");
 
 /// A output script and an amount of satoshis.
-// pub struct ScriptAmount {
-//     pub script: Arc<Script>,
-//     pub amount: u64,
-// }
+pub struct ScriptAmount {
+    pub script: Arc<Script>,
+    pub amount: u64,
+}
 
 /// A derived address and the index it was found at.
 pub struct AddressInfo {