From 8b3567dd1aca31e46837dca423c209cf8c33eb70 Mon Sep 17 00:00:00 2001
From: Wilmer Paulino <wilmer@wilmerpaulino.com>
Date: Mon, 14 Aug 2023 09:00:21 -0700
Subject: [PATCH] Implement bump_transaction::WalletSource for BitcoindClient

`BitcoindClient` will be used as the view into the onchain wallet from
which we'll source UTXOs.
---
 src/bitcoind_client.rs | 71 ++++++++++++++++++++++++++++++++++++++++--
 src/convert.rs         | 33 +++++++++++++++++++-
 2 files changed, 100 insertions(+), 4 deletions(-)

diff --git a/src/bitcoind_client.rs b/src/bitcoind_client.rs
index 228f27a..a093e6d 100644
--- a/src/bitcoind_client.rs
+++ b/src/bitcoind_client.rs
@@ -1,13 +1,19 @@
 use crate::convert::{
-	BlockchainInfo, FeeResponse, FundedTx, MempoolMinFeeResponse, NewAddress, RawTx, SignedTx,
+	BlockchainInfo, FeeResponse, FundedTx, ListUnspentResponse, MempoolMinFeeResponse, NewAddress,
+	RawTx, SignedTx,
 };
 use crate::disk::FilesystemLogger;
+use crate::hex_utils;
 use base64;
+use bitcoin::blockdata::constants::WITNESS_SCALE_FACTOR;
 use bitcoin::blockdata::transaction::Transaction;
-use bitcoin::consensus::encode;
+use bitcoin::consensus::{encode, Decodable, Encodable};
 use bitcoin::hash_types::{BlockHash, Txid};
-use bitcoin::util::address::Address;
+use bitcoin::hashes::Hash;
+use bitcoin::util::address::{Address, Payload, WitnessVersion};
+use bitcoin::{OutPoint, Script, TxOut, WPubkeyHash, XOnlyPublicKey};
 use lightning::chain::chaininterface::{BroadcasterInterface, ConfirmationTarget, FeeEstimator};
+use lightning::events::bump_transaction::{Utxo, WalletSource};
 use lightning::log_error;
 use lightning::routing::utxo::{UtxoLookup, UtxoResult};
 use lightning::util::logger::Logger;
@@ -250,6 +256,13 @@ impl BitcoindClient {
 			.await
 			.unwrap()
 	}
+
+	pub async fn list_unspent(&self) -> ListUnspentResponse {
+		self.bitcoind_rpc_client
+			.call_method::<ListUnspentResponse>("listunspent", &vec![])
+			.await
+			.unwrap()
+	}
 }
 
 impl FeeEstimator for BitcoindClient {
@@ -308,3 +321,55 @@ impl UtxoLookup for BitcoindClient {
 		todo!();
 	}
 }
+
+impl WalletSource for BitcoindClient {
+	fn list_confirmed_utxos(&self) -> Result<Vec<Utxo>, ()> {
+		let utxos = tokio::task::block_in_place(move || {
+			self.handle.block_on(async move { self.list_unspent().await }).0
+		});
+		Ok(utxos
+			.into_iter()
+			.filter_map(|utxo| {
+				let outpoint = OutPoint { txid: utxo.txid, vout: utxo.vout };
+				match utxo.address.payload {
+					Payload::WitnessProgram { version, ref program } => match version {
+						WitnessVersion::V0 => WPubkeyHash::from_slice(program)
+							.map(|wpkh| Utxo::new_v0_p2wpkh(outpoint, utxo.amount, &wpkh))
+							.ok(),
+						// TODO: Add `Utxo::new_v1_p2tr` upstream.
+						WitnessVersion::V1 => XOnlyPublicKey::from_slice(program)
+							.map(|_| Utxo {
+								outpoint,
+								output: TxOut {
+									value: utxo.amount,
+									script_pubkey: Script::new_witness_program(version, program),
+								},
+								satisfaction_weight: 1 /* empty script_sig */ * WITNESS_SCALE_FACTOR as u64 +
+									1 /* witness items */ + 1 /* schnorr sig len */ + 64, /* schnorr sig */
+							})
+							.ok(),
+						_ => None,
+					},
+					_ => None,
+				}
+			})
+			.collect())
+	}
+
+	fn get_change_script(&self) -> Result<Script, ()> {
+		tokio::task::block_in_place(move || {
+			Ok(self.handle.block_on(async move { self.get_new_address().await.script_pubkey() }))
+		})
+	}
+
+	fn sign_tx(&self, tx: Transaction) -> Result<Transaction, ()> {
+		let mut tx_bytes = Vec::new();
+		let _ = tx.consensus_encode(&mut tx_bytes).map_err(|_| ());
+		let tx_hex = hex_utils::hex_str(&tx_bytes);
+		let signed_tx = tokio::task::block_in_place(move || {
+			self.handle.block_on(async move { self.sign_raw_transaction_with_wallet(tx_hex).await })
+		});
+		let signed_tx_bytes = hex_utils::to_vec(&signed_tx.hex).ok_or(())?;
+		Transaction::consensus_decode(&mut signed_tx_bytes.as_slice()).map_err(|_| ())
+	}
+}
diff --git a/src/convert.rs b/src/convert.rs
index 84b033e..7f1bf10 100644
--- a/src/convert.rs
+++ b/src/convert.rs
@@ -1,7 +1,8 @@
 use bitcoin::hashes::hex::FromHex;
-use bitcoin::BlockHash;
+use bitcoin::{Address, BlockHash, Txid};
 use lightning_block_sync::http::JsonResponse;
 use std::convert::TryInto;
+use std::str::FromStr;
 
 pub struct FundedTx {
 	pub changepos: i64,
@@ -116,3 +117,33 @@ impl TryInto<BlockchainInfo> for JsonResponse {
 		})
 	}
 }
+
+pub struct ListUnspentUtxo {
+	pub txid: Txid,
+	pub vout: u32,
+	pub amount: u64,
+	pub address: Address,
+}
+
+pub struct ListUnspentResponse(pub Vec<ListUnspentUtxo>);
+
+impl TryInto<ListUnspentResponse> for JsonResponse {
+	type Error = std::io::Error;
+	fn try_into(self) -> Result<ListUnspentResponse, Self::Error> {
+		let utxos = self
+			.0
+			.as_array()
+			.unwrap()
+			.iter()
+			.map(|utxo| ListUnspentUtxo {
+				txid: Txid::from_str(&utxo["txid"].as_str().unwrap().to_string()).unwrap(),
+				vout: utxo["vout"].as_u64().unwrap() as u32,
+				amount: bitcoin::Amount::from_btc(utxo["amount"].as_f64().unwrap())
+					.unwrap()
+					.to_sat(),
+				address: Address::from_str(&utxo["address"].as_str().unwrap().to_string()).unwrap(),
+			})
+			.collect();
+		Ok(ListUnspentResponse(utxos))
+	}
+}
-- 
2.39.5