bark/onchain/

bdk.rs

use std::ops::{Deref, DerefMut};
use std::time::{SystemTime, UNIX_EPOCH};
use std::sync::Arc;

use anyhow::Context;
use bdk_esplora::EsploraAsyncExt;
use bdk_wallet::chain::{ChainPosition, CheckPoint};
use bdk_wallet::Wallet as BdkWallet;
use bdk_wallet::coin_selection::DefaultCoinSelectionAlgorithm;
use bdk_wallet::{Balance, KeychainKind, LocalOutput, SignOptions, TxBuilder, TxOrdering};
use bitcoin::{
	bip32, psbt, Address, Amount, FeeRate, Network, OutPoint, Psbt, Sequence, Transaction, TxOut,
	Txid,
};
use log::{debug, error, info, trace, warn};

use bitcoin_ext::{BlockHeight, BlockRef};
use bitcoin_ext::bdk::{CpfpInternalError, WalletExt};
use bitcoin_ext::cpfp::CpfpError;
use bitcoin_ext::rpc::RpcApi;

use crate::exit::ExitVtxo;
use crate::exit::models::ExitState;
use crate::onchain::{
	ChainSource, LocalUtxo, GetBalance, GetSpendingTx, GetWalletTx, MakeCpfp, MakeCpfpFees,
	PreparePsbt, SignPsbt, Utxo,
};
use crate::onchain::chain::ChainSourceClient;
use crate::persist::BarkPersister;
use crate::psbtext::PsbtInputExt;

const STOP_GAP: usize = 50;
const PARALLEL_REQS: usize = 4;
const GENESIS_HEIGHT: u32 = 0;

impl From<LocalOutput> for LocalUtxo {
	fn from(value: LocalOutput) -> Self {
		LocalUtxo {
			outpoint: value.outpoint,
			amount: value.txout.value,
			confirmation_height: value.chain_position.confirmation_height_upper_bound(),
		}
	}
}

/// Trait extension for TxBuilder to add exit outputs
///
/// When used, the resulting PSBT should be signed using
/// [crate::exit::Exit::sign_exit_claim_inputs].
pub trait TxBuilderExt {
	fn add_exit_claim_inputs(&mut self, exit_outputs: &[&ExitVtxo]) -> anyhow::Result<()>;
}

impl<Cs> TxBuilderExt for TxBuilder<'_, Cs> {
	fn add_exit_claim_inputs(&mut self, exit_outputs: &[&ExitVtxo]) -> anyhow::Result<()> {
		self.version(2);

		for input in exit_outputs {
			if !matches!(input.state(), ExitState::Claimable(..)) {
				bail!("VTXO exit is not spendable");
			}

			let vtxo = input.vtxo();

			let mut psbt_in = psbt::Input::default();
			psbt_in.set_exit_claim_input(&vtxo);
			psbt_in.witness_utxo = Some(TxOut {
				script_pubkey: vtxo.output_script_pubkey(),
				value: vtxo.amount(),
			});

			self.add_foreign_utxo_with_sequence(
				vtxo.point(),
				psbt_in,
				vtxo.claim_satisfaction_weight(),
				Sequence::from_height(vtxo.exit_delta()),
			).expect("error adding foreign utxo for claim input");
		}

		Ok(())
	}
}

impl <W: Deref<Target = BdkWallet>> GetBalance for W {
	fn get_balance(&self) -> Amount {
		self.deref().balance().total()
	}
}

impl SignPsbt for BdkWallet {
	fn finish_tx(&mut self, mut psbt: Psbt) -> anyhow::Result<Transaction> {
		let opts = SignOptions {
			trust_witness_utxo: true,
			..Default::default()
		};

		let finalized = self.sign(&mut psbt, opts).context("signing error")?;
		assert!(finalized);
		let tx = psbt.extract_tx()?;
		let unix = SystemTime::now().duration_since(UNIX_EPOCH).unwrap().as_secs();
		self.apply_unconfirmed_txs([(tx.clone(), unix)]);
		Ok(tx)
	}
}

impl <W: Deref<Target = BdkWallet>> GetWalletTx for W {
	/// Retrieves a transaction from the wallet
	///
	/// This method will only check the database and will not
	/// use a chain-source to find the transaction
	fn get_wallet_tx(&self, txid: Txid) -> Option<Arc<Transaction>> {
		self.deref().get_tx(txid).map(|tx| tx.tx_node.tx)
	}

	fn get_wallet_tx_confirmed_block(&self, txid: Txid) -> anyhow::Result<Option<BlockRef>> {
		match self.deref().get_tx(txid) {
			Some(tx) => match tx.chain_position {
				ChainPosition::Confirmed { anchor, .. } => Ok(Some(anchor.block_id.into())),
				ChainPosition::Unconfirmed { .. } => Ok(None),
			},
			None => Err(anyhow!("Tx {} does not exist in the wallet", txid)),
		}
	}
}

impl <W: DerefMut<Target = BdkWallet>> PreparePsbt for W {
	fn prepare_tx(
		&mut self,
		destinations: &[(Address, Amount)],
		fee_rate: FeeRate,
	) -> anyhow::Result<Psbt> {
		let mut b = self.deref_mut().build_tx();
		b.ordering(TxOrdering::Untouched);
		for (dest, amount) in destinations {
			b.add_recipient(dest.script_pubkey(), *amount);
		}
		b.fee_rate(fee_rate);
		b.finish().context("error building tx")
	}

	fn prepare_drain_tx(
		&mut self,
		destination: Address,
		fee_rate: FeeRate,
	) -> anyhow::Result<Psbt> {
		let mut b = self.deref_mut().build_tx();
		b.drain_to(destination.script_pubkey());
		b.fee_rate(fee_rate);
		b.drain_wallet();
		b.finish().context("error building tx")
	}
}

impl <W: Deref<Target = BdkWallet>> GetSpendingTx for W {
	fn get_spending_tx(&self, outpoint: OutPoint) -> Option<Arc<Transaction>> {
		for transaction in self.deref().transactions() {
			if transaction.tx_node.tx.input.iter().any(|i| i.previous_output == outpoint) {
				return Some(transaction.tx_node.tx);
			}
		}
		None
	}
}

impl MakeCpfp for BdkWallet {
	fn make_signed_p2a_cpfp(
		&mut self,
		tx: &Transaction,
		fees: MakeCpfpFees,
	) -> Result<Transaction, CpfpError> {
		 WalletExt::make_signed_p2a_cpfp(self, tx, fees)
			 .inspect_err(|e| error!("Error creating signed P2A CPFP: {}", e))
			 .map_err(|e| match e {
				 CpfpInternalError::General(s) => CpfpError::InternalError(s),
				 CpfpInternalError::Create(e) => CpfpError::CreateError(e.to_string()),
				 CpfpInternalError::Extract(e) => CpfpError::FinalizeError(e.to_string()),
				 CpfpInternalError::Fee() => CpfpError::InternalError(e.to_string()),
				 CpfpInternalError::FinalizeError(s) => CpfpError::FinalizeError(s),
				 CpfpInternalError::InsufficientConfirmedFunds(f) => {
					 CpfpError::InsufficientConfirmedFunds {
						 needed: f.needed, available: f.available,
					 }
				 },
				 CpfpInternalError::NoFeeAnchor(txid) => CpfpError::NoFeeAnchor(txid),
				 CpfpInternalError::Signer(e) => CpfpError::SigningError(e.to_string()),
			 })
	}

	fn store_signed_p2a_cpfp(&mut self, tx: &Transaction) -> anyhow::Result<(), CpfpError> {
		let unix = SystemTime::now().duration_since(UNIX_EPOCH)
			.map_err(|e| CpfpError::InternalError(
				format!("Unable to calculate time since UNIX epoch: {}", e.to_string()))
			)?.as_secs();
		self.apply_unconfirmed_txs([(tx.clone(), unix)]);
		trace!("Unconfirmed txs: {:?}", self.unconfirmed_txids().collect::<Vec<_>>());
		Ok(())
	}
}

/// A basic wrapper around the bdk wallet to showcase
/// how to use bark with an external onchain wallet.
///
/// Note: BDK wallet already implements all the traits
/// to be used as an onboard and exit wallet, so that
/// wrapper only needs to proxy the methods.
pub struct OnchainWallet {
	pub inner: BdkWallet,
	db: Arc<dyn BarkPersister>,
}

impl Deref for OnchainWallet {
	type Target = BdkWallet;

	fn deref(&self) -> &Self::Target {
		&self.inner
	}
}

impl DerefMut for OnchainWallet {
	fn deref_mut(&mut self) -> &mut Self::Target {
		&mut self.inner
	}
}

impl OnchainWallet {
	pub fn load_or_create(network: Network, seed: [u8; 64], db: Arc<dyn BarkPersister>) -> anyhow::Result<Self> {
		let xpriv = bip32::Xpriv::new_master(network, &seed).expect("valid seed");
		let desc = bdk_wallet::template::Bip86(xpriv, KeychainKind::External);

		let changeset = db.initialize_bdk_wallet().context("error reading bdk wallet state")?;
		let wallet_opt = bdk_wallet::Wallet::load()
			.descriptor(bdk_wallet::KeychainKind::External, Some(desc.clone()))
			.extract_keys()
			.check_network(network)
			.load_wallet_no_persist(changeset)?;

		let wallet = match wallet_opt {
			Some(wallet) => wallet,
			None => bdk_wallet::Wallet::create_single(desc)
				.network(network)
				.create_wallet_no_persist()?,
		};

		Ok(Self { inner: wallet, db })
	}
}

impl MakeCpfp for OnchainWallet {
	fn make_signed_p2a_cpfp(
		&mut self,
		tx: &Transaction,
		fees: MakeCpfpFees,
	) -> Result<Transaction, CpfpError> {
		MakeCpfp::make_signed_p2a_cpfp(&mut self.inner, tx, fees)
	}

	fn store_signed_p2a_cpfp(&mut self, tx: &Transaction) -> anyhow::Result<(), CpfpError> {
		self.inner.store_signed_p2a_cpfp(tx)?;
		self.persist()
			.map_err(|e| CpfpError::StoreError(e.to_string()))
	}
}

impl SignPsbt for OnchainWallet {
	fn finish_tx(&mut self, psbt: Psbt) -> anyhow::Result<Transaction> {
		let tx = self.inner.finish_tx(psbt)?;
		self.persist()?;
		Ok(tx)
	}
}

impl OnchainWallet {
	pub fn balance(&self) -> Balance {
		self.inner.balance()
	}

	pub fn list_unspent(&self) -> Vec<LocalOutput> {
		self.inner.list_unspent().collect()
	}

	pub fn list_transactions(&self) -> Vec<Arc<Transaction>> {
		self.inner.transactions().map(|tx| tx.tx_node.tx).collect()
	}

	pub fn address(&mut self) -> anyhow::Result<Address> {
		let ret = self.inner.reveal_next_address(bdk_wallet::KeychainKind::External).address;
		self.persist()?;
		Ok(ret)
	}

	pub fn utxos(&self) -> Vec<Utxo> {
		self.list_unspent().into_iter().map(|o| Utxo::Local(o.into())).collect()
	}

	pub async fn send(&mut self, chain: &ChainSource, dest: Address, amount: Amount, fee_rate: FeeRate
	)	-> anyhow::Result<Txid> {
		let psbt = self.prepare_tx(&[(dest, amount)], fee_rate)?;
		let tx = self.finish_tx(psbt)?;
		chain.broadcast_tx(&tx).await?;
		Ok(tx.compute_txid())
	}

	pub async fn send_many(
		&mut self,
		chain: &ChainSource,
		destinations: &[(Address, Amount)],
		fee_rate: FeeRate,
	) -> anyhow::Result<Txid> {
		let pbst = self.prepare_tx(destinations, fee_rate)?;
		let tx = self.finish_tx(pbst)?;
		chain.broadcast_tx(&tx).await?;
		Ok(tx.compute_txid())
	}


	pub async fn drain(
		&mut self,
		chain: &ChainSource,
		destination: Address,
		fee_rate: FeeRate,
	) -> anyhow::Result<Txid> {
		let psbt = self.prepare_drain_tx(destination, fee_rate)?;
		let tx = self.finish_tx(psbt)?;
		chain.broadcast_tx(&tx).await?;
		Ok(tx.compute_txid())
	}

	pub fn build_tx(&mut self) -> TxBuilder<'_, DefaultCoinSelectionAlgorithm> {
		self.inner.build_tx()
	}

	async fn inner_sync_bitcoind(
		&mut self,
		bitcoind: &bitcoin_ext::rpc::Client,
		prev_tip: CheckPoint,
	) -> anyhow::Result<()> {
		debug!("Syncing with bitcoind, starting at block height {}...", prev_tip.height());
		let mut emitter = bdk_bitcoind_rpc::Emitter::new(
			bitcoind, prev_tip.clone(), prev_tip.height(), self.unconfirmed_txs()
		);
		let mut count = 0;
		while let Some(em) = emitter.next_block()? {
			self.inner.apply_block_connected_to(
				&em.block, em.block_height(), em.connected_to(),
			)?;
			count += 1;

			if count % 10_000 == 0 {
				self.persist()?;
				info!("Synced until block height {}", em.block_height());
			}
		}

		let mempool = emitter.mempool()?;
		self.inner.apply_evicted_txs(mempool.evicted);
		self.inner.apply_unconfirmed_txs(mempool.update);
		self.persist()?;
		debug!("Finished syncing with bitcoind");

		Ok(())
	}

	async fn rebroadcast_txs(&mut self, chain: &ChainSource, sync_start: u64) -> anyhow::Result<Amount> {
		let balance = self.inner.balance();

		// Ultimately, let's try to rebroadcast all our unconfirmed txs.
		let transactions = self.inner.transactions().filter(|tx| {
			if let ChainPosition::Unconfirmed { last_seen, .. } = tx.chain_position {
				match last_seen {
					Some(last_seen) => last_seen < sync_start,
					None => true,
				}
			} else {
				false
			}
		}).collect::<Vec<_>>();

		for tx in transactions {
			if let Err(e) = chain.broadcast_tx(&tx.tx_node.tx).await {
				warn!("Error broadcasting tx {}: {}", tx.tx_node.txid, e);
			}
		}

		Ok(balance.total())
	}

	pub async fn sync(&mut self, chain: &ChainSource) -> anyhow::Result<Amount> {
		debug!("Starting wallet sync...");
		debug!("Starting balance: {}", self.inner.balance());
		trace!("Starting unconfirmed txs: {:?}", self.unconfirmed_txids().collect::<Vec<_>>());
		let now = SystemTime::now().duration_since(UNIX_EPOCH).expect("now").as_secs();

		match chain.inner() {
			ChainSourceClient::Bitcoind(bitcoind) => {
				let prev_tip = self.inner.latest_checkpoint();
				self.inner_sync_bitcoind(bitcoind, prev_tip).await?;
			},
			ChainSourceClient::Esplora(client) => {
				debug!("Syncing with esplora...");
				let request = self.inner.start_sync_with_revealed_spks()
					.outpoints(self.list_unspent().iter().map(|o| o.outpoint).collect::<Vec<_>>())
					.txids(self.inner.transactions().map(|tx| tx.tx_node.txid).collect::<Vec<_>>());

				let update = client.sync(request, PARALLEL_REQS).await?;
				self.inner.apply_update(update)?;
				self.persist()?;
				debug!("Finished syncing with esplora");
			},
		}

		debug!("Current balance: {}", self.inner.balance());
		trace!("Current unconfirmed txs: {:?}", self.unconfirmed_txids().collect::<Vec<_>>());
		self.rebroadcast_txs(chain, now).await
	}

	pub async fn initial_wallet_scan(
		&mut self,
		chain: &ChainSource,
		start_height: Option<BlockHeight>,
	) -> anyhow::Result<Amount> {
		info!("Starting initial wallet sync...");
		debug!("Starting balance: {}", self.inner.balance());
		let now = SystemTime::now().duration_since(UNIX_EPOCH).expect("now").as_secs();

		match chain.inner() {
			ChainSourceClient::Bitcoind(bitcoind) => {
				// Make sure we include the given start_height in the scan
				let height = start_height.unwrap_or(GENESIS_HEIGHT).saturating_sub(1);
				let block_hash = bitcoind.get_block_hash(height as u64)?;
				self.inner.set_checkpoint(height, block_hash);
				self.inner_sync_bitcoind(bitcoind, self.inner.latest_checkpoint()).await?;
			},
			// Esplora can't do a full scan from a given block height, so we can ignore start_height
			ChainSourceClient::Esplora(client) => {
				debug!("Starting full scan with esplora...");
				let request = self.inner.start_full_scan();
				let update = client.full_scan(request, STOP_GAP, PARALLEL_REQS).await?;
				self.inner.apply_update(update)?;
				self.persist()?;
				debug!("Finished scanning with esplora");
			},
		}

		debug!("Current balance: {}", self.inner.balance());
		self.rebroadcast_txs(chain, now).await
	}


	fn persist(&mut self) -> anyhow::Result<()> {
		if let Some(stage) = self.inner.staged() {
			self.db.store_bdk_wallet_changeset(&*stage)?;
			let _ = self.inner.take_staged();
		}
		Ok(())
	}
}