Implement Confirm trait to PaymentHandler

The `Confirm` trait is implemented in order to track the Payjoin
transaction(s). We track two different transaction:

1. Original PSBT, which is the initial transaction sent to the Payjoin
   receiver. The receiver can decide to broadcast this transaction
   instead of finishing the Payjoin flow. Those we track it.
2. Final Payjoin transaction. The transaction constructed after
   completing the Payjoin flow, validated and broadcasted by the Payjoin
   sender.

Author: jbesraa

src/payment/payjoin/handler.rs

@@ -1,6 +1,8 @@
 use bitcoin::address::NetworkChecked;
+use bitcoin::block::Header;
 use bitcoin::psbt::Psbt;
-use bitcoin::{Script, Transaction, Txid};
+use bitcoin::{BlockHash, Script, Transaction, Txid};
+use lightning::chain::transaction::TransactionData;
 
 use crate::config::PAYJOIN_REQUEST_TIMEOUT;
 use crate::error::Error;
@@ -13,7 +15,7 @@ use crate::types::{ChainSource, EventQueue, PaymentStore, Wallet};
 use crate::Event;
 use crate::PaymentDetails;
 
-use lightning::chain::Filter;
+use lightning::chain::{BestBlock, Confirm, Filter};
 use lightning::ln::channelmanager::PaymentId;
 use lightning::log_error;
 use lightning::util::logger::Logger;
@@ -165,4 +167,99 @@ impl PayjoinHandler {
 			Err(Error::PayjoinRequestSendingFailed)
 		}
 	}
+
+	fn internal_transactions_confirmed(
+		&self, header: &Header, txdata: &TransactionData, height: u32,
+	) {
+		for (_, tx) in txdata {
+			let confirmed_tx_txid = tx.txid();
+			let payment_store = self.payment_store.clone();
+			let payment_id = self.payment_id(&confirmed_tx_txid);
+			let payjoin_tx_filter = |payment_details: &&PaymentDetails| {
+				payment_details.txid == Some(confirmed_tx_txid)
+					&& payment_details.amount_msat.is_some()
+			};
+			let payjoin_tx_details = payment_store.list_filter(payjoin_tx_filter);
+			if let Some(payjoin_tx_details) = payjoin_tx_details.get(0) {
+				let mut payment_update = PaymentDetailsUpdate::new(payjoin_tx_details.id);
+				payment_update.status = Some(PaymentStatus::Succeeded);
+				payment_update.best_block = Some(BestBlock::new(header.block_hash(), height));
+				let _ = payment_store.update(&payment_update);
+				let _ = self.event_queue.add_event(Event::PayjoinPaymentSuccessful {
+					txid: confirmed_tx_txid,
+					amount_sats: payjoin_tx_details
+						.amount_msat
+						.expect("Unreachable, asserted in `payjoin_tx_filter`"),
+					is_original_psbt_modified: if payment_id == payjoin_tx_details.id {
+						false
+					} else {
+						true
+					},
+				});
+			// check if this is the original psbt transaction
+			} else if let Some(payment_details) = payment_store.get(&payment_id) {
+				let mut payment_update = PaymentDetailsUpdate::new(payment_id);
+				payment_update.status = Some(PaymentStatus::Succeeded);
+				let _ = payment_store.update(&payment_update);
+				payment_update.best_block = Some(BestBlock::new(header.block_hash(), height));
+				payment_update.txid = Some(confirmed_tx_txid);
+				let _ = self.event_queue.add_event(Event::PayjoinPaymentSuccessful {
+					txid: confirmed_tx_txid,
+					amount_sats: payment_details
+						.amount_msat
+						.expect("Unreachable, payjoin transactions must have amount"),
+					is_original_psbt_modified: false,
+				});
+			}
+		}
+	}
+
+	fn internal_get_relevant_txids(&self) -> Vec<(Txid, u32, Option<BlockHash>)> {
+		let payjoin_tx_filter = |payment_details: &&PaymentDetails| {
+			payment_details.txid.is_some()
+				&& payment_details.status == PaymentStatus::Succeeded
+				&& payment_details.kind == PaymentKind::Payjoin
+		};
+		let payjoin_tx_details = self.payment_store.list_filter(payjoin_tx_filter);
+		let mut ret = Vec::new();
+		for payjoin_tx_details in payjoin_tx_details {
+			if let (Some(txid), Some(best_block)) =
+				(payjoin_tx_details.txid, payjoin_tx_details.best_block)
+			{
+				ret.push((txid, best_block.height, Some(best_block.block_hash)));
+			}
+		}
+		ret
+	}
+
+	fn internal_best_block_updated(&self, height: u32, block_hash: BlockHash) {
+		let payment_store = self.payment_store.clone();
+		let payjoin_tx_filter = |payment_details: &&PaymentDetails| {
+			payment_details.kind == PaymentKind::Payjoin
+				&& payment_details.status == PaymentStatus::Succeeded
+		};
+		let payjoin_tx_details = payment_store.list_filter(payjoin_tx_filter);
+		for payjoin_tx_details in payjoin_tx_details {
+			let mut payment_update = PaymentDetailsUpdate::new(payjoin_tx_details.id);
+			payment_update.best_block = Some(BestBlock::new(block_hash, height));
+			let _ = payment_store.update(&payment_update);
+		}
+	}
+}
+
+impl Confirm for PayjoinHandler {
+	fn transactions_confirmed(&self, header: &Header, txdata: &TransactionData, height: u32) {
+		self.internal_transactions_confirmed(header, txdata, height);
+	}
+
+	fn get_relevant_txids(&self) -> Vec<(Txid, u32, Option<BlockHash>)> {
+		self.internal_get_relevant_txids()
+	}
+
+	fn best_block_updated(&self, header: &Header, height: u32) {
+		let block_hash = header.block_hash();
+		self.internal_best_block_updated(height, block_hash);
+	}
+
+	fn transaction_unconfirmed(&self, _txid: &Txid) {}
 }