improve usability of refund

swap/src/cli/cancel_and_refund.rs

@@ -1,6 +1,6 @@
 use crate::bitcoin::wallet::Subscription;
 use crate::bitcoin::{parse_rpc_error_code, RpcErrorCode, Wallet};
-use crate::protocol::bob::BobState;
+use crate::protocol::bob::{BobState, BtcPunishedWhileRefundError};
 use crate::protocol::Database;
 use anyhow::{bail, Result};
 use bitcoin::Txid;
@@ -105,7 +105,23 @@ pub async fn refund(
     };
 
     tracing::info!(%swap_id, "Manually refunding swap");
-    state6.publish_refund_btc(bitcoin_wallet.as_ref()).await?;
+
+    match state6.publish_refund_btc(bitcoin_wallet.as_ref()).await {
+        Ok(_) => (),
+        Err(refund_error) => {
+            if let Some(refund_error) = refund_error.downcast_ref::<BtcPunishedWhileRefundError>() {
+                let state = BobState::BtcPunished {
+                    tx_lock_id: state6.tx_lock_id(),
+                };
+                db.insert_latest_state(swap_id, state.clone().into())
+                    .await?;
+
+                println!("{}", refund_error);
+
+                return Ok(state);
+            }
+        }
+    }
 
     let state = BobState::BtcRefunded(state6);
     db.insert_latest_state(swap_id, state.clone().into())

swap/src/protocol/bob/state.rs

@@ -10,6 +10,7 @@ use crate::monero_ext::ScalarExt;
 use crate::protocol::{Message0, Message1, Message2, Message3, Message4, CROSS_CURVE_PROOF_SYSTEM};
 use anyhow::{anyhow, bail, Context, Result};
 use bdk::database::BatchDatabase;
+use bdk::electrum_client::Error as BdkError;
 use ecdsa_fun::adaptor::{Adaptor, HashTranscript};
 use ecdsa_fun::nonce::Deterministic;
 use ecdsa_fun::Signature;
@@ -21,6 +22,14 @@ use sigma_fun::ext::dl_secp256k1_ed25519_eq::CrossCurveDLEQProof;
 use std::fmt;
 use uuid::Uuid;
 
+#[derive(Debug)]
+pub struct BtcPunishedWhileRefundError;
+impl std::fmt::Display for BtcPunishedWhileRefundError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "Cannot refund because BTC is punished.")
+    }
+}
+
 #[derive(Debug, Clone, PartialEq)]
 pub enum BobState {
     Started {
@@ -662,9 +671,23 @@ impl State6 {
 
     pub async fn publish_refund_btc(&self, bitcoin_wallet: &bitcoin::Wallet) -> Result<()> {
         let signed_tx_refund = self.signed_refund_transaction()?;
-        bitcoin_wallet.broadcast(signed_tx_refund, "refund").await?;
-
-        Ok(())
+        let transaction_broadcast = bitcoin_wallet.broadcast(signed_tx_refund, "refund").await;
+
+        match transaction_broadcast {
+            Ok(_) => Ok(()),
+            Err(anyhow_error) => match anyhow_error.downcast_ref::<BdkError>() {
+                Some(&BdkError::Protocol(serde_json::Value::String(ref protocol_error)))
+                    // UTXO is already spent, swap timeout.
+                    if protocol_error.contains("bad-txns-inputs-missingorspent") =>
+                {
+                    // Correct the state and show friendly error.
+                    // Set state to CancelTimelockExpired
+
+                    Err(anyhow!(BtcPunishedWhileRefundError))
+                }
+               _ => Err(anyhow_error),
+            },
+        }
     }
 
     pub fn signed_refund_transaction(&self) -> Result<Transaction> {