From 535d2ec063aafe96b231b9558b2e21e152a6dbc7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Granh=C3=A3o?= <daniel.granhao@gmail.com>
Date: Tue, 31 Dec 2024 18:08:42 +0000
Subject: [PATCH] Always fill in the `actual_payer_amount_sat`

---
 lib/core/src/model.rs             | 14 +++++++++++++-
 lib/core/src/persist/mod.rs       |  9 ++++++---
 lib/core/src/recover/recoverer.rs | 12 +++---------
 3 files changed, 22 insertions(+), 13 deletions(-)

diff --git a/lib/core/src/model.rs b/lib/core/src/model.rs
index df4abb6..4737132 100644
--- a/lib/core/src/model.rs
+++ b/lib/core/src/model.rs
@@ -731,7 +731,8 @@ pub(crate) struct ChainSwap {
     pub(crate) description: Option<String>,
     /// Payer amount defined at swap creation
     pub(crate) payer_amount_sat: u64,
-    /// The actual payer amount in case it differs from `payer_amount_sat` (over/underpayment)
+    /// The actual payer amount as seen on the user lockup tx. Might differ from `payer_amount_sat`
+    /// in the case of an over/underpayment
     pub(crate) actual_payer_amount_sat: Option<u64>,
     /// Receiver amount defined at swap creation
     pub(crate) receiver_amount_sat: u64,
@@ -861,6 +862,17 @@ impl ChainSwap {
 
         Ok(create_response_json)
     }
+
+    pub(crate) fn is_amount_mismatch(&self) -> bool {
+        match self.actual_payer_amount_sat {
+            Some(actual_amount) => actual_amount != self.payer_amount_sat,
+            None => false,
+        }
+    }
+
+    pub(crate) fn is_waiting_fee_acceptance(&self) -> bool {
+        self.is_amount_mismatch() && self.accepted_receiver_amount_sat.is_none()
+    }
 }
 
 #[derive(Clone, Debug, Default)]
diff --git a/lib/core/src/persist/mod.rs b/lib/core/src/persist/mod.rs
index 85ddc62..15cee00 100644
--- a/lib/core/src/persist/mod.rs
+++ b/lib/core/src/persist/mod.rs
@@ -580,9 +580,12 @@ impl Persister {
                         let receiver_amount_sat =
                             match maybe_chain_swap_accepted_receiver_amount_sat {
                                 Some(accepted_receiver_amount_sat) => accepted_receiver_amount_sat,
-                                None => match maybe_chain_swap_actual_payer_amount_sat {
-                                    Some(_) => payer_amount_sat, // For over/underpaid chain swaps WaitingFeeAcceptance, show zero fees
-                                    None => maybe_chain_swap_receiver_amount_sat.unwrap_or(0),
+                                None => match (
+                                    maybe_chain_swap_actual_payer_amount_sat,
+                                    maybe_chain_swap_payer_amount_sat,
+                                ) {
+                                    (Some(actual), Some(expected)) if actual != expected => actual, // For over/underpaid chain swaps WaitingFeeAcceptance, show zero fees
+                                    _ => maybe_chain_swap_receiver_amount_sat.unwrap_or(0),
                                 },
                             };
                         let swapper_fees_sat = maybe_chain_swap_pair_fees
diff --git a/lib/core/src/recover/recoverer.rs b/lib/core/src/recover/recoverer.rs
index 2f1b549..bde28e1 100644
--- a/lib/core/src/recover/recoverer.rs
+++ b/lib/core/src/recover/recoverer.rs
@@ -212,20 +212,14 @@ impl Recoverer {
                             log::warn!("Could not apply recovered data for incoming Chain swap {swap_id}: recovery data not found");
                             continue;
                         };
-                        if chain_swap.payer_amount_sat != recovered_data.btc_user_lockup_amount_sat
-                        {
-                            chain_swap.actual_payer_amount_sat =
-                                Some(recovered_data.btc_user_lockup_amount_sat)
-                        }
+                        chain_swap.actual_payer_amount_sat =
+                            Some(recovered_data.btc_user_lockup_amount_sat);
                         let is_expired = bitcoin_height >= chain_swap.timeout_block_height;
                         let min_lockup_amount_sat = chain_swap.payer_amount_sat;
-                        let is_waiting_fee_acceptance =
-                            chain_swap.actual_payer_amount_sat.is_some()
-                                && chain_swap.accepted_receiver_amount_sat.is_none();
                         if let Some(new_state) = recovered_data.derive_partial_state(
                             min_lockup_amount_sat,
                             is_expired,
-                            is_waiting_fee_acceptance,
+                            chain_swap.is_waiting_fee_acceptance(),
                         ) {
                             chain_swap.state = new_state;
                         }