From 213f98b2e7a522f1396a34d660d3e3ac77703331 Mon Sep 17 00:00:00 2001
From: oyindamola oladapo <oyinoladapo5@gmail.com>
Date: Mon, 15 Sep 2025 12:09:27 +0100
Subject: [PATCH] fix: improve error handling when no spendable UTXOs

Previously, attempting payjoin operations with an empty wallet resulted in a generic "500 Internal Server Error" from bitcoind. This created a poor user experience because users could not understand why their payjoin failed or what action to take.
---
 payjoin-cli/src/app/mod.rs    | 7 +++++++
 payjoin-cli/src/app/v1.rs     | 9 +++++++++
 payjoin-cli/src/app/v2/mod.rs | 6 ++++++
 payjoin-cli/src/app/wallet.rs | 6 ++++++
 4 files changed, 28 insertions(+)

diff --git a/payjoin-cli/src/app/mod.rs b/payjoin-cli/src/app/mod.rs
index 2c7898d8b..a54509c95 100644
--- a/payjoin-cli/src/app/mod.rs
+++ b/payjoin-cli/src/app/mod.rs
@@ -34,6 +34,13 @@ pub trait App: Send + Sync {
         amount: Amount,
         fee_rate: FeeRate,
     ) -> Result<Psbt> {
+        // Check if wallet has spendable UTXOs before attempting to create PSBT
+        if !self.wallet().has_spendable_utxos()? {
+            return Err(anyhow::anyhow!(
+                "No spendable UTXOs available in wallet. Please ensure your wallet has confirmed funds."
+            ));
+        }
+
         // wallet_create_funded_psbt requires a HashMap<address: String, Amount>
         let mut outputs = HashMap::with_capacity(1);
         outputs.insert(address.to_string(), amount);
diff --git a/payjoin-cli/src/app/v1.rs b/payjoin-cli/src/app/v1.rs
index 4958afe24..2e344c4f0 100644
--- a/payjoin-cli/src/app/v1.rs
+++ b/payjoin-cli/src/app/v1.rs
@@ -378,6 +378,15 @@ fn try_contributing_inputs(
     let candidate_inputs =
         wallet.list_unspent().map_err(|e| ImplementationError::from(e.into_boxed_dyn_error()))?;
 
+    if candidate_inputs.is_empty() {
+        return Err(ImplementationError::from(
+            anyhow::anyhow!(
+                "No spendable UTXOs available in wallet. Please fund your wallet before resuming this session"
+            )
+            .into_boxed_dyn_error(),
+        ));
+    }
+
     let selected_input =
         payjoin.try_preserving_privacy(candidate_inputs).map_err(ImplementationError::new)?;
 
diff --git a/payjoin-cli/src/app/v2/mod.rs b/payjoin-cli/src/app/v2/mod.rs
index 5562dec33..6a7a73759 100644
--- a/payjoin-cli/src/app/v2/mod.rs
+++ b/payjoin-cli/src/app/v2/mod.rs
@@ -473,6 +473,12 @@ impl App {
         let wallet = self.wallet();
         let candidate_inputs = wallet.list_unspent()?;
 
+        if candidate_inputs.is_empty() {
+            return Err(anyhow::anyhow!(
+                "No spendable UTXOs available in wallet. Cannot contribute inputs to payjoin."
+            ));
+        }
+
         let selected_input = proposal.try_preserving_privacy(candidate_inputs)?;
         let proposal =
             proposal.contribute_inputs(vec![selected_input])?.commit_inputs().save(persister)?;
diff --git a/payjoin-cli/src/app/wallet.rs b/payjoin-cli/src/app/wallet.rs
index bebf9e44e..e15dfcaef 100644
--- a/payjoin-cli/src/app/wallet.rs
+++ b/payjoin-cli/src/app/wallet.rs
@@ -164,6 +164,12 @@ impl BitcoindWallet {
         Ok(unspent.into_iter().map(input_pair_from_corepc).collect())
     }
 
+    /// Check if wallet has any spendable UTXOs
+    pub fn has_spendable_utxos(&self) -> Result<bool> {
+        let unspent = self.list_unspent()?;
+        Ok(!unspent.is_empty())
+    }
+
     /// Get the network this wallet is operating on
     pub fn network(&self) -> Result<Network> {
         tokio::task::block_in_place(|| {