Fix rpc-error due to quick transaction lookup

This pr addresses an error that occurs due to rpc client
looking up the transaction right before it's on chain .
Error: Transient error: Implementation error: Obtained failure status(500): Internal Server Error

The delay introduced allows the transaction to broadcasted on chain before the lookup

fix format issue

fix long pooling test

Implement pooling mechanism for transaction check

Implement pooling mechanism for transaction check

fix rpc error

fix rpc error

fix lint error

Author: zealsham

payjoin-cli/src/app/v2/mod.rs

@@ -738,21 +738,54 @@ impl App {
         persister: &ReceiverPersister,
     ) -> Result<()> {
         // On a session resumption, the receiver will resume again in this state.
-        let _ = proposal
-            .check_payment(
-                |txid| {
-                    self.wallet()
-                        .get_raw_transaction(&txid)
-                        .map_err(|e| ImplementationError::from(e.into_boxed_dyn_error()))
-                },
-                |outpoint| {
-                    self.wallet()
-                        .is_outpoint_spent(&outpoint)
-                        .map_err(|e| ImplementationError::from(e.into_boxed_dyn_error()))
-                },
-            )
-            .save(persister)?;
-        Ok(())
+        let poll_interval = tokio::time::Duration::from_millis(200);
+        let timeout_duration = tokio::time::Duration::from_secs(5);
+
+        let mut interval = tokio::time::interval(poll_interval);
+        interval.tick().await;
+
+        tracing::debug!("Polling for payment confirmation");
+
+        let result = tokio::time::timeout(timeout_duration, async {
+            loop {
+                interval.tick().await;
+                let check_result = proposal
+                    .check_payment(
+                        |txid| {
+                            self.wallet()
+                                .get_raw_transaction(&txid)
+                                .map_err(|e| ImplementationError::from(e.into_boxed_dyn_error()))
+                        },
+                        |outpoint| {
+                            self.wallet()
+                                .is_outpoint_spent(&outpoint)
+                                .map_err(|e| ImplementationError::from(e.into_boxed_dyn_error()))
+                        },
+                    )
+                    .save(persister);
+
+                match check_result {
+                    Ok(_) => {
+                        println!("Payjoin transaction detected in the mempool!");
+                        return Ok(());
+                    }
+                    Err(_) => {
+                        // keep polling
+
+                        continue;
+                    }
+                }
+            }
+        })
+        .await;
+
+        match result {
+            Ok(ok) => ok,
+            Err(_) => Err(anyhow!(
+                "Timeout waiting for payment confirmation after {:?}",
+                timeout_duration
+            )),
+        }
     }
 
     async fn unwrap_relay_or_else_fetch(