From e297a4468aaf94484a2276857fec6d6e7a9866fd Mon Sep 17 00:00:00 2001
From: Thomas Eizinger <thomas@eizinger.io>
Date: Thu, 18 Nov 2021 18:07:50 +1100
Subject: [PATCH] Simplify invoking `oracle::GetAnnouncement`

Moving the error message into the handler reduces complexity in the
cfd actor.
---
 daemon/src/maker_cfd.rs              |  3 +--
 daemon/src/oracle.rs                 |  7 ++++++-
 daemon/tests/harness/mocks/mod.rs    |  2 +-
 daemon/tests/harness/mocks/oracle.rs | 10 ++++++++--
 4 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/daemon/src/maker_cfd.rs b/daemon/src/maker_cfd.rs
index eb86ee0..2b8673f 100644
--- a/daemon/src/maker_cfd.rs
+++ b/daemon/src/maker_cfd.rs
@@ -580,8 +580,7 @@ where
         let offer_announcement = self
             .oracle_actor
             .send(oracle::GetAnnouncement(cfd.order.oracle_event_id))
-            .await?
-            .with_context(|| format!("Announcement {} not found", cfd.order.oracle_event_id))?;
+            .await??;
 
         // 3. Notify the taker that we are ready for contract setup
         // Use `.send` here to ensure we only continue once the message has been sent
diff --git a/daemon/src/oracle.rs b/daemon/src/oracle.rs
index 872f6df..edf2f0a 100644
--- a/daemon/src/oracle.rs
+++ b/daemon/src/oracle.rs
@@ -218,7 +218,7 @@ impl Actor {
         &mut self,
         msg: GetAnnouncement,
         _ctx: &mut xtra::Context<Self>,
-    ) -> Option<Announcement> {
+    ) -> Result<Announcement, NoAnnouncement> {
         self.announcements
             .get_key_value(&msg.0)
             .map(|(id, (time, nonce_pks))| Announcement {
@@ -226,6 +226,7 @@ impl Actor {
                 expected_outcome_time: *time,
                 nonce_pks: nonce_pks.clone(),
             })
+            .ok_or(NoAnnouncement(msg.0))
     }
 
     fn handle_new_announcement_fetched(
@@ -243,6 +244,10 @@ impl Actor {
     }
 }
 
+#[derive(Debug, Clone, thiserror::Error)]
+#[error("Announcement {0} not found")]
+pub struct NoAnnouncement(pub BitMexPriceEventId);
+
 #[async_trait]
 impl xtra::Handler<NewAttestationFetched> for Actor {
     async fn handle(&mut self, msg: NewAttestationFetched, _ctx: &mut xtra::Context<Self>) {
diff --git a/daemon/tests/harness/mocks/mod.rs b/daemon/tests/harness/mocks/mod.rs
index 03d806f..7ab066b 100644
--- a/daemon/tests/harness/mocks/mod.rs
+++ b/daemon/tests/harness/mocks/mod.rs
@@ -58,7 +58,7 @@ impl Mocks {
         self.oracle()
             .await
             .expect_get_announcement()
-            .return_const(Some(oracle::dummy_announcement()));
+            .return_const(Ok(oracle::dummy_announcement()));
     }
 
     pub async fn mock_oracle_monitor_attestation(&mut self) {
diff --git a/daemon/tests/harness/mocks/oracle.rs b/daemon/tests/harness/mocks/oracle.rs
index 4aca9d4..e64d959 100644
--- a/daemon/tests/harness/mocks/oracle.rs
+++ b/daemon/tests/harness/mocks/oracle.rs
@@ -18,7 +18,10 @@ impl Oracle for OracleActor {}
 
 #[xtra_productivity(message_impl = false)]
 impl OracleActor {
-    async fn handle(&mut self, msg: oracle::GetAnnouncement) -> Option<oracle::Announcement> {
+    async fn handle(
+        &mut self,
+        msg: oracle::GetAnnouncement,
+    ) -> Result<oracle::Announcement, oracle::NoAnnouncement> {
         self.mock.lock().await.get_announcement(msg)
     }
 
@@ -33,7 +36,10 @@ impl OracleActor {
 
 #[automock]
 pub trait Oracle {
-    fn get_announcement(&mut self, _msg: oracle::GetAnnouncement) -> Option<oracle::Announcement> {
+    fn get_announcement(
+        &mut self,
+        _msg: oracle::GetAnnouncement,
+    ) -> Result<oracle::Announcement, oracle::NoAnnouncement> {
         unreachable!("mockall will reimplement this method")
     }