From c983b59ddcbea2494b19a93a5cb8bcebefcb4572 Mon Sep 17 00:00:00 2001
From: Nikita Vilunov <nikita@vilunov.me>
Date: Mon, 22 Apr 2024 21:27:14 +0200
Subject: [PATCH] fix

---
 crates/lavina-core/src/dialog.rs | 82 ++++++++++++++++++--------------
 1 file changed, 45 insertions(+), 37 deletions(-)

diff --git a/crates/lavina-core/src/dialog.rs b/crates/lavina-core/src/dialog.rs
index eae3915..f597295 100644
--- a/crates/lavina-core/src/dialog.rs
+++ b/crates/lavina-core/src/dialog.rs
@@ -60,51 +60,59 @@ impl DialogRegistry {
         body: Str,
         created_at: &DateTime<Utc>,
     ) -> Result<()> {
-        let guard = self.0.read().await;
+        let mut guard = self.0.read().await;
         let id = DialogId::new(from.clone(), to.clone());
         let dialog = guard.dialogs.get(&id);
         if let Some(d) = dialog {
             let mut d = d.write().await;
             guard.storage.increment_dialog_message_count(d.storage_id).await?;
             d.message_count += 1;
-            let Some(players) = &guard.players else {
-                tracing::error!("No player registry present");
-                return Ok(());
-            };
-            let Some(player) = players.get_player(&to).await else {
-                tracing::debug!("Player {to:?} not active, not sending message");
-                return Ok(());
-            };
-            let update = Updates::NewDialogMessage {
-                sender: from.clone(),
-                receiver: to.clone(),
-                body: body.clone(),
-                created_at: chrono::Utc::now(), // todo
-            };
-            player.update(update).await;
-            return Ok(());
-        }
-        drop(guard);
-        let mut guard = self.0.write().await;
-        let (p1, p2) = id.as_inner();
-        tracing::info!("Dialog {id:?} not found locally, trying to load from storage");
-        let stored_dialog = match guard.storage.retrieve_dialog(p1.as_inner(), p2.as_inner()).await? {
-            Some(t) => t,
-            None => {
-                tracing::info!("Dialog {id:?} does not exist, creating a new one in storage");
-                guard.storage.initialize_dialog(p1.as_inner(), p2.as_inner(), created_at).await?
+        } else {
+            drop(guard);
+            let mut guard2 = self.0.write().await;
+            // double check in case concurrent access has loaded this dialog
+            if let Some(d) = guard2.dialogs.get(&id) {
+                let mut d = d.write().await;
+                guard2.storage.increment_dialog_message_count(d.storage_id).await?;
+                d.message_count += 1;
+            } else {
+                let (p1, p2) = id.as_inner();
+                tracing::info!("Dialog {id:?} not found locally, trying to load from storage");
+                let stored_dialog = match guard2.storage.retrieve_dialog(p1.as_inner(), p2.as_inner()).await? {
+                    Some(t) => t,
+                    None => {
+                        tracing::info!("Dialog {id:?} does not exist, creating a new one in storage");
+                        guard2.storage.initialize_dialog(p1.as_inner(), p2.as_inner(), created_at).await?
+                    }
+                };
+                tracing::info!("Dialog {id:?} loaded");
+                guard2.storage.increment_dialog_message_count(stored_dialog.id).await?;
+                let dialog = Dialog {
+                    storage_id: stored_dialog.id,
+                    player_storage_id_1: stored_dialog.participant_1,
+                    player_storage_id_2: stored_dialog.participant_2,
+                    message_count: stored_dialog.message_count + 1,
+                };
+                guard2.dialogs.insert(id.clone(), AsyncRwLock::new(dialog));
             }
-        };
-        tracing::info!("Dialog {id:?} loaded");
-        guard.storage.increment_dialog_message_count(stored_dialog.id).await?;
-        let dialog = Dialog {
-            storage_id: stored_dialog.id,
-            player_storage_id_1: stored_dialog.participant_1,
-            player_storage_id_2: stored_dialog.participant_2,
-            message_count: stored_dialog.message_count + 1,
-        };
-        guard.dialogs.insert(id.clone(), AsyncRwLock::new(dialog));
+            guard = guard2.downgrade();
+        }
         // TODO send message to the other player and persist it
+        let Some(players) = &guard.players else {
+            tracing::error!("No player registry present");
+            return Ok(());
+        };
+        let Some(player) = players.get_player(&to).await else {
+            tracing::debug!("Player {to:?} not active, not sending message");
+            return Ok(());
+        };
+        let update = Updates::NewDialogMessage {
+            sender: from.clone(),
+            receiver: to.clone(),
+            body: body.clone(),
+            created_at: chrono::Utc::now(), // todo
+        };
+        player.update(update).await;
         return Ok(());
     }
 }