From 33a7016d65394622ad0f9f751468867c69e90a9d Mon Sep 17 00:00:00 2001
From: Mariusz Klochowicz <mariusz@klochowicz.com>
Date: Mon, 18 Sep 2023 15:33:19 -0700
Subject: [PATCH] feat: Send a notification prompt when executing AsyncTrade

When the other party is not online, send a notification that a position has expired.
---
 coordinator/src/bin/coordinator.rs   | 10 +++++++---
 coordinator/src/notifications.rs     | 16 +++++++++++++---
 coordinator/src/orderbook/trading.rs | 25 +++++++++++++++++++++++--
 3 files changed, 43 insertions(+), 8 deletions(-)

diff --git a/coordinator/src/bin/coordinator.rs b/coordinator/src/bin/coordinator.rs
index 87cf6a950..6eef98141 100644
--- a/coordinator/src/bin/coordinator.rs
+++ b/coordinator/src/bin/coordinator.rs
@@ -194,8 +194,14 @@ async fn main() -> Result<()> {
         }
     });
 
+    let notification_service = NotificationService::new(opts.fcm_api_key);
+
     let (tx_price_feed, _rx) = broadcast::channel(100);
-    let (_handle, trading_sender) = trading::start(pool.clone(), tx_price_feed.clone());
+    let (_handle, trading_sender) = trading::start(
+        pool.clone(),
+        tx_price_feed.clone(),
+        notification_service.get_sender(),
+    );
 
     tokio::spawn({
         let node = node.clone();
@@ -239,8 +245,6 @@ async fn main() -> Result<()> {
         tx_price_feed,
     );
 
-    let notification_service = NotificationService::new(opts.fcm_api_key);
-
     tokio::spawn({
         let sender = notification_service.get_sender();
         let pool = pool.clone();
diff --git a/coordinator/src/notifications.rs b/coordinator/src/notifications.rs
index c5e283a07..35416e8e5 100644
--- a/coordinator/src/notifications.rs
+++ b/coordinator/src/notifications.rs
@@ -124,7 +124,18 @@ fn build_notification<'a>(kind: NotificationKind) -> fcm::Notification<'a> {
 }
 
 #[derive(Clone, Debug, PartialEq, Eq)]
-pub struct FcmToken(pub String);
+pub struct FcmToken(String);
+
+impl FcmToken {
+    pub fn new(token: String) -> Result<Self> {
+        anyhow::ensure!(!token.is_empty(), "FCM token cannot be empty");
+        Ok(Self(token))
+    }
+
+    pub fn get(&self) -> &str {
+        &self.0
+    }
+}
 
 impl Display for FcmToken {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
@@ -140,7 +151,7 @@ async fn send_notification<'a>(
 ) -> Result<()> {
     anyhow::ensure!(!api_key.is_empty(), "FCM API key is empty");
 
-    let mut message_builder = fcm::MessageBuilder::new(api_key, &fcm_token.0);
+    let mut message_builder = fcm::MessageBuilder::new(api_key, fcm_token.get());
     message_builder.notification(notification);
     let message = message_builder.finalize();
     let response = client
@@ -353,4 +364,3 @@ pub mod tests {
         assert_eq!(notification.user_fcm_token, position_just_expired.1);
     }
 }
-
diff --git a/coordinator/src/orderbook/trading.rs b/coordinator/src/orderbook/trading.rs
index 471fa99f1..8ca9dfc35 100644
--- a/coordinator/src/orderbook/trading.rs
+++ b/coordinator/src/orderbook/trading.rs
@@ -1,3 +1,7 @@
+use crate::db::user;
+use crate::notifications::FcmToken;
+use crate::notifications::Notification;
+use crate::notifications::NotificationKind;
 use crate::orderbook::db::matches;
 use crate::orderbook::db::orders;
 use anyhow::anyhow;
@@ -96,6 +100,7 @@ impl From<&TradeParams> for TraderMatchParams {
 pub fn start(
     pool: Pool<ConnectionManager<PgConnection>>,
     tx_price_feed: broadcast::Sender<OrderbookMsg>,
+    notification_sender: mpsc::Sender<Notification>,
 ) -> (RemoteHandle<Result<()>>, mpsc::Sender<TradingMessage>) {
     let (sender, mut receiver) = mpsc::channel::<TradingMessage>(TRADING_MESSAGES_BUFFER_SIZE);
 
@@ -110,9 +115,10 @@ pub fn start(
                         let mut conn = pool.get()?;
                         let authenticated_users = authenticated_users.clone();
                         let tx_price_feed = tx_price_feed.clone();
+                        let notification_sender = notification_sender.clone();
                         async move {
                             let new_order = new_order_msg.new_order;
-                            let result = process_new_order(&mut conn, tx_price_feed, new_order, new_order_msg.order_reason, &authenticated_users)
+                            let result = process_new_order(&mut conn, tx_price_feed, new_order, new_order_msg.order_reason, &authenticated_users, notification_sender)
                                 .await;
                             if let Err(e) = new_order_msg.sender.send(result).await {
                                 tracing::error!("Failed to send new order message! Error: {e:#}");
@@ -160,6 +166,7 @@ async fn process_new_order(
     new_order: NewOrder,
     order_reason: OrderReason,
     authenticated_users: &HashMap<PublicKey, mpsc::Sender<OrderbookMsg>>,
+    notification_sender: mpsc::Sender<Notification>,
 ) -> Result<Order> {
     tracing::info!(trader_id=%new_order.trader_id, "Received a new {:?} order", new_order.order_type);
 
@@ -246,7 +253,21 @@ async fn process_new_order(
                 }
                 Err(e) => {
                     tracing::warn!(%trader_id, order_id, "{e:#}");
-                    // todo(holzeis): send push notification to user
+
+                    if let Some(user) = user::by_id(conn, trader_id.to_string())? {
+                        tracing::debug!(%trader_id, order_id, "Sending push notification to user");
+
+                        if let Ok(fcm_token) = FcmToken::new(user.fcm_token) {
+                            notification_sender
+                                .send(Notification {
+                                    user_fcm_token: fcm_token,
+                                    notification_kind: NotificationKind::PositionExpired,
+                                })
+                                .await?;
+                        }
+                    } else {
+                        tracing::warn!(%trader_id, order_id, "User has no FCM token");
+                    }
 
                     if order.order_type == OrderType::Limit {
                         // FIXME: The maker is currently not connected to the web socket so we