refactor(labrinth): combine logic for external notification endpoints (#6578)

* refactor(labrinth): combine logic for external notification endpoints

also introduce new notification that doesn't send an email

* style(labrinth): derive default

* feat(labrinth): return more detailed failure information for external
notifications

apps/labrinth/src/routes/internal/external_notifications.rs

@@ -1,3 +1,5 @@
+use std::collections::HashMap;
+
 use crate::auth::get_user_from_headers;
 use crate::database::PgPool;
 use crate::database::models::ids::{DBNotificationId, DBUserId};
@@ -5,26 +7,26 @@ use crate::database::models::notification_item::DBNotification;
 use crate::database::models::notification_item::NotificationBuilder;
 use crate::database::models::user_item::DBUser;
 use crate::database::redis::RedisPool;
+use crate::models::notifications::NotificationDeliveryStatus;
 use crate::models::users::Role;
-use crate::models::v3::notifications::{
-    Notification, NotificationBody, NotificationDeliveryStatus,
-};
+use crate::models::v3::notifications::{Notification, NotificationBody};
 use crate::models::v3::pats::Scopes;
 use crate::queue::email::EmailQueue;
 use crate::queue::session::AuthQueue;
 use crate::routes::ApiError;
+use crate::routes::internal::external_notifications::EmailFailure::{
+    FailedToSend, MailboxNotFound, UserNotFound,
+};
 use crate::routes::internal::statuses::broadcast_friends_message;
 use crate::sync::friends::RedisFriendsMessage;
 use crate::util::guards::external_notification_key_guard;
 use actix_web::http::StatusCode;
 use actix_web::web;
-use actix_web::{
-    CustomizeResponder, HttpRequest, HttpResponse, Responder, delete, post,
-};
+use actix_web::{HttpRequest, HttpResponse, delete, post};
 use ariadne::ids::UserId;
 use eyre::eyre;
 use lettre::message::Mailbox;
-use serde::Deserialize;
+use serde::{Deserialize, Serialize};
 
 pub fn config(cfg: &mut web::ServiceConfig) {
     cfg.service(create)
@@ -33,66 +35,72 @@ pub fn config(cfg: &mut web::ServiceConfig) {
         .service(send_custom_email);
 }
 
+#[derive(Deserialize, PartialEq, Default)]
+enum EmailStrategy {
+    #[default]
+    Async,
+    Sync,
+    None,
+}
+
 #[derive(Deserialize)]
 struct CreateNotification {
     pub body: NotificationBody,
     pub user_ids: Vec<UserId>,
+    #[serde(default)]
+    pub email: EmailStrategy,
+}
+
+#[derive(thiserror::Error, Debug, Serialize)]
+#[serde(tag = "type", content = "data")]
+enum EmailFailure {
+    #[error("user not found")]
+    UserNotFound,
+    #[error("mailbox not found")]
+    MailboxNotFound,
+    #[error("failed to send: {0:?}")]
+    FailedToSend(NotificationDeliveryStatus),
+    #[error("api error: {0}")]
+    ApiError(
+        #[serde(serialize_with = "serialize_api_error")]
+        #[from]
+        crate::routes::ApiError,
+    ),
+}
+
+fn serialize_api_error<S>(
+    error: &ApiError,
+    serializer: S,
+) -> Result<S::Ok, S::Error>
+where
+    S: serde::Serializer,
+{
+    error.as_api_error().serialize(serializer)
 }
 
 #[post("external_notifications", guard = "external_notification_key_guard")]
 pub async fn create(
     pool: web::Data<PgPool>,
     redis: web::Data<RedisPool>,
+    email_queue: web::Data<EmailQueue>,
     create_notification: web::Json<CreateNotification>,
-) -> Result<HttpResponse, ApiError> {
-    let CreateNotification { body, user_ids } =
-        create_notification.into_inner();
-    let user_ids = user_ids
-        .into_iter()
-        .map(|x| DBUserId(x.0 as i64))
-        .collect::<Vec<_>>();
-
-    let mut txn = pool.begin().await?;
-
-    if !DBUser::exists_many(&user_ids, &mut txn).await? {
-        return Err(ApiError::InvalidInput(
-            "One of the specified users do not exist.".to_owned(),
-        ));
-    }
-
-    let notification_ids = NotificationBuilder { body }
-        .insert_many(user_ids, &mut txn, &redis)
-        .await?;
-
-    let notifications =
-        get_site_exposed_notifications(&notification_ids, &mut txn).await?;
-
-    txn.commit().await?;
-
-    broadcast_notifications(&redis, notifications).await;
-
-    Ok(HttpResponse::Accepted().finish())
+) -> Result<(web::Json<HashMap<UserId, EmailFailure>>, StatusCode), ApiError> {
+    create_impl(pool, redis, email_queue, create_notification.into_inner())
+        .await
 }
 
-/// Inserts notifications for all users and tries to send emails immediately.
-///
-/// Responds with the user IDs that could not be emailed:
-/// - `200` if every recipient was emailed (empty list)
-/// - `207` if some recipients could not be emailed (list of failed IDs)
-#[post(
-    "external_notifications/email-sync",
-    guard = "external_notification_key_guard"
-)]
-pub async fn create_email_sync(
+async fn create_impl(
     pool: web::Data<PgPool>,
     redis: web::Data<RedisPool>,
     email_queue: web::Data<EmailQueue>,
-    create_notification: web::Json<CreateNotification>,
-) -> Result<CustomizeResponder<web::Json<Vec<UserId>>>, ApiError> {
-    let CreateNotification { body, user_ids } =
-        create_notification.into_inner();
+    data: CreateNotification,
+) -> Result<(web::Json<HashMap<UserId, EmailFailure>>, StatusCode), ApiError> {
+    let CreateNotification {
+        body,
+        user_ids,
+        email: email_strategy,
+    } = data;
     let raw_user_ids = user_ids.iter().map(|x| x.0 as i64).collect::<Vec<_>>();
-
     let user_ids = raw_user_ids
         .iter()
         .map(|x| DBUserId(*x))
@@ -129,9 +137,21 @@ pub async fn create_email_sync(
         .filter(|id| !already_notified.contains(id))
         .collect::<Vec<_>>();
 
-    let notification_ids = NotificationBuilder { body: body.clone() }
-        .insert_many_without_delivery(notification_user_ids, &mut txn, &redis)
-        .await?;
+    let notification_builder = NotificationBuilder { body: body.clone() };
+
+    let notification_ids = if email_strategy == EmailStrategy::Async {
+        notification_builder
+            .insert_many(notification_user_ids, &mut txn, &redis)
+            .await?
+    } else {
+        notification_builder
+            .insert_many_without_delivery(
+                notification_user_ids,
+                &mut txn,
+                &redis,
+            )
+            .await?
+    };
 
     let notifications =
         get_site_exposed_notifications(&notification_ids, &mut txn).await?;
@@ -140,42 +160,98 @@ pub async fn create_email_sync(
 
     broadcast_notifications(&redis, notifications).await;
 
-    let mut email_txn = pool.begin().await?;
+    if email_strategy == EmailStrategy::Sync {
+        let mut email_txn = pool.begin().await?;
 
-    let mut failed = Vec::new();
-    for user_id in &user_ids {
-        let Some(user) =
-            DBUser::get_id(*user_id, &mut email_txn, &redis).await?
-        else {
-            failed.push(UserId(user_id.0 as u64));
-            continue;
-        };
+        let mut failed = HashMap::new();
+        let users = DBUser::get_many_ids(&user_ids, &mut email_txn, &redis)
+            .await?
+            .into_iter()
+            .map(|user| (user.id, user))
+            .collect::<HashMap<_, _>>();
 
-        let delivered = match user
-            .email
-            .and_then(|email| email.parse::<Mailbox>().ok())
-        {
-            Some(mailbox) => {
-                email_queue
-                    .send_one(&mut email_txn, body.clone(), *user_id, mailbox)
-                    .await?
-                    == NotificationDeliveryStatus::Delivered
-            }
-            None => false,
-        };
+        for db_user_id in &user_ids {
+            let user_id = UserId(db_user_id.0 as u64);
+            let Some(user) = users.get(db_user_id) else {
+                failed.insert(user_id, UserNotFound);
+                continue;
+            };
 
-        if !delivered {
-            failed.push(UserId(user_id.0 as u64));
+            let Some(mailbox) = user
+                .email
+                .as_ref()
+                .and_then(|email| email.parse::<Mailbox>().ok())
+            else {
+                failed.insert(user_id, MailboxNotFound);
+                continue;
+            };
+
+            match email_queue
+                .send_one(&mut email_txn, body.clone(), *db_user_id, mailbox)
+                .await
+            {
+                Ok(status) => {
+                    if status != NotificationDeliveryStatus::Delivered {
+                        failed.insert(user_id, FailedToSend(status));
+                    }
+                }
+                Err(error) => {
+                    if matches!(
+                        error,
+                        ApiError::SqlxDatabase(_) | ApiError::Database(_)
+                    ) {
+                        return Err(error);
+                    };
+                    failed.insert(user_id, error.into());
+                }
+            };
         }
+
+        email_txn.commit().await?;
+
+        let status = if failed
+            .values()
+            .any(|x| matches!(x, EmailFailure::ApiError(_)))
+        {
+            StatusCode::INTERNAL_SERVER_ERROR
+        } else {
+            StatusCode::OK
+        };
+
+        return Ok((web::Json(failed), status));
     }
 
-    let status = if failed.is_empty() {
-        StatusCode::OK
-    } else {
-        StatusCode::MULTI_STATUS
-    };
+    Ok((web::Json(HashMap::new()), StatusCode::ACCEPTED))
+}
 
-    Ok(web::Json(failed).customize().with_status(status))
+/// Inserts notifications for all users and tries to send emails immediately.
+///
+/// Responds with the user IDs that could not be emailed and a reason why
+#[post(
+    "external_notifications/email-sync",
+    guard = "external_notification_key_guard"
+)]
+pub async fn create_email_sync(
+    pool: web::Data<PgPool>,
+    redis: web::Data<RedisPool>,
+    email_queue: web::Data<EmailQueue>,
+    data: web::Json<CreateNotification>,
+) -> Result<(web::Json<Vec<UserId>>, StatusCode), ApiError> {
+    let data = data.into_inner();
+    create_impl(
+        pool,
+        redis,
+        email_queue,
+        CreateNotification {
+            body: data.body,
+            user_ids: data.user_ids,
+            email: EmailStrategy::Sync,
+        },
+    )
+    .await
+    .map(|(res, code)| {
+        (web::Json(res.into_inner().into_keys().collect()), code)
+    })
 }
 
 #[derive(Deserialize)]