fix(api): harden broadcast and assistant fallback errors

packages/api/src/router/notification.ts

@@ -63,6 +63,31 @@ async function sendNotificationEmail(
   }
 }
 
+function rethrowNotificationReferenceError(error: unknown): never {
+  const candidate = error as {
+    code?: unknown;
+    message?: unknown;
+    meta?: { field_name?: unknown };
+  };
+  const fieldName = typeof candidate.meta?.field_name === "string"
+    ? candidate.meta.field_name.toLowerCase()
+    : "";
+
+  if (
+    typeof candidate.code === "string"
+    && (candidate.code === "P2003" || candidate.code === "P2025")
+    && fieldName.includes("sender")
+  ) {
+    throw new TRPCError({
+      code: "NOT_FOUND",
+      message: "Sender user not found",
+      cause: error,
+    });
+  }
+
+  throw error;
+}
+
 // ─── Zod Enums ────────────────────────────────────────────────────────────────
 
 const categoryEnum = z.enum(["NOTIFICATION", "REMINDER", "TASK", "APPROVAL"]);
@@ -590,28 +615,26 @@ export const notificationRouter = createTRPCRouter({
     .mutation(async ({ ctx, input }) => {
       const senderId = ctx.dbUser.id;
 
-      // 1. Create broadcast record
-      const broadcast = await ctx.db.notificationBroadcast.create({
-        data: {
-          senderId,
-          title: input.title,
-          ...(input.body !== undefined ? { body: input.body } : {}),
-          ...(input.link !== undefined ? { link: input.link } : {}),
-          category: input.category,
-          priority: input.priority,
-          channel: input.channel,
-          targetType: input.targetType,
-          ...(input.targetValue !== undefined ? { targetValue: input.targetValue } : {}),
-          ...(input.scheduledAt !== undefined ? { scheduledAt: input.scheduledAt } : {}),
-        },
-      });
-
-      // 2. If scheduled in the future, just return the broadcast
+      // Scheduled broadcasts can be stored immediately because fan-out is deferred.
       if (input.scheduledAt && input.scheduledAt > new Date()) {
-        return broadcast;
+        return ctx.db.notificationBroadcast.create({
+          data: {
+            senderId,
+            title: input.title,
+            ...(input.body !== undefined ? { body: input.body } : {}),
+            ...(input.link !== undefined ? { link: input.link } : {}),
+            category: input.category,
+            priority: input.priority,
+            channel: input.channel,
+            targetType: input.targetType,
+            ...(input.targetValue !== undefined ? { targetValue: input.targetValue } : {}),
+            ...(input.scheduledAt !== undefined ? { scheduledAt: input.scheduledAt } : {}),
+          },
+        });
       }
 
-      // 3. Resolve recipients
+      // Resolve recipients before persisting immediate broadcasts so empty targets
+      // do not leave orphaned broadcast rows behind.
       const recipientIds = await resolveRecipients(
         input.targetType,
         input.targetValue,
@@ -626,6 +649,26 @@ export const notificationRouter = createTRPCRouter({
         });
       }
 
+      let broadcast;
+      try {
+        broadcast = await ctx.db.notificationBroadcast.create({
+          data: {
+            senderId,
+            title: input.title,
+            ...(input.body !== undefined ? { body: input.body } : {}),
+            ...(input.link !== undefined ? { link: input.link } : {}),
+            category: input.category,
+            priority: input.priority,
+            channel: input.channel,
+            targetType: input.targetType,
+            ...(input.targetValue !== undefined ? { targetValue: input.targetValue } : {}),
+            ...(input.scheduledAt !== undefined ? { scheduledAt: input.scheduledAt } : {}),
+          },
+        });
+      } catch (error) {
+        rethrowNotificationReferenceError(error);
+      }
+
       // 4. Create individual notifications for each recipient
       const isTask = input.category === "TASK" || input.category === "APPROVAL";