Fix missing push notifications for thread subscriptions (#1843)

* Fix missing push notifications for thread subscriptions

* Filter by comments in calling context

* Fix mutes not considered

* Fix duplicate push notification (reply+thread subscription) sent

api/paidAction/itemCreate.js

@@ -1,5 +1,5 @@
 import { ANON_ITEM_SPAM_INTERVAL, ITEM_SPAM_INTERVAL, PAID_ACTION_PAYMENT_METHODS, USER_ID } from '@/lib/constants'
-import { notifyItemMention, notifyItemParents, notifyMention, notifyTerritorySubscribers, notifyUserSubscribers } from '@/lib/webPush'
+import { notifyItemMention, notifyItemParents, notifyMention, notifyTerritorySubscribers, notifyUserSubscribers, notifyThreadSubscribers } from '@/lib/webPush'
 import { getItemMentions, getMentions, performBotBehavior } from './lib/item'
 import { msatsToSats, satsToMsats } from '@/lib/format'
 import { GqlInputError } from '@/lib/error'
@@ -259,6 +259,7 @@ export async function nonCriticalSideEffects ({ invoice, id }, { models }) {
 
   if (item.parentId) {
     notifyItemParents({ item, models }).catch(console.error)
+    notifyThreadSubscribers({ models, item }).catch(console.error)
   }
   for (const { userId } of item.mentions) {
     notifyMention({ models, item, userId }).catch(console.error)

lib/webPush.js

@@ -202,6 +202,44 @@ export const notifyTerritorySubscribers = async ({ models, item }) => {
   }
 }
 
+export const notifyThreadSubscribers = async ({ models, item }) => {
+  try {
+    const author = await models.user.findUnique({ where: { id: item.userId } })
+
+    const subscribers = await models.$queryRaw`
+      SELECT DISTINCT "ThreadSubscription"."userId" FROM "ThreadSubscription"
+      JOIN users ON users.id = "ThreadSubscription"."userId"
+      JOIN "Reply" r ON "ThreadSubscription"."itemId" = r."ancestorId"
+      WHERE r."itemId" = ${item.id}
+      -- don't send notifications for own items
+      AND r."userId" <> "ThreadSubscription"."userId"
+      -- send notifications for all levels?
+      AND CASE WHEN users."noteAllDescendants" THEN TRUE ELSE r.level = 1 END
+      -- muted?
+      AND NOT EXISTS (SELECT 1 FROM "Mute" m WHERE m."muterId" = users.id AND m."mutedId" = r."userId")
+      -- already received notification as reply to self?
+      AND NOT EXISTS (
+        SELECT 1 FROM "Item" i
+        JOIN "Item" p ON p.path @> i.path
+        WHERE i.id = ${item.parentId} AND p."userId" = "ThreadSubscription"."userId" AND users."noteAllDescendants"
+      )`
+
+    await Promise.allSettled(subscribers.map(({ userId }) =>
+      sendUserNotification(userId, {
+        // we reuse the same payload as for user subscriptions because they use the same title+body we want to use here
+        // so we should also merge them together (= same tag+data) to avoid confusion
+        title: `@${author.name} replied to a post`,
+        body: item.text,
+        item,
+        data: { followeeName: author.name, subType: 'COMMENT' },
+        tag: `FOLLOW-${author.id}-COMMENT`
+      })
+    ))
+  } catch (err) {
+    console.error(err)
+  }
+}
+
 export const notifyItemParents = async ({ models, item }) => {
   try {
     const user = await models.user.findUnique({ where: { id: item.userId } })