[🐴] Decrement app badge when opening unread chat (#4040)

* decrement badge count for chats

* handle decrement in `useMarkAsRead`

* remove async

* oops

src/lib/hooks/useNotificationHandler.ts

@@ -169,10 +169,11 @@ export function useNotificationsHandler() {
           payload.reason === 'chat-message' &&
           payload.recipientDid === currentAccount?.did
         ) {
+          const isCurrentConvo = payload.convoId === currentConvoId
           return {
-            shouldShowAlert: payload.convoId !== currentConvoId,
+            shouldShowAlert: !isCurrentConvo,
             shouldPlaySound: false,
-            shouldSetBadge: false,
+            shouldSetBadge: !isCurrentConvo,
           }
         }
 

src/lib/notifications/notifications.ts

@@ -1,5 +1,6 @@
 import React from 'react'
 import * as Notifications from 'expo-notifications'
+import {getBadgeCountAsync, setBadgeCountAsync} from 'expo-notifications'
 import {BskyAgent} from '@atproto/api'
 
 import {logger} from '#/logger'
@@ -109,3 +110,14 @@ export function useRequestNotificationsPermission() {
     [gate],
   )
 }
+
+export async function decrementBadgeCount(by = 1) {
+  if (!isNative) return
+
+  const currCount = await getBadgeCountAsync()
+  let newCount = currCount - by
+  if (newCount < 0) {
+    newCount = 0
+  }
+  await setBadgeCountAsync(newCount)
+}