Delete os notification channel when unused

When deleting local channel from the UI

app/src/main/java/org/unifiedpush/distributor/nextpush/LocalNotification.kt

@@ -1,6 +1,9 @@
 package org.unifiedpush.distributor.nextpush
 
+import android.app.NotificationManager
 import android.content.Context
+import android.os.Build
+import androidx.annotation.RequiresApi
 import java.util.UUID
 import org.unifiedpush.distributor.nextpush.Database.Companion.getDb
 import org.unifiedpush.distributor.nextpush.api.Api
@@ -20,4 +23,20 @@ object LocalNotification {
         val title = getDb(context).getNotificationTitle(connectorToken) ?: context.getString(R.string.app_name)
         FromPushNotification(context, title, content).showBig()
     }
+
+    /**
+     * Remove the notification channel registered to the OS
+     */
+    @RequiresApi(Build.VERSION_CODES.O)
+    fun removeOsNotificationChannel(context: Context, connectorToken: String) {
+        val title = getDb(context).getNotificationTitle(connectorToken) ?: return
+        val notificationManager = context.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
+        notificationManager.deleteNotificationChannel(
+            getNotificationChannelId(context, title)
+        )
+    }
+
+    fun getNotificationChannelId(context: Context, title: String): String {
+        return "${context.getString(R.string.app_name)}.Push.$title"
+    }
 }

app/src/main/java/org/unifiedpush/distributor/nextpush/distributor/Distributor.kt

@@ -2,6 +2,7 @@ package org.unifiedpush.distributor.nextpush.distributor
 
 import android.content.Context
 import android.content.Intent
+import android.os.Build
 import android.util.Log
 import org.unifiedpush.distributor.nextpush.Database
 import org.unifiedpush.distributor.nextpush.Database.Companion.getDb
@@ -61,9 +62,20 @@ object Distributor {
         context.sendBroadcast(broadcastIntent)
     }
 
+    /**
+     * Send UNREGISTERED action.
+     *
+     * If this is for a local application: we remove the notification channel instead
+     */
     private fun sendUnregistered(context: Context, connectorToken: String) {
-        val application = getApp(context, connectorToken)
-        if (application.isNullOrBlank()) {
+        val application = getApp(context, connectorToken) ?: return
+        if (application == context.packageName) {
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+                LocalNotification.removeOsNotificationChannel(
+                    context,
+                    connectorToken
+                )
+            }
             return
         }
         val broadcastIntent = Intent()

app/src/main/java/org/unifiedpush/distributor/nextpush/utils/Notifications.kt

@@ -14,6 +14,7 @@ import androidx.core.app.ActivityCompat
 import androidx.core.app.NotificationManagerCompat
 import java.util.concurrent.atomic.AtomicBoolean
 import java.util.concurrent.atomic.AtomicInteger
+import org.unifiedpush.distributor.nextpush.LocalNotification
 import org.unifiedpush.distributor.nextpush.R
 import org.unifiedpush.distributor.nextpush.activities.MainActivity
 import org.unifiedpush.distributor.nextpush.services.RegistrationCountCache
@@ -280,8 +281,8 @@ class FromPushNotification(context: Context, title: String, content: String) : A
         false
     ),
     ChannelData(
-        "${context.getString(R.string.app_name)}.Push.$title",
-        "(Push) $title",
+        LocalNotification.getNotificationChannelId(context, title),
+        context.getString(R.string.list_registrations_local_title, title),
         NotificationManager.IMPORTANCE_HIGH,
         context.getString(R.string.list_registrations_local_description)
     )