Add push notifications

app/build.gradle

@@ -2,6 +2,7 @@ apply plugin: 'com.android.application'
 apply plugin: 'kotlin-android'
 apply plugin: 'kotlin-android-extensions'
 apply plugin: 'kotlin-kapt'
+apply plugin: 'com.google.gms.google-services'
 apply plugin: 'com.mikepenz.aboutlibraries.plugin'
 
 android {
@@ -39,7 +40,7 @@ dependencies {
     implementation 'androidx.appcompat:appcompat:1.2.0'
     implementation 'androidx.core:core-ktx:1.3.2'
     implementation 'com.google.android.material:material:1.3.0-alpha03'
-    implementation 'androidx.constraintlayout:constraintlayout:2.0.2'
+    implementation 'androidx.constraintlayout:constraintlayout:2.0.3'
     implementation 'androidx.lifecycle:lifecycle-extensions:2.2.0'
     implementation 'androidx.navigation:navigation-fragment-ktx:2.3.1'
     implementation 'androidx.navigation:navigation-ui-ktx:2.3.1'
@@ -60,4 +61,7 @@ dependencies {
     implementation 'com.github.tiper:MaterialSpinner:1.4.2'
     implementation "com.mikepenz:aboutlibraries-core:$about_libs_version"
     implementation "com.mikepenz:aboutlibraries:$about_libs_version"
+
+    implementation platform('com.google.firebase:firebase-bom:26.0.0')
+    implementation 'com.google.firebase:firebase-messaging-ktx'
 }

app/src/main/AndroidManifest.xml

@@ -37,7 +37,21 @@
                 <action android:name="android.intent.action.BOOT_COMPLETED" />
             </intent-filter>
         </receiver>
+
         <receiver android:name=".AlarmBroadcastReceiver" />
+
+        <service
+            android:name=".push.CircolappFirebaseMessagingService"
+            android:exported="false">
+            <intent-filter>
+                <action android:name="com.google.firebase.MESSAGING_EVENT" />
+            </intent-filter>
+        </service>
+
+        <meta-data
+            android:name="com.google.firebase.messaging.default_notification_icon"
+            android:resource="@drawable/ic_notification" />
+
     </application>
 
 </manifest>

app/src/main/java/net/underdesk/circolapp/SettingsActivity.kt

@@ -18,12 +18,14 @@
 
 package net.underdesk.circolapp
 
+import android.content.SharedPreferences
 import android.os.Bundle
 import android.text.InputType
 import androidx.appcompat.app.AppCompatActivity
 import androidx.appcompat.app.AppCompatDelegate
 import androidx.preference.*
 import kotlinx.android.synthetic.main.settings_activity.*
+import net.underdesk.circolapp.push.FirebaseTopicUtils
 import net.underdesk.circolapp.server.ServerAPI
 import net.underdesk.circolapp.works.PollWork
 
@@ -40,15 +42,19 @@ class SettingsActivity : AppCompatActivity() {
         supportActionBar?.setDisplayHomeAsUpEnabled(true)
     }
 
-    class SettingsFragment : PreferenceFragmentCompat() {
+    class SettingsFragment : PreferenceFragmentCompat(),
+        SharedPreferences.OnSharedPreferenceChangeListener {
         override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
             setPreferencesFromResource(R.xml.root_preferences, rootKey)
 
+            val sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context)
+            sharedPreferences.registerOnSharedPreferenceChangeListener(this)
+
             val schoolPreference = findPreference<ListPreference>("school")
             schoolPreference?.let { setSchoolListPreference(it) }
             val schoolPreferenceListener =
                 Preference.OnPreferenceChangeListener { _, value ->
-                    ServerAPI.changeServer(value.toString().toInt())
+                    ServerAPI.changeServer(value.toString().toInt(), requireContext())
                     true
                 }
             schoolPreference?.onPreferenceChangeListener = schoolPreferenceListener
@@ -69,17 +75,6 @@ class SettingsActivity : AppCompatActivity() {
             pollIntervalPreference?.setOnBindEditTextListener { editText ->
                 editText.inputType = InputType.TYPE_CLASS_NUMBER
             }
-
-            val notificationPreference =
-                findPreference<SwitchPreferenceCompat>("notify_new_circulars")
-
-            val notificationPrefChangedListener =
-                Preference.OnPreferenceChangeListener { _, _ ->
-                    activity?.let { PollWork.enqueue(it) }
-                    true
-                }
-            pollIntervalPreference?.onPreferenceChangeListener = notificationPrefChangedListener
-            notificationPreference?.onPreferenceChangeListener = notificationPrefChangedListener
         }
 
         private fun setSchoolListPreference(listPreference: ListPreference) {
@@ -96,5 +91,31 @@ class SettingsActivity : AppCompatActivity() {
             listPreference.entryValues = entryValues.toTypedArray()
             listPreference.entries = entryNames.toTypedArray()
         }
+
+        override fun onSharedPreferenceChanged(
+            sharedPreferences: SharedPreferences?,
+            key: String?
+        ) {
+            if (key != "notify_new_circulars" && key != "enable_polling" && key != "poll_interval")
+                return
+
+            if (sharedPreferences == null)
+                return
+
+            activity?.let { PollWork.enqueue(it) }
+
+            if (sharedPreferences.getBoolean(
+                    "notify_new_circulars",
+                    true
+                ) && !sharedPreferences.getBoolean("enable_polling", false)
+            ) {
+                val serverID = ServerAPI.getInstance(requireContext()).serverID()
+                val serverToken = ServerAPI.Companion.Servers.values()[serverID].toString()
+
+                FirebaseTopicUtils.selectTopic(serverToken, requireContext())
+            } else {
+                FirebaseTopicUtils.unsubscribe(requireContext())
+            }
+        }
     }
 }

app/src/main/java/net/underdesk/circolapp/fragments/intro/SchoolSelectionFragment.kt

@@ -53,7 +53,7 @@ class SchoolSelectionFragment : Fragment(), SlidePolicy, MaterialSpinner.OnItemS
         editor.putString("school", position.toString())
         editor.apply()
 
-        ServerAPI.changeServer(position)
+        ServerAPI.changeServer(position, requireContext())
         schoolSelected = true
 
         parent.error = null

app/src/main/java/net/underdesk/circolapp/push/CircolappFirebaseMessagingService.kt

@@ -0,0 +1,16 @@
+package net.underdesk.circolapp.push
+
+import android.annotation.SuppressLint
+import com.google.firebase.messaging.FirebaseMessagingService
+import com.google.firebase.messaging.RemoteMessage
+import net.underdesk.circolapp.works.PollWork
+
+// We don't need to get an Instance Token for topic notifications
+@SuppressLint("MissingFirebaseInstanceTokenRefresh")
+class CircolappFirebaseMessagingService : FirebaseMessagingService() {
+    override fun onMessageReceived(remoteMessage: RemoteMessage) {
+        if (remoteMessage.data.isNotEmpty()) {
+            PollWork.runWork(applicationContext)
+        }
+    }
+}

app/src/main/java/net/underdesk/circolapp/push/FirebaseTopicUtils.kt

@@ -0,0 +1,38 @@
+package net.underdesk.circolapp.push
+
+import android.content.Context
+import android.content.SharedPreferences
+import androidx.core.content.edit
+import androidx.preference.PreferenceManager
+import com.google.firebase.ktx.Firebase
+import com.google.firebase.messaging.ktx.messaging
+
+class FirebaseTopicUtils {
+    companion object {
+        fun selectTopic(newTopic: String, context: Context) {
+            val sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context)
+            unsubscribeFromTopic(sharedPreferences)
+
+            Firebase.messaging.subscribeToTopic(newTopic)
+
+            sharedPreferences.edit {
+                putString("topic", newTopic)
+            }
+        }
+
+        fun unsubscribe(context: Context) {
+            val sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context)
+
+            unsubscribeFromTopic(sharedPreferences)
+
+            sharedPreferences.edit {
+                putString("topic", null)
+            }
+        }
+
+        private fun unsubscribeFromTopic(sharedPreferences: SharedPreferences) {
+            val oldTopic = sharedPreferences.getString("topic", null)
+            oldTopic?.let { Firebase.messaging.unsubscribeFromTopic(it) }
+        }
+    }
+}

app/src/main/java/net/underdesk/circolapp/server/ServerAPI.kt

@@ -21,6 +21,7 @@ package net.underdesk.circolapp.server
 import android.content.Context
 import androidx.preference.PreferenceManager
 import net.underdesk.circolapp.data.Circular
+import net.underdesk.circolapp.push.FirebaseTopicUtils
 import net.underdesk.circolapp.server.curie.CurieServer
 import net.underdesk.circolapp.server.porporato.PorporatoServer
 
@@ -84,8 +85,18 @@ class ServerAPI(
             }
         }
 
-        fun changeServer(index: Int) {
-            instance?.changeServer(createServer(Servers.values()[index]))
+        fun changeServer(index: Int, context: Context) {
+            val sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context)
+            val newServer = Servers.values()[index]
+
+            if (sharedPreferences.getBoolean(
+                    "notify_new_circulars",
+                    true
+                ) && !sharedPreferences.getBoolean("enable_polling", false)
+            )
+                FirebaseTopicUtils.selectTopic(newServer.toString(), context)
+
+            instance?.changeServer(createServer(newServer))
         }
 
         private fun createServer(server: Servers) = when (server) {

app/src/main/java/net/underdesk/circolapp/works/PollWork.kt

@@ -65,7 +65,11 @@ class PollWork(appContext: Context, workerParams: WorkerParameters) :
         fun enqueue(context: Context) {
             val sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context)
 
-            if (sharedPreferences.getBoolean("notify_new_circulars", true)) {
+            if (sharedPreferences.getBoolean(
+                    "notify_new_circulars",
+                    true
+                ) && sharedPreferences.getBoolean("enable_polling", false)
+            ) {
                 WorkManager.getInstance(context)
                     .enqueueUniquePeriodicWork(
                         pollWorkName,
@@ -82,6 +86,11 @@ class PollWork(appContext: Context, workerParams: WorkerParameters) :
                     .cancelUniqueWork(pollWorkName)
             }
         }
+
+        fun runWork(context: Context) {
+            val oneTimeWork = OneTimeWorkRequestBuilder<PollWork>().build()
+            WorkManager.getInstance(context).enqueue(oneTimeWork)
+        }
     }
 
     override suspend fun doWork(): Result = coroutineScope {

app/src/main/res/values-it/strings.xml

@@ -15,8 +15,10 @@
     <string name="preferences_school">Scuola</string>
     <string name="preferences_dark_theme">Tema scuro</string>
     <string name="preferences_notify_new_circulars">Mostra notifiche</string>
+    <string name="preferences_polling">Esegui controllo dal telefono</string>
     <string name="preferences_poll_interval">Intervallo di sincronizzazione</string>
     <string name="preferences_notify_new_circulars_summary">Mostra una notifica quando una nuova circolare è pubblicata</string>
+    <string name="preferences_polling_summary">Sconsigliato. Disabilitare questa opzione per utilizzare le notifiche push</string>
     <string name="preferences_poll_interval_summary">Quanto tempo attendere tra una sincronizzazione ed un altra</string>
 
     <string name="notification_title">Circolare numero %1$d</string>

app/src/main/res/values/strings.xml

@@ -15,8 +15,10 @@
     <string name="preferences_school">School</string>
     <string name="preferences_dark_theme">Dark theme</string>
     <string name="preferences_notify_new_circulars">Show notifications</string>
+    <string name="preferences_polling">Run checks from this device</string>
     <string name="preferences_poll_interval">Synchronization interval</string>
     <string name="preferences_notify_new_circulars_summary">Show a notification when a new circular is published</string>
+    <string name="preferences_polling_summary">Not recommended. Disable this option to use push notifications</string>
     <string name="preferences_poll_interval_summary">How long to wait before checking if new circulars are published</string>
 
     <string name="notification_title">Circular letter number %1$d</string>

app/src/main/res/xml/root_preferences.xml

@@ -26,9 +26,16 @@
             app:key="notify_new_circulars"
             app:title="@string/preferences_notify_new_circulars" />
 
+        <SwitchPreferenceCompat
+            android:defaultValue="false"
+            android:summary="@string/preferences_polling_summary"
+            app:dependency="notify_new_circulars"
+            app:key="enable_polling"
+            app:title="@string/preferences_polling" />
+
         <EditTextPreference
             android:defaultValue="15"
-            android:dependency="notify_new_circulars"
+            android:dependency="enable_polling"
             android:key="poll_interval"
             android:selectAllOnFocus="true"
             android:singleLine="true"