Android push notification handler

AndroidManifest.xml

<service
    android:name=".services.FirebaseMessageService"
    android:exported="false">
    <intent-filter>
        <action android:name="com.google.firebase.MESSAGING_EVENT" />
    </intent-filter>
</service>

FirebaseMessageService.kt

import com.google.firebase.messaging.FirebaseMessagingService
import com.google.firebase.messaging.RemoteMessage
import timber.log.Timber
import javax.inject.Inject

class FirebaseMessageService : FirebaseMessagingService() {

    @Inject 
    lateinit var pushNotificationManager: PushNotificationManager

    @Inject 
    lateinit var settingsUseCase: SettingsUseCase

    override fun onCreate() {
        super.onCreate()
    }

    override fun onMessageReceived(remoteMessage: RemoteMessage) {
        super.onMessageReceived(remoteMessage)

        val notificationData = remoteMessage.data["custom_notification"]
        val notificationId = remoteMessage.data["notification_id"]

        Timber.tag("PushNotification").d("Received push notification: $notificationData")
        Timber.tag("PushNotification").d("Notification id: $notificationId")

        pushNotificationManager.showNotification(notificationId, notificationData)
    }

    override fun onNewToken(token: String) {
        super.onNewToken(token)
        settingsUseCase.setPushToken(token)
    }
}

PushNotificationManager.kt

import android.app.NotificationChannel
import android.app.NotificationManager
import android.app.PendingIntent
import android.content.Context
import android.content.Intent
import android.os.Build
import androidx.core.app.NotificationCompat
import androidx.core.app.NotificationManagerCompat
import androidx.core.content.ContextCompat
import com.google.gson.GsonBuilder
import kotlin.random.Random

class PushNotificationManager(private val context: Context) {
    companion object {
        private const val DEFAULT_GROUP_KEY = "my_package.DEFAULT_GROUP"
        private const val DEFAULT_CHANNEL_ID = "default_channel_id"
        private const val PUSH_DATA_KEY = "push_data_key"
        private const val NOTIFICATION_ID_KEY = "notification_id_key"
    }

    private val gson by lazy { GsonBuilder().create() }

    private val notificationManager by lazy { NotificationManagerCompat.from(context) }

    init {
        deleteOldNotificationChannels()
        createNotificationChannels()
    }

    fun showNotification(notificationId: String?, jsonData: String?) {
        jsonData?: return

        val pushData = gson.fromJson(jsonData, PushData::class.java)

        val channelId = pushData.type?.id ?: DEFAULT_CHANNEL_ID

        if (pushData.title.isNullOrBlank() || pushData.body.isNullOrBlank()) {
            return
        }

        val builder = NotificationCompat.Builder(context, channelId)
            .setSmallIcon(R.drawable.ic_notification)
            .setContentTitle(pushData.title)
            .setStyle(NotificationCompat.BigTextStyle().bigText(pushData.body))
            .setColor(ContextCompat.getColor(context, R.color.push_notification))
            .setContentIntent(getPendingIntent(notificationId, pushData))
            .setAutoCancel(true)
            .setDefaults(NotificationCompat.DEFAULT_ALL)
            .setPriority(NotificationCompat.PRIORITY_HIGH)
            .setVisibility(NotificationCompat.VISIBILITY_PUBLIC)

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
            builder.setGroup(DEFAULT_GROUP_KEY)

            val groupBuilder = NotificationCompat.Builder(context, channelId)
                .setSmallIcon(R.drawable.ic_notification)
                .setColor(ContextCompat.getColor(context, R.color.push_notification))
                .setGroup(DEFAULT_GROUP_KEY)
                .setAutoCancel(true)
                .setContentIntent(getGroupPendingIntent())
                .setGroupSummary(true)

            notificationManager.notify(Random.nextInt(0, 1000), builder.build())
            notificationManager.notify(DEFAULT_GROUP_KEY.hashCode(), groupBuilder.build())
        } else {
            notificationManager.notify(Random.nextInt(0, 1000), builder.build())
        }
    }

    private fun createNotificationChannels() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            val importance = NotificationManager.IMPORTANCE_HIGH

            notificationManager.createNotificationChannels(
                PushDataType.values()
                    .filterNot { it == PushDataType.NONE }
                    .map { type ->
                        val name = context.getString(type.nameResId)
                        val description = context.getString(type.descriptionResId)

                        NotificationChannel(type.id, name, importance)
                            .apply {
                                this.description = description
                                this.enableVibration(false)
                            }
                    }
            )
        }
    }

    private fun deleteOldNotificationChannels() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            notificationManager.deleteNotificationChannel("notification_channel")
        }
    }

    private fun getGroupPendingIntent(): PendingIntent? {
        val intent = Intent(context, SplashActivity::class.java)
        intent.flags = Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK

        return PendingIntent.getActivity(
            context,
            System.currentTimeMillis().toInt(),
            intent,
            PendingIntent.FLAG_UPDATE_CURRENT
        )
    }

    private fun getPendingIntent(notificationId: String?, data: PushData): PendingIntent? {
        val intent = Intent(context, SplashActivity::class.java)
        intent.flags = Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK
        intent.putExtra(PUSH_DATA_KEY, data)
        intent.putExtra(NOTIFICATION_ID_KEY, notificationId)

        return PendingIntent.getActivity(
            context,
            System.currentTimeMillis().toInt(),
            intent,
            PendingIntent.FLAG_UPDATE_CURRENT
        )
    }
}