KotlinPush.kt

package com.sergiocasero.backend.push

import com.google.api.client.googleapis.auth.oauth2.GoogleCredential
import com.sergiocasero.jvm.network.createService
import com.sergiocasero.model.PushTopic
import com.sergiocasero.properties.Property
import kotlinx.coroutines.Deferred
import kotlinx.coroutines.runBlocking
import okhttp3.ResponseBody
import retrofit2.http.Body
import retrofit2.http.POST
import java.io.FileInputStream
import java.util.*

interface FcmApiService {
    companion object {
        const val ENDPOINT = "https://fcm.googleapis.com/v1/projects/fibraclim-223015/"
    }

    @POST("./messages:send")
    fun sendPush(@Body push: Push): Deferred<ResponseBody>
}

fun sendPush(topic: PushTopic, title: String, body: String) {
    val push = Push(Message(topic = topic.label, notification = Notification(body = body, title = title)))

    val googleCredential = GoogleCredential
            .fromStream(FileInputStream(Property.Backend.pushFile))
            .createScoped(Arrays.asList("https://www.googleapis.com/auth/firebase.messaging"))
    googleCredential.refreshToken()

    val service = createService<FcmApiService>(FcmApiService.ENDPOINT, "Bearer " + googleCredential.accessToken)

    runBlocking {
        val response = service.sendPush(push).await()
        println(response.string())
    }
}


data class Push(val message: Message)

data class Message(val topic: String, val notification: Notification)

data class Notification(val body: String, val title: String)