package actors.auctions

import com.google.inject.Provides
import com.hivemq.client.mqtt.datatypes.MqttQos
import com.hivemq.client.mqtt.mqtt5.Mqtt5AsyncClient
import com.hivemq.client.mqtt.mqtt5.message.publish.Mqtt5Publish
import models.{Auction, User}
import mqttClient.MqttClientFactory
import org.apache.pekko.actor.typed.Behavior
import org.apache.pekko.actor.typed.scaladsl.Behaviors
import play.api.{Configuration, Logging}
import play.api.libs.concurrent.ActorModule
import play.api.libs.json.{JsObject, Json}

import javax.inject.Singleton

object AuctionPublisher extends ActorModule with Logging {
  sealed trait Command
  private case object Ready extends Command
  case class Publish(auction: Auction, author: User) extends Command

  private final val topic = "auctions/created"

  override type Message = Command

  @Provides
  @Singleton
  def apply(configuration: Configuration): Behavior[Message] = Behaviors.setup { context =>
    val client = MqttClientFactory.createClient(configuration, "-auction-publisher")
    client.connect().whenComplete { (_action, _throwable) =>
      context.self ! Ready
    }

    idle(client)
  }

  private def idle(client: Mqtt5AsyncClient, waitingPublishes: Seq[Publish] = List()): Behaviors.Receive[Command] = Behaviors.receiveMessage[Command] {
    case p: Publish =>
      idle(client, waitingPublishes :+ p)
    case Ready =>
      for { publish <- waitingPublishes } publishAuction(client, publish.auction, publish.author)
      ready(client)
  }

  private def ready(client: Mqtt5AsyncClient): Behaviors.Receive[Command] = Behaviors.receiveMessage[Command] {
    case Publish(auction, author) =>
      publishAuction(client, auction, author)
      ready(client)
    case Ready =>
      logger.warn("Message Ready received after having already received it before")
      ready(client)
  }

  private def publishAuction(client: Mqtt5AsyncClient, auction: Auction, author: User): Unit = {
    val payload = Json.toBytes(auction_payload(auction, author))

    val publish = Mqtt5Publish.builder()
      .topic(topic)
      .payload(payload)
      .qos(MqttQos.EXACTLY_ONCE)
      .build()
    logger.info(s"Publishing auction ${auction.id.getOrElse(-1)}")
    client.publish(publish)
  }

  private def auction_payload(auction: Auction, author: User): JsObject = {
    Json.obj(
      "gid" -> auction.gid,
      "author_gid" -> author.gid,
      "starting_price" -> auction.startingPrice
    )
  }
}