lm-sistemi-software-distribuiti/src/main/kotlin/drills/drill09/average/AverageNode.kt

package drills.drill09.average

import util.network.epidemic.EpidemicNode
import util.network.epidemic.packet.EpidemicPacket
import util.network.epidemic.packet.FeedbackEpidemicPacket
import util.network.simulator.Address
import util.network.simulator.Network

class AverageNode(
    address: Address,
    network: Network,
    initialValue: Double,
    val infectStrategy: InfectStrategy = InfectStrategy.PUSH,
    bufferSize: Int = 1
) : EpidemicNode<Double, FeedbackEpidemicPacket<Double>>(
    address, network, initialValue, bufferSize
) {
    override fun receivePushOrReply(packet: FeedbackEpidemicPacket<Double>) {
        val payload = packet.payload

        if (packet.isFeedback)
            changeValue(payload)
        else {
            computeAverage(payload)
            sendFeedback(packet.senderAddress)
            spreadNewValue()
        }
    }

    private fun computeAverage(payload: Double) {
        val newValue = (nodeValue + payload) / 2
        changeValue(newValue)
    }

    private fun sendFeedback(receiverAddress: Address) {
        send(
            FeedbackEpidemicPacket(
                address,
                receiverAddress,
                nodeValue,
                if (infectStrategy == InfectStrategy.PUSH)
                    EpidemicPacket.Type.PUSH else EpidemicPacket.Type.REPLY,
                true
            )
        )
    }

    private fun spreadNewValue() {
        when (infectStrategy) {
            InfectStrategy.PUSH -> sendPushToRandom()
            InfectStrategy.PULL -> sendPullToRandom()
            InfectStrategy.PUSHPULL -> sendPushPullToRandom()
        }
    }

    override fun receivePull(packet: FeedbackEpidemicPacket<Double>) {
        if (packet.type == EpidemicPacket.Type.PUSHPULL)
            return

        send(
            makeInfectionPacket(
                packet.senderAddress,
                EpidemicPacket.Type.REPLY
            )
        )
    }

    override fun infect() {
        Thread.interrupted()
    }

    override fun makeInfectionPacket(
        receiverAddress: Address,
        type: EpidemicPacket.Type
    ): EpidemicPacket<Double> {
        return FeedbackEpidemicPacket(
            address,
            receiverAddress,
            nodeValue,
            type,
            false
        )
    }

    companion object {
        fun createPushNode(
            address: Address,
            network: Network,
            initialValue: Double,
            bufferSize: Int = 1
        ) = AverageNode(address, network, initialValue, InfectStrategy.PUSH, bufferSize)

        fun createPullNode(
            address: Address,
            network: Network,
            initialValue: Double,
            bufferSize: Int = 1
        ) = AverageNode(address, network, initialValue, InfectStrategy.PULL, bufferSize)

        fun createPushPullNode(
            address: Address,
            network: Network,
            initialValue: Double,
            bufferSize: Int = 1
        ) = AverageNode(address, network, initialValue, InfectStrategy.PUSHPULL, bufferSize)
    }
}