package net.shadowfacts.phycon.network

import net.minecraft.block.entity.BlockEntity
import net.minecraft.block.entity.BlockEntityType
import net.minecraft.nbt.CompoundTag
import net.minecraft.util.Tickable
import net.shadowfacts.phycon.api.PacketSink
import net.shadowfacts.phycon.api.packet.Packet
import net.shadowfacts.phycon.api.util.MACAddress
import java.lang.ref.WeakReference
import java.util.*

/**
 * @author shadowfacts
 */
abstract class DeviceBlockEntity(type: BlockEntityType<*>): BlockEntity(type), Tickable, PacketSink {

	var macAddress = MACAddress.random()
		protected set

	private val sendQueue = LinkedList<Pair<Packet, WeakReference<PacketSink>>>()

	override fun getMACAddress(): MACAddress {
		return macAddress
	}

	override fun handle(packet: Packet) {
		if (acceptsPacket(packet)) {
			handlePacket(packet)
		}
	}

	protected abstract fun handlePacket(packet: Packet)

	fun acceptsPacket(packet: Packet): Boolean {
		return when (packet.destination.type) {
			MACAddress.Type.BROADCAST -> true
			MACAddress.Type.UNICAST -> macAddress == packet.destination
			MACAddress.Type.MULTICAST -> acceptsMulticastPacket(packet)
		}
	}

	open fun acceptsMulticastPacket(packet: Packet): Boolean {
		return false
	}

	fun enqueue(packet: Packet, destination: PacketSink) {
		sendQueue.add(packet to WeakReference(destination))
	}

	// todo: better name for this
	fun enqueueToSingle(packet: Packet) {
		val destinations = NetworkUtil.findDestinations(world!!, pos)
		if (destinations.size != 1) {
			// todo: handle this better
			println("Can't send packet, multiple destinations available: $destinations")
			return
		}
		enqueue(packet, destinations.first())
	}

	fun enqueueToAll(packet: Packet) {
		enqueueToAll(packet, NetworkUtil.findDestinations(world!!, pos))
	}

	fun enqueueToAll(packet: Packet, destinations: Iterable<PacketSink>) {
		sendQueue.addAll(destinations.map { packet to WeakReference(it) })
	}

	override fun tick() {
		if (sendQueue.isNotEmpty()) {
			val (packet, destination) = sendQueue.pop()
			destination.get()?.handle(packet)
		}
	}

	override fun toTag(tag: CompoundTag): CompoundTag {
		tag.putLong("MACAddress", macAddress.address)
		return super.toTag(tag)
	}

	override fun fromTag(tag: CompoundTag) {
		super.fromTag(tag)
		macAddress = MACAddress(tag.getLong("MACAddress"))
	}

}