package net.shadowfacts.phycon.block.miner

import alexiil.mc.lib.attributes.item.GroupedItemInvView
import alexiil.mc.lib.attributes.item.ItemStackUtil
import alexiil.mc.lib.attributes.item.filter.ItemFilter
import net.minecraft.block.Block
import net.minecraft.block.BlockState
import net.minecraft.item.ItemStack
import net.minecraft.item.Items
import net.minecraft.nbt.NbtCompound
import net.minecraft.server.world.ServerWorld
import net.minecraft.text.TranslatableText
import net.minecraft.util.math.BlockPos
import net.minecraft.util.math.Direction
import net.minecraft.world.World
import net.shadowfacts.phycon.api.packet.Packet
import net.shadowfacts.phycon.init.PhyBlockEntities
import net.shadowfacts.phycon.block.DeviceBlockEntity
import net.shadowfacts.phycon.block.terminal.AbstractTerminalBlockEntity
import net.shadowfacts.phycon.component.*
import net.shadowfacts.phycon.packet.*
import net.shadowfacts.phycon.util.ActivationMode
import net.shadowfacts.phycon.util.ClientConfigurableDevice
import net.shadowfacts.phycon.util.copyWithCount
import kotlin.math.min

/**
 * @author shadowfacts
 */
class MinerBlockEntity(pos: BlockPos, state: BlockState): DeviceBlockEntity(PhyBlockEntities.MINER, pos, state),
	NetworkStackProvider,
	NetworkStackDispatcher<MinerBlockEntity.PendingInsertion>,
	ActivationController.ActivatableDevice,
	ClientConfigurableDevice {

	private val facing: Direction
		get() = cachedState[MinerBlock.FACING]

	private val invProxy = MinerInvProxy(this)

	override val pendingInsertions = mutableListOf<PendingInsertion>()
	override val dispatchStackTimeout = AbstractTerminalBlockEntity.INSERTION_TIMEOUT
	override val controller = ActivationController(40L, this)
	override var providerPriority = 0

	var minerMode = MinerMode.ON_DEMAND

	override fun handle(packet: Packet) {
		when (packet) {
			is RequestInventoryPacket -> handleRequestInventory(packet)
			is LocateStackPacket -> handleLocateStack(packet)
			is ExtractStackPacket -> handleExtractStack(packet)
			is CapacityPacket -> handleCapacity(packet)
			is ItemStackPacket -> handleItemStack(packet)
			is RemoteActivationPacket -> controller.handleRemoteActivation(packet)
		}
	}

	private fun handleRequestInventory(packet: RequestInventoryPacket) {
		if (minerMode != MinerMode.ON_DEMAND) {
			return
		}
		sendPacket(ReadInventoryPacket(invProxy, ipAddress, packet.source))
	}

	private fun handleLocateStack(packet: LocateStackPacket) {
		if (minerMode != MinerMode.ON_DEMAND) {
			return
		}
		val amount = invProxy.getAmount(packet.stack)
		if (amount > 0) {
			sendPacket(StackLocationPacket(packet.stack, amount, this, ipAddress, packet.source))
		}
	}

	private fun handleExtractStack(packet: ExtractStackPacket) {
		if (minerMode != MinerMode.ON_DEMAND) {
			return
		}

		// always recalculate immediately before breaking
		val drops = invProxy.getDrops(recalculate = true)
		if (invProxy.getAmount(packet.stack) > 0) {
			world!!.breakBlock(pos.offset(facing), false)

			// send the requested amount back to the requester
			var remaining = packet.amount
			for (droppedStack in drops) {
				if (remaining <= 0) {
					break
				}
				if (!ItemStackUtil.areEqualIgnoreAmounts(droppedStack, packet.stack)) {
					continue
				}

				val toDecr = min(droppedStack.count, remaining)
				val copy = droppedStack.copyWithCount(toDecr)
				droppedStack.decrement(toDecr)
				remaining -= toDecr

				// todo: should this try to combine stacks and send as few packets as possible?
				sendPacket(ItemStackPacket(copy, ipAddress, packet.source))
			}

			// dump any remaining drops into the network
			for (droppedStack in drops) {
				if (droppedStack.isEmpty) continue
				dispatchItemStack(droppedStack)
			}
		}
	}

	override fun doHandleItemStack(packet: ItemStackPacket): ItemStack {
		// miner can't receive stacks, so remaining is the entire packet stack
		return packet.stack
	}

	override fun createPendingInsertion(stack: ItemStack) = PendingInsertion(stack, counter)

	override fun tick() {
		super.tick()

		if (!world!!.isClient) {
			if (minerMode == MinerMode.AUTOMATIC) {
				controller.tick()
			}
			finishTimedOutPendingInsertions()
		}
	}

	override fun activate(): Boolean {
		if (minerMode == MinerMode.ON_DEMAND) {
			return false
		}

		val drops = invProxy.getDrops(recalculate = true)
		if (!world!!.getBlockState(pos.offset(facing)).isAir) {
			world!!.breakBlock(pos.offset(facing), false)

			for (stack in drops) {
				if (stack.isEmpty) continue
				dispatchItemStack(stack)
			}

			return true
		} else {
			return false
		}
	}

	override fun canConfigureActivationController(): Boolean {
		return minerMode == MinerMode.AUTOMATIC
	}

	override fun canConfigureProviderPriority(): Boolean {
		return minerMode == MinerMode.ON_DEMAND
	}

	override fun toCommonTag(tag: NbtCompound) {
		super.toCommonTag(tag)
		writeDeviceConfiguration(tag)
	}

	override fun fromCommonTag(tag: NbtCompound) {
		super.fromCommonTag(tag)
		loadDeviceConfiguration(tag)
	}

	override fun writeDeviceConfiguration(tag: NbtCompound) {
		tag.putString("MinerMode", minerMode.name)
		tag.putString("ActivationMode", controller.activationMode.name)
		tag.putInt("ProviderPriority", providerPriority)
	}

	override fun loadDeviceConfiguration(tag: NbtCompound) {
		minerMode = MinerMode.valueOf(tag.getString("MinerMode"))
		controller.activationMode = ActivationMode.valueOf(tag.getString("ActivationMode"))
		providerPriority = tag.getInt("ProviderPriority")
	}

	enum class MinerMode {
		ON_DEMAND, AUTOMATIC;

		val friendlyName = TranslatableText("gui.phycon.miner_mode.${name.lowercase()}")
	}

	class MinerInvProxy(val miner: MinerBlockEntity): GroupedItemInvView {
		companion object {
			val TOOL = ItemStack(Items.DIAMOND_PICKAXE)
		}

		private var cachedState: BlockState? = null
		private var cachedDrops: List<ItemStack>? = null

		private val world: World
			get() = miner.world!!
		private val pos: BlockPos
			get() = miner.pos!!
		private val facing: Direction
			get() = miner.facing

		fun getDrops(recalculate: Boolean = false): List<ItemStack> {
			val targetPos = pos.offset(facing)
			val realState = world.getBlockState(targetPos)
			// todo: does BlockState.equals actually work or is reference equality fine for BlockStates?
			if (cachedDrops == null || realState != cachedState || recalculate) {
				cachedState = realState

				val be = if (realState.hasBlockEntity()) world.getBlockEntity(targetPos) else null
				cachedDrops = Block.getDroppedStacks(realState, world as ServerWorld, targetPos, be, null, TOOL)
			}
			return cachedDrops!!
		}

		override fun getStoredStacks(): Set<ItemStack> {
			if (miner.minerMode != MinerMode.ON_DEMAND) {
				return setOf()
			}
			return getDrops().toSet()
		}

		override fun getTotalCapacity(): Int {
			return Int.MAX_VALUE
		}

		override fun getStatistics(filter: ItemFilter): GroupedItemInvView.ItemInvStatistic {
			var totalCount = 0
			for (s in storedStacks) {
				if (filter.matches(s)) {
					totalCount += s.count
				}
			}
			return GroupedItemInvView.ItemInvStatistic(filter, totalCount, 0, Int.MAX_VALUE)
		}
	}

	class PendingInsertion(stack: ItemStack, timestamp: Long): NetworkStackDispatcher.PendingInsertion<PendingInsertion>(stack, timestamp) {
	}

}