package buildcraft.transport;

import java.util.Arrays;
import java.util.BitSet;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import com.google.common.collect.EnumMultiset;
import com.google.common.collect.Multiset;

import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.item.ItemStack;
import net.minecraft.nbt.NBTTagCompound;
import net.minecraft.tileentity.TileEntity;

import net.minecraftforge.common.util.ForgeDirection;
import net.minecraftforge.fluids.Fluid;
import net.minecraftforge.fluids.FluidEvent;
import net.minecraftforge.fluids.FluidStack;
import net.minecraftforge.fluids.FluidTankInfo;
import net.minecraftforge.fluids.IFluidHandler;

import buildcraft.BuildCraftCore;
import buildcraft.BuildCraftTransport;
import buildcraft.api.core.SafeTimeTracker;
import buildcraft.api.tiles.IDebuggable;
import buildcraft.api.transport.IPipeTile;
import buildcraft.core.DefaultProps;
import buildcraft.core.lib.utils.MathUtils;
import buildcraft.transport.network.PacketFluidUpdate;
import buildcraft.transport.pipes.PipeFluidsClay;
import buildcraft.transport.pipes.PipeFluidsCobblestone;
import buildcraft.transport.pipes.PipeFluidsDiamond;
import buildcraft.transport.pipes.PipeFluidsEmerald;
import buildcraft.transport.pipes.PipeFluidsGold;
import buildcraft.transport.pipes.PipeFluidsIron;
import buildcraft.transport.pipes.PipeFluidsQuartz;
import buildcraft.transport.pipes.PipeFluidsSandstone;
import buildcraft.transport.pipes.PipeFluidsStone;
import buildcraft.transport.pipes.PipeFluidsVoid;
import buildcraft.transport.pipes.PipeFluidsWood;
import buildcraft.transport.pipes.events.PipeEventFluid;
import buildcraft.transport.utils.FluidRenderData;

public class PipeTransportFluids extends PipeTransport implements IFluidHandler, IDebuggable {
	public static final Map<Class<? extends Pipe<?>>, Integer> fluidCapacities = new HashMap<Class<? extends Pipe<?>>, Integer>();

	/**
	 * The amount of liquid contained by a pipe section. For simplicity, all
	 * pipe sections are assumed to be of the same volume.
	 */
	public static int MAX_TRAVEL_DELAY = 12;
	public static short INPUT_TTL = 60; // 100
	public static short OUTPUT_TTL = 80; // 80
	public static short OUTPUT_COOLDOWN = 30; // 30

	private static int NETWORK_SYNC_TICKS = BuildCraftCore.updateFactor / 2;
	private static final ForgeDirection[] directions = ForgeDirection.VALID_DIRECTIONS;
	private static final ForgeDirection[] orientations = ForgeDirection.values();

	public class PipeSection {
		public int amount;

		private short currentTime = 0;
		private short[] incoming = new short[MAX_TRAVEL_DELAY];

		public int fill(int maxFill, boolean doFill) {
			int amountToFill = Math.min(getMaxFillRate(), maxFill);
			if (amountToFill <= 0) {
				return 0;
			}

			if (doFill) {
				incoming[currentTime] += amountToFill;
				amount += amountToFill;
			}
			return amountToFill;
		}

		public int drain(int maxDrain, boolean doDrain) {
			int maxToDrain = getAvailable();
			if (maxToDrain > maxDrain) {
				maxToDrain = maxDrain;
			}
			if (maxToDrain > flowRate) {
				maxToDrain = flowRate;
			}
			if (maxToDrain <= 0) {
				return 0;
			} else {
				if (doDrain) {
					amount -= maxToDrain;
				}
				return maxToDrain;
			}
		}

		public void moveFluids() {
			incoming[currentTime] = 0;
		}

		public void setTime(short newTime) {
			currentTime = newTime;
		}

		public void reset() {
			this.amount = 0;
			incoming = new short[MAX_TRAVEL_DELAY];
		}

		/**
		 * Get the amount of fluid available to move. This nicely takes care
		 * of the travel delay mechanic.
		 *
		 * @return
		 */
		public int getAvailable() {
			int all = amount;
			for (short slot : incoming) {
				all -= slot;
			}
			return all;
		}

		public int getMaxFillRate() {
			return Math.min(getCapacity() - amount, flowRate - incoming[currentTime]);
		}

		public void readFromNBT(NBTTagCompound compoundTag) {
			this.amount = compoundTag.getShort("capacity");

			for (int i = 0; i < travelDelay; ++i) {
				incoming[i] = compoundTag.getShort("in[" + i + "]");
			}
		}

		public void writeToNBT(NBTTagCompound subTag) {
			subTag.setShort("capacity", (short) amount);

			for (int i = 0; i < travelDelay; ++i) {
				subTag.setShort("in[" + i + "]", incoming[i]);
			}
		}
	}

	public PipeSection[] sections = new PipeSection[7];
	public FluidStack fluidType;

	public FluidRenderData renderCache = new FluidRenderData();

	private final SafeTimeTracker networkSyncTracker = new SafeTimeTracker(NETWORK_SYNC_TICKS);
	private final TransferState[] transferState = new TransferState[directions.length];
	private final int[] inputPerTick = new int[directions.length];
	private final short[] inputTTL = new short[]{0, 0, 0, 0, 0, 0};
	private final short[] outputTTL = new short[]{OUTPUT_TTL, OUTPUT_TTL, OUTPUT_TTL, OUTPUT_TTL, OUTPUT_TTL, OUTPUT_TTL};
	private final short[] outputCooldown = new short[]{0, 0, 0, 0, 0, 0};
	private final boolean[] canReceiveCache = new boolean[6];
	private int clientSyncCounter = 0;
	private int capacity, flowRate;
	private int travelDelay = MAX_TRAVEL_DELAY;

	public enum TransferState {
		None, Input, Output
	}

	public PipeTransportFluids() {
		for (ForgeDirection direction : directions) {
			sections[direction.ordinal()] = new PipeSection();
			transferState[direction.ordinal()] = TransferState.None;
		}
		sections[6] = new PipeSection();
	}

	/**
	 * This value has to be the same on client and server!
	 *
	 * @return
	 */
	public int getCapacity() {
		return capacity;
	}

	public int getFlowRate() {
		return flowRate;
	}

	public void initFromPipe(Class<? extends Pipe<?>> pipeClass) {
		capacity = 25 * Math.min(1000, BuildCraftTransport.pipeFluidsBaseFlowRate);
		flowRate = fluidCapacities.get(pipeClass);
		travelDelay = MathUtils.clamp(Math.round(16F / (flowRate / BuildCraftTransport.pipeFluidsBaseFlowRate)), 1, MAX_TRAVEL_DELAY);
	}

	@Override
	public void initialize() {
		super.initialize();

		for (ForgeDirection d : directions) {
			canReceiveCache[d.ordinal()] = canReceiveFluid(d);
		}
	}

	@Override
	public IPipeTile.PipeType getPipeType() {
		return IPipeTile.PipeType.FLUID;
	}

	private boolean canReceiveFluid(ForgeDirection o) {
		TileEntity tile = container.getTile(o);

		if (!container.isPipeConnected(o)) {
			return false;
		}

		if (tile instanceof IPipeTile) {
			Pipe<?> pipe = (Pipe<?>) ((IPipeTile) tile).getPipe();

			if (pipe == null || !inputOpen(o.getOpposite())) {
				return false;
			}
		}

		if (tile instanceof IFluidHandler) {
			return true;
		}

		return false;
	}

	@Override
	public void updateEntity() {
		if (container.getWorldObj().isRemote) {
			return;
		}

		moveFluids();

		if (networkSyncTracker.markTimeIfDelay(container.getWorldObj())) {
			boolean init = false;
			if (++clientSyncCounter > BuildCraftCore.longUpdateFactor * 2) {
				clientSyncCounter = 0;
				init = true;
			}
			PacketFluidUpdate packet = computeFluidUpdate(init, true);

			if (packet != null) {
				BuildCraftTransport.instance.sendToPlayers(packet, container.getWorldObj(), container.xCoord, container.yCoord, container.zCoord, DefaultProps.PIPE_CONTENTS_RENDER_DIST);
			}
		}
	}

	private void moveFluids() {
		if (fluidType != null) {
			short newTimeSlot = (short) (container.getWorldObj().getTotalWorldTime() % travelDelay);
			int outputCount = computeCurrentConnectionStatesAndTickFlows(newTimeSlot > 0 && newTimeSlot < travelDelay ? newTimeSlot : 0);

			if (fluidType != null) {
				moveFromPipe(outputCount);
				moveFromCenter();
				moveToCenter();
			}
		} else {
			computeTTLs();
		}
	}

	private void moveFromPipe(int outputCount) {
		// Move liquid from the non-center to the connected output blocks
		if (outputCount > 0) {
			for (ForgeDirection o : directions) {
				if (transferState[o.ordinal()] == TransferState.Output) {
					TileEntity target = this.container.getTile(o);
					if (!(target instanceof IFluidHandler)) {
						continue;
					}

					PipeSection section = sections[o.ordinal()];
					FluidStack liquidToPush = new FluidStack(fluidType, section.drain(flowRate, false));

					if (liquidToPush.amount > 0) {
						int filled = ((IFluidHandler) target).fill(o.getOpposite(), liquidToPush, true);
						if (filled <= 0) {
							outputTTL[o.ordinal()]--;
						} else {
							section.drain(filled, true);
						}
					}
				}
			}
		}
	}

	private void moveFromCenter() {
		// Split liquids moving to output equally based on flowrate, how much each side can accept and available liquid
		int pushAmount = sections[6].amount;
		int totalAvailable = sections[6].getAvailable();
		if (totalAvailable < 1 || pushAmount < 1) {
			return;
		}

		int testAmount = flowRate;
		// Move liquid from the center to the output sides
		Multiset<ForgeDirection> realDirections = EnumMultiset.create(ForgeDirection.class);
		for (ForgeDirection direction : directions) {
			if (transferState[direction.ordinal()] == TransferState.Output) {
				realDirections.add(direction);
			}
		}

		if (realDirections.size() > 0) {
			container.pipe.eventBus.handleEvent(PipeEventFluid.FindDest.class, new PipeEventFluid.FindDest(container.pipe, new FluidStack(fluidType, pushAmount), realDirections));
			float min = Math.min(flowRate * realDirections.size(), totalAvailable) / (float) flowRate / realDirections.size();

			for (ForgeDirection direction : realDirections.elementSet()) {
				int available = sections[direction.ordinal()].fill(testAmount, false);
				int amountToPush = (int) (available * min * realDirections.count(direction));
				if (amountToPush < 1) {
					amountToPush++;
				}

				amountToPush = sections[6].drain(amountToPush, false);
				if (amountToPush > 0) {
					int filled = sections[direction.ordinal()].fill(amountToPush, true);
					sections[6].drain(filled, true);
				}
			}
		}
	}

	private void moveToCenter() {
		int transferInCount = 0;
		int spaceAvailable = getCapacity() - sections[6].amount;

		for (ForgeDirection dir : directions) {
			inputPerTick[dir.ordinal()] = 0;
			if (transferState[dir.ordinal()] != TransferState.Output) {
				inputPerTick[dir.ordinal()] = sections[dir.ordinal()].drain(flowRate, false);
				if (inputPerTick[dir.ordinal()] > 0) {
					transferInCount++;
				}
			}
		}

		float min = Math.min(flowRate * transferInCount, spaceAvailable) / (float) flowRate / transferInCount;

		for (ForgeDirection dir : directions) {
			// Move liquid from input sides to the center
			if (inputPerTick[dir.ordinal()] > 0) {
				int amountToDrain = (int) (inputPerTick[dir.ordinal()] * min);
				if (amountToDrain < 1) {
					amountToDrain++;
				}

				int amountToPush = sections[dir.ordinal()].drain(amountToDrain, false);
				if (amountToPush > 0) {
					int filled = sections[6].fill(amountToPush, true);
					sections[dir.ordinal()].drain(filled, true);
				}
			}
		}
	}

	private void computeTTLs() {
		for (int i = 0; i < 6; i++) {
			if (transferState[i] == TransferState.Input) {
				if (inputTTL[i] > 0) {
					inputTTL[i]--;
				} else {
					transferState[i] = TransferState.None;
				}
			}

			if (outputCooldown[i] > 0) {
				outputCooldown[i]--;
			}
		}
	}

	private int computeCurrentConnectionStatesAndTickFlows(short newTimeSlot) {
		int outputCount = 0;
		int fluidAmount = 0;

		// Processes all internal tanks
		for (ForgeDirection direction : orientations) {
			int dirI = direction.ordinal();
			PipeSection section = sections[dirI];

			fluidAmount += section.amount;
			section.setTime(newTimeSlot);
			section.moveFluids();

			// Input processing
			if (direction == ForgeDirection.UNKNOWN) {
				continue;
			}
			if (transferState[dirI] == TransferState.Input) {
				inputTTL[dirI]--;
				if (inputTTL[dirI] <= 0) {
					transferState[dirI] = TransferState.None;
				}
				continue;
			}
			if (!container.pipe.outputOpen(direction)) {
				transferState[dirI] = TransferState.None;
				continue;
			}
			if (outputCooldown[dirI] > 0) {
				outputCooldown[dirI]--;
				continue;
			}
			if (outputTTL[dirI] <= 0) {
				transferState[dirI] = TransferState.None;
				outputCooldown[dirI] = OUTPUT_COOLDOWN;
				outputTTL[dirI] = OUTPUT_TTL;
				continue;
			}
			if (canReceiveCache[dirI] && container.pipe.outputOpen(direction)) {
				transferState[dirI] = TransferState.Output;
				outputCount++;
			}
		}

		if (fluidAmount == 0) {
			setFluidType(null);
		}

		return outputCount;
	}

	/**
	 * Computes the PacketFluidUpdate packet for transmission to a client
	 *
	 * @param initPacket    everything is sent, no delta stuff ( first packet )
	 * @param persistChange The render cache change is persisted
	 * @return PacketFluidUpdate liquid update packet
	 */
	private PacketFluidUpdate computeFluidUpdate(boolean initPacket, boolean persistChange) {
		boolean changed = false;
		BitSet delta = new BitSet(8);

		FluidRenderData renderCacheCopy = this.renderCache;

		if (initPacket || (fluidType == null && renderCacheCopy.fluidID != 0)
				|| (fluidType != null && renderCacheCopy.fluidID != fluidType.getFluid().getID())) {
			changed = true;
			renderCache.fluidID = fluidType != null ? fluidType.getFluid().getID() : 0;
			renderCache.color = fluidType != null ? fluidType.getFluid().getColor(fluidType) : 0;
			renderCache.flags = FluidRenderData.getFlags(fluidType);
			delta.set(0);
		}

		for (ForgeDirection dir : orientations) {
			int pamount = renderCache.amount[dir.ordinal()];
			int camount = sections[dir.ordinal()].amount;
			int displayQty = (pamount * 4 + camount) / 5;
			if (displayQty == 0 && camount > 0 || initPacket) {
				displayQty = camount;
			}
			displayQty = Math.min(getCapacity(), displayQty);

			if (pamount != displayQty || initPacket) {
				changed = true;
				renderCache.amount[dir.ordinal()] = displayQty;
				delta.set(dir.ordinal() + 1);
			}
		}

		if (persistChange) {
			this.renderCache = renderCacheCopy;
		}

		if (changed || initPacket) {
			PacketFluidUpdate packet = new PacketFluidUpdate(container.xCoord, container.yCoord, container.zCoord, initPacket, getCapacity() > 255);
			packet.renderCache = renderCacheCopy;
			packet.delta = delta;
			return packet;
		}

		return null;
	}

	private void setFluidType(FluidStack type) {
		fluidType = type;
	}

	/**
	 * Initializes client
	 */
	@Override
	public void sendDescriptionPacket() {
		super.sendDescriptionPacket();

		PacketFluidUpdate update = computeFluidUpdate(true, true);
		BuildCraftTransport.instance.sendToPlayers(update, container.getWorldObj(), container.xCoord, container.yCoord, container.zCoord, DefaultProps.PIPE_CONTENTS_RENDER_DIST);
	}

	public FluidStack getStack(ForgeDirection direction) {
		if (fluidType == null) {
			return null;
		} else {
			return new FluidStack(fluidType, sections[direction.ordinal()].amount);
		}
	}

	@Override
	public void dropContents() {
		if (fluidType != null) {
			int totalAmount = 0;
			for (int i = 0; i < 7; i++) {
				totalAmount += sections[i].amount;
			}
			if (totalAmount > 0) {
				FluidEvent.fireEvent(new FluidEvent.FluidSpilledEvent(
						new FluidStack(fluidType, totalAmount),
						getWorld(), container.xCoord, container.yCoord, container.zCoord
				));
			}
		}
	}

	@Override
	public void readFromNBT(NBTTagCompound nbttagcompound) {
		super.readFromNBT(nbttagcompound);

		if (nbttagcompound.hasKey("fluid")) {
			setFluidType(FluidStack.loadFluidStackFromNBT(nbttagcompound.getCompoundTag("fluid")));
		} else {
			setFluidType(null);
		}

		for (ForgeDirection direction : orientations) {
			if (nbttagcompound.hasKey("tank[" + direction.ordinal() + "]")) {
				NBTTagCompound compound = nbttagcompound.getCompoundTag("tank[" + direction.ordinal() + "]");
				if (compound.hasKey("FluidType")) {
					FluidStack stack = FluidStack.loadFluidStackFromNBT(compound);
					if (fluidType == null) {
						setFluidType(stack);
					}
					if (stack.isFluidEqual(fluidType)) {
						sections[direction.ordinal()].readFromNBT(compound);
					}
				} else {
					sections[direction.ordinal()].readFromNBT(compound);
				}
			}
			if (direction != ForgeDirection.UNKNOWN) {
				transferState[direction.ordinal()] = TransferState.values()[nbttagcompound.getShort("transferState[" + direction.ordinal() + "]")];
			}
		}
	}

	@Override
	public void writeToNBT(NBTTagCompound nbttagcompound) {
		super.writeToNBT(nbttagcompound);

		if (fluidType != null) {
			NBTTagCompound fluidTag = new NBTTagCompound();
			fluidType.writeToNBT(fluidTag);
			nbttagcompound.setTag("fluid", fluidTag);

			for (ForgeDirection direction : orientations) {
				NBTTagCompound subTag = new NBTTagCompound();
				sections[direction.ordinal()].writeToNBT(subTag);
				nbttagcompound.setTag("tank[" + direction.ordinal() + "]", subTag);
				if (direction != ForgeDirection.UNKNOWN) {
					nbttagcompound.setShort("transferState[" + direction.ordinal() + "]", (short) transferState[direction.ordinal()].ordinal());
				}
			}
		}
	}

	@Override
	public int fill(ForgeDirection from, FluidStack resource, boolean doFill) {
		if (from != ForgeDirection.UNKNOWN && !inputOpen(from)) {
			return 0;
		}

		if (resource == null || (fluidType != null && !resource.isFluidEqual(fluidType))) {
			return 0;
		}

		int filled;

		if (this.container.pipe instanceof IPipeTransportFluidsHook) {
			filled = ((IPipeTransportFluidsHook) this.container.pipe).fill(from, resource, doFill);
		} else {
			filled = sections[from.ordinal()].fill(resource.amount, doFill);
		}

		if (doFill && filled > 0) {
			if (fluidType == null) {
				setFluidType(new FluidStack(resource, 0));
			}
			if (from != ForgeDirection.UNKNOWN) {
				transferState[from.ordinal()] = TransferState.Input;
				inputTTL[from.ordinal()] = INPUT_TTL;
			}
		}

		return filled;
	}

	@Override
	public FluidStack drain(ForgeDirection from, FluidStack resource, boolean doDrain) {
		return null;
	}

	@Override
	public FluidStack drain(ForgeDirection from, int maxDrain, boolean doDrain) {
		return null;
	}

	@Override
	public boolean canFill(ForgeDirection from, Fluid fluid) {
		return inputOpen(from);
	}

	@Override
	public boolean canDrain(ForgeDirection from, Fluid fluid) {
		return false;
	}

	@Override
	public FluidTankInfo[] getTankInfo(ForgeDirection from) {
		return new FluidTankInfo[]{new FluidTankInfo(fluidType, sections[from.ordinal()].amount)};
	}

	@Override
	public void onNeighborChange(ForgeDirection direction) {
		super.onNeighborChange(direction);

		if (!container.isPipeConnected(direction)) {
			sections[direction.ordinal()].reset();
			transferState[direction.ordinal()] = TransferState.None;
			renderCache.amount[direction.ordinal()] = 0;
			canReceiveCache[direction.ordinal()] = false;
		} else {
			canReceiveCache[direction.ordinal()] = canReceiveFluid(direction);
		}
	}

	@Override
	public boolean canPipeConnect(TileEntity tile, ForgeDirection side) {
		if (tile instanceof IPipeTile) {
			Pipe<?> pipe2 = (Pipe<?>) ((IPipeTile) tile).getPipe();
			if (BlockGenericPipe.isValid(pipe2) && !(pipe2.transport instanceof PipeTransportFluids)) {
				return false;
			}
		}

		if (tile instanceof IFluidHandler) {
			return true;
		}

		return tile instanceof IPipeTile;
	}

	@Override
	public void getDebugInfo(List<String> info, ForgeDirection side, ItemStack debugger, EntityPlayer player) {
		int[] amount = new int[7];
		for (int i = 0; i < 7; i++) {
			if (sections[i] != null) {
				amount[i] = sections[i].amount;
			}
		}
		info.add(String.format("PipeTransportFluids (%s, %d mB, %d mB/t)", fluidType != null ? fluidType.getLocalizedName() : "Empty", capacity, flowRate));
		info.add("- Stored: " + Arrays.toString(amount));
	}

	static {
		fluidCapacities.put(PipeFluidsVoid.class, 1 * BuildCraftTransport.pipeFluidsBaseFlowRate);

		fluidCapacities.put(PipeFluidsWood.class, 1 * BuildCraftTransport.pipeFluidsBaseFlowRate);
		fluidCapacities.put(PipeFluidsCobblestone.class, 1 * BuildCraftTransport.pipeFluidsBaseFlowRate);

		fluidCapacities.put(PipeFluidsSandstone.class, 2 * BuildCraftTransport.pipeFluidsBaseFlowRate);
		fluidCapacities.put(PipeFluidsStone.class, 2 * BuildCraftTransport.pipeFluidsBaseFlowRate);

		fluidCapacities.put(PipeFluidsClay.class, 4 * BuildCraftTransport.pipeFluidsBaseFlowRate);
		fluidCapacities.put(PipeFluidsEmerald.class, 4 * BuildCraftTransport.pipeFluidsBaseFlowRate);
		fluidCapacities.put(PipeFluidsIron.class, 4 * BuildCraftTransport.pipeFluidsBaseFlowRate);
		fluidCapacities.put(PipeFluidsQuartz.class, 4 * BuildCraftTransport.pipeFluidsBaseFlowRate);

		fluidCapacities.put(PipeFluidsDiamond.class, 8 * BuildCraftTransport.pipeFluidsBaseFlowRate);
		fluidCapacities.put(PipeFluidsGold.class, 8 * BuildCraftTransport.pipeFluidsBaseFlowRate);
	}
}