/*
 * Minecraft Forge
 * Copyright (c) 2016-2020.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation version 2.1
 * of the License.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

package net.minecraftforge.fml.common.network.handshake;

import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;

import java.util.Map;
import java.util.function.Consumer;

import com.google.common.collect.Maps;
import com.google.common.collect.Multimap;
import com.google.common.util.concurrent.Futures;

import net.minecraft.client.Minecraft;
import net.minecraft.util.ResourceLocation;
import net.minecraftforge.fml.common.FMLLog;
import net.minecraftforge.fml.common.Loader;
import net.minecraftforge.fml.common.network.NetworkRegistry;
import net.minecraftforge.fml.common.network.handshake.FMLHandshakeMessage.ServerHello;
import net.minecraftforge.fml.common.network.internal.FMLMessage;
import net.minecraftforge.fml.common.network.internal.FMLNetworkHandler;
import net.minecraftforge.fml.relauncher.Side;
import net.minecraftforge.registries.ForgeRegistry;
import net.minecraftforge.registries.GameData;

/**
 * Packet handshake sequence manager- client side (responding to remote server)
 *
 * Flow:
 * 1. Wait for server hello. (START). Move to HELLO state.
 * 2. Receive Server Hello. Send customchannel registration. Send Client Hello. Send our modlist. Move to WAITINGFORSERVERDATA state.
 * 3. Receive server modlist. Send ack if acceptable, else send nack and exit error. Receive server IDs. Move to COMPLETE state. Send ack.
 *
 * @author cpw
 *
 */
enum FMLHandshakeClientState implements IHandshakeState<FMLHandshakeClientState>
{
    START
    {
        @Override
        public void accept(ChannelHandlerContext ctx, FMLHandshakeMessage msg, Consumer<? super FMLHandshakeClientState> cons)
        {
            cons.accept(HELLO);
            NetworkDispatcher dispatcher = ctx.channel().attr(NetworkDispatcher.FML_DISPATCHER).get();
            dispatcher.clientListenForServerHandshake();
        }
    },
    HELLO
    {
        @Override
        public void accept(ChannelHandlerContext ctx, FMLHandshakeMessage msg, Consumer<? super FMLHandshakeClientState> cons)
        {
            boolean isVanilla = msg == null;
            if (isVanilla)
            {
                cons.accept(DONE);
            }
            else
            {
                cons.accept(WAITINGSERVERDATA);
            }
            /////////////////////////////////////////////
            // HERE
            /////////////////////////////////////////////
            
            // write our custom packet registration, always
            ctx.writeAndFlush(FMLHandshakeMessage.makeCustomChannelRegistration(NetworkRegistry.INSTANCE.channelNamesFor(Side.CLIENT)));
            if (isVanilla)
            {
                NetworkDispatcher dispatcher = ctx.channel().attr(NetworkDispatcher.FML_DISPATCHER).get();
                dispatcher.abortClientHandshake("VANILLA");
                // VANILLA login
                return;
            }

            ServerHello serverHelloPacket = (FMLHandshakeMessage.ServerHello)msg;
            FMLLog.log.info("Server protocol version {}", Integer.toHexString(serverHelloPacket.protocolVersion()));
            if (serverHelloPacket.protocolVersion() > 1)
            {
                // Server sent us an extra dimension for the logging in player - stash it for retrieval later
                NetworkDispatcher dispatcher = ctx.channel().attr(NetworkDispatcher.FML_DISPATCHER).get();
                dispatcher.setOverrideDimension(serverHelloPacket.overrideDim());
            }
            ctx.writeAndFlush(new FMLHandshakeMessage.ClientHello()).addListener(ChannelFutureListener.FIRE_EXCEPTION_ON_FAILURE);
            ctx.writeAndFlush(new FMLHandshakeMessage.ModList(Loader.instance().getActiveModList())).addListener(ChannelFutureListener.FIRE_EXCEPTION_ON_FAILURE);
        }
    },

    @Override
    public void sendPluginMessage(Plugin source, String channel, byte[] message) {
        StandardMessenger.validatePluginMessage(server.getMessenger(), source, channel, message);
        if (getHandle().playerConnection == null) return;

        if (channels.contains(channel)) {
            PacketPlayOutCustomPayload packet = new PacketPlayOutCustomPayload(channel, new PacketDataSerializer(Unpooled.wrappedBuffer(message)));
            getHandle().playerConnection.sendPacket(packet);
        }
    }

    public void addChannel(String channel) {
        com.google.common.base.Preconditions.checkState(DISABLE_CHANNEL_LIMIT || channels.size() < 128, "Too many channels registered"); // Spigot // Paper - flag to disable channel limit
        if (channels.add(channel)) {
            server.getPluginManager().callEvent(new PlayerRegisterChannelEvent(this, channel));
        }
    }