//Declaration
public static final SimpleNetworkWrapper SNW_INSTANCE = NetworkRegistry.INSTANCE.newSimpleChannel(MODID);

//PreInit Call
SNW_INSTANCE.registerMessage(SkillExecutionPacketHandler.class, SkillExecutionPacket.class, 0, Side.SERVER);
SNW_INSTANCE.registerMessage(SkillFailedPacketHandler.class, SkillFailedPacket.class, 1, Side.CLIENT);
SNW_INSTANCE.registerMessage(SkillSuccessPacketHandler.class, SkillSuccessPacket.class, 2, Side.CLIENT);

//Packet class
package mcd.rivenmod.packet;

import io.netty.buffer.ByteBuf;
import mcd.rivenmod.gui.InGameOverlay;
import net.minecraft.entity.player.EntityPlayerMP;
import net.minecraft.util.ChatComponentText;
import net.minecraftforge.fml.common.network.simpleimpl.IMessage;
import net.minecraftforge.fml.common.network.simpleimpl.IMessageHandler;
import net.minecraftforge.fml.common.network.simpleimpl.MessageContext;

public class SkillSuccessPacket implements IMessage
{
    private int id;

    public SkillSuccessPacket() {
    }

    public SkillSuccessPacket(int id) {
        this.id = id;
    }

    @Override
    public void toBytes(ByteBuf bb) {
        bb.writeInt(id);
    }

    @Override
    public void fromBytes(ByteBuf bb) {
        id = bb.readInt();
    }

    public class SkillSuccessPacketHandler implements IMessageHandler<SkillSuccessPacket, IMessage>
    {
        @Override
        public IMessage onMessage(SkillSuccessPacket message, MessageContext ctx) {
            EntityPlayerMP serverPlayer = ctx.getServerHandler().playerEntity;
            int skillID = message.id;

            serverPlayer.addChatMessage(new ChatComponentText("Skill Success!"));
            InGameOverlay.renewCooldown(id);
            return null;
        }
    }
}