/*
 * This file is part of EssentialCmds, licensed under the MIT License (MIT).
 *
 * Copyright (c) 2015 - 2015 HassanS6000
 * Copyright (c) contributors
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package io.github.hsyyid.essentialcmds.cmdexecutors;

import org.spongepowered.api.command.CommandException;
import org.spongepowered.api.command.CommandResult;
import org.spongepowered.api.command.CommandSource;
import org.spongepowered.api.command.args.CommandContext;
import org.spongepowered.api.command.spec.CommandExecutor;
import org.spongepowered.api.entity.living.player.Player;
import org.spongepowered.api.item.inventory.ItemStack;
import org.spongepowered.api.text.Text;

import java.util.Optional;

public class HatExecutor implements CommandExecutor
{
	@Override
	public CommandResult execute(CommandSource src, CommandContext args) throws CommandException
	{
		if (src instanceof Player)
		{
			Player player = (Player) src;
			Optional<ItemStack> itemInHand = player.getItemInHand();

			if (itemInHand.isPresent())
			{
				ItemStack hatStack = itemInHand.get();
				hatStack.setQuantity(1);
				player.setHelmet(hatStack);

				if (itemInHand.get().getQuantity() > 1)
				{
					ItemStack stack = itemInHand.get();
					stack.setQuantity(itemInHand.get().getQuantity() - 1);
					player.setItemInHand(stack);
				}
				else
				{
					player.setItemInHand(null);
				}
			}
			else
			{
				player.sendMessage(Text.of("No item selected in hotbar."));
				return CommandResult.empty();
			}
		}
		return CommandResult.success();
	}
}

/*
 * This file is part of EssentialCmds, licensed under the MIT License (MIT).
 *
 * Copyright (c) 2015 - 2015 HassanS6000
 * Copyright (c) contributors
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package io.github.hsyyid.essentialcmds.cmdexecutors;

import org.spongepowered.api.command.CommandException;
import org.spongepowered.api.command.CommandResult;
import org.spongepowered.api.command.CommandSource;
import org.spongepowered.api.command.args.CommandContext;
import org.spongepowered.api.command.spec.CommandExecutor;
import org.spongepowered.api.entity.living.player.Player;
import org.spongepowered.api.item.inventory.ItemStack;
import org.spongepowered.api.text.Text;

import java.util.Optional;

public class HatExecutor implements CommandExecutor
{
	@Override
	public CommandResult execute(CommandSource src, CommandContext args) throws CommandException
	{
		if (src instanceof Player)
		{
			Player player = (Player) src;
			Optional<ItemStack> itemInHand = player.getItemInHand();

			if (itemInHand.isPresent())
			{
				player.setHelmet(itemInHand.get());

				if (itemInHand.get().getQuantity() > 1)
				{
					itemInHand.get().setQuantity(itemInHand.get().getQuantity() - 1);
				}
				else
				{
					player.setItemInHand(null);
				}
			}
			else
			{
				player.sendMessage(Text.of("No item selected in hotbar."));
			}
		}
		
		return CommandResult.success();
	}
}

Fix /hat