PlaceholderAPI/src/main/java/me/clip/placeholderapi/replacer/CharsReplacer.java

/*
 * This file is part of PlaceholderAPI
 *
 * PlaceholderAPI
 * Copyright (c) 2015 - 2020 PlaceholderAPI Team
 *
 * PlaceholderAPI free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * PlaceholderAPI 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

package me.clip.placeholderapi.replacer;

import me.clip.placeholderapi.expansion.PlaceholderExpansion;
import org.bukkit.ChatColor;
import org.bukkit.OfflinePlayer;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

import java.util.function.Function;

public final class CharsReplacer implements Replacer
{

	@NotNull
	private final Closure closure;

	public CharsReplacer(@NotNull final Closure closure)
	{
		this.closure = closure;
	}


	@NotNull
	@Override
	public String apply(@NotNull final String text, @Nullable final OfflinePlayer player, @NotNull final Function<String, @Nullable PlaceholderExpansion> lookup)
	{
		final char[]        chars   = text.toCharArray();
		final StringBuilder builder = new StringBuilder(text.length());

		final StringBuilder identifier = new StringBuilder();
		final StringBuilder parameters = new StringBuilder();

		for (int i = 0; i < chars.length; i++)
		{
			final char l = chars[i];

			if (l == '&' && ++i < chars.length)
			{
				final char c = Character.toLowerCase(chars[i]);

				if (c != '0' && c != '1' && c != '2' && c != '3' && c != '4' && c != '5' && c != '6' && c != '7' && c != '8' && c != '9' && c != 'a' && c != 'b' && c != 'c' && c != 'd' && c != 'e' && c != 'f' && c != 'k' && c != 'l' && c != 'm' && c != 'o' && c != 'r' && c != 'x')
				{
					builder.append(l).append(chars[i]);
				}
				else
				{
					builder.append(ChatColor.COLOR_CHAR);

					if (c != 'x')
					{
						builder.append(chars[i]);
						continue;
					}

					if ((i > 1 && chars[i - 2] == '\\') /*allow escaping &x*/)
					{
						builder.setLength(builder.length() - 2);
						builder.append('&').append(chars[i]);
						continue;
					}

					builder.append(c);

					int j = 0;
					while (++j <= 6)
					{
						if (i + j >= chars.length)
						{
							break;
						}

						final char x = chars[i + j];
						builder.append(ChatColor.COLOR_CHAR).append(x);
					}

					if (j == 7)
					{
						i += 6;
					}
					else
					{
						builder.setLength(builder.length() - (j * 2)); // undo &x parsing
					}
				}
				continue;
			}

			if (l != closure.head || i + 1 >= chars.length)
			{
				builder.append(l);
				continue;
			}

			boolean identified = false;
			boolean oopsitsbad = true;

			while (++i < chars.length)
			{
				final char p = chars[i];

				if (p == ' ')
				{
					break;
				}
				if (p == closure.tail)
				{
					oopsitsbad = false;
					break;
				}

				if (p == '_' && !identified)
				{
					identified = true;
					continue;
				}

				if (identified)
				{
					parameters.append(p);
				}
				else
				{
					identifier.append(p);
				}
			}

			final String identifierString = identifier.toString();
			final String parametersString = parameters.toString();

			identifier.setLength(0);
			parameters.setLength(0);

			if (oopsitsbad)
			{
				builder.append(closure.head).append(identifierString);

				if (identified)
				{
					builder.append('_').append(parametersString);
				}

				builder.append(' ');
				continue;
			}

			final PlaceholderExpansion placeholder = lookup.apply(identifierString);
			if (placeholder == null)
			{
				builder.append(closure.head).append(identifierString);

				if (identified)
				{
					builder.append('_');
				}

				builder.append(parametersString).append(closure.tail);
				continue;
			}

			final String replacement = placeholder.onRequest(player, parametersString);
			if (replacement == null)
			{
				builder.append(closure.head).append(identifierString);

				if (identified)
				{
					builder.append('_');
				}

				builder.append(parametersString).append(closure.tail);
				continue;
			}

			builder.append(replacement);
		}

		return builder.toString();
	}

}