extras/src/main/java/pw/kaboom/extras/modules/server/ServerCommand.java

package pw.kaboom.extras;

import org.bukkit.ChatColor;

import org.bukkit.command.BlockCommandSender;
import org.bukkit.command.Command;
import org.bukkit.command.CommandSender;

import org.bukkit.block.Block;
import org.bukkit.block.CommandBlock;

import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;

import org.bukkit.event.server.RemoteServerCommandEvent;
import org.bukkit.event.server.ServerCommandEvent;

class ServerCommand implements Listener {
	public static String checkCommand(CommandSender sender, String command, boolean isConsoleCommand) {
		final String[] arr = command.split(" ");
		String commandName = arr[0].toLowerCase();
		
		if (isConsoleCommand) {
			commandName = "/" + arr[0].toLowerCase();
		}
		
		try {
			switch (commandName) {
				case "/minecraft:execute":
				case "/execute":
					if (arr.length >= 2) {
						int asAtCount = 0;
			
						for (int i = 1; i < arr.length; i++) {
							if ("run".equalsIgnoreCase(arr[i])) {
								if (i+1 < arr.length) {
									if ("execute".equalsIgnoreCase(arr[i+1]) ||
										"particle".equalsIgnoreCase(arr[i+1]) ||
										"save-off".equalsIgnoreCase(arr[i+1]) ||
										"spreadplayers".equalsIgnoreCase(arr[i+1]) ||
										"stop".equalsIgnoreCase(arr[i+1])) {
										Command.broadcastCommandMessage(sender, "Forbidden execute command detected");
										return "cancel";
									} else if (i+3 < arr.length &&
										"gamerule".equalsIgnoreCase(arr[i+1])) {
										if ("randomTickSpeed".equalsIgnoreCase(arr[i+2]) &&
											Double.parseDouble(arr[i+3]) > 6) {
											return command.replaceFirst("(?i)" + "randomTickSpeed " + arr[i+3], "randomTickSpeed 6");
										} else if ("spawnRadius".equalsIgnoreCase(arr[i+2]) &&
											Double.parseDouble(arr[i+3]) > 100) {
											return command.replaceFirst("(?i)" + "spawnRadius " + arr[i+3], "spawnRadius 100");
										}
									} else if ("give".equalsIgnoreCase(arr[i+1])) {
										if (Double.parseDouble(arr[arr.length-1]) > 1024) {
											arr[arr.length-1] = "1024";
											return String.join(" ", arr);
										}
									}
								}
								break;
							}
			
							if ("as".equalsIgnoreCase(arr[i]) ||
								"at".equalsIgnoreCase(arr[i])) {
								asAtCount++;
							}
						}
						
						if (asAtCount >= 2) {
							Command.broadcastCommandMessage(sender, "Forbidden execute pattern detected");
							return "cancel";
						}
					}
					break;
				case "/minecraft:gamerule":
				case "/gamerule":
					if (arr.length >= 3) {
						if ("randomTickSpeed".equalsIgnoreCase(arr[1]) &&
							Double.parseDouble(arr[2]) > 6) {
							return command.replaceFirst(arr[2], "6");
						} else if ("spawnRadius".equalsIgnoreCase(arr[1]) &&
							Double.parseDouble(arr[2]) > 100) {
							return command.replaceFirst(arr[2], "100");
						}
					}
					break;
				case "/minecraft:give":
				case "/give":
					if (Double.parseDouble(arr[arr.length-1]) > 1024) {
						arr[arr.length-1] = "1024";
						return String.join(" ", arr);
					}
					break;
				case "/minecraft:particle":
				case "/particle":
					if (arr.length >= 10 &&
						Double.parseDouble(arr[9]) > 10) {
						arr[9] = "10";
						return String.join(" ", arr);
					}
					break;
				case "/bukkit:reload":
				case "/bukkit:rl":
				case "/reload":
				case "/rl":
					if (sender.hasPermission("bukkit.command.reload") &&
						arr.length >= 2 &&
						"confirm".equalsIgnoreCase(arr[1])) {
						Command.broadcastCommandMessage(sender, ChatColor.RED + "Please note that this command is not supported and may cause issues when using some plugins.");
						Command.broadcastCommandMessage(sender, ChatColor.RED + "If you encounter any issues please use the /stop command to restart your server.");
						Command.broadcastCommandMessage(sender, ChatColor.GREEN + "Reload complete.");
						return "cancel";
					}
					break;
				case "/spigot:restart":
				case "/restart":
					if (sender.hasPermission("bukkit.command.restart")) {
						return "cancel";
					}
					break;
				case "/minecraft:save-off":
				case "/save-off":
					if (sender.hasPermission("minecraft.command.save.disable")) {
						Command.broadcastCommandMessage(sender, "Automatic saving is now disabled");
						return "cancel";
					}
					break;
				case "/minecraft:spreadplayers":
				case "/spreadplayers":
					if (arr.length >= 5) {
						if (Double.parseDouble(arr[3]) > 0)
							arr[3] = "0";
						if (Double.parseDouble(arr[4]) < 8)
							arr[4] = "8";
						if (Double.parseDouble(arr[4]) > 50)
							arr[4] = "50";

						return String.join(" ", arr);
					}
					break;
				case "/minecraft:stop":
				case "/stop":
					if (sender.hasPermission("minecraft.command.stop")) {
						Command.broadcastCommandMessage(sender, "Stopping the server");
						return "cancel";
					}
			}
		} catch (NumberFormatException exception) {
			// Do nothing
		}
		return null;
	}

	@EventHandler
	void onServerCommand(ServerCommandEvent event) {
		final CommandSender sender = event.getSender();
		final String[] arr = event.getCommand().split(" ");

		if (sender instanceof BlockCommandSender) {
			if (Main.consoleCommandBlacklist.contains(arr[0].toLowerCase())) {
				event.setCancelled(true);
			}
		}

		final String command = event.getCommand();
		final boolean isConsoleCommand = true;
		final String checkedCommand = checkCommand(sender, command, isConsoleCommand);
		
		if (checkedCommand != null) {
			if (checkedCommand.equals("cancel")) {
				event.setCancelled(true);
			} else {
				event.setCommand(checkedCommand);
			}
		}
	}
}