ChatInject.java

package me.lucko.chatinject;

import net.minecraft.client.Minecraft;
import net.minecraft.command.CommandBase;
import net.minecraft.command.CommandException;
import net.minecraft.command.ICommandSender;
import net.minecraft.util.ChatComponentText;
import net.minecraftforge.client.ClientCommandHandler;
import net.minecraftforge.fml.common.Mod;
import net.minecraftforge.fml.common.Mod.EventHandler;
import net.minecraftforge.fml.common.event.FMLInitializationEvent;
import org.apache.commons.lang3.StringUtils;

@Mod(modid = ChatInject.MODID, name = ChatInject.MODNAME, version = ChatInject.VERSION)
public class ChatInject {
    public static final String MODID = "chatinject";
    public static final String MODNAME = "ChatInject";
    public static final String VERSION = "1.0";

    @EventHandler
    public void init(FMLInitializationEvent event) {
        ClientCommandHandler.instance.registerCommand(new CommandBase() {
            @Override
            public String getCommandName() {
                return "inject";
            }

            @Override
            public String getCommandUsage(ICommandSender sender) {
                return "/inject <message>";
            }

            @Override
            public void processCommand(ICommandSender sender, String[] args) throws CommandException {
                if (args.length != 0) {
                    final String s = StringUtils.join(args, " ");
                    Minecraft.getMinecraft().thePlayer.addChatMessage(new ChatComponentText(translateColorCodes('&', s)));
                } else {
                    Minecraft.getMinecraft().thePlayer.addChatMessage(new ChatComponentText("Usage: /inject <message>"));
                }
            }

            @Override
            public int getRequiredPermissionLevel() {
                return 0;
            }

            private String translateColorCodes(char altColorChar, String textToTranslate) {
                char[] b = textToTranslate.toCharArray();

                for(int i = 0; i < b.length - 1; ++i) {
                    if(b[i] == altColorChar && "0123456789AaBbCcDdEeFfKkLlMmNnOoRr".indexOf(b[i + 1]) > -1) {
                        b[i] = 167;
                        b[i + 1] = Character.toLowerCase(b[i + 1]);
                    }
                }

                return new String(b);
            }
        });
    }
}