minecraft-kajetans-core-mod/src/main/java/me/kcm/KajetansTransformer.java

package me.kcm;

import java.util.ListIterator;
import me.kcm.events.*;
import net.minecraft.launchwrapper.IClassTransformer;
import net.minecraftforge.fml.common.asm.transformers.DeobfuscationTransformer;
import net.minecraftforge.fml.common.asm.transformers.deobf.FMLDeobfuscatingRemapper;
import org.objectweb.asm.ClassReader;
import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.tree.AbstractInsnNode;
import org.objectweb.asm.tree.ClassNode;
import org.objectweb.asm.tree.FieldInsnNode;
import org.objectweb.asm.tree.FrameNode;
import org.objectweb.asm.tree.InsnList;
import org.objectweb.asm.tree.InsnNode;
import org.objectweb.asm.tree.JumpInsnNode;
import org.objectweb.asm.tree.LabelNode;
import org.objectweb.asm.tree.LineNumberNode;
import org.objectweb.asm.tree.MethodInsnNode;
import org.objectweb.asm.tree.MethodNode;
import org.objectweb.asm.tree.VarInsnNode;

public class KajetansTransformer implements IClassTransformer
{
    private void printPatch(Class c)
    {
        System.out.println("|‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾");
        System.out.println("| Patching " + c.getSimpleName());
        System.out.println("|___________________________________________________");
    }
    
    @Override
    public byte[] transform(String old, String searge, byte[] bytes)
    {
        switch(searge)
        {
            case "net.minecraft.entity.EntityLivingBase":
                printPatch(LivingDamageCalculationEvent.class);
                return patchDamageHook(old, bytes, !old.equals(searge));
            case "net.minecraft.entity.player.EntityPlayerMP":
                printPatch(PlayerTabListNameEvent.class);
                return patchTabList(old, bytes, !old.equals(searge));
            case "net.minecraft.entity.Entity":
                printPatch(FarmlandTrampleEvent.class);
                return patchEntityCanTrample(old, bytes, !old.equals(searge));
            case "net.minecraft.server.management.PlayerList":
                printPatch(PlayerConnectionEvent.class);
                return patchPlayerList(old, bytes, !old.equals(searge));
        }
        return bytes;
    }
    
    /*ListIterator<AbstractInsnNode> list = ins.iterator();
    while(list.hasNext())
    {
        AbstractInsnNode next = list.next();
        System.out.println(getString(next));
    }*/
    
    public byte[] patchDamageHook(String c, byte[] bytes, boolean obfuscated)
    {
        try
        {
            ClassNode classNode = new ClassNode();
            ClassReader classReader = new ClassReader(bytes);
            classReader.accept(classNode, 0);
            
            // EntityLivingBase <--> vp
            // damageEntity <--> func_70665_d <--> d
            MethodNode mn;
            if(obfuscated)
            {
                mn = classNode.methods.stream().filter(me -> me.name.equals("d")).filter(me -> "(Lur;F)V".equals(me.desc)).findAny().get();
            }
            else
            {
                mn = classNode.methods.stream().filter(me -> me.name.equals("damageEntity")).findAny().get();
            }
            
            InsnList ins = mn.instructions;
            ins.insert(ins.get(3), new VarInsnNode(Opcodes.FLOAD, 2));
            if(obfuscated)
            {
                ins.insert(ins.get(4), new MethodInsnNode(Opcodes.INVOKESTATIC, "me/kcm/events/Hooks", "onDamageCalculation", "(Lvp;Lur;F)V", false));
            }
            else
            {
                ins.insert(ins.get(4), new MethodInsnNode(Opcodes.INVOKESTATIC, "me/kcm/events/Hooks", 
                    "onDamageCalculation", "(Lnet/minecraft/entity/EntityLivingBase;Lnet/minecraft/util/DamageSource;F)V", false));
            }
                       
            while(ins.size() > 8)
            {
                ins.remove(ins.get(6));
            }

            ClassWriter writer = new ClassWriter(ClassWriter.COMPUTE_MAXS | ClassWriter.COMPUTE_FRAMES);
            classNode.accept(writer);
            return writer.toByteArray();
        }
        catch(Exception ex)
        {
            ex.printStackTrace();
        }       
        return bytes;
    }
    
    public byte[] patchTabList(String c, byte[] bytes, boolean obfuscated)
    {
        try
        {
            ClassNode classNode = new ClassNode();
            ClassReader classReader = new ClassReader(bytes);
            classReader.accept(classNode, 0);
            
            // EntityPlayerMP <--> oq
            // getTabListDisplayName <--> func_175396_E <--> K
            // MD: oq/K ()Lhh; net/minecraft/entity/player/EntityPlayerMP/func_175396_E ()Lnet/minecraft/util/text/ITextComponent;
            MethodNode mn;
            if(obfuscated)
            {
                mn = classNode.methods.stream().filter(me -> me.name.equals("K")).filter(me -> "()Lhh;".equals(me.desc)).findAny().get();
            }
            else
            {
                mn = classNode.methods.stream().filter(me -> me.name.equals("getTabListDisplayName")).findAny().get();
            }

            InsnList ins = mn.instructions;
            ins.remove(ins.get(2));
            ins.insert(ins.get(1), new VarInsnNode(Opcodes.ALOAD, 0));
            if(obfuscated)
            {
                ins.insert(ins.get(2), new MethodInsnNode(Opcodes.INVOKESTATIC, "me/kcm/events/Hooks", "onGetTabListDisplayName", "(Loq;)Lhh;", false));
            }
            else
            {
                ins.insert(ins.get(2), new MethodInsnNode(Opcodes.INVOKESTATIC, "me/kcm/events/Hooks", 
                    "onGetTabListDisplayName", "(Lnet/minecraft/entity/player/EntityPlayerMP;)Lnet/minecraft/util/text/ITextComponent;", false));
            }
            
            ClassWriter writer = new ClassWriter(ClassWriter.COMPUTE_MAXS | ClassWriter.COMPUTE_FRAMES);
            classNode.accept(writer);
            return writer.toByteArray();
        }
        catch(Exception ex)
        {
            ex.printStackTrace();
        }       
        return bytes;
    }
    
    public byte[] patchEntityCanTrample(String c, byte[] bytes, boolean obfuscated)
    {
        try
        {
            ClassNode classNode = new ClassNode();
            ClassReader classReader = new ClassReader(bytes);
            classReader.accept(classNode, 0);
            
            // CL: vg net/minecraft/entity/Entity
            // Entity <--> vg
            // canTrample is forge function
            // Lnet/minecraft/world/World;Lnet/minecraft/block/Block;Lnet/minecraft/util/math/BlockPos;F
            // World <--> amu
            // Block <--> aow
            // BlockPos <--> et
            MethodNode mn = classNode.methods.stream().filter(me -> me.name.equals("canTrample")).findAny().get();

            InsnList ins = mn.instructions;

            int i = ins.size();
            LabelNode label = null;
            int counter = 0;
            while(counter < 3)
            {
                i--;
                if(ins.get(i) instanceof LabelNode)
                {
                    counter++;
                    label = (LabelNode) ins.get(i);
                }
            }
            
            while(ins.get(i).getOpcode() != Opcodes.IFLE)
            {
                i--;
            }
            
            ins.insert(ins.get(i), new JumpInsnNode(Opcodes.IFEQ, label));
            if(obfuscated)
            {
                ins.insert(ins.get(i), new MethodInsnNode(Opcodes.INVOKESTATIC, "me/kcm/events/Hooks", 
                    "onEntityCanTrample", "(Lvg;Lamu;Laow;Let;F)Z", false));
            }
            else
            {
                ins.insert(ins.get(i), new MethodInsnNode(Opcodes.INVOKESTATIC, "me/kcm/events/Hooks", 
                    "onEntityCanTrample", "(Lnet/minecraft/entity/Entity;Lnet/minecraft/world/World;"
                            + "Lnet/minecraft/block/Block;Lnet/minecraft/util/math/BlockPos;F)Z", false));
            }
            ins.insert(ins.get(i), new VarInsnNode(Opcodes.FLOAD, 4));
            ins.insert(ins.get(i), new VarInsnNode(Opcodes.ALOAD, 3));
            ins.insert(ins.get(i), new VarInsnNode(Opcodes.ALOAD, 2));
            ins.insert(ins.get(i), new VarInsnNode(Opcodes.ALOAD, 1));      
            ins.insert(ins.get(i), new VarInsnNode(Opcodes.ALOAD, 0));    
            
            ClassWriter writer = new ClassWriter(ClassWriter.COMPUTE_MAXS | ClassWriter.COMPUTE_FRAMES);
            classNode.accept(writer);
            return writer.toByteArray();
        }
        catch(Exception ex)
        {
            ex.printStackTrace();
        }       
        return bytes;
    }
    
    public byte[] patchPlayerList(String c, byte[] bytes, boolean obfuscated)
    {
        try
        {
            ClassNode classNode = new ClassNode();
            ClassReader classReader = new ClassReader(bytes);
            classReader.accept(classNode, 0);
            
            // EntityPlayerMP <--> oq
            // initializeConnectionToPlayer <--> func_72355_a <--> a
            //MD: pl/a (Lgw;Loq;)V net/minecraft/server/management/PlayerList/func_72355_a 
            // (Lnet/minecraft/network/NetworkManager;Lnet/minecraft/entity/player/EntityPlayerMP;)V
            // CL: pa net/minecraft/network/NetHandlerPlayServer
            // public void initializeConnectionToPlayer(NetworkManager netManager, EntityPlayerMP playerIn, NetHandlerPlayServer nethandlerplayserver)
            // its something else: (Lgw;Loq;Lpa;)V
            // it seems forge is already overwriting this method
            MethodNode mn = classNode.methods.stream().filter(me -> me.name.equals("initializeConnectionToPlayer")).findAny().get();
            
            InsnList ins = mn.instructions;
            int index = 0;
            AbstractInsnNode node;
            // first part - inserting PlayerConnectionEvent hook
            // connection <--> field_71135_a <--> a
            // FD: oq/a net/minecraft/entity/player/EntityPlayerMP/field_71135_a
            String search = obfuscated ? "a" : "connection";
            String playerOwner = obfuscated ? "oq" : "net/minecraft/entity/player/EntityPlayerMP";
            boolean found = false;
            while(index < ins.size())
            {
                node = ins.get(index);
                if(node instanceof FieldInsnNode)
                {
                    FieldInsnNode field = (FieldInsnNode) node;
                    if(field.name.equals(search) && field.owner.equals(playerOwner))
                    {
                        found = true;
                        break;
                    }
                }
                index++;
            }
            
            if(!found)
            {
                System.out.println("Start of player connection was not found");
                return bytes;
            }
            
            if(obfuscated)
            {
                ins.insert(ins.get(index), new MethodInsnNode(Opcodes.INVOKESTATIC, "me/kcm/events/Hooks", "onPlayerConnection", "(Loq;)V", false));
            }
            else
            {
                ins.insert(ins.get(index), new MethodInsnNode(Opcodes.INVOKESTATIC, "me/kcm/events/Hooks", 
                    "onPlayerConnection", "(Lnet/minecraft/entity/player/EntityPlayerMP;)V", false));
            }
            ins.insert(ins.get(index), new VarInsnNode(Opcodes.ALOAD, 2));
            // end of first part - inserting PlayerConnectionEvent hook
            // second part - removing join message
            // func_70005_c_
            // MD: aed/h_ ()Ljava/lang/String; net/minecraft/entity/player/EntityPlayer/func_70005_c_ ()Ljava/lang/String;
            String start = "equalsIgnoreCase";
            String startDesc = "(Ljava/lang/String;)Z";
            
            // func_148539_a
            // MD: pl/a (Lhh;)V net/minecraft/server/management/PlayerList/func_148539_a (Lnet/minecraft/util/text/ITextComponent;)V
            String end = obfuscated ? "a" : "sendMessage";
            String endDesc = obfuscated ? "(Lhh;)V" : "(Lnet/minecraft/util/text/ITextComponent;)V";
            
            found = false;
            while(index < ins.size())
            {
                node = ins.get(index);
                if(node instanceof MethodInsnNode)
                {
                    MethodInsnNode mnode = (MethodInsnNode) node;
                    if(mnode.name.equals(start) && mnode.desc.equals(startDesc))
                    {
                        found = true;
                        break;
                    }
                }
                index++;
            }
            
            if(!found)
            {
                System.out.println("Start of player join message was not found");
                return bytes;
            }
            
            // moving to real start of the block "p.getName()..."
            index -= 3;
            while(true)
            {
                node = ins.get(index);
                if(node instanceof MethodInsnNode)
                {
                    MethodInsnNode mnode = (MethodInsnNode) node;
                    if(mnode.name.equals(end) && mnode.desc.equals(endDesc))
                    {
                        ins.remove(node);
                        break;
                    }
                }
                ins.remove(node);
            }
            
            // End of second Part - Removing join message
            
            ListIterator<AbstractInsnNode> list = ins.iterator();
            while(list.hasNext())
            {
                AbstractInsnNode next = list.next();
                System.out.println(getString(next));
            }
            
            ClassWriter writer = new ClassWriter(ClassWriter.COMPUTE_MAXS | ClassWriter.COMPUTE_FRAMES);
            classNode.accept(writer);
            return writer.toByteArray();
        }
        catch(Exception ex)
        {
            ex.printStackTrace();
        }       
        return bytes;
    }
    
    public String getString(AbstractInsnNode node)
    {
        StringBuilder sb = new StringBuilder();
        sb.append(node.getClass().getSimpleName());
        sb.append("  ");
        sb.append(node.getOpcode());
        sb.append("  ");
        sb.append(node.getType());
        sb.append("  ");
        if(node instanceof LineNumberNode)
        {
            LineNumberNode n = (LineNumberNode) node;
            sb.append(n.line);
            sb.append(" ");
            sb.append(n.start);
        }
        else if(node instanceof VarInsnNode)
        {
            VarInsnNode n = (VarInsnNode) node;
            sb.append(n.var);
        }
        else if(node instanceof MethodInsnNode)
        {
            MethodInsnNode n = (MethodInsnNode) node;
            sb.append(n.desc);
            sb.append(" ");
            sb.append(n.itf);
            sb.append(" ");
            sb.append(n.name);
            sb.append(" ");
            sb.append(n.owner);
        }
        else if(node instanceof FrameNode)
        {
            FrameNode n = (FrameNode) node;
            if(n.local != null)
            {
                n.local.forEach(s -> {sb.append(s); sb.append(" ");});
            }
            if(n.stack != null)
            {
                n.stack.forEach(s -> {sb.append(s); sb.append(" ");});
            }
        }
        else if(node instanceof InsnNode)
        {
        }
        else if(node instanceof FieldInsnNode)
        {
            FieldInsnNode n = (FieldInsnNode) node;
            sb.append(n.desc);
            sb.append(" ");
            sb.append(n.name);
            sb.append(" ");
            sb.append(n.owner);
        }
        return sb.toString();
    }
}