Grasscutter/src/main/java/emu/grasscutter/net/packet/PacketOpcodesUtils.java

package emu.grasscutter.net.packet;

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.lang.reflect.Field;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
import java.util.stream.Collectors;

import emu.grasscutter.GameConstants;
import emu.grasscutter.Grasscutter;
import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;

public class PacketOpcodesUtils {
    private static Int2ObjectMap<String> opcodeMap;

    public static final Set<Integer> BANNED_PACKETS = Set.of(
        PacketOpcodes.WindSeedClientNotify,
        PacketOpcodes.PlayerLuaShellNotify
    );
    
    public static final Set<Integer> LOOP_PACKETS = Set.of(
        PacketOpcodes.PingReq,
        PacketOpcodes.PingRsp,
        PacketOpcodes.WorldPlayerRTTNotify,
        PacketOpcodes.UnionCmdNotify,
        PacketOpcodes.QueryPathReq
    );
	
	static {
		opcodeMap = new Int2ObjectOpenHashMap<String>();

		Field[] fields = PacketOpcodes.class.getFields();

		for (Field f : fields) {
			if(f.getType().equals(int.class)) {
				try {
					opcodeMap.put(f.getInt(null), f.getName());
				} catch (Exception e) {
					e.printStackTrace();
				}
			}
		}
	}

	public static String getOpcodeName(int opcode) {
		if (opcode <= 0) return "UNKNOWN";
		return opcodeMap.getOrDefault(opcode, "UNKNOWN");
	}

	public static void dumpPacketIds() {
	    try (FileWriter writer = new FileWriter("./PacketIds_" + GameConstants.VERSION + ".json")) {
	        // Create sorted tree map
	        Map<Integer, String> packetIds = opcodeMap.int2ObjectEntrySet().stream()
	                .filter(e -> e.getIntKey() > 0)
	                .collect(Collectors.toMap(Int2ObjectMap.Entry::getIntKey, Int2ObjectMap.Entry::getValue, (k, v) -> v, TreeMap::new));
	        // Write to file
			writer.write(Grasscutter.getGsonFactory().toJson(packetIds));
			Grasscutter.getLogger().info("Dumped packet ids.");
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
}