Fix crashing and try to optimize performance

.gitignore

@@ -106,3 +106,6 @@ gradle-app.setting
 # JDT-specific (Eclipse Java Development Tools)
 .classpath
 .gitsync.json
+
+# NixOS flake.nix
+flake.*

common/src/main/java/com/elfmcys/yesstevemodel/client/ClientModelManager.java

@@ -193,6 +193,22 @@ private static void processServerData(ByteBuffer data) {
     }
 
     private static void handlePacket01(byte[] decryptedBuffer) throws Exception {
+        // Plaintext shape (server nativeSyncModels + encrypt appendNextKey):
+        //   [garbageLen|0x80] [0x00] [garbage] [0x01] [56-byte nextKey]
+        // garbageLen fits in 7 bits, so total = 2 + garbageLen + 1 + 56 ∈ [59, 186].
+        // A late packet 05 chunk decrypted with the wrong key shows up here as
+        // kilobytes of structurally-invalid bytes — drop it instead of accepting
+        // it as a key exchange, which would corrupt lastKey and cascade into a
+        // handlePacket03 crash on the next inbound chunk.
+        if (decryptedBuffer == null || decryptedBuffer.length < 59 || decryptedBuffer.length > 186) {
+            return;
+        }
+        int rxGarbageLen = decryptedBuffer[0] & 0x7F;
+        if (decryptedBuffer.length != 2 + rxGarbageLen + 1 + 56
+                || decryptedBuffer[2 + rxGarbageLen] != 0x01) {
+            return;
+        }
+
         key1 = new byte[56];
         System.arraycopy(decryptedBuffer, decryptedBuffer.length - 56, key1, 0, 56);
         syncStep = 2;
@@ -223,7 +239,11 @@ private record ModelHash(long hash1, long hash2) {
 
     private static void handlePacket03(YSMByteBuf buf) throws Exception {
         buf.skipGarbageHeader();
-        int type = buf.readVarInt(); // expect 3
+        int type = buf.readVarInt();
+        // Defense in depth: a wrong-key decryption here would have lastKey pointing
+        // at junk and `type` reading as anything. handlePacket05 already does the
+        // same guard with `if (type != 5) return`.
+        if (type != 3) return;
         long folderHash = buf.readVarLong();
         currentCacheFolderName = Long.toHexString(folderHash);
 

common/src/main/java/com/elfmcys/yesstevemodel/client/texture/OuterFileTexture.java

@@ -16,11 +16,21 @@
 
 public class OuterFileTexture extends AbstractTexture implements ITextureMap {
     private final byte[] data;
+    private final int rawRgbaWidth;
+    private final int rawRgbaHeight;
 
     private Map<ShadersTextureType, OuterFileTexture> suffixTextures = Reference2ReferenceMaps.emptyMap();
 
     public OuterFileTexture(byte[] data) {
         this.data = data;
+        this.rawRgbaWidth = 0;
+        this.rawRgbaHeight = 0;
+    }
+
+    public OuterFileTexture(byte[] rawRgbaData, int width, int height) {
+        this.data = rawRgbaData;
+        this.rawRgbaWidth = width;
+        this.rawRgbaHeight = height;
     }
 
     @Override
@@ -34,7 +44,7 @@ public void load(@NotNull ResourceManager resourceManager) {
 
     public void doLoad() {
         try {
-            NativeImage imageIn = NativeImage.read(new ByteArrayInputStream(data));
+            NativeImage imageIn = isRawRgba() ? readRawRgba() : NativeImage.read(new ByteArrayInputStream(data));
             int width = imageIn.getWidth();
             int height = imageIn.getHeight();
             TextureUtil.prepareImage(this.getId(), 0, width, height);
@@ -44,11 +54,36 @@ public void doLoad() {
         }
     }
 
+    private boolean isRawRgba() {
+        return rawRgbaWidth > 0 && rawRgbaHeight > 0;
+    }
+
+    private NativeImage readRawRgba() throws IOException {
+        long expectedLength = (long) rawRgbaWidth * (long) rawRgbaHeight * 4L;
+        if (data == null || data.length < expectedLength) {
+            throw new IOException("Invalid raw RGBA texture data");
+        }
+
+        NativeImage image = new NativeImage(rawRgbaWidth, rawRgbaHeight, false);
+        for (int y = 0; y < rawRgbaHeight; y++) {
+            int row = y * rawRgbaWidth * 4;
+            for (int x = 0; x < rawRgbaWidth; x++) {
+                int offset = row + x * 4;
+                int r = data[offset] & 0xFF;
+                int g = data[offset + 1] & 0xFF;
+                int b = data[offset + 2] & 0xFF;
+                int a = data[offset + 3] & 0xFF;
+                image.setPixelRGBA(x, y, (a << 24) | (b << 16) | (g << 8) | r);
+            }
+        }
+        return image;
+    }
+
     public void setSuffixTextures(Map<ShadersTextureType, OuterFileTexture> map) {
         this.suffixTextures = Reference2ReferenceMaps.unmodifiable(new Reference2ReferenceOpenHashMap<>(map));
     }
 
     public Map<ShadersTextureType, ? extends AbstractTexture> getSuffixTextures() {
         return this.suffixTextures;
     }
-}
+}

common/src/main/java/com/elfmcys/yesstevemodel/resource/YSMBinaryDeserializer.java

@@ -1,5 +1,6 @@
 package com.elfmcys.yesstevemodel.resource;
 
+import com.elfmcys.yesstevemodel.YesSteveModel;
 import com.elfmcys.yesstevemodel.resource.pojo.RawYsmModel;
 import io.netty.buffer.Unpooled;
 import rip.ysm.security.YSMByteBuf;
@@ -28,7 +29,7 @@ public YSMBinaryDeserializer(byte[] decompressedData, int format) {
 
 
     private RawYsmModel deserializeInternal(boolean closeOnExit) {
-        System.out.println("deserializing format " + format + " file...");
+        YesSteveModel.LOGGER.debug("deserializing format {} file...", format);
         if (format < 4) {
             deserializeLegacyV1();
         } else if (format <= 15) {
@@ -46,7 +47,7 @@ private RawYsmModel deserializeInternal(boolean closeOnExit) {
         if (closeOnExit) {
             this.reader.close();
         }
-        System.out.println("end offset: 0x" + Integer.toHexString(offset));
+        YesSteveModel.LOGGER.debug("end offset: 0x{}", Integer.toHexString(offset));
         return model;
     }
 
@@ -82,8 +83,8 @@ public void parseYSMFooter(RawYsmModel footer) {
             }
 
         } catch (Throwable t) {
-            System.out.println("ERROR");
-            t.printStackTrace(System.out);
+            YesSteveModel.LOGGER.debug("Failed to parse YSM footer (format={}, offset=0x{})",
+                    format, Integer.toHexString(reader.getOffset()), t);
         }
     }
 
@@ -400,7 +401,7 @@ private void deserializeModern() {
             geoRef.sha256 = hash;
             geoRef.modelType = modelType;
             tempMainModels.add(geoRef);
-            System.out.println("Model Table Entry: ID=" + modelType + ", Hash=" + hash);
+            YesSteveModel.LOGGER.debug("Model Table Entry: ID={}, Hash={}", modelType, hash);
         }
         assignMainModels(tempMainModels);