import com.google.common.io.ByteStreams;
import net.minecraft.nbt.CompressedStreamTools;
import net.minecraft.nbt.NBTTagCompound;
import net.minecraft.util.ResourceLocation;
import net.minecraftforge.fml.common.FMLCommonHandler;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.zip.GZIPInputStream;

public class GLBLoader {
    public static NBTTagCompound loadGLBFile(File file) throws IOException {
        if (!file.exists()) {
            throw new IOException("File does not exist");
        }
        if (!file.isFile()) {
            throw new IOException("File is not a valid file");
        }
        if (!file.canRead()) {
            throw new IOException("File cannot be read");
        }
        String fileName = file.getName();
        String fileExtension = fileName.substring(fileName.lastIndexOf(".") + 1);
        if (!fileExtension.equalsIgnoreCase("glb")) {
            throw new IOException("File is not a valid .glb file");
        }
        InputStream inputStream = new FileInputStream(file);
        byte[] magicNumber = new byte[4];
        inputStream.read(magicNumber);
        if (!magicNumber[0] == 'g' || !magicNumber[1] == 'l' || !magicNumber[2] == 'b') {
            throw new IOException("File is not a valid .glb file");
        }
        int version = inputStream.read();
        if (version != 2) {
            throw new IOException("Unsupported .glb file version");
        }
        int totalLength = readInt32(inputStream);
        int modelLength = readInt32(inputStream);
        //Skip model data for now
        inputStream.skip(modelLength);
        int sceneLength = readInt32(inputStream);
        byte[] sceneData = new byte[sceneLength];
        inputStream.read(sceneData);
        InputStream sceneInputStream = new ByteArrayInputStream(sceneData);
        NBTTagCompound nbtTagCompound = CompressedStreamTools.read(new GZIPInputStream(sceneInputStream), new
 NBTSizeTracker(Integer.MAX_VALUE));
        inputStream.close();
        sceneInputStream.close();
        return nbtTagCompound;
    }
}