import java.nio.ByteBuffer;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintStream;
import java.io.RandomAccessFile;
import java.io.Reader;

public class NDSRomInfo {
    static File file;

     public static byte[] getBytes(int start, int end, boolean reverse) {
        RandomAccessFile raf = null;
        byte[] header = new byte[end + 1 - start];
        try {
            raf = new RandomAccessFile(file, "r");
            raf.seek(start);
            for (int i = 0; i < header.length; ++i) {
                if(reverse == true){
                    header[(header.length-1) - i] = raf.readByte();
                } else {
                    header[i] = raf.readByte();
                }
            }
            return header;
        }
        catch (IOException ex) {
            return null;
        }
    }

    public static void main(String[] args) {
        if(args.length == 0){
          System.out.printf("Please specify an input file.");
          return;
        }
        file = new File(args[0]);

        if(file.exists() && !file.isDirectory()) {
            ByteBuffer bannerLocation = ByteBuffer.wrap(getBytes(0x68, 0x6B, true));
            ByteBuffer bannerSize = ByteBuffer.wrap(getBytes(0x208, 0x20B, true));
            String ndsData = "";

            try {
                FileInputStream fis = new FileInputStream(file);
                byte[] data = new byte[(int) file.length()];
                fis.read(data);
                fis.close();
                ndsData = new String(data);
                data = null;
            } catch (IOException ex) {
                return;
            }


            int gamePathStartOffset = ndsData.indexOf("<<<Start NDS Path");
            int gamePathEndOffset = ndsData.indexOf("End NDS Path>>>");

            if(gamePathEndOffset > -1){
                gamePathEndOffset += 15;
            }

            if(gamePathStartOffset > -1){
                System.out.printf(" GamePath Start: 0x%X\n", gamePathStartOffset);
            } else {
                System.out.printf(" GamePath Start: NOT FOUND\n");
            }

            if(gamePathEndOffset > -1){
                System.out.printf("GamePath Length: %d\n", (gamePathEndOffset - gamePathStartOffset));
            } else {
                System.out.printf("GamePath Length: 0\n");
            }

            System.out.printf("Banner Location: 0x%X\n", bannerLocation.getInt());
            System.out.printf("    Banner Size: 0x%X\n", bannerSize.getInt());

        } else {
            System.out.printf("File not found.");
        }

    }

}