package test;

import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;

public class XLDContainer {
    public static final String XLD_SIGNATURE = "XLD0I\0";

    // Header
    public int   magic   = 0;
    public byte  unknown = 0;
    public short entries = 0;
    public int[] length  = new int[0];
    public byte[][] subfiles = new byte[0][];

    public XLDContainer(File xldFile) throws Exception {
        if (xldFile.exists() && xldFile.isFile()) {
            parseXLD(xldFile);
        } else {
            System.err.println(String.format("Invalid File: %s", xldFile.getName()));
            return;
        }
    }

    public void parseXLD(File file) throws Exception {
        FileInputStream fin = new FileInputStream(file);
        DataInputStream din = new DataInputStream(fin);

        // dbg
        debug(String.valueOf(swapInteger(1)));
        debug(String.valueOf(swapInteger(255)));
        //debug(String.valueOf(swapInteger(4278190080)));

        int    lastEntry = -1;
        short  nEntries  = 0;
        int[]  entrylen  = null;
        String sig       = "";

        // Read signature
        byte[] sigBuf = new byte[6];
        din.read(sigBuf, 0, 6);
        sig = new String(sigBuf);

        if (sig.equals(XLD_SIGNATURE)) {
            nEntries = (short) swapShort(din.readShort());
            entrylen = new int[nEntries];

            debug("nEntries: " + nEntries);

            for (int i = 0; i < nEntries; i++) {
                entrylen[i] = din.readInt();

                debug("EntryLen[" + i + "] = " + swapInteger(entrylen[i]));
            }

            byte[][] entries = new byte[nEntries][];
            for(int i = 0; i < nEntries; i++)
            {
                lastEntry = i;
                //din.read(entries[i], 0, entrylen[i]);
            }

            din.close();
        } else {
            din.close();
            throw new Exception("This is not a valid XLD File.");
        }
    }

    public static short swapShort(short val) {
        return (short) (((val & 0xFF00) >> 8) + ((val & 0xFF) << 8));
    }

    public static int swapInteger(int value) {
        return ((value&0xFF)<<24)|((value&0xFF00)<<8)|((value&0xFF0000)>>8)|((value&0xFF000000)>>24);
    }



    public static void debug(final String str) {
        System.out.printf("[DEBUG] %s\n", str);
    }
}