package eu.meinemensa.light.activities;

import java.io.IOException;
import java.math.BigInteger;
import android.annotation.TargetApi;
import android.app.Activity;
import android.nfc.NfcAdapter;
import android.nfc.Tag;
import android.nfc.tech.IsoDep;
import android.os.Build;
import android.os.Bundle;
import android.util.Log;

public class NFCActivity extends Activity
{
    private IsoDep desfire;
    private final byte[] NATIVE_SELECT_APP_COMMAND = new byte[]
    {
        (byte) 0x90, (byte) 0x5A, (byte) 0x00, (byte) 0x00, 3,  // SELECT
        (byte) 0x5F, (byte) 0x84, (byte) 0x15, (byte) 0x00      // APPLICATION ID
    };
    private final byte[] NATIVE_SELECT_FILE_COMMAND = new byte[]
    {
        (byte) 0x90, (byte) 0xBD, (byte) 0x00, (byte) 0x00, 7,  // READ
        (byte) 0x01,                                            // FILE ID
        (byte) 0x00, (byte) 0x00, (byte) 0x00,                  // OFFSET
        (byte) 0x00, (byte) 0x00, (byte) 0x00,                  // LENGTH
        (byte) 0x00
    };
    private final String TAG = "MyApp";

    /**
     *
     */
    @TargetApi(Build.VERSION_CODES.GINGERBREAD_MR1)
    @Override
    public void onCreate (Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);

        String action = getIntent().getAction();
        if (NfcAdapter.ACTION_TECH_DISCOVERED.equals(action))
        {
            Tag tag = getIntent().getParcelableExtra(NfcAdapter.EXTRA_TAG);
            desfire = IsoDep.get(tag);

            try
            {
                desfire.connect();

                selectApplication();
                readFile();

                desfire.close();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
        }
    }

    @TargetApi(Build.VERSION_CODES.GINGERBREAD_MR1)
    private void readFile ()
    {
        byte[] response;
        try
        {
            response = desfire.transceive(NATIVE_SELECT_FILE_COMMAND);
            DisplayInfo("Read DATA", response);
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
    }

    @TargetApi(Build.VERSION_CODES.GINGERBREAD_MR1)
    private void selectApplication ()
    {
        byte[] response;
        try
        {
            response = desfire.transceive(NATIVE_SELECT_APP_COMMAND);
            DisplayInfo("Select APPLICATION", response);
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
    }

    private void DisplayInfo (String string, byte[] transceive)
    {
        Log.i(TAG, string + ": " + bin2hex(transceive));
    }

    private String bin2hex (byte[] data)
    {
        return String.format("%0" + (data.length * 2) + "X", new BigInteger(1, data));
    }

}