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));
	}

}