#!/usr/bin/env python

from smartcard.scard import *
import smartcard.util

SELECT = [0xA0, 0xA4, 0x00, 0x00, 0x02, 0x3F, 0x00]
COMMAND = [0x00, 0x00, 0x00, 0x00]

def select():
    try:
        hresult, hcontext = SCardEstablishContext(SCARD_SCOPE_USER)
        if hresult != SCARD_S_SUCCESS:
            raise Exception('Failed to establish context : ' +
                SCardGetErrorMessage(hresult))
        print 'Context established!'

        try:
            hresult, readers = SCardListReaders(hcontext, [])
            if hresult != SCARD_S_SUCCESS:
                raise Exception('Failed to list readers: ' +
                    SCardGetErrorMessage(hresult))
            print 'PCSC Readers:', readers

            if len(readers) < 1:
                raise Exception('No smart card readers')

            reader = readers[0]
            print "Using reader:", reader
            
            try:
                hresult, hcard, dwActiveProtocol = SCardConnect(hcontext, reader,
                    SCARD_SHARE_SHARED, SCARD_PROTOCOL_T0 | SCARD_PROTOCOL_T1)
                if hresult != SCARD_S_SUCCESS:
                    raise Exception('Unable to connect: ' +
                        SCardGetErrorMessage(hresult))
                print 'Connected with active protocol', dwActiveProtocol

                try:
                    hresult, response = SCardTransmit(hcard, dwActiveProtocol,
                        SELECT)
                    if hresult != SCARD_S_SUCCESS:
                        raise Exception('Failed to transmit: ' +
                            SCardGetErrorMessage(hresult))
                    print 'Select: ' + smartcard.util.toHexString(response,
                        smartcard.util.HEX)
                    hresult, response = SCardTransmit(hcard, dwActiveProtocol,
                        COMMAND)
                    if hresult != SCARD_S_SUCCESS:
                        raise Exception('Failed to transmit: ' +
                            SCardGetErrorMessage(hresult))
                    print 'Command: ' + smartcard.util.toHexString(response,
                        smartcard.util.HEX)
                finally:
                    hresult = SCardDisconnect(hcard, SCARD_UNPOWER_CARD)
                    if hresult != SCARD_S_SUCCESS:
                        raise Exception('Failed to disconnect: ' +
                            SCardGetErrorMessage(hresult))
                    print 'Disconnected'


            except Exception, message:
                print "Exception:", message

        finally:
            hresult = SCardReleaseContext(hcontext)
            if hresult != SCARD_S_SUCCESS:
                raise Exception('Failed to release context: ' +
                        SCardGetErrorMessage(hresult))
            print 'Released context.'

    except Exception, message:
        print "Exception:", message