#include <sys/types.h>
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <pcsclite.h>
#include <winscard.h>

extern SCARDCONTEXT hContext;
extern SCARDHANDLE hCard;
extern char *selected_reader;

static
decode_hex_digit(c)
{
	if (isdigit(c))
		return c - '0';
	else if (islower(c))
		return c - 'a' + 10;
	else
		return c - 'A' + 10;
}

static
parse_hex_input(inbuf, outbuf)
	char *inbuf;
	u_char *outbuf;
{
	char *cp;
	unsigned count;

	count = 0;
	for (cp = inbuf; ; ) {
		while (isspace(*cp))
			cp++;
		if (!*cp)
			break;
		if (!isxdigit(cp[0]) || !isxdigit(cp[1])) {
			printf("error: invalid hex APDU input\n");
			return(-1);
		}
		if (count >= 260) {
			printf("error: command APDU is too long\n");
			return(-1);
		}
		outbuf[count++] = (decode_hex_digit(cp[0]) << 4) |
				  decode_hex_digit(cp[1]);
		cp += 2;
	}
	return count;
}

static void
apdu_exchange(cmd_apdu, cmd_apdu_len)
	u_char *cmd_apdu;
	unsigned cmd_apdu_len;
{
	LONG rv;
	DWORD dwRecvLength;
	u_char sim_resp_data[258];
	unsigned n;

	dwRecvLength = 258;
	rv = SCardTransmit(hCard, SCARD_PCI_T0, cmd_apdu, cmd_apdu_len, NULL,
			   sim_resp_data, &dwRecvLength);
	if (rv != SCARD_S_SUCCESS) {
		printf("SCardTransmit error: %s\n", pcsc_stringify_error(rv));
		return;
	}
	if (dwRecvLength < 2) {
		printf(
		"error: SCardTransmit response is shorter than 2 SW bytes\n");
		return;
	}
	for (n = 0; n < dwRecvLength; n++)
		printf("%02X", sim_resp_data[n]);
	putchar('\n');
}

main(argc, argv)
	char **argv;
{
	char inbuf[576];
	u_char cmd[260];
	int rc;

	parse_reader_select_opt(argc, argv);
	setup_pcsc_context();
	get_reader_list();
	select_reader_by_num();
	printf("R %s\n", selected_reader);
	connect_to_card();
	retrieve_atr("A");
	putchar('\n');
	fflush(stdout);

	for (; fgets(inbuf, sizeof inbuf, stdin); fflush(stdout)) {
		rc = parse_hex_input(inbuf, cmd);
		if (rc < 0)
			continue;
		if (rc < 5) {
			printf("error: command APDU is too short\n");
			continue;
		}
		apdu_exchange(cmd, rc);
	}

	SCardDisconnect(hCard, SCARD_UNPOWER_CARD);
	SCardReleaseContext(hContext);
	exit(0);
}