#if defined(HAVE_CONFIG_H)
    #include "config.h"
#endif

#include <err.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <freefare.h>

/*
 * This example was written based on information provided by the
 * following documents:
 *
 * Mifare DESFire as Type 4 Tag
 * NFC Forum Type 4 Tag Extensions for Mifare DESFire
 * Rev. 1.1 - 21 August 2007
 * Rev. 2.2 - 4 January 2012
 *
 */

// Note that it is using specific Desfire commands, not ISO7816 NDEF Tag Type4 commands

uint8_t key_data_app[8]  = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };

uint8_t *cc_data;
uint8_t *ndef_msg;
uint16_t  ndef_msg_len;

struct {
    bool interactive;
} read_options = {
    .interactive = true
};

static void
usage(char *progname)
{
    fprintf(stderr, "This application reads a NDEF payload from a Mifare DESFire formatted as NFC Forum Type 4 Tag.\n");
    fprintf(stderr, "usage: %s [-y] -o FILE [-k 11223344AABBCCDD]\n", progname);
    fprintf(stderr, "\nOptions:\n");
    fprintf(stderr, "  -y     Do not ask for confirmation\n");
    fprintf(stderr, "  -o     Extract NDEF message if available in FILE\n");
    fprintf(stderr, "  -k     Provide another NDEF Tag Application key than the default one\n");
}

int
main(int argc, char *argv[])
{
    int ch;
    int error = EXIT_SUCCESS;
    nfc_device *device = NULL;
    FreefareTag *tags = NULL;

    char *ndef_output = NULL;
    while ((ch = getopt(argc, argv, "hyo:k:")) != -1) {
	switch (ch) {
	case 'h':
	    usage(argv[0]);
	    exit(EXIT_SUCCESS);
	    break;
	case 'y':
	    read_options.interactive = false;
	    break;
	case 'o':
	    ndef_output = optarg;
	    break;
	case 'k':
	    if (strlen(optarg) != 16) {
		usage(argv[0]);
		exit(EXIT_FAILURE);
	    }
	    uint64_t n = strtoull(optarg, NULL, 16);
	    int i;
	    for (i = 7; i >= 0; i--) {
		key_data_app[i] = (uint8_t) n;
		n >>= 8;
	    }
	    break;
	default:
	    usage(argv[0]);
	    exit(EXIT_FAILURE);
	}
    }
    // Remaining args, if any, are in argv[optind .. (argc-1)]

    if (ndef_output == NULL) {
	usage(argv[0]);
	exit(EXIT_FAILURE);
    }
    FILE *message_stream = NULL;
    FILE *ndef_stream = NULL;

    if ((strlen(ndef_output) == 1) && (ndef_output[0] == '-')) {
	message_stream = stderr;
	ndef_stream = stdout;
    } else {
	message_stream = stdout;
	ndef_stream = fopen(ndef_output, "wb");
	if (!ndef_stream) {
	    fprintf(stderr, "Could not open file %s.\n", ndef_output);
	    exit(EXIT_FAILURE);
	}
    }

    nfc_connstring devices[8];
    size_t device_count;

    nfc_context *context;
    nfc_init(&context);
    if (context == NULL)
	errx(EXIT_FAILURE, "Unable to init libnfc (malloc)");

    device_count = nfc_list_devices(context, devices, 8);
    if (device_count <= 0)
	errx(EXIT_FAILURE, "No NFC device found.");

    for (size_t d = 0; d < device_count; d++) {
	device = nfc_open(context, devices[d]);

	if (!device) {
	    warnx("nfc_open() failed.");
	    error = EXIT_FAILURE;
	    continue;
	}

	tags = freefare_get_tags(device);
	if (!tags) {
	    nfc_close(device);
	    errx(EXIT_FAILURE, "Error listing tags.");
	}

	for (int i = 0; (!error) && tags[i]; i++) {
	    if (MIFARE_DESFIRE != freefare_get_tag_type(tags[i]))
		continue;

	    char *tag_uid = freefare_get_tag_uid(tags[i]);
	    char buffer[BUFSIZ];

	    fprintf(message_stream, "Found %s with UID %s. ", freefare_get_tag_friendly_name(tags[i]), tag_uid);

	    bool read_ndef = true;
	    if (read_options.interactive) {
		fprintf(message_stream, "Read NDEF [yN] ");
		fgets(buffer, BUFSIZ, stdin);
		read_ndef = ((buffer[0] == 'y') || (buffer[0] == 'Y'));
	    } else {
		fprintf(message_stream, "\n");
	    }

	    if (read_ndef) {
		int res;

		res = mifare_desfire_connect(tags[i]);
		if (res < 0) {
		    warnx("Can't connect to Mifare DESFire target.");
		    error = EXIT_FAILURE;
		    break;
		}

		// We've to track DESFire version as NDEF mapping is different
		struct mifare_desfire_version_info info;
		res = mifare_desfire_get_version(tags[i], &info);
		if (res < 0) {
		    freefare_perror(tags[i], "mifare_desfire_get_version");
		    error = 1;
		    break;
		}

		MifareDESFireKey key_app;
		key_app  = mifare_desfire_des_key_new_with_version(key_data_app);

		// Mifare DESFire SelectApplication (Select application)
		MifareDESFireAID aid;
		if (info.software.version_major == 0)
		    aid = mifare_desfire_aid_new(0xEEEE10);
		else
		    // There is no more relationship between DESFire AID and ISO AID...
		    // Let's assume it's in AID 000001h as proposed in the spec
		    aid = mifare_desfire_aid_new(0x000001);
		res = mifare_desfire_select_application(tags[i], aid);
		if (res < 0)
		    errx(EXIT_FAILURE, "Application selection failed. Try mifare-desfire-create-ndef before running %s.", argv[0]);
		free(aid);

		// Authentication with NDEF Tag Application master key (Authentication with key 0)
		res = mifare_desfire_authenticate(tags[i], 0, key_app);
		if (res < 0)
		    errx(EXIT_FAILURE, "Authentication with NDEF Tag Application master key failed");

		// Read Capability Container file E103
		uint8_t lendata[20]; // cf FIXME in mifare_desfire.c read_data()
		if (info.software.version_major == 0)
		    res = mifare_desfire_read_data(tags[i], 0x03, 0, 2, lendata);
		else
		    // There is no more relationship between DESFire FID and ISO FileID...
		    // Let's assume it's in FID 01h as proposed in the spec
		    res = mifare_desfire_read_data(tags[i], 0x01, 0, 2, lendata);
		if (res < 0)
		    errx(EXIT_FAILURE, "Read CC len failed");
		uint16_t cclen = (((uint16_t) lendata[0]) << 8) + ((uint16_t) lendata[1]);
		if (cclen < 15)
		    errx(EXIT_FAILURE, "CC too short IMHO");
		if (!(cc_data = malloc(cclen + 20))) // cf FIXME in mifare_desfire.c read_data()
		    errx(EXIT_FAILURE, "malloc");
		if (info.software.version_major == 0)
		    res = mifare_desfire_read_data(tags[i], 0x03, 0, cclen, cc_data);
		else
		    res = mifare_desfire_read_data(tags[i], 0x01, 0, cclen, cc_data);
		if (res < 0)
		    errx(EXIT_FAILURE, "Read CC data failed");
		// Search NDEF File Control TLV
		uint8_t off = 7;
		while (((off + 7) < cclen) && (cc_data[off] != 0x04)) {
		    // Skip TLV
		    off += cc_data[off + 1] + 2;
		}
		if (off + 7 >= cclen)
		    errx(EXIT_FAILURE, "CC does not contain expected NDEF File Control TLV");
		if (cc_data[off + 2] != 0xE1)
		    errx(EXIT_FAILURE, "Unknown NDEF File reference in CC");
		uint8_t file_no;
		if (info.software.version_major == 0)
		    file_no = cc_data[off + 3];
		else
		    // There is no more relationship between DESFire FID and ISO FileID...
		    // Let's assume it's in FID 02h as proposed in the spec
		    file_no = 2;
		uint16_t ndefmaxlen = (((uint16_t) cc_data[off + 4]) << 8) + ((uint16_t) cc_data[off + 5]);
		fprintf(message_stream, "Max NDEF size: %i bytes\n", ndefmaxlen);
		if (!(ndef_msg = malloc(ndefmaxlen + 20))) // cf FIXME in mifare_desfire.c read_data()
		    errx(EXIT_FAILURE, "malloc");

		res = mifare_desfire_read_data(tags[i], file_no, 0, 2, lendata);
		if (res < 0)
		    errx(EXIT_FAILURE, "Read NDEF len failed");
		ndef_msg_len = (((uint16_t) lendata[0]) << 8) + ((uint16_t) lendata[1]);
		fprintf(message_stream, "NDEF size: %i bytes\n", ndef_msg_len);
		if (ndef_msg_len + 2 > ndefmaxlen)
		    errx(EXIT_FAILURE, "Declared NDEF size larger than max NDEF size");
		res = mifare_desfire_read_data(tags[i], file_no, 2, ndef_msg_len, ndef_msg);
		if (res < 0)
		    errx(EXIT_FAILURE, "Read data failed");
		if (fwrite(ndef_msg, 1, ndef_msg_len, ndef_stream) != ndef_msg_len)
		    errx(EXIT_FAILURE, "Write to file failed");
		free(cc_data);
		free(ndef_msg);
		mifare_desfire_key_free(key_app);

		mifare_desfire_disconnect(tags[i]);
	    }
	    free(tag_uid);
	}
	freefare_free_tags(tags);
	nfc_close(device);
    }
    nfc_exit(context);
    exit(error);
}