//-----------------------------------------------------------------------------
//
// This code is licensed to you under the terms of the GNU GPL, version 2 or,
// at your option, any later version. See the LICENSE.txt file for the text of
// the license.
//-----------------------------------------------------------------------------
// Low frequency Farpoint G Prox II / Pyramid tag commands
// Biphase, rf/ , 96 bits  (unknown key calc + some bits)
//-----------------------------------------------------------------------------
#include "cmdlfguard.h"

#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>

#include "cmdparser.h"    // command_t
#include "comms.h"
#include "ui.h"
#include "cmddata.h"
#include "cmdlf.h"
#include "protocols.h"  // for T55xx config register definitions
#include "lfdemod.h"    // parityTest
#include "cmdlft55xx.h" // verifywrite

static int CmdHelp(const char *Cmd);

static int usage_lf_guard_clone(void) {
    PrintAndLogEx(NORMAL, "clone a Guardall tag to a T55x7 tag.");
    PrintAndLogEx(NORMAL, "The facility-code is 8-bit and the card number is 16-bit.  Larger values are truncated. ");
    PrintAndLogEx(NORMAL, "Currently work only on 26bit");
    PrintAndLogEx(NORMAL, "");
    PrintAndLogEx(NORMAL, "Usage: lf gprox clone [h] <format> <Facility-Code> <Card-Number>");
    PrintAndLogEx(NORMAL, "Options:");
    PrintAndLogEx(NORMAL, "         <format> :  format length 26|32|36|40");
    PrintAndLogEx(NORMAL, "  <Facility-Code> :  8-bit value facility code");
    PrintAndLogEx(NORMAL, "  <Card Number>   : 16-bit value card number");
    PrintAndLogEx(NORMAL, "");
    PrintAndLogEx(NORMAL, "Examples:");
    PrintAndLogEx(NORMAL, "       lf gprox clone 26 123 11223");
    return PM3_SUCCESS;
}

static int usage_lf_guard_sim(void) {
    PrintAndLogEx(NORMAL, "Enables simulation of Guardall card with specified card number.");
    PrintAndLogEx(NORMAL, "Simulation runs until the button is pressed or another USB command is issued.");
    PrintAndLogEx(NORMAL, "The facility-code is 8-bit and the card number is 16-bit.  Larger values are truncated.");
    PrintAndLogEx(NORMAL, "Currently work only on 26bit");
    PrintAndLogEx(NORMAL, "");
    PrintAndLogEx(NORMAL, "Usage:  lf gprox sim [h] <format> <Facility-Code> <Card-Number>");
    PrintAndLogEx(NORMAL, "Options:");
    PrintAndLogEx(NORMAL, "         <format> :  format length 26|32|36|40");
    PrintAndLogEx(NORMAL, "  <Facility-Code> :  8-bit value facility code");
    PrintAndLogEx(NORMAL, "  <Card Number>   : 16-bit value card number");
    PrintAndLogEx(NORMAL, "");
    PrintAndLogEx(NORMAL, "Examples:");
    PrintAndLogEx(NORMAL, "       lf gprox sim 26 123 11223");
    return PM3_SUCCESS;
}

//by marshmellow
//attempts to demodulate and identify a G_Prox_II verex/chubb card
//WARNING: if it fails during some points it will destroy the DemodBuffer data
// but will leave the GraphBuffer intact.
//if successful it will push askraw data back to demod buffer ready for emulation
static int CmdGuardDemod(const char *Cmd) {
    (void)Cmd; // Cmd is not used so far

    //Differential Biphase
    //get binary from ask wave
    if (ASKbiphaseDemod("0 64 0 0", false) != PM3_SUCCESS) {
        PrintAndLogEx(DEBUG, "DEBUG: Error - gProxII ASKbiphaseDemod failed");
        return PM3_ESOFT;
    }

    size_t size = DemodBufferLen;

    int preambleIndex = detectGProxII(DemodBuffer, &size);
    if (preambleIndex < 0) {

        if (preambleIndex == -1)
            PrintAndLogEx(DEBUG, "DEBUG: Error - gProxII too few bits found");
        else if (preambleIndex == -2)
            PrintAndLogEx(DEBUG, "DEBUG: Error - gProxII preamble not found");
        else if (preambleIndex == -3)
            PrintAndLogEx(DEBUG, "DEBUG: Error - gProxII size not correct: %d", size);
        else if (preambleIndex == -5)
            PrintAndLogEx(DEBUG, "DEBUG: Error - gProxII wrong spacerbits");
        else
            PrintAndLogEx(DEBUG, "DEBUG: Error - gProxII ans: %d", preambleIndex);
        return PM3_ESOFT;
    }

    //got a good demod of 96 bits
    uint8_t ByteStream[8] = {0x00};
    uint8_t xorKey = 0;
    size_t startIdx = preambleIndex + 6; //start after 6 bit preamble

    uint8_t bits_no_spacer[90];
    //so as to not mess with raw DemodBuffer copy to a new sample array
    memcpy(bits_no_spacer, DemodBuffer + startIdx, 90);
    // remove the 18 (90/5=18) parity bits (down to 72 bits (96-6-18=72))
    size_t len = removeParity(bits_no_spacer, 0, 5, 3, 90); //source, startloc, paritylen, ptype, length_to_run
    if (len != 72) {
        PrintAndLogEx(DEBUG, "DEBUG: Error - gProxII spacer removal did not produce 72 bits: %u, start: %u", len, startIdx);
        return PM3_ESOFT;
    }
    // get key and then get all 8 bytes of payload decoded
    xorKey = (uint8_t)bytebits_to_byteLSBF(bits_no_spacer, 8);
    for (size_t idx = 0; idx < 8; idx++) {
        ByteStream[idx] = ((uint8_t)bytebits_to_byteLSBF(bits_no_spacer + 8 + (idx * 8), 8)) ^ xorKey;
        PrintAndLogEx(DEBUG, "DEBUG: gProxII byte %u after xor: %02x", (unsigned int)idx, ByteStream[idx]);
    }

    setDemodBuff(DemodBuffer, 96, preambleIndex);
    setClockGrid(g_DemodClock, g_DemodStartIdx + (preambleIndex * g_DemodClock));

    //ByteStream contains 8 Bytes (64 bits) of decrypted raw tag data
    uint8_t fmtLen = ByteStream[0] >> 2;
    uint32_t FC = 0;
    uint32_t Card = 0;
    //get raw 96 bits to print
    uint32_t raw1 = bytebits_to_byte(DemodBuffer, 32);
    uint32_t raw2 = bytebits_to_byte(DemodBuffer + 32, 32);
    uint32_t raw3 = bytebits_to_byte(DemodBuffer + 64, 32);
    bool unknown = false;
    switch (fmtLen) {
        case 36:
            FC = ((ByteStream[3] & 0x7F) << 7) | (ByteStream[4] >> 1);
            Card = ((ByteStream[4] & 1) << 19) | (ByteStream[5] << 11) | (ByteStream[6] << 3) | (ByteStream[7] >> 5);
            break;
        case 26:
            FC = ((ByteStream[3] & 0x7F) << 1) | (ByteStream[4] >> 7);
            Card = ((ByteStream[4] & 0x7F) << 9) | (ByteStream[5] << 1) | (ByteStream[6] >> 7);
            break;
        default :
            unknown = true;
            break;
    }
    if (!unknown)
        PrintAndLogEx(SUCCESS, "G-Prox-II Found: Format Len: %ubit - FC: %u - Card: %u, Raw: %08x%08x%08x", fmtLen, FC, Card, raw1, raw2, raw3);
    else
        PrintAndLogEx(SUCCESS, "Unknown G-Prox-II Fmt Found: Format Len: %u, Raw: %08x%08x%08x", fmtLen, raw1, raw2, raw3);

    return PM3_SUCCESS;
}

static int CmdGuardRead(const char *Cmd) {
    lf_read(true, 10000);
    return CmdGuardDemod(Cmd);
}

static int CmdGuardClone(const char *Cmd) {

    char cmdp = tolower(param_getchar(Cmd, 0));
    if (strlen(Cmd) == 0 || cmdp == 'h') return usage_lf_guard_clone();

    uint32_t facilitycode = 0, cardnumber = 0, fc = 0, cn = 0, fmtlen = 0;
    uint8_t bs[96];
    memset(bs, 0x00, sizeof(bs));

    //GuardProxII - compat mode, ASK/Biphase,  data rate 64, 3 data blocks
    uint32_t blocks[4] = {T55x7_MODULATION_BIPHASE | T55x7_BITRATE_RF_64 | 3 << T55x7_MAXBLOCK_SHIFT, 0, 0, 0};

    if (sscanf(Cmd, "%u %u %u", &fmtlen, &fc, &cn) != 3) return usage_lf_guard_clone();

    fmtlen &= 0x7f;
    facilitycode = (fc & 0x000000FF);
    cardnumber = (cn & 0x0000FFFF);

    if (getGuardBits(fmtlen, facilitycode, cardnumber, bs) != PM3_SUCCESS) {
        PrintAndLogEx(ERR, "Error with tag bitstream generation.");
        return PM3_ESOFT;
    }

    // Q5
    if (param_getchar(Cmd, 3) == 'Q' || param_getchar(Cmd, 3) == 'q')
        blocks[0] = T5555_MODULATION_FSK2 | T5555_SET_BITRATE(50) | 3 << T5555_MAXBLOCK_SHIFT;

    blocks[1] = bytebits_to_byte(bs, 32);
    blocks[2] = bytebits_to_byte(bs + 32, 32);
    blocks[3] = bytebits_to_byte(bs + 64, 32);

    PrintAndLogEx(INFO, "Preparing to clone Guardall to T55x7 with Facility Code: %u, Card Number: %u", facilitycode, cardnumber);
    print_blocks(blocks, 4);

    uint8_t res = 0;
    PacketResponseNG resp;

    // fast push mode
    conn.block_after_ACK = true;
    for (uint8_t i = 0; i < 4; i++) {
        if (i == 3) {
            // Disable fast mode on last packet
            conn.block_after_ACK = false;
        }
        clearCommandBuffer();

        t55xx_write_block_t ng;
        ng.data = blocks[i];
        ng.pwd = 0;
        ng.blockno = i;
        ng.flags = 0;

        SendCommandNG(CMD_LF_T55XX_WRITEBL, (uint8_t *)&ng, sizeof(ng));
        if (!WaitForResponseTimeout(CMD_LF_T55XX_WRITEBL, &resp, T55XX_WRITE_TIMEOUT)) {
            PrintAndLogEx(ERR, "Error occurred, device did not respond during write operation.");
            return PM3_ETIMEOUT;
        }

        if (i == 0) {
            SetConfigWithBlock0(blocks[0]);
            if ( t55xxAquireAndCompareBlock0(false, 0, blocks[0], false) )
                continue;
        }
        
        if (t55xxVerifyWrite(i, 0, false, false, 0, 0xFF, blocks[i]) == false)
            res++;
    }

    if ( res == 0 )
        PrintAndLogEx(SUCCESS, "Success writing to tag");

    return PM3_SUCCESS;
}

static int CmdGuardSim(const char *Cmd) {

    uint32_t facilitycode = 0, cardnumber = 0, fc = 0, cn = 0, fmtlen = 0;

    char cmdp = tolower(param_getchar(Cmd, 0));
    if (strlen(Cmd) == 0 || cmdp == 'h') return usage_lf_guard_sim();

    if (sscanf(Cmd, "%u %u %u", &fmtlen, &fc, &cn) != 3) return usage_lf_guard_sim();

    uint8_t bs[96];
    memset(bs, 0x00, sizeof(bs));

    fmtlen &= 0x7F;
    facilitycode = (fc & 0x000000FF);
    cardnumber = (cn & 0x0000FFFF);

    if (getGuardBits(fmtlen, facilitycode, cardnumber, bs) != PM3_SUCCESS) {
        PrintAndLogEx(ERR, "Error with tag bitstream generation.");
        return PM3_ESOFT;
    }

    PrintAndLogEx(SUCCESS, "Simulating Guardall - Facility Code: %u, CardNumber: %u", facilitycode, cardnumber);

    // Guard uses:  clk: 64, invert: 0, encoding: 2 (ASK Biphase)
    lf_asksim_t *payload = calloc(1, sizeof(lf_asksim_t) + sizeof(bs));
    payload->encoding =  2;
    payload->invert = 0;
    payload->separator = 0;
    payload->clock = 64;
    memcpy(payload->data, bs, sizeof(bs));

    clearCommandBuffer();
    SendCommandNG(CMD_LF_ASK_SIMULATE, (uint8_t *)payload,  sizeof(lf_asksim_t) + sizeof(bs));
    free(payload);

    PacketResponseNG resp;
    WaitForResponse(CMD_LF_ASK_SIMULATE, &resp);

    PrintAndLogEx(INFO, "Done");
    if (resp.status != PM3_EOPABORTED)
        return resp.status;
    return PM3_SUCCESS;
}

static command_t CommandTable[] = {
    {"help",    CmdHelp,        AlwaysAvailable, "this help"},
    {"demod",   CmdGuardDemod,  AlwaysAvailable, "demodulate a G Prox II tag from the GraphBuffer"},
    {"read",    CmdGuardRead,   IfPm3Lf,         "attempt to read and extract tag data from the antenna"},
    {"clone",   CmdGuardClone,  IfPm3Lf,         "clone Guardall tag"},
    {"sim",     CmdGuardSim,    IfPm3Lf,         "simulate Guardall tag"},
    {NULL, NULL, NULL, NULL}
};

static int CmdHelp(const char *Cmd) {
    (void)Cmd; // Cmd is not used so far
    CmdsHelp(CommandTable);
    return PM3_SUCCESS;
}

int CmdLFGuard(const char *Cmd) {
    clearCommandBuffer();
    return CmdsParse(CommandTable, Cmd);
}

// by marshmellow
// demod gProxIIDemod
// error returns as -x
// success returns start position in bitstream
// Bitstream must contain previously askrawdemod and biphasedemoded data
int detectGProxII(uint8_t *bits, size_t *size) {

    size_t startIdx = 0;
    uint8_t preamble[] = {1, 1, 1, 1, 1, 0};

    // sanity check
    if (*size < sizeof(preamble)) return -1;

    if (!preambleSearch(bits, preamble, sizeof(preamble), size, &startIdx))
        return -2; //preamble not found

    //gProxII should be 96 bits
    if (*size != 96) return -3;

    //check first 6 spacer bits to verify format
    if (!bits[startIdx + 5] && !bits[startIdx + 10] && !bits[startIdx + 15] && !bits[startIdx + 20] && !bits[startIdx + 25] && !bits[startIdx + 30]) {
        //confirmed proper separator bits found
        //return start position
        return (int) startIdx;
    }
    return -5; //spacer bits not found - not a valid gproxII
}

int demodGuard(void) {
    return CmdGuardDemod("");
}

// Works for 26bits.
int getGuardBits(uint8_t fmtlen, uint32_t fc, uint32_t cn, uint8_t *guardBits) {

    uint8_t xorKey = 0x66;
    uint8_t i;
    uint8_t pre[96];
    uint8_t rawbytes[12];
    memset(pre, 0x00, sizeof(pre));
    memset(rawbytes, 0x00, sizeof(rawbytes));

    // add format length (decimal)
    switch (fmtlen) {
        case 32: {
            rawbytes[1] = (32 << 2);

            break;
        }
        case 36: {
            // FC = ((ByteStream[3] & 0x7F)<<7) | (ByteStream[4]>>1);
            // Card = ((ByteStream[4]&1)<<19) | (ByteStream[5]<<11) | (ByteStream[6]<<3) | (ByteStream[7]>>5);
            rawbytes[1] = (36 << 2);
            // Get 26 wiegand from FacilityCode, CardNumber
            uint8_t wiegand[34];
            memset(wiegand, 0x00, sizeof(wiegand));
            num_to_bytebits(fc, 8, wiegand);
            num_to_bytebits(cn, 26, wiegand + 8);

            // add wiegand parity bits (dest, source, len)
            wiegand_add_parity(pre, wiegand, 34);
            break;
        }
        case 40: {
            rawbytes[1] = (40 << 2);
            break;
        }
        case 26:
        default: {
            rawbytes[1] = (26 << 2);
            // Get 26 wiegand from FacilityCode, CardNumber
            uint8_t wiegand[24];
            memset(wiegand, 0x00, sizeof(wiegand));
            num_to_bytebits(fc, 8, wiegand);
            num_to_bytebits(cn, 16, wiegand + 8);

            // add wiegand parity bits (dest, source, len)
            wiegand_add_parity(pre, wiegand, 24);
            break;
        }
    }
    // 2bit checksum, unknown today,
    // these two bits are the last ones of rawbyte[1], hence the LSHIFT above.


    // xor key
    rawbytes[0] = xorKey;

    rawbytes[2] = 1;
    rawbytes[3] = 0;

    // add wiegand to rawbytes
    for (i = 0; i < 4; ++i)
        rawbytes[i + 4] = bytebits_to_byte(pre + (i * 8), 8);

    PrintAndLogEx(DEBUG, " WIE | %s\n", sprint_hex(rawbytes, sizeof(rawbytes)));


    // XOR (only works on wiegand stuff)
    for (i = 1; i < 12; ++i)
        rawbytes[i] ^= xorKey ;

    PrintAndLogEx(DEBUG, " XOR | %s \n", sprint_hex(rawbytes, sizeof(rawbytes)));

    // convert rawbytes to bits in pre
    for (i = 0; i < 12; ++i)
        num_to_bytebitsLSBF(rawbytes[i], 8, pre + (i * 8));

    PrintAndLogEx(DEBUG, "\n Raw | %s \n", sprint_hex(rawbytes, sizeof(rawbytes)));
    PrintAndLogEx(DEBUG, " Raw | %s\n", sprint_bin(pre, 64));

    // add spacer bit 0 every 4 bits, starting with index 0,
    // 12 bytes, 24 nibbles.  24+1 extra bites. 3bytes.  ie 9bytes | 1byte xorkey, 8bytes rawdata (64bits, should be enough for a 40bit wiegand)
    addParity(pre, guardBits + 6, 64, 5, 3);

    // preamble
    guardBits[0] = 1;
    guardBits[1] = 1;
    guardBits[2] = 1;
    guardBits[3] = 1;
    guardBits[4] = 1;
    guardBits[5] = 0;

    PrintAndLogEx(DEBUG, " FIN | %s\n", sprint_bin(guardBits, 96));
    return PM3_SUCCESS;
}