/*
  xsns_40_pn532.ino - Support for PN532 (HSU) NFC Tag Reader on Tasmota

  Copyright (C) 2021  Andre Thomas and Theo Arends

  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifdef USE_PN532_HSU
/*********************************************************************************************\
 * PN532 - 13.56 MHz RFID and NFC reader
\*********************************************************************************************/

#define XSNS_40                                     40

#include <TasmotaSerial.h>

TasmotaSerial *PN532_Serial;

#define PN532_INVALID_ACK                           -1
#define PN532_TIMEOUT                               -2
#define PN532_INVALID_FRAME                         -3
#define PN532_NO_SPACE                              -4

#define PN532_PREAMBLE                              0x00
#define PN532_STARTCODE1                            0x00
#define PN532_STARTCODE2                            0xFF
#define PN532_POSTAMBLE                             0x00

#define PN532_HOSTTOPN532                           0xD4
#define PN532_PN532TOHOST                           0xD5

#define PN532_ACK_WAIT_TIME                         0x0A

#define PN532_COMMAND_GETFIRMWAREVERSION            0x02
#define PN532_COMMAND_SAMCONFIGURATION              0x14
#define PN532_COMMAND_RFCONFIGURATION               0x32
#define PN532_COMMAND_INDATAEXCHANGE                0x40
#define PN532_COMMAND_INLISTPASSIVETARGET           0x4A

#define PN532_MIFARE_ISO14443A                      0x00
#define MIFARE_CMD_READ                             0x30
#define MIFARE_CMD_AUTH_A                           0x60
#define MIFARE_CMD_AUTH_B                           0x61
#define MIFARE_CMD_WRITE                            0xA0

struct PN532 {
  char uids[21];                // Number of bytes in the UID. 4, 7 or 10
  uint8_t packetbuffer[64];     // Global buffer used to store packet
  uint8_t command = 0;          // Carry command code between functions
  uint8_t scantimer = 0;        // Prevent multiple successful reads within 2 second window
  bool present = false;         // Maintain detection flag
#ifdef USE_PN532_DATA_FUNCTION
  uint8_t newdata[16];
  uint8_t function = 0;
  uint8_t newdata_len = 0;
#endif  // USE_PN532_DATA_FUNCTION
} Pn532;

void PN532_Init(void) {
  if (PinUsed(GPIO_PN532_RXD) && PinUsed(GPIO_PN532_TXD)) {
    PN532_Serial = new TasmotaSerial(Pin(GPIO_PN532_RXD), Pin(GPIO_PN532_TXD), 1);
    if (PN532_Serial->begin(115200)) {
      if (PN532_Serial->hardwareSerial()) { ClaimSerial(); }
      PN532_wakeup();
      uint32_t ver = PN532_getFirmwareVersion();
      if (ver) {
        uint8_t empty_uid[4] = { 0 };
        ToHex_P((unsigned char*)empty_uid, sizeof(empty_uid), Pn532.uids, sizeof(Pn532.uids));
        PN532_setPassiveActivationRetries(0xFF);
        PN532_SAMConfig();
        AddLog(LOG_LEVEL_INFO,"NFC: PN532 NFC Reader detected v%u.%u",(ver>>16) & 0xFF, (ver>>8) & 0xFF);
        Pn532.present = true;
      }
    }
  }
}

int8_t PN532_receive(uint8_t *buf, int len, uint16_t timeout) {
  int read_bytes = 0;
  int ret;
  unsigned long start_millis;
  while (read_bytes < len) {
    start_millis = millis();
    do {
      ret = PN532_Serial->read();
      if (ret >= 0) {
        break;
      }
    } while((timeout == 0) || ((millis()- start_millis ) < timeout));

    if (ret < 0) {
      if (read_bytes) {
        return read_bytes;
      } else {
        return PN532_TIMEOUT;
      }
    }
    buf[read_bytes] = (uint8_t)ret;
    read_bytes++;
  }
  return read_bytes;
}

int8_t PN532_readAckFrame(void) {
  const uint8_t PN532_ACK[] = {0, 0, 0xFF, 0, 0xFF, 0};
  uint8_t ackBuf[sizeof(PN532_ACK)];

  if (PN532_receive(ackBuf, sizeof(PN532_ACK), PN532_ACK_WAIT_TIME) <= 0) {
    return PN532_TIMEOUT;
  }

  if (memcmp(&ackBuf, &PN532_ACK, sizeof(PN532_ACK))) {
    return PN532_INVALID_ACK;
  }
  return 0;
}

int8_t PN532_writeCommand(const uint8_t *header, uint8_t hlen, const uint8_t *body = 0, uint8_t blen = 0) {
  // Clear the serial buffer just in case
  PN532_Serial->flush();

  Pn532.command = header[0];
  PN532_Serial->write((uint8_t)PN532_PREAMBLE);
  PN532_Serial->write((uint8_t)PN532_STARTCODE1);
  PN532_Serial->write(PN532_STARTCODE2);

  uint8_t length = hlen + blen + 1;   // length of data field: TFI + DATA
  PN532_Serial->write(length);
  PN532_Serial->write(~length + 1);         // checksum of length

  PN532_Serial->write(PN532_HOSTTOPN532);
  uint8_t sum = PN532_HOSTTOPN532;    // sum of TFI + DATA

  PN532_Serial->write(header, hlen);
  for (uint32_t i = 0; i < hlen; i++) {
    sum += header[i];
  }

  PN532_Serial->write(body, blen);
  for (uint32_t i = 0; i < blen; i++) {
    sum += body[i];
  }

  uint8_t checksum = ~sum + 1;            // checksum of TFI + DATA
  PN532_Serial->write(checksum);
  PN532_Serial->write((uint8_t)PN532_POSTAMBLE);

  return PN532_readAckFrame();
}

int16_t PN532_readResponse(uint8_t buf[], uint8_t len, uint16_t timeout = 50) {
  uint8_t tmp[3];

  // Read preamble and start code
  if (PN532_receive(tmp, 3, timeout)<=0) {
    return PN532_TIMEOUT;
  }
  if (0 != tmp[0] || 0!= tmp[1] || 0xFF != tmp[2]) {
    return PN532_INVALID_FRAME;
  }

  // Get length of data to be received
  uint8_t length[2];
  if (PN532_receive(length, 2, timeout) <= 0) {
    return PN532_TIMEOUT;
  }
  // Validate that frame is valid
  if (0 != (uint8_t)(length[0] + length[1])) {
    return PN532_INVALID_FRAME;
  }
  length[0] -= 2;
  if (length[0] > len) {   // If this happens, then Pn532.packetbuffer is not large enough
    return PN532_NO_SPACE;
  }

  // Get the command byte
  uint8_t cmd = Pn532.command + 1;
  if (PN532_receive(tmp, 2, timeout) <= 0) { // Time out while receiving
    return PN532_TIMEOUT;
  }
  if (PN532_PN532TOHOST != tmp[0] || cmd != tmp[1]) { // Invalid frame received
    return PN532_INVALID_FRAME;
  }

  if (PN532_receive(buf, length[0], timeout) != length[0]) { // Timed out
    return PN532_TIMEOUT;
  }

  uint8_t sum = PN532_PN532TOHOST + cmd;
  for (uint32_t i=0; i<length[0]; i++) {
    sum += buf[i];
  }

  // Checksum & postamble
  if (PN532_receive(tmp, 2, timeout) <= 0) {
    return PN532_TIMEOUT;
  }
  if (0 != (uint8_t)(sum + tmp[0]) || 0 != tmp[1]) { // Checksum fail, so frame must be invalid
    return PN532_INVALID_FRAME;
  }

  return length[0];
}

uint32_t PN532_getFirmwareVersion(void) {
  uint32_t response;

  Pn532.packetbuffer[0] = PN532_COMMAND_GETFIRMWAREVERSION;

  if (PN532_writeCommand(Pn532.packetbuffer, 1)) {
    return 0;
  }

  // Read data packet
  int16_t status = PN532_readResponse(Pn532.packetbuffer, sizeof(Pn532.packetbuffer));
  if (0 > status) {
    return 0;
  }

  response = Pn532.packetbuffer[0];
  response <<= 8;
  response |= Pn532.packetbuffer[1];
  response <<= 8;
  response |= Pn532.packetbuffer[2];
  response <<= 8;
  response |= Pn532.packetbuffer[3];

  return response;
}

void PN532_wakeup(void) {
  uint8_t wakeup[5] = {0x55, 0x55, 0, 0, 0 };
  PN532_Serial->write(wakeup,sizeof(wakeup));

  // Flush the serial buffer just in case there's garbage in there
  PN532_Serial->flush();
}

bool PN532_readPassiveTargetID(uint8_t cardbaudrate, uint8_t *uid, uint8_t *uidLength, uint16_t timeout = 50) {
  Pn532.packetbuffer[0] = PN532_COMMAND_INLISTPASSIVETARGET;
  Pn532.packetbuffer[1] = 1;  // max 1 cards at once (we can set this to 2 later)
  Pn532.packetbuffer[2] = cardbaudrate;
  if (PN532_writeCommand(Pn532.packetbuffer, 3)) {
    return 0x0;  // command failed
  }
  // read data packet
  if (PN532_readResponse(Pn532.packetbuffer, sizeof(Pn532.packetbuffer), timeout) < 0) {
    return 0x0;
  }

  /* Check some basic stuff
     b0              Tags Found
     b1              Tag Number (only one used in this example)
     b2..3           SENS_RES
     b4              SEL_RES
     b5              NFCID Length
     b6..NFCIDLen    NFCID
    */

  if (Pn532.packetbuffer[0] != 1) {
    return 0;
  }

  uint16_t sens_res = Pn532.packetbuffer[2];
  sens_res <<= 8;
  sens_res |= Pn532.packetbuffer[3];

  /* Card appears to be Mifare Classic */
  *uidLength = Pn532.packetbuffer[5];

  for (uint32_t i = 0; i < Pn532.packetbuffer[5]; i++) {
    uid[i] = Pn532.packetbuffer[6 + i];
  }

  return 1;
}

bool PN532_setPassiveActivationRetries(uint8_t maxRetries) {
  Pn532.packetbuffer[0] = PN532_COMMAND_RFCONFIGURATION;
  Pn532.packetbuffer[1] = 5;    // Config item 5 (MaxRetries)
  Pn532.packetbuffer[2] = 0xFF; // MxRtyATR (default = 0xFF)
  Pn532.packetbuffer[3] = 0x01; // MxRtyPSL (default = 0x01)
  Pn532.packetbuffer[4] = maxRetries;
  if (PN532_writeCommand(Pn532.packetbuffer, 5)) {
    return 0; // no ACK
  }
  return (0 < PN532_readResponse(Pn532.packetbuffer, sizeof(Pn532.packetbuffer)));
}

bool PN532_SAMConfig(void) {
  Pn532.packetbuffer[0] = PN532_COMMAND_SAMCONFIGURATION;
  Pn532.packetbuffer[1] = 0x01; // normal mode
  Pn532.packetbuffer[2] = 0x14; // timeout 50ms * 20 = 1 second
  Pn532.packetbuffer[3] = 0x00; // we don't need the external IRQ pin
  if (PN532_writeCommand(Pn532.packetbuffer, 4)) {
    return false;
  }
  return (0 < PN532_readResponse(Pn532.packetbuffer, sizeof(Pn532.packetbuffer)));
}

#ifdef USE_PN532_DATA_FUNCTION

uint8_t mifareclassic_AuthenticateBlock (uint8_t *uid, uint8_t uidLen, uint32_t blockNumber, uint8_t keyNumber, uint8_t *keyData) {
  uint8_t i;
  uint8_t _key[6];
  uint8_t _uid[7];
  uint8_t _uidLen;

  // Hang on to the key and uid data
  memcpy(&_key, keyData, 6);
  memcpy(&_uid, uid, uidLen);
  _uidLen = uidLen;

  // Prepare the authentication command //
  Pn532.packetbuffer[0] = PN532_COMMAND_INDATAEXCHANGE;   /* Data Exchange Header */
  Pn532.packetbuffer[1] = 1;                              /* Max card numbers */
  Pn532.packetbuffer[2] = (keyNumber) ? MIFARE_CMD_AUTH_B : MIFARE_CMD_AUTH_A;
  Pn532.packetbuffer[3] = blockNumber;                    /* Block Number (1K = 0..63, 4K = 0..255 */
  memcpy(&Pn532.packetbuffer[4], &_key, 6);
  for (i = 0; i < _uidLen; i++) {
    Pn532.packetbuffer[10 + i] = _uid[i];              /* 4 bytes card ID */
  }

  if (PN532_writeCommand(Pn532.packetbuffer, 10 + _uidLen)) { return 0; }

  // Read the response packet
  PN532_readResponse(Pn532.packetbuffer, sizeof(Pn532.packetbuffer));

  // Check if the response is valid and we are authenticated???
  // for an auth success it should be bytes 5-7: 0xD5 0x41 0x00
  // Mifare auth error is technically byte 7: 0x14 but anything other and 0x00 is not good
  if (Pn532.packetbuffer[0] != 0x00) {
    // Authentification failed
    return 0;
  }

  return 1;
}

uint8_t mifareclassic_ReadDataBlock (uint8_t blockNumber, uint8_t *data) {
  /* Prepare the command */
  Pn532.packetbuffer[0] = PN532_COMMAND_INDATAEXCHANGE;
  Pn532.packetbuffer[1] = 1;                      /* Card number */
  Pn532.packetbuffer[2] = MIFARE_CMD_READ;        /* Mifare Read command = 0x30 */
  Pn532.packetbuffer[3] = blockNumber;            /* Block Number (0..63 for 1K, 0..255 for 4K) */

  /* Send the command */
  if (PN532_writeCommand(Pn532.packetbuffer, 4)) {
    return 0;
  }

  /* Read the response packet */
  PN532_readResponse(Pn532.packetbuffer, sizeof(Pn532.packetbuffer));

  /* If byte 8 isn't 0x00 we probably have an error */
  if (Pn532.packetbuffer[0] != 0x00) {
    return 0;
  }

  /* Copy the 16 data bytes to the output buffer        */
  /* Block content starts at byte 9 of a valid response */
  memcpy (data, &Pn532.packetbuffer[1], 16);

  return 1;
}

uint8_t mifareclassic_WriteDataBlock (uint8_t blockNumber, uint8_t *data) {
  /* Prepare the first command */
  Pn532.packetbuffer[0] = PN532_COMMAND_INDATAEXCHANGE;
  Pn532.packetbuffer[1] = 1;                      /* Card number */
  Pn532.packetbuffer[2] = MIFARE_CMD_WRITE;       /* Mifare Write command = 0xA0 */
  Pn532.packetbuffer[3] = blockNumber;            /* Block Number (0..63 for 1K, 0..255 for 4K) */
  memcpy(&Pn532.packetbuffer[4], data, 16);       /* Data Payload */

  /* Send the command */
  if (PN532_writeCommand(Pn532.packetbuffer, 20)) {
    return 0;
  }

  /* Read the response packet */
  return (0 < PN532_readResponse(Pn532.packetbuffer, sizeof(Pn532.packetbuffer)));
}

#endif  // USE_PN532_DATA_FUNCTION

void PN532_ScanForTag(void) {
  uint8_t uid[] = { 0, 0, 0, 0, 0, 0, 0 };
  uint8_t uid_len = 0;
  if (PN532_readPassiveTargetID(PN532_MIFARE_ISO14443A, uid, &uid_len)) {

    ToHex_P((unsigned char*)uid, uid_len, Pn532.uids, sizeof(Pn532.uids));

#ifdef USE_PN532_DATA_FUNCTION
    bool erase_success = false;
    bool set_success = false;
    char card_datas[34];
    if (uid_len == 4) { // Lets try to read block 1 of the mifare classic card for more information
      uint8_t keyuniversal[6] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
      if (mifareclassic_AuthenticateBlock (uid, uid_len, 1, 1, keyuniversal)) {
        uint8_t card_data[16];
        if (mifareclassic_ReadDataBlock(1, card_data)) {
#ifdef USE_PN532_DATA_RAW
          memcpy(&card_datas,&card_data,sizeof(card_data));
#else
          for (uint32_t i = 0;i < sizeof(card_data);i++) {
            if ((isalpha(card_data[i])) || ((isdigit(card_data[i])))) {
              card_datas[i] = char(card_data[i]);
            } else {
              card_datas[i] = '\0';
            }
          }
#endif  // USE_PN532_DATA_RAW
        }
        if (Pn532.function == 1) { // erase block 1 of card
          for (uint32_t i = 0;i<16;i++) {
            card_data[i] = 0x00;
          }
          if (mifareclassic_WriteDataBlock(1, card_data)) {
            erase_success = true;
            AddLog(LOG_LEVEL_INFO, PSTR("NFC: PN532 NFC - Erase success"));
            memcpy(&card_datas,&card_data,sizeof(card_data)); // Cast block 1 to a string
          }
        }
        if (Pn532.function == 2) {
#ifdef USE_PN532_DATA_RAW
          memcpy(&card_data,&Pn532.newdata,sizeof(card_data));
          if (mifareclassic_WriteDataBlock(1, card_data)) {
            set_success = true;
            AddLog(LOG_LEVEL_INFO, PSTR("NFC: PN532 NFC - Data write successful"));
            memcpy(&card_datas,&card_data,sizeof(card_data)); // Cast block 1 to a string
          }
#else
          bool IsAlphaNumeric = true;
          for (uint32_t i = 0;i < Pn532.newdata_len;i++) {
            if ((!isalpha(Pn532.newdata[i])) && (!isdigit(Pn532.newdata[i]))) {
              IsAlphaNumeric = false;
            }
          }
          if (IsAlphaNumeric) {
            memcpy(&card_data,&Pn532.newdata,Pn532.newdata_len);
            card_data[Pn532.newdata_len] = '\0'; // Enforce null termination
            if (mifareclassic_WriteDataBlock(1, card_data)) {
              set_success = true;
              AddLog(LOG_LEVEL_INFO, PSTR("NFC: PN532 NFC - Data write successful"));
              memcpy(&card_datas,&card_data,sizeof(card_data)); // Cast block 1 to a string
            }
          } else {
            AddLog(LOG_LEVEL_INFO, PSTR("NFC: PN532 NFC - Data must be alphanumeric"));
          }
#endif  // USE_PN532_DATA_RAW
        }
      } else {
        sprintf_P(card_datas, PSTR("AUTHFAIL"));
      }
    }
    switch (Pn532.function) {
      case 0x01:
        if (!erase_success) {
          AddLog(LOG_LEVEL_INFO, PSTR("NFC: PN532 NFC - Erase fail - exiting erase mode"));
        }
        break;
      case 0x02:
        if (!set_success) {
          AddLog(LOG_LEVEL_INFO, PSTR("NFC: PN532 NFC - Write failed - exiting set mode"));
        }
      default:
        break;
    }
    Pn532.function = 0;
    ResponseTime_P(PSTR(",\"PN532\":{\"UID\":\"%s\",\"" D_JSON_DATA "\":\"%s\"}}"), Pn532.uids, card_datas);
#else
    ResponseTime_P(PSTR(",\"PN532\":{\"UID\":\"%s\"}}"), Pn532.uids);
#endif  // USE_PN532_DATA_FUNCTION
    MqttPublishTeleSensor();

    Pn532.scantimer = 7; // Ignore tags found for two seconds
  }
}

#ifdef USE_PN532_DATA_FUNCTION

bool PN532_Command(void) {
  bool serviced = true;
  uint8_t paramcount = 0;
  if (XdrvMailbox.data_len > 0) {
    paramcount=1;
  } else {
    serviced = false;
    return serviced;
  }
  char sub_string[XdrvMailbox.data_len];
  char sub_string_tmp[XdrvMailbox.data_len];
  for (uint32_t ca=0;ca<XdrvMailbox.data_len;ca++) {
    if ((' ' == XdrvMailbox.data[ca]) || ('=' == XdrvMailbox.data[ca])) { XdrvMailbox.data[ca] = ','; }
    if (',' == XdrvMailbox.data[ca]) { paramcount++; }
  }
  UpperCase(XdrvMailbox.data,XdrvMailbox.data);
  if (!strcmp(subStr(sub_string, XdrvMailbox.data, ",", 1),"E")) {
    Pn532.function = 1; // Block 1 of next card/tag will be reset to 0x00...
    AddLog(LOG_LEVEL_INFO, PSTR("NFC: PN532 NFC - Next scanned tag data block 1 will be erased"));
    ResponseTime_P(PSTR(",\"PN532\":{\"COMMAND\":\"E\"}}"));
    return serviced;
  }
  if (!strcmp(subStr(sub_string, XdrvMailbox.data, ",", 1),"S")) {
    if (paramcount > 1) {
      if (XdrvMailbox.data[XdrvMailbox.data_len-1] == ',') {
        serviced = false;
        return serviced;
      }
      sprintf(sub_string_tmp,subStr(sub_string, XdrvMailbox.data, ",", 2));
      Pn532.newdata_len = strlen(sub_string_tmp);
      if (Pn532.newdata_len > 15) { Pn532.newdata_len = 15; }
      memcpy(&Pn532.newdata,&sub_string_tmp,Pn532.newdata_len);
      Pn532.newdata[Pn532.newdata_len] = 0x00; // Null terminate the string
      Pn532.function = 2;
      AddLog(LOG_LEVEL_INFO, PSTR("NFC: PN532 NFC - Next scanned tag data block 1 will be set to '%s'"), Pn532.newdata);
      ResponseTime_P(PSTR(",\"PN532\":{\"COMMAND\":\"S\"}}"));
      return serviced;
    }
  }
  return false;
}

#endif  // USE_PN532_DATA_FUNCTION

#ifdef USE_WEBSERVER
void PN532_Show(void) {
  WSContentSend_PD(PSTR("{s}PN532 UID{m}%s{e}"), Pn532.uids);
}
#endif  // USE_WEBSERVER

/*********************************************************************************************\
 * Interface
\*********************************************************************************************/

bool Xsns40(uint8_t function) {
  bool result = false;

  if (FUNC_INIT == function) {
    PN532_Init();
  }
  else if (Pn532.present) {
    switch (function) {
      case FUNC_EVERY_250_MSECOND:
        if (Pn532.scantimer > 0) {
          Pn532.scantimer--;
        } else {
          PN532_ScanForTag();
        }
        break;
#ifdef USE_WEBSERVER
      case FUNC_WEB_SENSOR:
        PN532_Show();
        break;
#endif  // USE_WEBSERVER
#ifdef USE_PN532_DATA_FUNCTION
      case FUNC_COMMAND_SENSOR:
        if (XSNS_40 == XdrvMailbox.index) {
          result = PN532_Command();
        }
        break;
#endif  // USE_PN532_DATA_FUNCTION
    }
  }
  return result;
}

#endif  // USE_PN532_HSU