#include "PacketCRC.h"

PacketCRC::PacketCRC() : crc(CRC16(0x755B, 0x0, 0xBA68, false, false)) {
  // Constructor implementation (if needed)
}

PacketCRC::~PacketCRC() {
  // Destructor implementation (if needed)
}

bool PacketCRC::check(const uint8_t* packet) {
  uint8_t length = packet[1];
  switch(length) {
    case 0x11:
    case 0x15:
    case 0x19:
      break;
    default:
      return false;
  }

  uint16_t result = calculate(packet);
  uint8_t checksum1 = (uint8_t)((result & 0xFF00) >> 8);
  uint8_t checksum2 = (uint8_t)(result & 0x00FF);

  if (packet[length + 2] == checksum1 && packet[length + 3] == checksum2) {
    return true;
  }

  return false;
}

uint16_t PacketCRC::calculate(const uint8_t* packet) {
  crc.restart();
  uint8_t length = packet[1];
  switch(length) {
    case 0x11:
      crc.setXorOut(0x539E);
      break;
    case 0x15:
      crc.setXorOut(0x3B0E);
      break;
    case 0x19:
      crc.setXorOut(0x5C02);
      break;
    default:
      return 0x0000;
  }
  crc.add(packet, length + 2);
  return crc.calc();
}