#include <fsfw/globalfunctions/CRC.h>
#include <mission/payload/scexHelpers.h>

#include <cstring>

uint8_t scex::createCmdByte(Cmds cmd, bool tempCheck) {
  return (IDLE_BIT_0_DEF_STATE << 7) | (IDLE_BIT_1_DEF_STATE << 6) | (cmd << 1) | tempCheck;
}

ReturnValue_t scex::prepareScexCmd(Cmds cmd, std::pair<uint8_t*, size_t> cmdBufPair, size_t& cmdLen,
                                   std::pair<const uint8_t*, size_t> usrDataPair, bool tempCheck) {
  using namespace scex;
  uint8_t* cmdBuf = cmdBufPair.first;
  const uint8_t* userData = usrDataPair.first;
  // Send command
  if (cmdBuf == nullptr or (cmdBufPair.second < usrDataPair.second + HEADER_LEN + CRC_LEN) or
      (usrDataPair.second > 0 and userData == nullptr)) {
    cmdLen = 0;
    return returnvalue::FAILED;
  }
  cmdBuf[0] = createCmdByte(cmd, tempCheck);
  // These two fields are the packet counter and the total packet count. Those are 1 and 1 for each
  // telecommand so far
  cmdBuf[1] = 1;
  cmdBuf[2] = 1;
  cmdBuf[3] = (usrDataPair.second >> 8) & 0xff;
  cmdBuf[4] = usrDataPair.second & 0xff;
  std::memcpy(cmdBuf + HEADER_LEN, userData, usrDataPair.second);
  uint16_t crc = CRC::crc16ccitt(cmdBuf, usrDataPair.second + HEADER_LEN);
  cmdBuf[usrDataPair.second + HEADER_LEN] = (crc >> 8) & 0xff;
  cmdBuf[usrDataPair.second + HEADER_LEN + 1] = crc & 0xff;
  cmdLen = usrDataPair.second + HEADER_LEN + CRC_LEN;
  return returnvalue::OK;
}