//
// Warning: Not working yet !
//
// Special Wokwi settings:
//   Use this in the Chrome browser.
//   The Serial input is from a real serial port on the computer !
//   For example the real device or a real Arduino board.
//   The Serial output is redirected to the simulated Serial Monitor
//   I tried to move everything to 115200, but that dit not work either.
//
//  MysterySerialReceiver.ino   (this sketch)
//    https://wokwi.com/arduino/projects/310261647915614785
//  MysterySerialSender.ino
//    https://wokwi.com/arduino/projects/310250258016764481
//
//
// Receive packages of 8 byte
// 0x75, 0x60, 0x??, 0x??, 0x??, 0x??, 0x??, checksum
// The checksum is a 2's complement ?

// Set _SERIAL_ to the used serial bus.
#define _SERIAL_ Serial

byte buffer[8];
int index = 0;

void setup() 
{
  _SERIAL_.begin( 9600);     // 9600, 8N1
}

void loop() 
{
  if( _SERIAL_.available() > 0)
  {
    buffer[index] = (byte) Serial.read();
    Serial.print( buffer[index], HEX);
    index++;


    if( index == 8)          // received eight bytes ?
    {
      if( buffer[0] == 0x75 && buffer[1] == 0x60 && checksum( buffer, sizeof(buffer) == 0))
      {
        // The data is valid
        Serial.println( "New Data ");
        for( int i=0; i<8; i++)
        {
          Serial.print( "0x");
          if( buffer[i] < 0x10)
            Serial.print( "0");
          Serial.print( buffer[i], HEX);
          Serial.print( ", ");
        }
        // Create the counter from the MysterySerialSender.ino sketch.
        uint32_t counter;
        counter = (uint32_t) buffer[5];
        counter |= ((uint32_t) buffer[4]) << 8;
        counter |= ((uint32_t) buffer[3]) << 16;
        counter |= ((uint32_t) buffer[2]) << 24;
        Serial.print( " (");
        Serial.print( counter);
        Serial.print( ")");
        Serial.println();

        index = 0;           // clear the buffer, use the buffer from the beginning
      }
      else
      {
        // Shift everything one location to the left and check the data
        // the next time that the loop() runs and something is received.
        for( int i=0; i<7; i++)
          buffer[i] = buffer[i+1];
        index = 7;           // there is new free spot at the end of the buffer
      }
    }
  }
}


byte checksum( byte data[], int len)
{
  byte total;

  for( int i=0; i<len; i++)
  {
    total += data[i];
  }
  byte chk = (byte) (256 - (int) total);
  return( chk);
}