// racy pulse generator wave drawing

//void xprintf(const char *, ...);    // needed this? no did it help? seemed to but


struct NAND {
  unsigned char in1Pin, in2Pin;
  unsigned char outPin;

  unsigned char input1;
  unsigned char input2;
  unsigned char outputValue;

  unsigned char initMe;

  void begin(unsigned char a, unsigned char b, unsigned char c, unsigned char init) {
    initMe = init;
    begin(a, b, c);

    digitalWrite(outPin, initMe);
  };

  void begin(unsigned char a, unsigned char b, unsigned char c) {
 //   xprintf("begin NAND %d  %d  %d\n", a, b, c);

    pinMode(a, INPUT_PULLUP);
    in1Pin = a;

    pinMode(b, INPUT_PULLUP);
    in2Pin = b;

    pinMode(c, OUTPUT);
    outPin = c;
  };

  void read() {
    input1 = digitalRead(in1Pin);
    input2 = digitalRead(in2Pin);
  };

  void evaluate() {
    outputValue = !(input1 && input2);
  };

  void propogate() {
    digitalWrite(outPin, outputValue);
  };

  unsigned char spill() {
    return outputValue;
  }
};

NAND SQ, RQN, OP;

void setup()
{
  Serial.begin(115200);
//  xprintf("synthetic MIT racy pulse generator\n");

  SQ.begin(4, 3, 2, 1); // yes need one or the other or startup is odd
  RQN.begin(7, 6, 5); // , 1);
  OP.begin(10, 9, 8);

  pinMode(A4, OUTPUT);
}


unsigned long now;
unsigned long lastTime;

void loop()
{
  //    xprintf("Hello World\n");

  now = millis();
  if (now - lastTime < 100) return;
  lastTime = now;

  digitalWrite(A4, digitalRead(A4) == LOW ? HIGH : LOW); // a transition at every update

  SQ.read(); SQ.evaluate(); 
  RQN.read(); RQN.evaluate(); 
  OP.read(); OP.evaluate(); 
  
  SQ.propogate();
  RQN.propogate();
  OP.propogate();

/*
  Serial.print(digitalRead(10)); Serial.print(",");
  Serial.print(OP.spill()); Serial.print(",");
  Serial.print(SQ.spill()); Serial.print(",");
  Serial.print(RQN.spill()); Serial.println("");
*/
//  delay(1);

//  static int fork = 20;
//  if (!--fork) for (; ; );
}

// programmer misses printf... THX @Danois90 https://forum.arduino.cc/t/pure-c-hello-world/1042838/21
void xprintf(const char *format, ...)
{
  char buffer[256];
  va_list args;
  va_start(args, format);
  vsprintf(buffer, format, args);
  va_end(args);
  Serial.print(buffer);
}