//input for ROM
int IN_1 = 0; //LSB
int IN_2 = 1;
int IN_3 = 2;
int IN_4 = 3;

//output from ROM
int OUT_1 = 4; //LSB
int OUT_2 = 5;
int OUT_3 = 6;
int OUT_4 = 7;
int OUT_5 = 8;
int OUT_6 = 9;
int OUT_7 = 10;
int OUT_8 = 11;

//output for seg decoder
int OUTPUT1 = A0; //LSB
int OUTPUT2 = A1;
int OUTPUT3 = A2;
int OUTPUT4 = A3;

int counter = 0;

void setup() {
  Serial.begin(9600);
  pinMode(IN_1, OUTPUT);
  pinMode(IN_2, OUTPUT);
  pinMode(IN_3, OUTPUT);
  pinMode(IN_4, OUTPUT);
  pinMode(OUT_1, INPUT);
  pinMode(OUT_2, INPUT);
  pinMode(OUT_3, INPUT);
  pinMode(OUT_4, INPUT);
  pinMode(OUT_5, INPUT);
  pinMode(OUT_6, INPUT);
  pinMode(OUT_7, INPUT);
  pinMode(OUT_8, INPUT);
  pinMode(OUTPUT1, OUTPUT);
  pinMode(OUTPUT2, OUTPUT);
  pinMode(OUTPUT3, OUTPUT);
  pinMode(OUTPUT4, OUTPUT);
}

void loop() {

  checkROM();

  Serial.print("COUNTER: ");
  Serial.println(counter);
  int input1, input2, input3, input4;
  switch(counter){
    case 0:
      input1 = 0;
      input2 = 0;
      input3 = 0;
      input4 = 0;

      break;
    case 1:
      input1 = 1;
      input2 = 0;
      input3 = 0;
      input4 = 0;
      break;
    case 2:
      input1 = 0;
      input2 = 1;
      input3 = 0;
      input4 = 0;
      break;
    case 3:
      input1 = 1;
      input2 = 1;
      input3 = 0;
      input4 = 0;
      break;
    case 4:
      input1 = 0;
      input2 = 0;
      input3 = 1;
      input4 = 0;
      break;
    case 5:
      input1 = 1;
      input2 = 0;
      input3 = 1;
      input4 = 0;
      break;
    case 6:
      input1 = 0;
      input2 = 1;
      input3 = 1;
      input4 = 0;
      break;
    case 7:
      input1 = 1;
      input2 = 1;
      input3 = 1;
      input4 = 0;
      break;
  }

  digitalWrite(IN_4, input4);
  digitalWrite(IN_3, input3);
  digitalWrite(IN_2, input2);
  digitalWrite(IN_1, input1);

  Serial.print("Input address: ");
  Serial.print(input4);
  Serial.print(input3);
  Serial.print(input2);
  Serial.println(input1);

  checkROM();

  delay(500);

  checkROM();
  //get address from D region
  int add_1 = digitalRead(OUT_1);
  int add_2 = digitalRead(OUT_2);
  int add_3 = digitalRead(OUT_3);

  Serial.print("D-region address: ");
  Serial.print(add_3);
  Serial.print(add_2);
  Serial.println(add_1);

  // get operation (two bits)
  // massave ba to? yep
  int op_1 = digitalRead(OUT_4);
  int op_2 = digitalRead(OUT_5);

  Serial.print("Operation: ");
  Serial.print(op_2);
  Serial.println(op_1);

  //set address of D-region
  digitalWrite(IN_4, HIGH);
  digitalWrite(IN_3, add_3);
  digitalWrite(IN_2, add_2);
  digitalWrite(IN_1, add_1);

  Serial.print("D-region address: ");
  Serial.print("1");
  Serial.print(add_3);
  Serial.print(add_2);
  Serial.println(add_1);

  Serial.print("D-region");
  checkROM();

  //get four bit outputs
  int output_1; //lsb
  int output_2;
  int output_3;
  int output_4;

//  delay(250);

  if(op_2 == HIGH){

    //LSB
    int carry = LOW;
    if(digitalRead(OUT_5) == HIGH && digitalRead(OUT_1) == HIGH){
      output_1 = LOW;
      carry = HIGH;
    } else if((digitalRead(OUT_5) == HIGH && digitalRead(OUT_1) == LOW) ||
            (digitalRead(OUT_5) == LOW && digitalRead(OUT_1) == HIGH)){
      output_1 == HIGH;
    } else { //both are LOW
      output_1 = LOW;
    }

    //2ND SB
    if(digitalRead(OUT_6) == HIGH && digitalRead(OUT_2) == HIGH){
      if(carry = HIGH){
        output_2 = HIGH;
      } else{
        output_2 = LOW;
      }
      carry = HIGH;
    } else if((digitalRead(OUT_6) == HIGH && digitalRead(OUT_2) == LOW) ||
            (digitalRead(OUT_6) == LOW && digitalRead(OUT_2) == HIGH)){
      if(carry = HIGH){
        output_2 = LOW;
        carry = HIGH;
      } else{
        output_2 = HIGH;
        carry = LOW;
      }
    } else { //both are LOW
      if(carry = HIGH){
        output_2 = HIGH;
        carry = LOW;
      } else{
        output_2 = LOW;
        carry = LOW;
      }
    }
      //3RD SB
      if(digitalRead(OUT_7) == HIGH && digitalRead(OUT_3) == HIGH){
        if(carry = HIGH){
          output_3 = HIGH;
        } else{
          output_3 = LOW;
        }
        carry = HIGH;
      } else if((digitalRead(OUT_7) == HIGH && digitalRead(OUT_3) == LOW) ||
            (digitalRead(OUT_7) == LOW && digitalRead(OUT_3) == HIGH)){
        if(carry = HIGH){
          output_3 = LOW;
          carry = HIGH;
        } else{
          output_3 = HIGH;
          carry = LOW;
        }
      } else { //both are LOW
        if(carry = HIGH){
          output_3 = HIGH;
          carry = LOW;
        } else{
          output_3 = LOW;
          carry = LOW;
        }
      }

      //4TH SB
      if(digitalRead(OUT_8) == HIGH && digitalRead(OUT_4) == HIGH){
        if(carry = HIGH){
          output_4 = HIGH;
        } else{
          output_4 = LOW;
        }
        carry = HIGH;
      } else if((digitalRead(OUT_8) == HIGH && digitalRead(OUT_4) == LOW) ||
            (digitalRead(OUT_8) == LOW && digitalRead(OUT_4) == HIGH)){
        if(carry = HIGH){
          output_4 = LOW;
          carry = HIGH;
        } else{
          output_4 = HIGH;
          carry = LOW;
        }
      } else { //both are LOW
        if(carry = HIGH){
          output_4 = HIGH;
          carry = LOW;
        } else{
          output_4 = LOW;
          carry = LOW;
        }
      }
  }

  if(op_2 == LOW && op_1 == LOW){
    output_1 = digitalRead(OUT_5);
    output_2 = digitalRead(OUT_6);
    output_3 = digitalRead(OUT_7);
    output_4 = digitalRead(OUT_8);
  } else if (op_2 == LOW && op_1 == HIGH){
    output_1 = digitalRead(OUT_1);
    output_2 = digitalRead(OUT_2);
    output_3 = digitalRead(OUT_3);
    output_4 = digitalRead(OUT_4);
  }

  checkROM();

  //display outputs
  digitalWrite(OUTPUT4, output_4);
  digitalWrite(OUTPUT3, output_3);
  digitalWrite(OUTPUT2, output_2);
  digitalWrite(OUTPUT1, output_1);


  counter++;
  if(counter > 7) counter = 0;
  delay(500);
}

void checkROM(){
  Serial.print("ROM OUTPUTS: ");
  Serial.print(digitalRead(OUT_8));
  Serial.print(digitalRead(OUT_7));
  Serial.print(digitalRead(OUT_6));
  Serial.print(digitalRead(OUT_5));
  Serial.print(digitalRead(OUT_4));
  Serial.print(digitalRead(OUT_3));
  Serial.print(digitalRead(OUT_2));
  Serial.print(digitalRead(OUT_1));
  Serial.println();
}