#include <LiquidCrystal_I2C.h>
int columns = 16;
int rows = 2;

LiquidCrystal_I2C lcd(0x27, columns, rows);
// define pin led
const int led0 = 3;
const int led1 = 4;
const int led2 = 5;
const int led3 = 6;
const int led4 = 7;
const int led5 = 8;
const int led6 = 9;
const int led7 = 10;
const int led8 = 11;
const int led9 = 12;
// defines led states
int st0 = LOW;
int st1 = LOW;
int st2 = LOW;
int st3 = LOW;
int st4 = LOW;
int st5 = LOW;
int st6 = LOW;
int st7 = LOW;
int st8 = LOW;
int st9 = LOW;

int number = 0;
int previousNumber = number;  

void setup() {
  // put your setup code here, to run once:
  pinMode(led0, OUTPUT);
  pinMode(led1, OUTPUT);
  pinMode(led2, OUTPUT);
  pinMode(led3, OUTPUT);
  pinMode(led4, OUTPUT);
  pinMode(led5, OUTPUT);
  pinMode(led6, OUTPUT);
  pinMode(led7, OUTPUT);
  pinMode(led8, OUTPUT);
  pinMode(led9, OUTPUT);
  pinMode(2, INPUT);

  lcd.begin(16,2);
  lcd.init();
  lcd.backlight();

  number = 1;
}

void controlLEDState() {
  digitalWrite(3,st0);
  digitalWrite(4,st1);
  digitalWrite(5,st2);
  digitalWrite(6,st3);
  digitalWrite(7,st4);
  digitalWrite(8,st5);
  digitalWrite(9,st6);
  digitalWrite(10,st7);
  digitalWrite(11,st8);
  digitalWrite(12,st9);
}

void clearLED() {
  digitalWrite(3,LOW);
  digitalWrite(4,LOW);
  digitalWrite(5,LOW);
  digitalWrite(6,LOW);
  digitalWrite(7,LOW);
  digitalWrite(8,LOW);
  digitalWrite(9,LOW);
  digitalWrite(10,LOW);
  digitalWrite(11,LOW);
  digitalWrite(12,LOW);
}

void setLed(int itr, bool yes) {
  int whathi = LOW;
  if (yes) {
    whathi = HIGH;
  } else {
    whathi = LOW;
  }
  if (itr==1) {
    st0 = whathi;
  } else if (itr==2) {
    st1 = whathi;
  } else if (itr==3) {
    st2 = whathi;
  } else if (itr==4) {
    st3 = whathi;
  } else if (itr==5) {
    st4 = whathi;
  } else if (itr==6) {
    st5 = whathi;
  } else if (itr==7) {
    st6 = whathi;
  } else if (itr==8) {
    st7 = whathi;
  } else if (itr==9) {
    st8 = whathi;
  } else if (itr==10) {
    st9 = whathi;
  }
}

int decimalToBinary(int num) {
    int decimal;
    int a = num;
    int logx=0;
    // logx is the number of digits a binary number has. 
    // up to 10 because of the amount of leds.
    if (a<2) {
      logx=1;
    } else if (a<4) {
      logx=2;
    } else if (a<8) {
      logx=3;
    } else if (a<16) {
      logx=4;
    } else if (a<32) {
      logx=5;
    } else if (a<64) {
      logx=6;
    } else if (a<128) {
      logx=7;
    } else if (a<256) {
      logx=8;
    } else if (a<512) {
      logx=9;
    } else if (a<1024) {
      logx=10;
    } else {
      logx = 11;
    }
    // loop until the n-th loop, where n is the log base 2 of num.
    for (int i = 0; i <= logx; i++) {
      // divide a (num) by 2, see if there is a remainder, if not, 
      // the i-th digit is 0, where i=1 equals the ones place, and i=10 equal the 10^9th place
      if (a % 2 == 0) {
        // set digit to 0
        setLed(i+1,false);
      } else {
        // set digit to 1
        setLed(i+1,true);
      }
      if (a >= 2) {
        a = floor(a / 2);
      } else {
        break;
      }
    }
    return decimal;
}


void test() {
  decimalToBinary(number);
  controlLEDState();
}

void loop() {
  // put your main code here, to run repeatedly:
  if (digitalRead(2) == HIGH) {
    decimalToBinary(number);
    controlLEDState();
    lcd.setCursor(0,0);
    lcd.print(number);
    delay(300);
    number++;
  }
}