#include <LiquidCrystal.h>
LiquidCrystal lcd(12, 11, 10, 9, 8, 7);

// These constants won't change. They're used to give names to the pins used:
const int analogInPin = A0;  // Analog input pin that the potentiometer is attached to

int sensorValue = 0;        // value read from the pot
int mapValue = 0;        // delay value in ms
float delay_time = 0.0;

boolean ledState = false; 
unsigned long startTime;  // start time of the LED that turned ON
unsigned long delayTimeLED;  // delay time of the LED that need to be ON/OFF based on the light
unsigned long endTime=0;  // the time the LED turned OFF


void setup() {
  lcd.begin(16, 2);
  // initialize serial communications at 9600 bps:
  Serial.begin(9600);
  // initialize digital pin LED_BUILTIN as an output.
  pinMode(LED_BUILTIN, OUTPUT);
}

void loop() {
  // read the analog in value:
  sensorValue = analogRead(analogInPin);

  // map it to the range of the analog out:
  mapValue = map(sensorValue, 0, 1023, 4000, 250);
  delay_time = float(mapValue) / 1000.0;

  // print the results to the Serial Monitor:
  Serial.print("sensor = ");
  Serial.print(sensorValue);
  Serial.print("\t time lap [sec] = ");
  Serial.println(delay_time);

  // set the current time
  unsigned long currentTime = millis();
  // set the delay time of the LED based on the light
  delayTimeLED = mapValue;

  if(currentTime <= 4000){
    // display my name on screen
    lcd.setCursor(0,0);
    lcd.println("Or Bacalu");
    lcd.setCursor(0,1);
    lcd.print("Represent");
  }else{
    // display light sensor value on screen:
    lcd.setCursor(0,0);
    lcd.println("Light Sensor");
    lcd.setCursor(0,1);
    lcd.print("Display: ");
    lcd.setCursor(10,1);
    lcd.print(sensorValue);
  }
  
  if(ledState == false && currentTime - endTime >= delayTimeLED){
    digitalWrite(LED_BUILTIN, HIGH);   // turn the LED on (HIGH is the voltage level)
    ledState = true;
    startTime = currentTime;
  }

  if(ledState && currentTime - startTime >= delayTimeLED){
    digitalWrite(LED_BUILTIN, LOW);    // turn the LED off by making the voltage LOW
    ledState = false;
    endTime = currentTime;
  }

  // wait 2 milliseconds before the next loop for the analog-to-digital
  // converter to settle after the last reading:
  delay(2);
}