nightlight changes as environment changes

/*
 * Manvi Mittal
 * Photoresistor Project
 */

const int pinPhoto = A0;
const int pinLedRed = 9; // red
const int pinLedGreen = 10; // green
const int pinLedBlue = 11; // blue
const int pinButt = 2;
int minimum = 5000;
int maximum = -5000;
int lightLevel = 0;
int brightness = 0;
unsigned long timeVal;
int newButt = 0;
int lastButt = 0;

void setup() {
  // put your setup code here, to run once:
  pinMode (pinPhoto, INPUT);
  pinMode (pinLedRed, OUTPUT);
  pinMode (pinLedGreen, OUTPUT);
  pinMode (pinLedBlue, OUTPUT);
  pinMode (pinButt, INPUT);
  Serial.begin (9600);

  analogWrite (pinLedRed, 100);
  delay (500);
  analogWrite (pinLedRed, 0);
  delay (500);

  analogWrite (pinLedGreen, 100);
  delay (500);
  analogWrite (pinLedGreen, 0);
  delay (500);

  analogWrite (pinLedBlue, 100);
  delay (500);
  analogWrite (pinLedBlue, 0);
  delay (500);

}

void calibrate()
{
  maximum = -5000;
  minimum = 5000;
  analogWrite (pinLedBlue, HIGH);
  analogWrite (pinLedRed, HIGH);
  analogWrite (pinLedGreen, LOW);
  delay (300);
  analogWrite (pinLedBlue, LOW);
  analogWrite (pinLedRed, LOW);
  analogWrite (pinLedGreen, LOW);
  timeVal = millis();

  while (millis() - timeVal < 5000)
  {
    lightLevel = analogRead (pinPhoto);
    if (lightLevel > maximum)
    {
      maximum = lightLevel;
    }
    else if (lightLevel < minimum)
    {
      minimum = lightLevel;
    }
  }
  analogWrite (pinLedBlue, HIGH);
  analogWrite (pinLedRed, HIGH);
  analogWrite (pinLedGreen, LOW);
  delay (300);
  analogWrite (pinLedBlue, LOW);
  analogWrite (pinLedRed, LOW);
  analogWrite (pinLedGreen, LOW);
  Serial.println (minimum);
  Serial.println (maximum);
}

void loop() {
  newButt = digitalRead (pinButt);
  //Serial.print (newButt);
  if (newButt == HIGH && lastButt == LOW)
  {
    Serial.println ("Calibrating...");
    calibrate ();
  }

  lastButt = newButt;

  lightLevel = analogRead (pinPhoto);
  brightness = map (lightLevel, minimum, maximum, 255, 0);
  brightness = constrain (brightness, 0, 255);
 // Serial.println (brightness);

  if (lightLevel > minimum && lightLevel < (maximum - minimum) / 3)
  {
    analogWrite (pinLedRed, brightness/2);
    analogWrite (pinLedBlue, brightness);
    analogWrite (pinLedGreen, brightness/23);
  }

  else if (lightLevel > minimum && lightLevel < 2*(maximum - minimum) / 3)
  {
    analogWrite (pinLedRed, brightness);
    analogWrite (pinLedBlue, brightness);
    analogWrite (pinLedGreen, brightness/5);
  }

   else if (lightLevel > minimum && lightLevel < (maximum - minimum))
  {
    analogWrite (pinLedRed, brightness/5);
    analogWrite (pinLedBlue, brightness/5);
    analogWrite (pinLedGreen, brightness);
  }
}



boolean debounce(boolean last)
{
  boolean current = digitalRead(pinButt);
  if (last != current)
  {
    delay(5);
    current = digitalRead(pinButt);
  }
  return current;
}