int photoCellPin = A0;
int switchPin = D4;

// Create a variable to hold the light reading
int photoCellReading = 0;

// Define a pin we'll place an LED on
int ledPin = D2;

// Create a variable to store the LED brightness.
int ledBrightness = 0;

void setup()
{
  // Set up the LED for output
  pinMode(ledPin, OUTPUT);
  pinMode( switchPin , INPUT_PULLUP);

  // Create a cloud variable of type integer
  // called 'light' mapped to photoCellReading
  Particle.variable("light", &photoCellReading, INT);

}

void loop()
{

  int buttonState = digitalRead( switchPin );

  // Using a pulldown resistor we get a LOW
  // Signal when its on
  
  if( buttonState == LOW )
  {
    photoCellReading = analogRead(photoCellPin);

    ledBrightness = map(photoCellReading, 0, 2000, 0, 255);
    
    analogWrite(ledPin, ledBrightness);
    
    delay(50);
  }else{
    // otherwise
    // turn the LED Off
    digitalWrite( ledPin, LOW);

  }

  // Use analogRead to read the photo cell reading
  // This gives us a value from 0 to 4095

}