// Note that pin 7 is not PWM
// See: https://www.arduino.cc/reference/en/language/functions/analog-io/analogwrite/

// Global variables
int green_light_pin = 5; ;// Green pin connected to digital pin 5
int blue_light_pin = 6; // Blue pin connected to digital pin 6
int red_light_pin = 9; // Red pin connected to digital pin 9

int switch_on_pin = 11; // switch on pin connected to digital pin 11
int switch_off_pin = 10; // switch off pin connected to digital pin 10

int previousLEDval = 0;

// Setup
void setup() {
  // initialize serial communication:
  Serial.begin(9600);
  Serial.println( "The sketch has started");

  pinMode(green_light_pin, OUTPUT); // sets the greenPin as an output
  pinMode(blue_light_pin, OUTPUT); // sets the bluePin as an output
  pinMode(red_light_pin, OUTPUT); // sets the redPin as an output

  pinMode(switch_on_pin, INPUT_PULLUP);    // declare on switch as input + activate internal pull-up resistor
  pinMode(switch_off_pin, INPUT_PULLUP);    // declare off switch as input + activate internal pull-up resistor

  // soft glow after start
  RGB_color(15, 15, 15);
} // close setup


// Loop
void loop() 
{
  // Definition for LEDval
  // 0 = centre/idle, 1 = red/up/on, 2 = green/down/off, -1 error
  int LEDval;

  int switch_on_val = digitalRead(switch_on_pin); // read the state
  int switch_off_val = digitalRead(switch_off_pin); // read the state

  if (switch_on_val == HIGH and switch_off_val == HIGH)
  {
    // Neither is pressed, switch in central position
    LEDval = 0;
  }
  else if (switch_on_val == LOW and switch_off_val == HIGH)
  {
    // Button 'up' or 'on' is pressed, and the other is not.
    LEDval = 1;
  }
  else if (switch_on_val == HIGH and switch_off_val == LOW)
  {
    // Button 'down' or 'off' is pressed, and the other is not.
    LEDval = 2;
  }
  else
  {
    // Both are pressed, that is an error
    LEDval = -1;  
  }

  if( LEDval != previousLEDval)
  {
    switch (LEDval)    // Select the RGB colour according to switch value
    {
      case 0:  // central position, Blue
        RGB_color(0, 0, 255);
        Serial.println("Switch in CENTRE BLUE position");
        break;
      case 1:  // Red
        RGB_color(255, 0, 0);
        Serial.println("Switch in RED position");
        break;
      case 2:  // Green
        RGB_color(0, 255, 0);
        Serial.println("Switch in GREEN position");
        break;
      case -1:  // both are pressed, not valid
        RGB_color(0, 0, 0);
        break;
      default:
        Serial.println( "Error");
        break;
    }
    previousLEDval = LEDval;
  }

  delay(10);  // a small delay for debouncing
}

void RGB_color(int r, int g, int b)
{
  analogWrite(red_light_pin, r);
  analogWrite(green_light_pin, g);
  analogWrite(blue_light_pin, b);
}