/* 
*  This program codes a toggleable button that controls the power supply of a potentiometer.
*  The potentiometer controls the voltage of an RGB LED, which is set to rotate through colors
*  in a series of for loops.
*  
*  Code used: 
*  Debounce by Davit A. Mellis (2006), last modified by Arturo Guadalupi (2016) 
*  http://www.arduino.cc/en/Tutorial/Debounce
*/


// initalize button and potentiometer pins
const int buttonInPin = 2;  // the number of the input pushbutton pin
const int buttonOutPin = 4; // the number of the output pushbutton pin
const int analogInPin = A0; // the number of the analog input pin

// initailize the RGB LED pins
const int redPin = 9;       // the number of the red light on the RGB LED pin
const int greenPin = 10;    // the number of the green light on the RGB LED pin
const int bluePin = 11;     // the number of the blue light on the RGB LED pin

int ledState = LOW;         // the current state of the output pin
int buttonState;             // the current reading from the input pin
int lastButtonState = LOW;   // the previous reading from the input pin
int sensorValue = 0;         // value read from the pot
int maxValue = 255;          // value computed after sensor value mapping


unsigned long lastDebounceTime = 0;  // stores the last instance of state change
unsigned long debounceDelay = 100;    // the debounce time

void setup() {
 // Initializes the pins to output or input
 pinMode(buttonInPin, INPUT);
 pinMode(redPin, OUTPUT);
 pinMode(greenPin, OUTPUT);
 pinMode(bluePin, OUTPUT);
 pinMode(buttonOutPin, OUTPUT);

 // Sets the initial LED state
 digitalWrite(buttonOutPin, ledState);
}

void loop() {
 /*
  * Code taken from Debounce. Allows the push button to have a toggle state
  */
 // reads the state of the button and assigns into a local variable:
 int reading = digitalRead(buttonInPin);

 // checks if the button state changed due to noise or pressing:
 if (reading != lastButtonState) {
   // reset the debouncing timer
   lastDebounceTime = millis();
 }

 // checks if the reading has been there longer than the debounce delay
 if ((millis() - lastDebounceTime) > debounceDelay) {
  
   // checks if buton state changes
   if (reading != buttonState) {
     buttonState = reading;

     // toggles the LED if the new button state is HIGH
     if (buttonState == HIGH) {
       ledState = !ledState;
     }
   }
 }
 

 // writes HIGH to the button's output pin:
 digitalWrite(buttonOutPin, ledState);

 // saves the current reading to be referred in the next loop
 lastButtonState = reading;

 /*
  * End code taken from Debounce.
  */

 // read the potentiometer value:
 sensorValue = analogRead(analogInPin);
 
 // map it to the luminosity range:
 maxValue = map(sensorValue, 0, 1023, 0, 255);

 // loops up to max value, writing analog value to red pin and decreasing blue pin
 for (int i = 0; i < maxValue+1; i++) {
   analogWrite(redPin, i);             // increases value of red
   analogWrite(bluePin, maxValue-i);   // decreases value of blue
   delay(5);                           // slight delay in calls
 }

 // adds green, decreases red
 for (int i = 0; i < maxValue+1; i++) {
   analogWrite(greenPin, i);
   analogWrite(redPin, maxValue-i);
   delay(5);
 }

 // adds blue, decreases green
 for (int i = 0; i < maxValue+1; i++) {
   analogWrite(bluePin, i);
   analogWrite(greenPin, maxValue-i);
   delay(5);
 }
}