/*
 *  RunningLights.ino
 *  Created by Christoffer Andersson, 2012-08-26
 *  This file is released under the GNU GPL
 */


//First we define starting and ending pin for the leds
#define lowPin 4
#define highPin 12


//Various declarations
int currentPin;    //Which pin as the current
boolean reverse;   //The current direction
boolean run;       //Is the lights paused

unsigned long tick = 0, now;  //Variables for loop speed
unsigned long speed = 0;  //The speed (we read this from the pot)

boolean btnVal; //The buttons value the last time we checked
unsigned long btnLastChange = 0;  //At what time did we read the button

void setup()
{
  //Lets initialize the Arduiono
  int i;

  //Lets set the outputs
  for(i = lowPin;i <= highPin;i++)
  {
    pinMode(i, OUTPUT);
  }

  //The switch is attached to pin 13
  pinMode(13, INPUT);

  reverse = false;
  run = false;
  currentPin = lowPin+1;

//  Serial.begin(9600);
};




void loop()
{
  speed = analogRead(0); //Read the value from the pot
  now = millis();  //What "time is it now?

  //I want this function to toggle run when the button is released, regarless of how long its been pressed
  if(btnLastChange+50 <= now){ //The 50ms delay is to avoid switch bounce
    if(btnVal != digitalRead(13)) //Has the switch changed since last time we checked?
    {
      btnVal = !btnVal; //Change the value
      btnLastChange = now; //Update last read time
      if(btnVal) //if the button was pressed, stop the lights from running
        toggleRun();
    }
  }


  //Check if enough time has passed, if so update the leds
  if(((tick+speed) <= now) && run) {
    runningLights();
    tick = millis();
  }

};


void toggleRun()
{
  //This function turns of all leds and then toggles the run.
  int i;
  for(i=lowPin;i<=highPin;i++)
    digitalWrite(i, LOW);

  run = !run;
}



void runningLights()
{
  switch(currentPin)
  {
    case lowPin:
      reverse = !reverse;
      break;
    case highPin:
      reverse = !reverse;
      break;
    default:
      break;
  };

  if(reverse){
    digitalWrite(currentPin, LOW);
    currentPin--;
    digitalWrite(currentPin, HIGH);
  } else {
    digitalWrite(currentPin, LOW);
    currentPin++;
    digitalWrite(currentPin, HIGH);
  }
}