/*
 Arduino Dice :)

 Simulate throwing a dice (1d6), and displaying the result using 6 LEDs.

 The circuit:
 * 6 LEDs attached to consecutive digital pins (with 560 Ohm current limiting resistors)
 * button (switch) connected to a digital pin

 Created 26 Jan 2017
 By H Phil Duby

 Adapted from https://www.hackster.io/EvdS/led-dice-885cf1
 By Esther van der Stappen

 This code is in the public domain.
 */

// set to 1 if we're debugging
#define DEBUG 0

// Set the die rolling animation speed (smaller is faster)
const long ANIM_WAIT = 100; // milliseconds (0.1 seconds)
const int IS_PRESSED = LOW; // Pullup resistor makes normal (not pressed) value HIGH

// 6 consecutive digital pins for the LEDs
const int first = 2;
const int second = 3;
const int third = 4;
const int fourth = 5;
const int fifth = 6;
const int sixth = 7;

// pin for the button to trigger a die roll
const int rollBtn = 12;

void setup() {
  // set all LED pins to OUTPUT
  for ( int  i = first; i <= sixth; i++ ) {
    pinMode ( i, OUTPUT );
  }
  // set button pin to INPUT, and use internal pullup resistor
  pinMode ( rollBtn, INPUT_PULLUP );

  // initialize random seed by noise from analog pin 0 (should be unconnected)
  randomSeed ( analogRead ( 0 ));

  // if we're debugging, connect to serial
  #ifdef DEBUG
    Serial.begin ( 9600 );
  #endif
}

void loop()
{
  // Declare local variables
  int dieResult;
  int btnState;

  btnState = digitalRead ( rollBtn ); // Check button

  if ( btnState == IS_PRESSED ) { // is button currently pressed?
    setAllLEDs ( LOW ); // remove previous number

    // Different ways to animate the wait for the roll
    animateDieRolling();
//    animateWithMemory();

    dieResult = roll1d6();

    // Different ways to turn on the LEDs that show the result
    showDieByIf ( dieResult );
//    showDieBySwitch ( dieResult );
//    showDieByFor( dieResult );
  }
}// ./void loop()

/**
 * light individual LEDs from left to right and back to build up tension while
 * waiting for the dice to be thrown.
 */
void animateDieRolling()
{
  // left to right
  for ( int i = first; i <= sixth; i++ ) {
    if ( i != first ) {
      digitalWrite ( i - 1, LOW );
    }
    digitalWrite ( i, HIGH );
    delay ( ANIM_WAIT );
  }
  // right to left
  for ( int i = sixth; i >= first; i-- ) {
    if ( i != sixth ) {
      digitalWrite ( i + 1, LOW );
    }
    digitalWrite ( i, HIGH );
    delay ( ANIM_WAIT );
  }
}// ./void animateDieRolling()

/**
 * Remember the pin number for the LED being turned ON, then use that to turn
 * it OFF again when turn the next one ON
 */
void animateWithMemory()
{
  int prevLed = sixth;
  // left to right
  for ( int i = first; i <= sixth; i++ ) {
    digitalWrite ( prevLed, LOW ); // Turn previous LED OFF
    digitalWrite ( i, HIGH ); // Turn current LED ON
    prevLed = i; // Remember the pin for the currently ON LED
    delay ( ANIM_WAIT );
  }
  // right to left
  for ( int i = sixth; i >= first; i-- ) {
    digitalWrite ( prevLed, LOW ); // Turn previous LED OFF
    digitalWrite ( i, HIGH ); // Turn current LED ON
    prevLed = i; // Remember the pin for the currently ON LED
    delay ( ANIM_WAIT );
  }
  // This leaves the final (first) LED on, but that is OK.  It will always be
  // Turned on any when displaying the roll result
//  digitalWrite ( prevLed, LOW ); // Turn final LED OFF
}// ./void animateWithMemory()

/**
 * Use if statements to decide whether to turn ON each LED.  The first is always
 * turned ON.
 *
 * @param number the 1d6 value to display
 */
void showDieByIf( int number )
{
  digitalWrite ( first, HIGH );
  if ( number >= 2 ) {
    digitalWrite(second, HIGH );
  }
  if ( number >= 3 ) {
    digitalWrite ( third, HIGH );
  }
  if ( number >= 4 ) {
    digitalWrite ( fourth, HIGH );
  }
  if ( number >= 5 ) {
    digitalWrite ( fifth, HIGH );
  }
  if ( number == 6 ) {
    digitalWrite ( sixth, HIGH );
  }
}// ./void showDieByIf( int number )

/**
 * Use a switch statement to pick the highest LED pin number to set, then turn
 * it and all lower pin numbers ON
 *
 * @param number the 1d6 value to display
 */
void showDieBySwitch( int number )
{
  // When not using 'break' at the end of each case, all of the cases following
  // the matched one are executed as well.
  switch ( number ) {
  case 6:
    digitalWrite ( sixth, HIGH );
  case 5:
    digitalWrite ( fifth, HIGH );
  case 4:
    digitalWrite ( fourth, HIGH );
  case 3:
    digitalWrite ( third, HIGH );
  case 2:
    digitalWrite ( second, HIGH );
  }
  digitalWrite ( first, HIGH ); // Always at least one
}// ./void showDieBySwitch( int number )

/**
 * Use a for loop to sequence through the LED pin numbers to be turned ON
 *
 * @param number the 1d6 value to display
 */
void showDieByFor( int number )
{
  // Turn on the first 'number' LEDs
  for ( int i = first; i < first + number; i++ ) {
    digitalWrite ( i, HIGH );
  }
}// ./void showDieByFor( int number )

/**
 * generate a random 1d6 value
 *
 * @return random 1d6 value
 */
int roll1d6()
{
  // get a random number in the range [1,6]
  int random1d6 = random ( 1, 7 );

  #ifdef DEBUG
    Serial.println ( random1d6 );
  #endif

  return random1d6;
}// ./int roll1d6()

/**
 * Set all LEDs to a single state
 *
 * @param value the state to set the pins to
 */
void setAllLEDs( int value )
{
  for ( int i = first; i <= sixth; i++ ) {
    digitalWrite ( i, value );
  }
}// ./void setAllLEDs( int value )