/* flash 3 Pixel LED strips randomly version 2
  www. steamtraininfo.com.
  This sketch uses 3
  WS2812B pixel strips.
*/

#include <FastLED.h>

#define NUM_LEDS 15 /*the number of leds that will light. If */
//****************************
#define LED_PIN 6 // Connect to the data wires on the pixel strips


CRGB _leds[NUM_LEDS];


  bool _isStartDone = false;
  bool _isNumLedsEven = NUM_LEDS % 2 == 0;
  uint8_t _halfLedSize = NUM_LEDS / 2;
  uint8_t _startCycleCount = 0;
  uint8_t _startPos = 0; // this is one position ahead



void setup() {
  FastLED.addLeds<WS2812B, LED_PIN, GRB>(_leds, NUM_LEDS);
  FastLED.setBrightness(100);
}

void loop() {
    if (!_isStartDone) {
      _animateStart();
    } else {
      fill_solid(_leds, NUM_LEDS, CRGB::Red);
      FastLED.show();
    }
}



  void _animateStart() {
    if (_isNumLedsEven)
      _animateStartEven();
    else
      _animateStartOdd();
  }

  void _animateStartEven() {
    _animateStart(_halfLedSize - _startPos - 1, _halfLedSize + _startPos);
  }

  void _animateStartOdd() {
    _animateStart(_halfLedSize - _startPos - 1, _halfLedSize + _startPos - 1);
  }

  void _animateStart(uint8_t leftPos, uint8_t rightPos) {
    EVERY_N_MILLISECONDS(60) {

      // 2 waves outward
      _leds[leftPos] = CRGB(255, 0, 0);
      _leds[rightPos] = CRGB(255, 0, 0);

      // Serial.print("leftPos:");
      // Serial.print(leftPos);
      // Serial.print(" rightPos:");
      // Serial.print(rightPos);
      // Serial.print(" _startPos:");
      // Serial.print(_startPos);
      // Serial.print(" _halfLedSize:");
      // Serial.print(_halfLedSize);
      // Serial.println();

      _startPos++;
      if (_startPos == _halfLedSize) {
        _startCycleCount++;
        _startPos = 0;

        if (_startCycleCount == 2)
          _isStartDone = true;
      }

      FastLED.show();
    }

    EVERY_N_MILLISECONDS(5) {
      fadeToBlackBy(_leds, NUM_LEDS, 5);
      FastLED.show();
    }
  }