// Experiments with Fastled beatsin16, beatsin88
// Based on code from https://forum.arduino.cc/t/fastled-beatsin16-just-one-way/1085303/4?u=davex
// modified to be mostly non-blocking
// Wokwi simulation at https://wokwi.com/projects/355578772690767873

#include <FastLED.h>

#define NUM_LEDS  250
#define LED_PIN   6
//CRGB leds[NUM_LEDS];
CRGBArray <NUM_LEDS> leds;
uint8_t data[ NUM_LEDS];

const float BPMf = 20; // BPM in floating point
const uint32_t BPM88 = BPMf * 256; // Q8.8 fixed point
const uint16_t BPM = BPMf; // integer

void setup() {
  delay(300);
  FastLED.addLeds<WS2812B, LED_PIN, GRB>(leds, NUM_LEDS).setCorrection(TypicalLEDStrip);
  FastLED.setBrightness(255);
}

void movingDotred() {
  const uint32_t interval = 60000UL / BPMf / 2; // = (60000ms/min)/20BPM/2
  static unsigned long lastOffsetTime = -interval; // make an immediate change with -interval initialization trick
  static uint32_t t0 = 0; // timebase
  static uint16_t phase = 1 * 32768 / 2; // which segment of sine
  if (millis() - lastOffsetTime >= interval) {
    lastOffsetTime += interval;
    t0 = millis() ; // update timebase
  }

  uint16_t sinBeat = beatsin88(BPM88, 0, NUM_LEDS - 1, t0, phase);
  if(sinBeat < 150)
  {
    leds[sinBeat] = CRGB(0, 255, 0);
  }
  else
  {
    leds[sinBeat] = CRGB(255, 0, 0);
  }
  fadeToBlackBy(leds, NUM_LEDS, 3);
  FastLED.show();
}


void loop() {

  static uint32_t loopcount = 0;
  static uint32_t fastcount = 0;

  static uint32_t now = 0;
  static uint32_t lastnow = -1;
  static int seqVar = -1;

  // use millis to update sequence:
  static uint32_t lastseq = -1;
  static uint32_t period2 = 0L;      // X seconds
  now = millis(); loopcount++;
  if ( now - lastseq >= period2) { //change sequence
    lastseq += period2;
    seqVar++;
    if (seqVar > 8) seqVar = 0;
    //seqVar = 7; // override
    period2 = random(10, 20) * 1000L;      // X seconds
    loopcount = 0; fastcount = 0;

  }

  movingDotred();
}