// For: https://forum.arduino.cc/t/fastled-help-with-splitting-a-strip-into-segments/1035740
// 4 * 8 leds is 32, but the sketch says 36 led ?

#include <FastLED.h>

#define LED_PIN     2
#define COLOR_ORDER GRB
#define CHIPSET     WS2812B
#define NUM_LEDS    36       //LEDS on strip 

#define ENGINE_1  8
#define ENGINE_2  8 


///////Engine 1///////
#define EngineSize1 8
#define EngineStart1 0
#define EngineEnd1 8

///////Engine 2///////
#define EngineSize2 8
#define EngineStart2 8
#define EngineEnd2 16

///////Engine 3///////
#define EngineSize3 8
#define EngineStart3 16
#define EngineEnd3 24

///////Engine 4///////
#define EngineSize4 8
#define EngineStart4 24
#define EngineEnd4 32



#define BRIGHTNESS  255
#define FRAMES_PER_SECOND 100

bool gReverseDirection = false;

CRGB leds[NUM_LEDS];


CRGBPalette16 gPal;

void setup() {
  delay(300); // sanity delay
  FastLED.addLeds<CHIPSET, LED_PIN, COLOR_ORDER>(leds, NUM_LEDS).setCorrection( TypicalLEDStrip );
  
  FastLED.setBrightness( BRIGHTNESS );

  gPal = CRGBPalette16( CRGB::Black, CRGB::Red, CRGB::Yellow, CRGB::OrangeRed );

FastLED.show(); // display this frame
}

void loop()
{
  // Add entropy to random number generator; we use a lot of it. 
  random16_add_entropy( esp_random());                                        // <<< use random() for ardunino esp_random() for ESP32

  //ENGINE(EngineSize1,EngineStart1,EngineEnd1);
  //ENGINE(EngineSize2,EngineStart2,EngineEnd2);
  //ENGINE(EngineSize3,EngineStart3,EngineEnd3);
  ENGINE(EngineSize4,EngineStart4,EngineEnd4);
  
  FastLED.show(); // display this frame
  FastLED.delay(1000 / FRAMES_PER_SECOND);
}


// COOLING: How much does the air cool as it rises?
// Less cooling = taller flames.  More cooling = shorter flames.
// Default 55, suggested range 20-100 
#define COOLING  20

// SPARKING: What chance (out of 255) is there that a new spark will be lit?
// Higher chance = more roaring fire.  Lower chance = more flickery fire.
// Default 120, suggested range 50-200.
#define SPARKING 200


///////////////////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////////////////
void ENGINE(int EngineSize, int EngineStart, int EngineEnd)
{
// Array of temperature readings at each simulation cell
  static uint8_t heat[8];

  // Step 1.  Cool down every cell a little
    for( int i = EngineStart; i < EngineEnd; i++) {
      heat[i] = qsub8( heat[i],  random8(0, ((COOLING * 10) / EngineSize) + 2));
    }
  
    // Step 2.  Heat from each cell drifts 'up' and diffuses a little
    for( int k= EngineEnd - 1; k >= EngineStart; k--) {
      heat[k] = (heat[k - 1] + heat[k - 2] + heat[k - 2] ) / 3;
    }
    
    // Step 3.  Randomly ignite new 'sparks' of heat near the bottom
    if( random8() < SPARKING ) {
      int y = random8(EngineStart,EngineEnd);
      heat[y] = qadd8( heat[y], random8(160,255) );
    }

    // Step 4.  Map from heat cells to LED colors
    for( int j = EngineStart; j < EngineEnd; j++) {
      // Scale the heat value from 0-255 down to 0-240
      // for best results with color palettes.
      uint8_t colorindex = scale8( heat[j], 240);
      CRGB color = ColorFromPalette( gPal, colorindex);
      int pixelnumber;
      if( gReverseDirection ) {    //if( gReverseDirection ) { if( random(0,1) ) { //
        pixelnumber = (NUM_LEDS-1) - j;
      } else {
        pixelnumber = j;
      }
      leds[pixelnumber] = color;
    }
}
///////////////////////////////////////////////////////////////////////////////////////////