#include <FastLED.h>

#define NUM_LEDS      100
#define LED_TYPE   WS2811
#define COLOR_ORDER   GRB
#define DATA_PIN        6
#define VOLTS         3.3
#define MAX_MA       2500
#define buttonPin       2
volatile byte buttonState = 0;
CRGBArray<NUM_LEDS> leds;

// Overall twinkle speed.
// 0 (VERY slow) to 8 (VERY fast).
// 4, 5, and 6 are recommended, default is 4.
#define TWINKLE_SPEED 4

// Overall twinkle density.
// 0 (NONE lit) to 8 (ALL lit at once).
// Default is 5.
#define TWINKLE_DENSITY 6

// How often to change color palettes.
#define SECONDS_PER_PALETTE  60
// Also: toward the bottom of the file is an array
// called "ActivePaletteList" which controls which color
// palettes are used; you can add or remove color palettes
// from there freely.

// Background color for 'unlit' pixels
// Can be set to CRGB::Black if desired.
//CRGB gBackgroundColor = CRGB::DeepSkyBlue;
CRGB gBackgroundColor = CRGB::Black;
// Example of dim incandescent fairy light background color
//  CRGB gBackgroundColor = CRGB(CRGB::FairyLight).nscale8_video(16);

// If AUTO_SELECT_BACKGROUND_COLOR is set to 1,
// then for any palette where the first two entries
// are the same, a dimmed version of that color will
// automatically be used as the background color.
#define AUTO_SELECT_BACKGROUND_COLOR 1

// If COOL_LIKE_INCANDESCENT is set to 1, colors will
// fade out slighted 'reddened', similar to how
// incandescent bulbs change color as they get dim down.
#define COOL_LIKE_INCANDESCENT 0


CRGBPalette16 gCurrentPalette;
CRGBPalette16 gTargetPalette;

void setup() {
  delay( 3000 ); //safety startup delay
  FastLED.setMaxPowerInVoltsAndMilliamps( VOLTS, MAX_MA);
  FastLED.addLeds<LED_TYPE, DATA_PIN, COLOR_ORDER>(leds, NUM_LEDS)
  .setCorrection(TypicalLEDStrip);
  chooseNextColorPalette(gTargetPalette);
  pinMode(2, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(2), increaseState, CHANGE);
  //FastLED.clear();
}


void loop()
{
  //readButton(); // put the pushbutton-read in a function
  if (buttonState > 1) {
    buttonState = 0;
  }

  if (buttonState == 0) { //turn all leds off
    for (int i = 0; i < 101; i++) {
      leds[i] = CRGB::Black;;
    }
    FastLED.show();
    FastLED.clear(); //when buttons state is zero turn off all leds
  }
  else { /*(buttonState == 1)*/  //run code to turn all leds simply on
    EVERY_N_SECONDS( SECONDS_PER_PALETTE ) {
      chooseNextColorPalette( gTargetPalette );
    }

    EVERY_N_MILLISECONDS( 10 ) {
      nblendPaletteTowardPalette( gCurrentPalette, gTargetPalette, 12);
    }

    drawTwinkles( leds);

    FastLED.show();
  }
}

void increaseState() {
  if (digitalRead(2) == LOW) {
    buttonState++;
  }
}

//  This function loops over each pixel, calculates the
//  adjusted 'clock' that this pixel should use, and calls
//  "CalculateOneTwinkle" on each pixel.  It then displays
//  either the twinkle color of the background color,
//  whichever is brighter.
void drawTwinkles( CRGBSet& L)
{
  // "PRNG16" is the pseudorandom number generator
  // It MUST be reset to the same starting value each time
  // this function is called, so that the sequence of 'random'
  // numbers that it generates is (paradoxically) stable.
  uint16_t PRNG16 = 11337;

  uint32_t clock32 = millis();

  // Set up the background color, "bg".
  // if AUTO_SELECT_BACKGROUND_COLOR == 1, and the first two colors of
  // the current palette are identical, then a deeply faded version of
  // that color is used for the background color
  CRGB bg;
  if ( (AUTO_SELECT_BACKGROUND_COLOR == 1) &&
       (gCurrentPalette[0] == gCurrentPalette[1] )) {
    bg = gCurrentPalette[0];
    uint8_t bglight = bg.getAverageLight();
    if ( bglight > 64) {
      bg.nscale8_video( 16); // very bright, so scale to 1/16th
    } else if ( bglight > 16) {
      bg.nscale8_video( 64); // not that bright, so scale to 1/4th
    } else {
      bg.nscale8_video( 86); // dim, scale to 1/3rd.
    }
  } else {
    bg = gBackgroundColor; // just use the explicitly defined background color
  }

  uint8_t backgroundBrightness = bg.getAverageLight();

  for ( CRGB& pixel : L) {
    PRNG16 = (uint16_t)(PRNG16 * 2053) + 1384; // next 'random' number
    uint16_t myclockoffset16 = PRNG16; // use that number as clock offset
    PRNG16 = (uint16_t)(PRNG16 * 2053) + 1384; // next 'random' number
    // use that number as clock speed adjustment factor (in 8ths, from 8/8ths to 23/8ths)
    uint8_t myspeedmultiplierQ5_3 =  ((((PRNG16 & 0xFF) >> 4) + (PRNG16 & 0x0F)) & 0x0F) + 0x08;
    uint32_t myclock30 = (uint32_t)((clock32 * myspeedmultiplierQ5_3) >> 3) + myclockoffset16;
    uint8_t  myunique8 = PRNG16 >> 8; // get 'salt' value for this pixel

    // We now have the adjusted 'clock' for this pixel, now we call
    // the function that computes what color the pixel should be based
    // on the "brightness = f( time )" idea.
    CRGB c = computeOneTwinkle( myclock30, myunique8);

    uint8_t cbright = c.getAverageLight();
    int16_t deltabright = cbright - backgroundBrightness;
    if ( deltabright >= 32 || (!bg)) {
      // If the new pixel is significantly brighter than the background color,
      // use the new color.
      pixel = c;
    } else if ( deltabright > 0 ) {
      // If the new pixel is just slightly brighter than the background color,
      // mix a blend of the new color and the background color
      pixel = blend( bg, c, deltabright * 8);
    } else {
      // if the new pixel is not at all brighter than the background color,
      // just use the background color.
      pixel = bg;
    }
  }
}


//  This function takes a time in pseudo-milliseconds,
//  figures out brightness = f( time ), and also hue = f( time )
//  The 'low digits' of the millisecond time are used as
//  input to the brightness wave function.
//  The 'high digits' are used to select a color, so that the color
//  does not change over the course of the fade-in, fade-out
//  of one cycle of the brightness wave function.
//  The 'high digits' are also used to determine whether this pixel
//  should light at all during this cycle, based on the TWINKLE_DENSITY.
CRGB computeOneTwinkle( uint32_t ms, uint8_t salt)
{
  uint16_t ticks = ms >> (8 - TWINKLE_SPEED);
  uint8_t fastcycle8 = ticks;
  uint16_t slowcycle16 = (ticks >> 8) + salt;
  slowcycle16 += sin8( slowcycle16);
  slowcycle16 =  (slowcycle16 * 2053) + 1384;
  uint8_t slowcycle8 = (slowcycle16 & 0xFF) + (slowcycle16 >> 8);

  uint8_t bright = 0;
  if ( ((slowcycle8 & 0x0E) / 2) < TWINKLE_DENSITY) {
    bright = attackDecayWave8( fastcycle8);
  }

  uint8_t hue = slowcycle8 - salt;
  CRGB c;
  if ( bright > 0) {
    c = ColorFromPalette( gCurrentPalette, hue, bright, NOBLEND);
    //if( COOL_LIKE_INCANDESCENT == 1 ) {
    //  coolLikeIncandescent( c, fastcycle8);
    //}
  } else {
    c = CRGB::Black;
  }
  return c;
}


// This function is like 'triwave8', which produces a
// symmetrical up-and-down triangle sawtooth waveform, except that this
// function produces a triangle wave with a faster attack and a slower decay:
//
//     / \ 
//    /     \ 
//   /         \ 
//  /             \ 
//

uint8_t attackDecayWave8( uint8_t i)
{
  if ( i < 86) {
    return i * 3;
  } else {
    i -= 86;
    return 255 - (i + (i / 2));
  }
}

// This function takes a pixel, and if its in the 'fading down'
// part of the cycle, it adjusts the color a little bit like the
// way that incandescent bulbs fade toward 'red' as they dim.
//void coolLikeIncandescent( CRGB& c, uint8_t phase)
//{
//  if( phase < 128) return;

// uint8_t cooling = (phase - 128) >> 4;
// c.g = qsub8( c.g, cooling);
// c.b = qsub8( c.b, cooling * 2);
//}

// A mostly blue palette with white accents.
// "CRGB::Gray" is used as white to keep the brightness more uniform.
const TProgmemRGBPalette16 BlueWhite_p FL_PROGMEM =
{ CRGB::Blue, CRGB::Blue, CRGB::Blue, CRGB::Blue,
  CRGB::Blue, CRGB::Blue, CRGB::Blue, CRGB::Blue,
  CRGB::Blue, CRGB::Blue, CRGB::Blue, CRGB::Blue,
  CRGB::Blue, CRGB::Gray, CRGB::Gray, CRGB::Gray
};

// Cloudy Blue
const TProgmemRGBPalette16 BlueCloud_p FL_PROGMEM =
{ CRGB::DodgerBlue, CRGB::DodgerBlue, CRGB::DodgerBlue, CRGB::DodgerBlue,
  CRGB::DodgerBlue, CRGB::DodgerBlue, CRGB::DodgerBlue, CRGB::DodgerBlue,
  CRGB::DodgerBlue, CRGB::DodgerBlue, CRGB::DodgerBlue, CRGB::DodgerBlue,
  CRGB::DodgerBlue, CRGB::Gray, CRGB::Gray, CRGB::Gray
};

// A palette of soft snowflakes with the occasional bright one
const TProgmemRGBPalette16 Snow_p FL_PROGMEM =
{ 0x304048, 0x304048, 0x304048, 0x304048,
  0x304048, 0x304048, 0x304048, 0x304048,
  0x304048, 0x304048, 0x304048, 0x304048,
  0x304048, 0x304048, 0x304048, 0xE0F0FF
};

// A cold, icy pale blue palette
#define Ice_Blue1 0x0C1040
#define Ice_Blue2 0x182080
#define Ice_Blue3 0x5080C0
const TProgmemRGBPalette16 Ice_p FL_PROGMEM =
{
  Ice_Blue1, Ice_Blue1, Ice_Blue1, Ice_Blue1,
  Ice_Blue1, Ice_Blue1, Ice_Blue1, Ice_Blue1,
  Ice_Blue1, Ice_Blue1, Ice_Blue1, Ice_Blue1,
  Ice_Blue2, Ice_Blue2, Ice_Blue2, Ice_Blue3
};


// Add or remove palette names from this list to control which color
// palettes are used, and in what order.
const TProgmemRGBPalette16* ActivePaletteList[] = {
  //&BlueWhite_p,
  &Snow_p,
  &Ice_p,
  &BlueCloud_p
};


// Advance to the next color palette in the list (above).
void chooseNextColorPalette( CRGBPalette16& pal)
{
  const uint8_t numberOfPalettes = sizeof(ActivePaletteList) / sizeof(ActivePaletteList[0]);
  static uint8_t whichPalette = -1;
  whichPalette = addmod8( whichPalette, 1, numberOfPalettes);

  pal = *(ActivePaletteList[whichPalette]);
}