# include <Adafruit_NeoPixel.h>
# define PIN 2          // the pin
# define NPIXELS (16)     // number of LEDs on strip

Adafruit_NeoPixel stab(NPIXELS, PIN, NEO_GRB + NEO_KHZ800); 

void setup() {
  Serial.begin(115200);
  Serial.println("\nHi Mom!\n");

//  Serial.pr intln(1 << 15);
//  Serial.pr intln(1ul << 15);

  pinMode(3, INPUT_PULLUP);

  smartLampSetup();

  stab.show();
  delay(777);

//  for (; ; );
}

void smartLampSetup() {
  stab.begin();
  stab.setPixelColor(0, 0xff0000);
  stab.setPixelColor(1, 0x00ff00);
  stab.setPixelColor(2, 0x0000ff);
  stab.setPixelColor(NPIXELS - 1, 0x808080);
  stab.show();
  stab.clear();
  delay(1777);

  for (byte ii = 0; ii < NPIXELS; ii++) stab.setPixelColor(ii, 0x000001);
}

//unsigned long it = 1;
// unsigned long long it = 1; // 0xa5f9;

unsigned long long it = 0x4000; // 0xa5f9;

/*
15      15,14             15, 14, 13, 11      // 37 37, 36, 33, 31 59 59, 57, 55, 52
16      16, 14, 13, 11
*/
void loop() {
  static unsigned long lastTick;
  static int bpm;
  unsigned long now = millis();


  if (now - lastTick < bpm) { delay(1); return;}
  lastTick = now;

// one chatGPT idea
  float t = analogRead(A0) / 1023.0;
  float bpmx = 25.0 * pow(300.0 / 25.0, t);
  float period_ms = 60000.0 / bpmx;

  bpm = period_ms + 0.5 - 2;

//  Serial.println(bpm);
  
/*
if (0)
  if (digitalRead(2) == LOW) stabIt();
  else stabIt5X5();

if (0)  stabIt2X3();
*/

  stabIt();

  stab.show();


//  delay(227);  // so sue me.

  // now show 64 is ~ 2 ms. we will assume that, and slide fade from 40 to 220 BPM

  mobe16();

//  xAdvance();

//  advance();
//  advanceG();
}

void advance16()
{
  unsigned char a = it & (1ul << 15) ? 1 : 0;  // 15 (16/1)
  unsigned char b = it & (1 << 13) ? 1 : 0;  // 13 (14/1)
  unsigned char c = it & (1 << 12) ? 1 : 0;  // 12 (13/1)
  unsigned char d = it & (1 << 10) ? 1 : 0;  // 10 (11/1)

//  unsigned char e = a ^ b ^ c ^ d;
  unsigned char e = a + b + c + d;

  it <<= 1;
  if (e & 1) it |= 0x1;
}

// central mapping location.
// just linear
void stabIt() {

// hardcode ... 5x5 inset on 8x8 x+1 y+2 ??
  
  unsigned long long fIt = it;
  for (byte ii = 0; ii < NPIXELS; ii++) {
    stab.setPixelColor(ii, fIt & 0x1 ? 0xc040a0 : 0x0c0318);
    fIt >>= 1;
  }
}

// 5x5 in the middle of eight +1 x, +1 y
void stabIt5X5() {
  const byte XPIXELS = 25;
  byte asX, asY;
  
// hardcode ... 5x5 inset on 8x8 x+1 y+2 ??
  
  unsigned long long fIt = it;
  for (byte ii = 0; ii < XPIXELS; ii++) {
    asX = ii / 5;
    asY = ii % 5;

    int pixel = (asX + 1) * 8 + asY + 1;
    stab.setPixelColor(pixel, fIt & 0x1 ? 0x804060 : 0x240014);
    fIt >>= 1;
  }
}


// (2x3)^ 2  pattern from map

// (2 + 3)^2
const byte map2X3[] = {
  9, 10, 12, 13, 14,
  17, 18, 20, 21, 22,
  33, 34, 36, 37, 38,
  41, 42, 44, 45, 46, 
  49, 50, 52, 53, 54
};

const byte altMap[] = {
  9, 10, 17, 18, 12, 13, 14, 20, 21, 22,
  33, 34, 41, 42, 49, 50,
  36, 37, 38, 44, 45, 46, 52, 53, 54,
};

const byte XPIXELS = sizeof map2X3 / sizeof *map2X3;

void stabIt2X3() {

  byte asX, asY;
  
// hardcode ... 5x5 inset on 8x8 x+1 y+2 ??
  
  unsigned long long fIt = it;
  for (byte ii = 0; ii < XPIXELS; ii++) {


//    int pixel = map2X3[ii];
    int pixel = altMap[ii];
    stab.setPixelColor(pixel, fIt & 0x1 ? 0x804060 : 0x243014);
    fIt >>= 1;
  }
}



// feed in the XOR of the feedback bits here 2^15 and 2^14
void advance0()
{
  it <<= 1;
  if (it & 0x8000)
    if (it & 0x4000); else it |= 1;  // <--

  else if (it & 0x4000) it |= 1;
}

void advance()
{
  unsigned long long itt = it;

  advanceA();
  unsigned long long itA = it;

  it = itt;

  advanceB();
  unsigned long long itB = it;
}

// *it* is unsigned and either 32 or 64 bits.
// so far all LFSR have been 16 or fewer. displays from 2x2 to 8x8

void advanceA()
{
  it <<= 1;
  if (it & (1ul << 15))  // 0x8000ul, gack! chain reaction interesting affect
    if (it & (1 << 14)); else it |= 1;  // <--

  else if (it & (1 << 14)) it |= 1;

if (1) {
  static int counter;
  Serial.print(counter); Serial.print(" ");
  counter++;
  unsigned int the = it & 0xffff;
  Serial.println(the, HEX);
}
}

void advanceB()
{
  bool msb = it & (1 << 14);

  it <<= 1;
  if (msb)
    it ^= 0x3;

if (1) {
  static int counter;
  Serial.print(counter + 1000); Serial.print(" ");
  counter++;
  unsigned int the = it & 0xffff;
  Serial.println(the, HEX);
}
}

void advance16_2()
{
  bool msb = it & (1ul << 15);

  it <<= 1;
  if (msb)
    it ^= 0x002Du;       
}
/*
void advanceG16()
{
  bool msb = it & 0x8000ul; 
  
  it <<= 1;                         
  if (msb)                      
    it ^= 0x002Du;       
}
*/

# define lamp it

//void advanceLikeOldways()
void xAdvance()
{
  lamp >>= 1;
//  return;   /* to find why neopixels 0 and 1 get turned on */
  
  if (digitalRead(3) == HIGH) {
    if (lamp & 1)
      if (lamp & 2) lamp &= 0x7fff;
      else lamp |= 0x8000;
    else
      if (lamp & 2) lamp |= 0x8000;
      else lamp &= 0x7fff;
/*
    if (lamp & 2)
      if (lamp & 4) nextBit = 0;
      else nextBit = 1;
    else
      if (lamp & 4) nextBit = 1;
      else nextBit = 0;
*/
  }
  else {
    if (lamp & 0x4000)
      if (lamp & 1) lamp &= 0x7fff;
      else lamp |= 0x8000;
    else
      if (lamp & 1) lamp |= 0x8000;
      else lamp &= 0x7fff;
  }
}

void mobe15()
{
  if (digitalRead(3) == HIGH) it = advanceK15(it);
  else it = reverseK15(it);
}

unsigned int advanceK15(unsigned int it)
{
  unsigned int bits = it & 0x6000;
  bool parity = false;

  while (bits) {
    bits &= bits - 1;
    parity = !parity;
  }

  it <<= 1;
  if (parity) it |= 0x1;

  return it;
}

unsigned int reverseK15(unsigned int it)
{
  unsigned int bits = it & 0x8002;
  bool parity = false;

  while (bits) {
    bits &= bits - 1;
    parity = !parity;
  }

  it >>= 1;
  if (parity) it |= 0x8000;

  return it;
}

void mobe16()
{
  if (digitalRead(3) == HIGH) it = advanceK16(it);
  else it = reverseK16(it);
}

unsigned int advanceK16(unsigned int it)
{
  unsigned int bits = it & 0xb400;
  bool parity = false;

  while (bits) {
    bits &= bits - 1;
    parity = !parity;
  }

  it <<= 1;
  if (parity) it |= 0x1;

  return it;
}

unsigned int reverseK16(unsigned int it)
{
  unsigned int bits = it & 0x5a1;
  bool parity = false;

  while (bits) {
    bits &= bits - 1;
    parity = !parity;
  }

  it >>= 1;
  if (parity) it |= 0x8000;

  return it;
}