#include "wled.h"
#include "fcn_declare.h"
#include "const.h"
#ifdef ESP8266
#include "user_interface.h" // for bootloop detection
#include <Hash.h>            // for SHA1 on ESP8266
#else
#include "mbedtls/sha1.h"   // for SHA1 on ESP32
#include "esp_efuse.h"
#endif

//helper to get int value at a position in string
int getNumVal(const String* req, uint16_t pos)
{
  return req->substring(pos+3).toInt();
}


//helper to get int value with in/decrementing support via ~ syntax
void parseNumber(const char* str, byte* val, byte minv, byte maxv)
{
  if (str == nullptr || str[0] == '\0') return;
  if (str[0] == 'r') {*val = random8(minv,maxv?maxv:255); return;} // maxv for random cannot be 0
  bool wrap = false;
  if (str[0] == 'w' && strlen(str) > 1) {str++; wrap = true;}
  if (str[0] == '~') {
    int out = atoi(str +1);
    if (out == 0) {
      if (str[1] == '0') return;
      if (str[1] == '-') {
        *val = (int)(*val -1) < (int)minv ? maxv : min((int)maxv,(*val -1)); //-1, wrap around
      } else {
        *val = (int)(*val +1) > (int)maxv ? minv : max((int)minv,(*val +1)); //+1, wrap around
      }
    } else {
      if (wrap && *val == maxv && out > 0) out = minv;
      else if (wrap && *val == minv && out < 0) out = maxv;
      else {
        out += *val;
        if (out > maxv) out = maxv;
        if (out < minv) out = minv;
      }
      *val = out;
    }
    return;
  } else if (minv == maxv && minv == 0) { // limits "unset" i.e. both 0
    byte p1 = atoi(str);
    const char* str2 = strchr(str,'~'); // min/max range (for preset cycle, e.g. "1~5~")
    if (str2) {
      byte p2 = atoi(++str2);           // skip ~
      if (p2 > 0) {
        while (isdigit(*(++str2)));     // skip digits
        parseNumber(str2, val, p1, p2);
        return;
      }
    }
  }
  *val = atoi(str);
}


bool getVal(JsonVariant elem, byte* val, byte vmin, byte vmax) {
  if (elem.is<int>()) {
		if (elem < 0) return false; //ignore e.g. {"ps":-1}
    *val = elem;
    return true;
  } else if (elem.is<const char*>()) {
    const char* str = elem;
    size_t len = strnlen(str, 12);
    if (len == 0 || len > 10) return false;
    parseNumber(str, val, vmin, vmax);
    return true;
  }
  return false; //key does not exist
}


bool updateVal(const char* req, const char* key, byte* val, byte minv, byte maxv)
{
  const char *v = strstr(req, key);
  if (v) v += strlen(key);
  else return false;
  parseNumber(v, val, minv, maxv);
  return true;
}


//append a numeric setting to string buffer
void sappend(char stype, const char* key, int val)
{
  char ds[] = "d.Sf.";

  switch(stype)
  {
    case 'c': //checkbox
      oappend(ds);
      oappend(key);
      oappend(".checked=");
      oappendi(val);
      oappend(";");
      break;
    case 'v': //numeric
      oappend(ds);
      oappend(key);
      oappend(".value=");
      oappendi(val);
      oappend(";");
      break;
    case 'i': //selectedIndex
      oappend(ds);
      oappend(key);
      oappend(SET_F(".selectedIndex="));
      oappendi(val);
      oappend(";");
      break;
  }
}


//append a string setting to buffer
void sappends(char stype, const char* key, char* val)
{
  switch(stype)
  {
    case 's': {//string (we can interpret val as char*)
      String buf = val;
      //convert "%" to "%%" to make EspAsyncWebServer happy
      //buf.replace("%","%%");
      oappend("d.Sf.");
      oappend(key);
      oappend(".value=\"");
      oappend(buf.c_str());
      oappend("\";");
      break;}
    case 'm': //message
      oappend(SET_F("d.getElementsByClassName"));
      oappend(key);
      oappend(SET_F(".innerHTML=\""));
      oappend(val);
      oappend("\";");
      break;
  }
}


bool oappendi(int i)
{
  char s[16];               // WLEDMM max 32bit integer needs 11 chars (sign + 10) not 10
  snprintf(s, 15, "%d", i); // WLEDMM
  return oappend(s);
}

static bool squeezeStrings = false;
void oappendUseDeflate(bool OnOff) { squeezeStrings = OnOff; }

bool oappend(const char* txt)
{
  String str = squeezeStrings ? String(txt) : String("");
  if (squeezeStrings) {
    // simple fixed-dictionary deflate
    str.replace(F("addField("),    F("adF("));
    str.replace(F("addDropdown("), F("adD("));
    str.replace(F("addOption("),   F("adO("));
    str.replace(F("addInfo("),     F("adI("));
  }
  const char* finalTxt = squeezeStrings ? str.c_str() : txt;

  size_t len = strlen(finalTxt);
  if ((obuf == nullptr) || (olen + len >= SETTINGS_STACK_BUF_SIZE)) { // sanity checks
	  if (obuf == nullptr) { USER_PRINTLN(F("oappend() error: obuf == nullptr."));
	  } else {
	    USER_PRINT(F("oappend() error: buffer full. Increase SETTINGS_STACK_BUF_SIZE for "));
      USER_PRINTF("%2u bytes \t\"", len /*1 + olen + len - SETTINGS_STACK_BUF_SIZE*/);
      USER_PRINT(finalTxt);
      USER_PRINTLN(F("\""));
      errorFlag = ERR_LOW_AJAX_MEM;
	  }
    return false;        // buffer full
  }
  strcpy(obuf + olen, finalTxt);
  olen += len;
  return true;
}


void prepareHostname(char* hostname)
{
  sprintf_P(hostname, "wled-%*s", 6, escapedMac.c_str() + 6);
  const char *pC = serverDescription;
  uint8_t pos = 5;          // keep "wled-"
  while (*pC && pos < 24) { // while !null and not over length
    if (isalnum(*pC)) {     // if the current char is alpha-numeric append it to the hostname
      hostname[pos] = *pC;
      pos++;
    } else if (*pC == ' ' || *pC == '_' || *pC == '-' || *pC == '+' || *pC == '!' || *pC == '?' || *pC == '*') {
      hostname[pos] = '-';
      pos++;
    }
    // else do nothing - no leading hyphens and do not include hyphens for all other characters.
    pC++;
  }
  //last character must not be hyphen
  if (pos > 5) {
    while (pos > 4 && hostname[pos -1] == '-') pos--;
    hostname[pos] = '\0'; // terminate string (leave at least "wled")
  }
}


bool isAsterisksOnly(const char* str, byte maxLen)
{
  for (byte i = 0; i < maxLen; i++) {
    if (str[i] == 0) break;
    if (str[i] != '*') return false;
  }
  //at this point the password contains asterisks only
  return (str[0] != 0); //false on empty string
}


//threading/network callback details: https://github.com/Aircoookie/WLED/pull/2336#discussion_r762276994
bool requestJSONBufferLock(uint8_t module)
{
  unsigned long now = millis();

  while (jsonBufferLock && millis()-now < 1100) delay(1); // wait for fraction for buffer lock

  if (jsonBufferLock) {
    USER_PRINT(F("ERROR: Locking JSON buffer failed! (still locked by "));
    USER_PRINT(jsonBufferLock);
    USER_PRINTLN(")");
    return false; // waiting time-outed
  }

  jsonBufferLock = module ? module : 255;
  DEBUG_PRINT(F("JSON buffer locked. ("));
  DEBUG_PRINT(jsonBufferLock);
  DEBUG_PRINTLN(")");
  fileDoc = &doc;  // used for applying presets (presets.cpp)
  doc.clear();
  return true;
}


void releaseJSONBufferLock()
{
  DEBUG_PRINT(F("JSON buffer released. ("));
  DEBUG_PRINT(jsonBufferLock);
  DEBUG_PRINTLN(")");
  fileDoc = nullptr;
  jsonBufferLock = 0;
}


// extracts effect mode (or palette) name from names serialized string
// caller must provide large enough buffer for name (including SR extensions)!
uint8_t extractModeName(uint8_t mode, const char *src, char *dest, uint8_t maxLen)
{
  if (src == JSON_mode_names || src == nullptr) {
    if (mode < strip.getModeCount()) {
      char lineBuffer[256] = { '\0' };
      //strcpy_P(lineBuffer, (const char*)pgm_read_dword(&(WS2812FX::_modeData[mode])));
      strncpy_P(lineBuffer, strip.getModeData(mode), sizeof(lineBuffer)/sizeof(char)-1);
      lineBuffer[sizeof(lineBuffer)/sizeof(char)-1] = '\0'; // terminate string
      size_t len = strlen(lineBuffer);
      size_t j = 0;
      for (; j < maxLen && j < len; j++) {
        if (lineBuffer[j] == '\0' || lineBuffer[j] == '@') break;
        dest[j] = lineBuffer[j];
      }
      dest[j] = 0; // terminate string
      return strlen(dest);
    } else return 0;
  }

  if (src == JSON_palette_names && mode > (GRADIENT_PALETTE_COUNT + 13)) {
    snprintf_P(dest, maxLen, PSTR("~ Custom %d ~"), 255-mode);
    dest[maxLen-1] = '\0';
    return strlen(dest);
  }

  uint8_t qComma = 0;
  bool insideQuotes = false;
  uint8_t printedChars = 0;
  char singleJsonSymbol;
  size_t len = strlen_P(src);

  // Find the mode name in JSON
  for (size_t i = 0; i < len; i++) {
    singleJsonSymbol = pgm_read_byte_near(src + i);
    if (singleJsonSymbol == '\0') break;
    if (singleJsonSymbol == '@' && insideQuotes && qComma == mode) break; //stop when SR extension encountered
    switch (singleJsonSymbol) {
      case '"':
        insideQuotes = !insideQuotes;
        break;
      case '[':
      case ']':
        break;
      case ',':
        if (!insideQuotes) qComma++;
      default:
        if (!insideQuotes || (qComma != mode)) break;
        dest[printedChars++] = singleJsonSymbol;
    }
    if ((qComma > mode) || (printedChars >= maxLen)) break;
  }
  dest[printedChars] = '\0';
  return strlen(dest);
}


// extracts effect slider data (1st group after @)
uint8_t extractModeSlider(uint8_t mode, uint8_t slider, char *dest, uint8_t maxLen, uint8_t *var)
{
  dest[0] = '\0'; // start by clearing buffer

  if (mode < strip.getModeCount()) {
    String lineBuffer = FPSTR(strip.getModeData(mode));
    if (lineBuffer.length() > 0) {
      int16_t start = lineBuffer.indexOf('@');
      int16_t stop  = lineBuffer.indexOf(';', start);
      if (start>0 && stop>0) {
        String names = lineBuffer.substring(start, stop); // include @
        int16_t nameBegin = 1, nameEnd, nameDefault;
        if (slider < 10) {
          for (size_t i=0; i<=slider; i++) {
            const char *tmpstr;
            dest[0] = '\0'; //clear dest buffer
            if (nameBegin == 0) break; // there are no more names
            nameEnd = names.indexOf(',', nameBegin);
            if (i == slider) {
              nameDefault = names.indexOf('=', nameBegin); // find default value
              if (nameDefault > 0 && var && ((nameEnd>0 && nameDefault<nameEnd) || nameEnd<0)) {
                *var = (uint8_t)atoi(names.substring(nameDefault+1).c_str());
              }
              if (names.charAt(nameBegin) == '!') {
                switch (slider) {
                  case  0: tmpstr = PSTR("FX Speed");     break;
                  case  1: tmpstr = PSTR("FX Intensity"); break;
                  case  2: tmpstr = PSTR("FX Custom 1");  break;
                  case  3: tmpstr = PSTR("FX Custom 2");  break;
                  case  4: tmpstr = PSTR("FX Custom 3");  break;
                  default: tmpstr = PSTR("FX Custom");    break;
                }
                strncpy_P(dest, tmpstr, maxLen); // copy the name into buffer (replacing previous)
                dest[maxLen-1] = '\0';
              } else {
                // WLEDMM bugfix for WLED-MM #272
                // names.substring(...).c_str() returns a pointer to a temporary; it’s invalid by the next statement. Added result buffer "sub" to avoid use-after-free
                String sub = (nameEnd<0) ? names.substring(nameBegin) : names.substring(nameBegin, nameEnd); // special handling in case we did not find "," (last name)
                strlcpy(dest, sub.c_str(), maxLen); // copy the name into buffer (replacing previous)
			  }
            }
            nameBegin = nameEnd+1; // next name (if "," is not found it will be 0)
          } // next slider
        } else if (slider == 255) {
          // palette
          strlcpy(dest, "pal", maxLen);
          names = lineBuffer.substring(stop+1); // stop has index of color slot names
          nameBegin = names.indexOf(';'); // look for palette
          if (nameBegin >= 0) {
            nameEnd = names.indexOf(';', nameBegin+1);
            if (!isdigit(names[nameBegin+1])) nameBegin = names.indexOf('=', nameBegin+1); // look for default value
            if (nameEnd >= 0 && nameBegin > nameEnd) nameBegin = -1;
            if (nameBegin >= 0 && var) {
              *var = (uint8_t)atoi(names.substring(nameBegin+1).c_str());
            }
          }
        }
        // we have slider name (including default value) in the dest buffer
        for (size_t i=0; i<strlen(dest); i++) if (dest[i]=='=') { dest[i]='\0'; break; } // truncate default value

      } else {
        // defaults to just speed and intensity since there is no slider data
        switch (slider) {
          case 0:  strncpy_P(dest, PSTR("FX Speed"), maxLen); break;
          case 1:  strncpy_P(dest, PSTR("FX Intensity"), maxLen); break;
        }
        dest[maxLen] = '\0'; // strncpy does not necessarily null terminate string
      }
    }
    return strlen(dest);
  }
  return 0;
}


// extracts mode parameter defaults from last section of mode data (e.g. "Juggle@!,Trail;!,!,;!;sx=16,ix=240,1d")
int16_t extractModeDefaults(uint8_t mode, const char *segVar)
{
  if (mode < strip.getModeCount()) {
    char lineBuffer[256] = { '\0' };
    strncpy_P(lineBuffer, strip.getModeData(mode), sizeof(lineBuffer)/sizeof(char)-1);
    lineBuffer[sizeof(lineBuffer)/sizeof(char)-1] = '\0'; // terminate string
    if (lineBuffer[0] != 0) {
      char* startPtr = strrchr(lineBuffer, ';'); // last ";" in FX data
      if (!startPtr) return -1;

      char* stopPtr = strstr(startPtr, segVar);
      if (!stopPtr) return -1;

      stopPtr += strlen(segVar) +1; // skip "="
      return atoi(stopPtr);
    }
  }
  return -1;
}


void checkSettingsPIN(const char* pin) {
  if (!pin) return;
  if (!correctPIN && millis() - lastEditTime < PIN_RETRY_COOLDOWN) return; // guard against PIN brute force
  bool correctBefore = correctPIN;
  correctPIN = (strlen(settingsPIN) == 0 || strncmp(settingsPIN, pin, 4) == 0);
  if (correctBefore != correctPIN) createEditHandler(correctPIN);
  lastEditTime = millis();
}


uint16_t crc16(const unsigned char* data_p, size_t length) {
  uint8_t x;
  uint16_t crc = 0xFFFF;
  if (!length) return 0x1D0F;
  while (length--) {
    x = crc >> 8 ^ *data_p++;
    x ^= x>>4;
    crc = (crc << 8) ^ ((uint16_t)(x << 12)) ^ ((uint16_t)(x <<5)) ^ ((uint16_t)x);
  }
  return crc;
}

// fastled beatsin: 1:1 replacements to remove the use of fastled sin16()
// Generates a 16-bit sine wave at a given BPM that oscillates within a given range. see fastled for details.
uint16_t beatsin88_t(accum88 beats_per_minute_88, uint16_t lowest, uint16_t highest, uint32_t timebase, uint16_t phase_offset)
{
    uint16_t beat = beat88( beats_per_minute_88, timebase);
    uint16_t beatsin (sin16_t( beat + phase_offset) + 32768);
    uint16_t rangewidth = highest - lowest;
    uint16_t scaledbeat = scale16( beatsin, rangewidth);
    uint16_t result = lowest + scaledbeat;
    return result;
}

// Generates a 16-bit sine wave at a given BPM that oscillates within a given range. see fastled for details.
uint16_t beatsin16_t(accum88 beats_per_minute, uint16_t lowest, uint16_t highest, uint32_t timebase, uint16_t phase_offset)
{
    uint16_t beat = beat16( beats_per_minute, timebase);
    uint16_t beatsin = (sin16_t( beat + phase_offset) + 32768);
    uint16_t rangewidth = highest - lowest;
    uint16_t scaledbeat = scale16( beatsin, rangewidth);
    uint16_t result = lowest + scaledbeat;
    return result;
}

// Generates an 8-bit sine wave at a given BPM that oscillates within a given range. see fastled for details.
uint8_t beatsin8_t(accum88 beats_per_minute, uint8_t lowest, uint8_t highest, uint32_t timebase, uint8_t phase_offset)
{
    uint8_t beat = beat8( beats_per_minute, timebase);
    uint8_t beatsin = sin8_t( beat + phase_offset);
    uint8_t rangewidth = highest - lowest;
    uint8_t scaledbeat = scale8( beatsin, rangewidth);
    uint8_t result = lowest + scaledbeat;
    return result;
}

///////////////////////////////////////////////////////////////////////////////
// Begin simulateSound (to enable audio enhanced effects to display something)
///////////////////////////////////////////////////////////////////////////////
// Currently 4 types defined, to be fine tuned and new types added
// (only 2 used as stored in 1 bit in segment options, consider switching to a single global simulation type)
typedef enum UM_SoundSimulations {
  UMS_BeatSin = 0,
  UMS_WeWillRockYou,
  UMS_10_13,
  UMS_14_3
} um_soundSimulations_t;

um_data_t* simulateSound(uint8_t simulationId)
{
  static uint8_t samplePeak;
  static float   FFT_MajorPeak;
  static uint8_t maxVol;
  static uint8_t binNum;

  static float    volumeSmth;
  static uint16_t volumeRaw;
  static float    my_magnitude;
  static uint16_t zeroCrossingCount = 0; // number of zero crossings in the current batch of 512 samples

  //arrays
  uint8_t *fftResult;

  static um_data_t* um_data = nullptr;

  if (!um_data) {
    //claim storage for arrays
    fftResult = (uint8_t *)malloc(sizeof(uint8_t) * 16);

    // initialize um_data pointer structure
    // NOTE!!!
    // This may change as AudioReactive usermod may change
    um_data = new um_data_t;
    um_data->u_size = 12;
    um_data->u_type = new um_types_t[um_data->u_size];
    um_data->u_data = new void*[um_data->u_size];
    um_data->u_data[0] = &volumeSmth;
    um_data->u_data[1] = &volumeRaw;
    um_data->u_data[2] = fftResult;
    um_data->u_data[3] = &samplePeak;
    um_data->u_data[4] = &FFT_MajorPeak;
    um_data->u_data[5] = &my_magnitude;
    um_data->u_data[6] = &maxVol;
    um_data->u_data[7] = &binNum;
    um_data->u_data[8]  = &FFT_MajorPeak; // dummy (FFT Peak smoothed)
    um_data->u_data[9]  = &volumeSmth;    // dummy (soundPressure)
    um_data->u_data[10] = &volumeSmth;    // dummy (agcSensitivity)
    um_data->u_data[11] = &zeroCrossingCount;
  } else {
    // get arrays from um_data
    fftResult =  (uint8_t*)um_data->u_data[2];
  }

  uint32_t ms = millis();

  switch (simulationId) {
    default:
    case UMS_BeatSin:
      for (int i = 0; i<16; i++)
        fftResult[i] = beatsin8_t(120 / (i+1), 0, 255);
        // fftResult[i] = (beatsin8_t(120, 0, 255) + (256/16 * i)) % 256;
        volumeSmth = fftResult[8];
      break;
    case UMS_WeWillRockYou:
      if (ms%2000 < 200) {
        volumeSmth = random8(255);
        for (int i = 0; i<5; i++)
          fftResult[i] = random8(255);
      }
      else if (ms%2000 < 400) {
        volumeSmth = 0;
        for (int i = 0; i<16; i++)
          fftResult[i] = 0;
      }
      else if (ms%2000 < 600) {
        volumeSmth = random8(255);
        for (int i = 5; i<11; i++)
          fftResult[i] = random8(255);
      }
      else if (ms%2000 < 800) {
        volumeSmth = 0;
        for (int i = 0; i<16; i++)
          fftResult[i] = 0;
      }
      else if (ms%2000 < 1000) {
        volumeSmth = random8(255);
        for (int i = 11; i<16; i++)
          fftResult[i] = random8(255);
      }
      else {
        volumeSmth = 0;
        for (int i = 0; i<16; i++)
          fftResult[i] = 0;
      }
      break;
    case UMS_10_13:
      for (int i = 0; i<16; i++)
        fftResult[i] = inoise8(beatsin8_t(90 / (i+1), 0, 200)*15 + (ms>>10), ms>>3);
        volumeSmth = fftResult[8];
      break;
    case UMS_14_3:
      for (int i = 0; i<16; i++)
        fftResult[i] = inoise8(beatsin8_t(120 / (i+1), 10, 30)*10 + (ms>>14), ms>>3);
      volumeSmth = fftResult[8];
      break;
  }

  samplePeak    = random8() > 250;
  FFT_MajorPeak = 21 + (volumeSmth*volumeSmth) / 8.0f; // walk thru full range of 21hz...8200hz
  maxVol        = 31;  // this gets feedback fro UI
  binNum        = 8;   // this gets feedback fro UI
  volumeRaw = volumeSmth;
  my_magnitude = 10000.0f / 8.0f; //no idea if 10000 is a good value for FFT_Magnitude ???
  if (volumeSmth < 1 ) my_magnitude = 0.001f;             // noise gate closed - mute
  zeroCrossingCount = floorf(FFT_MajorPeak / 36.0f); // 9Khz max frequency => 255 zero crossings

  return um_data;
}

//WLEDMM enumerateLedmaps moved to FX_fcn.cpp

//WLEDMM netmindz ar palette
CRGB getCRGBForBand(int x, uint8_t *fftResult, int pal) { 
  CRGB value;
  CHSV hsv;
  if(pal == 71) { // bit hacky to use palette id here, but don't want to litter the code with lots of different methods. TODO: add enum for palette creation type
    if(x == 1) {
      value = CRGB(fftResult[10]/2, fftResult[4]/2, fftResult[0]/2);
    }
    else if(x == 255) {
      value = CRGB(fftResult[10]/2, fftResult[0]/2, fftResult[4]/2);
    } 
    else {
      value = CRGB(fftResult[0]/2, fftResult[4]/2, fftResult[10]/2);
    } 
  }
  else if(pal == 72) {
    int b = map(x, 1, 255, 0, 10); // convert palette position to lower half of freq band
    hsv = CHSV(fftResult[b], 255, map(fftResult[b], 0, 255, 30, 255));  // pick hue
    hsv2rgb_rainbow(hsv, value);  // convert to R,G,B
  }
  else if(pal == 73) {
    int b = map(x, 0, 255, 0, 8); // convert palette position to lower half of freq band
    hsv = CHSV(uint8_t(fftResult[b]), 255, x);
    hsv2rgb_rainbow(hsv, value);  // convert to R,G,B
  }

  return value;
}

/*
 * Returns a new, random color wheel index with a minimum distance of 42 from pos.
 */
uint8_t get_random_wheel_index(uint8_t pos) {
  uint8_t r = 0, x = 0, y = 0, d = 0;
  while (d < 42) {
    r = random8();
    x = abs(pos - r);
    y = 255 - x;
    d = MIN(x, y);
  }
  return r;
}

// WLEDMM extended "trim string" function to support enumerateLedmaps
// The function takes char* as input, and removes all leading and trailing "decorations" like spaces, tabs, line endings, quotes, colons
// The conversion is "in place" (destructive).
// example: cleanUpName("\t \"Ring241x 60/9 squeeze \" ,\r") returns "Ring241x 60/9 squeeze"
// 
// Null pointer and zero size "C strings" are handled correctly.
// Will not work with flash strings. Unicode encoded multi-byte char strings may get corrupted.
//
static const char *unwantedChars = "\r\n\t\b ,;:\"\'`´\\"; // list of chars to delete
//
char *cleanUpName(char *in) {
  if (nullptr == in) return(in);
  size_t len = strlen(in);
  if (len == 0) return(in);

  // delete trailing garbage
  while ((len > 0) && (strchr(unwantedChars, in[len-1]) != nullptr)) {
    in[len-1] = '\0'; // deletes last char
    len--;
  }
  // delete leading garbage
  while ((len > 0) && (strchr(unwantedChars, in[0]) != nullptr)) {
    (void) memmove(in, in+1, len); // shifts string left by one
    len--;
  }
  
  return(in);
}

// 32 bit hardware random number generator, inlining uses more code, use hw_random16() if speed is critical (see fcn_declare.h)
uint32_t hw_random(uint32_t upperlimit) {
  uint32_t rnd = hw_random();
  uint64_t scaled = uint64_t(rnd) * uint64_t(upperlimit);
  return scaled >> 32;
}

int32_t hw_random(int32_t lowerlimit, int32_t upperlimit) {
  if(lowerlimit >= upperlimit) {
    return lowerlimit;
  }
  uint32_t diff = upperlimit - lowerlimit;
  return hw_random(diff) + lowerlimit;
}

// Platform-agnostic SHA1 computation from String input
String computeSHA1(const String& input) {
  #ifdef ESP8266
    return sha1(input); // ESP8266 has built-in sha1() function
  #else
    // ESP32: Compute SHA1 hash using mbedtls
    unsigned char shaResult[20]; // SHA1 produces 20 bytes
    mbedtls_sha1_context ctx;

    mbedtls_sha1_init(&ctx);
    mbedtls_sha1_starts_ret(&ctx);
    mbedtls_sha1_update_ret(&ctx, (const unsigned char*)input.c_str(), input.length());
    mbedtls_sha1_finish_ret(&ctx, shaResult);
    mbedtls_sha1_free(&ctx);

    // Convert to hexadecimal string
    char hexString[41];
    for (int i = 0; i < 20; i++) {
      sprintf(&hexString[i*2], "%02x", shaResult[i]);
    }
    hexString[40] = '\0';

    return String(hexString);
  #endif
}

#ifdef ESP32
static String dump_raw_block(esp_efuse_block_t block)
{
  const int WORDS = 8; // ESP32: 8×32-bit words per block i.e. 256bits
  uint32_t buf[WORDS] = {0};

  const esp_efuse_desc_t d = {
    .efuse_block = block,
    .bit_start = 0,
    .bit_count = WORDS * 32
  };
  const esp_efuse_desc_t* field[2] = { &d, NULL };

  esp_err_t err = esp_efuse_read_field_blob(field, buf, WORDS * 32);
  if (err != ESP_OK) {
    return "";
  }

  String result = "";
  for (const unsigned int i : buf) {
    char line[32];
    sprintf(line, "0x%08X", i);
    result += line;
  }
  return result;
}
#endif


// Generate a device ID based on SHA1 hash of MAC address salted with "WLED"
// Returns: original SHA1 + last 2 chars of double-hashed SHA1 (42 chars total)
String getDeviceId() {
  static String cachedDeviceId = "";
  if (cachedDeviceId.length() > 0) return cachedDeviceId;

  uint8_t mac[6];
  WiFi.macAddress(mac);
  char macStr[18];
  sprintf(macStr, "%02x:%02x:%02x:%02x:%02x:%02x", mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);

  // The device string is deterministic as it needs to be consistent for the same device, even after a full flash erase
  // MAC is salted with other consistent device info to avoid rainbow table attacks.
  // If the MAC address is known by malicious actors, they could precompute SHA1 hashes to impersonate devices,
  // but as WLED developers are just looking at statistics and not authenticating devices, this is acceptable.
  // If the usage data was exfiltrated, you could not easily determine the MAC from the device ID without brute forcing SHA1
#ifdef ESP8266
  String deviceString = String(macStr) + "WLED" + ESP.getFlashChipId();
#else
  String deviceString = String(macStr) + "WLED" + ESP.getChipModel() + ESP.getChipRevision();
  deviceString += dump_raw_block(EFUSE_BLK0);
  deviceString += dump_raw_block(EFUSE_BLK1);
  deviceString += dump_raw_block(EFUSE_BLK2);
  deviceString += dump_raw_block(EFUSE_BLK3);
#endif
  String firstHash = computeSHA1(deviceString);

  // Second hash: SHA1 of the first hash
  String secondHash = computeSHA1(firstHash);

  // Concatenate first hash + last 2 chars of second hash
  cachedDeviceId = firstHash + secondHash.substring(38);

  return cachedDeviceId;
}