#include <Adafruit_NeoPixel.h>

uint32_t Wheel(byte WheelPos,byte brightness=255);


const int PWM_PIN=5;
const int BTN_PIN=3;
const int PWM_FB =A1;
const int POT_PIN = A0;
const int LED_PIN = 2 ;

int pwm = 10;
int target = 400;  //target voltage for step up : 5V
int hysteresis = 3;

Adafruit_NeoPixel strip = Adafruit_NeoPixel(6, LED_PIN, NEO_GRB + NEO_KHZ800);

void setup(){
  pinMode(PWM_PIN,OUTPUT);
  setPwmFrequency(PWM_PIN, 1);
  analogWrite(PWM_PIN,pwm);
  analogReference(INTERNAL);
  strip.begin();
  strip.show();
  Serial.begin(9600);
  
}

uint16_t counter=0;
uint16_t scaler=20;
void loop(){
  
  // ********************* //
  //  Fin de régulation    //
  // ********************* //
  // rainbow
  int init=0;
  int prescale=0;
  while(digitalRead(BTN_PIN) == LOW){
    regul_tension();
    int pot = analogRead(POT_PIN);  
    rainbow((init+255-(10*pot)>>2)%255);
    if(prescale++==800)
      prescale=0;
      init++;
    delay(200);
  }
  
  uint16_t i;
  for(i=0; i<20; i++)
    delay(500);
    
  // one color
  while(digitalRead(BTN_PIN) == LOW){
    regul_tension();
    int pot = analogRead(POT_PIN);  
    uint16_t i;
    for(i=0; i<strip.numPixels(); i++) {
      strip.setPixelColor(i, Wheel(pot>>2));
    }
    strip.show();
    delay(500);
  }
  
  for(i=0; i<20; i++)
    delay(500);
    
    
  // girophare
  float angle=0;
  while(digitalRead(BTN_PIN) == LOW){
    regul_tension();
    int pot = analogRead(POT_PIN);
    for(i=0; i<strip.numPixels(); i++) {
      float angle_i=(i*180)/strip.numPixels();
      uint8_t b = (uint8_t)(215+40*abs(sin((angle-angle_i)*3.1416/180)));
      strip.setPixelColor(i, Wheel(pot>>2,b));       
    }
    strip.show();
    angle = (angle+1);
    if(angle==180) angle = 0;
    delay(200);
  }
  for(i=0; i<20; i++)
    delay(500);
 
 // lumière blanche   
 while(digitalRead(BTN_PIN) == LOW){
    regul_tension();
    int pot = analogRead(POT_PIN);
    for(i=0; i<strip.numPixels(); i++) {
      strip.setPixelColor(i, strip.Color(pot>>2,pot>>2,pot>>2));       
    }
    strip.show();
    delay(1);
  }
  for(i=0; i<20; i++)
    delay(500);
}

void rainbow(uint16_t j) {
  uint16_t i;
  for(i=0; i<strip.numPixels(); i++) {
    strip.setPixelColor(i, Wheel((255/strip.numPixels()*i+j) % 255));
  }
  strip.show();
}

// Input a value 0 to 255 to get a color value.
// The colours are a transition r - g - b - back to r.
uint32_t Wheel(byte WheelPos,byte b) {
  WheelPos = 255 - WheelPos;
  b=255-b;
  if(b==0) b++;
  if(WheelPos < 85) {
   return strip.Color((255 - WheelPos * 3)/b, 0, (WheelPos * 3)/b);
  } else if(WheelPos < 170) {
    WheelPos -= 85;
   return strip.Color(0, (WheelPos * 3)/b, (255 - WheelPos * 3)/b);
  } else {
   WheelPos -= 170;
   return strip.Color((WheelPos * 3)/b, (255 - WheelPos * 3)/b, 0);
  }
}

// ********************* //
// Régulation de tension //
// ********************* //
void regul_tension(){
  int value = analogRead(PWM_FB);
  if(value>target+hysteresis){
    if(pwm>0)
      pwm--;
  }
  else if(value<target-hysteresis){
    if(pwm<70)
      pwm++;
  }
  analogWrite(PWM_PIN,pwm);
}


void setPwmFrequency(int pin, int divisor) {
  byte mode;
  if(pin == 5 || pin == 6 || pin == 9 || pin == 10) {
    switch(divisor) {
      case 1: mode = 0x01; break;
      case 8: mode = 0x02; break;
      case 64: mode = 0x03; break;
      case 256: mode = 0x04; break;
      case 1024: mode = 0x05; break;
      default: return;
    }
    if(pin == 5 || pin == 6) {
      TCCR0B = TCCR0B & 0b11111000 | mode;
    } else {
      TCCR1B = TCCR1B & 0b11111000 | mode;
    }
  } else if(pin == 3 || pin == 11) {
    switch(divisor) {
      case 1: mode = 0x01; break;
      case 8: mode = 0x02; break;
      case 32: mode = 0x03; break;
      case 64: mode = 0x04; break;
      case 128: mode = 0x05; break;
      case 256: mode = 0x06; break;
      case 1024: mode = 0x7; break;
      default: return;
    }
    TCCR2B = TCCR2B & 0b11111000 | mode;
  }
}