#include <cmath>


#define LENGTH 10
#define PHOTOR 34
int values[LENGTH];
int diffs[LENGTH-1];   // diffs is one element shorter than values

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
  pinMode(PHOTOR, INPUT);
  Serial.println(analogRead(PHOTOR));

   

}
  
void loop() {  
  // put your main code here, to run repeatedly:
  for(int i=0; i<LENGTH; i++) {
    values[i] = values[i+1];
  }
  values[LENGTH-1]=1023-analogRead(PHOTOR);

   // Calculate the differences
  for (int i = 1; i < LENGTH; i++) {
    //int prev = (i > 0) ? (i - 1) : LENGTH - 1;
    diffs[i-1] = values[i] - values[i-1];
  }
  double y = diffs[LENGTH-2];
  double mn = mean(diffs, LENGTH-1);
  double std = stdev(diffs, LENGTH - 1);

  // Calculate Z-Score for the current reading 
  double zscore = (y - mn) / std;
  Serial.print(zscore > 1.5);


  analogRead((PHOTOR));
  delay(1000); // this speeds up the simulation
}


double mean(int* arr, int length) {
  double sum = 0;
  for (int i = 0; i < length; i++) {
    sum += arr[i];
  }
  return sum / length;
}

double variance(int* arr, int length) {
  double m = mean(arr, length);
  double sum = 0;
  for (int i = 0; i < length; i++) {
    sum += pow(arr[i] - m, 2);
  }
  return sum / (length - 1);
}

double stdev(int* arr, int length) {
  return sqrt(variance(arr, length));
}