// https://github.com/kosme/arduinoFFT/blob/master/Examples/FFT_01/FFT_01.ino

#include <arduinoFFT.h>

/*
These values can be changed in order to evaluate the functions
*/
const uint16_t samples = 64; //This value MUST ALWAYS be a power of 2

const double samplingFrequency = 5000;


const double signalFrequency1 = 500;  // Prima frequenza (Hz)
const double signalFrequency2 = 1200; // Seconda frequenza (Hz)
const uint8_t amplitude1 = 100;       // Ampiezza della prima sinusoide
const uint8_t amplitude2 = 50;        // Ampiezza della seconda sinusoide

/*
These are the input and output vectors
Input vectors receive computed results from FFT
*/
double vReal[samples];
double vImag[samples];

/* Create FFT object */
ArduinoFFT<double> FFT = ArduinoFFT<double>(vReal, vImag, samples, samplingFrequency);

#define SCL_INDEX 0x00
#define SCL_TIME 0x01
#define SCL_FREQUENCY 0x02
#define SCL_PLOT 0x03

void setup()
{
  Serial.begin(115200);
  while(!Serial);
  Serial.println("Ready");
}

void loop()
{
  /* Build raw data */

 double ratio1 = twoPi * signalFrequency1 / samplingFrequency;
 double ratio2 = twoPi * signalFrequency2 / samplingFrequency;


  for (uint16_t i = 0; i < samples; i++)
  {
    vReal[i] = double(amplitude1 * sin(i * ratio1) + amplitude2 * sin(i * ratio2));/* Build data with positive and negative values*/
    vImag[i] = 0.0; //Imaginary part must be zeroed in case of looping to avoid wrong calculations and overflows
  }
  /* Print the results of the simulated sampling according to time */
  Serial.println("Data:");
  PrintVector(vReal, samples, SCL_TIME);
  FFT.windowing(FFTWindow::Hamming, FFTDirection::Forward);	/* Weigh data */
  Serial.println("Weighed data:");
  PrintVector(vReal, samples, SCL_TIME);
  FFT.compute(FFTDirection::Forward); /* Compute FFT */
  Serial.println("Computed Real values:");
  PrintVector(vReal, samples, SCL_INDEX);
  Serial.println("Computed Imaginary values:");
  PrintVector(vImag, samples, SCL_INDEX);
  FFT.complexToMagnitude(); /* Compute magnitudes */
  Serial.println("Computed magnitudes:");
  PrintVector(vReal, (samples >> 1), SCL_FREQUENCY);
  double x = FFT.majorPeak();
  Serial.println(x, 6);
  while(1); /* Run Once */
  // delay(2000); /* Repeat after delay */
}

void PrintVector(double *vData, uint16_t bufferSize, uint8_t scaleType)
{
  for (uint16_t i = 0; i < bufferSize; i++)
  {
    double abscissa;
    /* Print abscissa value */
    switch (scaleType)
    {
      case SCL_INDEX:
        abscissa = (i * 1.0);
	break;
      case SCL_TIME:
        abscissa = ((i * 1.0) / samplingFrequency);
	break;
      case SCL_FREQUENCY:
        abscissa = ((i * 1.0 * samplingFrequency) / samples);
	break;
    }
    Serial.print(abscissa, 6);
    if(scaleType==SCL_FREQUENCY)
      Serial.print("Hz");
    Serial.print(" ");
    Serial.println(vData[i], 4);
  }
  Serial.println();
}