#include <arduinoFFT.h>

const uint16_t samples = 128;          //This value MUST ALWAYS be a power of 2
const float samplingFrequency = 4000;  //Hz, must be less than 10000 due to ADC
unsigned int sampling_period_us;
unsigned long microseconds;

float vReal[samples];
float vImag[samples];

ArduinoFFT<float> FFT = ArduinoFFT<float>(vReal, vImag, samples, samplingFrequency);

const int micPin = A0;



void setup() {
  Serial.begin(115200);
  sampling_period_us = round(1000000 * (1.0 / samplingFrequency));
}

void loop() {
  // Sample signal
  for (int i = 0; i < samples; i++) {
    microseconds = micros();  // Overflows after ~70 min

    vReal[i] = analogRead(micPin);  // Read mic input
    vImag[i] = 0;

    while (micros() - microseconds < sampling_period_us) {
      // wait
    }
  }


intsimmm(vReal, vImag,samples, samplingFrequency);

  // Apply FFT
  FFT.windowing(FFTWindow::Hamming, FFTDirection::Forward);
  FFT.compute(FFTDirection::Forward);
  FFT.complexToMagnitude();
  // Find peak
  double peak = FFT.majorPeak();

  Serial.print("Detected Frequency: ");
  Serial.print(peak);
  Serial.println(" Hz");

  // You can now match the frequency to a guitar string:
  identifyNote(peak);

  delay(500);
}

void identifyNote(double frequency) {
  if (frequency > 75 && frequency < 85) {
    Serial.println("Note: E2 (Low E String)");
  } else if (frequency > 95 && frequency < 105) {
    Serial.println("Note: A2 (A String)");
  } else if (frequency > 125 && frequency < 135) {
    Serial.println("Note: D3 (D String)");
  } else if (frequency > 165 && frequency < 175) {
    Serial.println("Note: G3 (G String)");
  } else if (frequency > 245 && frequency < 255) {
    Serial.println("Note: B3 (B String)");
  } else if (frequency > 325 && frequency < 335) {
    Serial.println("Note: E4 (High E String)");
  } else {
    Serial.println("Note: Unknown");
  }
}

 
void intsimmm(float* vReal, float* vImag, int samples, float samplingFrequency) {

  float freq = 330.0;
  
  for (int i = 0; i < samples; i++) {
    vReal[i] = 512.0 + (511.0 * sin(i * 2.0 * PI * freq / samplingFrequency));
    vImag[i]=0.0;
    // Serial.println(sample[sampleCnt]);
  }
}