#include <Wire.h>
#include <arduinoFFT.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

// --- Configuraciones de Hardware ---
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET -1
#define OLED_ADDR 0x3C

// --- Pines de entrada de Audio para ESP32 ---
#define audioInL 36 // Canal Izquierdo (ADC1_CH0)
#define audioInR 39 // Canal Derecho (ADC1_CH3)

// --- Parámetros de la FFT ---
#define SAMPLES 128
#define SAMPLING_FREQUENCY 40000.0              // <<< CORRECCIÓN 1: Especificar como double/float
#define AMPLITUDE 1500                          

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

// --- Arrays para la FFT ---
double vRealL[SAMPLES], vImagL[SAMPLES];
double vRealR[SAMPLES], vImagR[SAMPLES];

// --- Crear objetos FFT para cada canal ---
// <<< CORRECCIÓN 2: Especificar explícitamente el tipo <double> en la declaración
ArduinoFFT<double> fftL = ArduinoFFT<double>(vRealL, vImagL, SAMPLES, SAMPLING_FREQUENCY);
ArduinoFFT<double> fftR = ArduinoFFT<double>(vRealR, vImagR, SAMPLES, SAMPLING_FREQUENCY);


void setup() {
  display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDR);
  display.clearDisplay();
  display.display();
}

void loop() {
  // --- 1. Muestreo de los dos canales de audio ---
  for (int i = 0; i < SAMPLES; i++) {
    vRealL[i] = (double)analogRead(audioInL) - 2048.0; 
    vImagL[i] = 0.0;

    vRealR[i] = (double)analogRead(audioInR) - 2048.0;
    vImagR[i] = 0.0;
  }

  // --- 2. Procesamiento FFT para ambos canales ---
  fftL.windowing(FFT_WIN_TYP_HAMMING, FFT_FORWARD);
  fftL.compute(FFT_FORWARD);
  fftL.complexToMagnitude();

  fftR.windowing(FFT_WIN_TYP_HAMMING, FFT_FORWARD);
  fftR.compute(FFT_FORWARD);
  fftR.complexToMagnitude();

  // --- 3. Visualización en la Pantalla OLED ---
  display.clearDisplay();

  int displayBins = SAMPLES / 2;
  int barHeight = (SCREEN_HEIGHT / 2) - 1;

  for (int i = 2; i < displayBins; i++) {
    int magnitudeL = vRealL[i] / AMPLITUDE;
    magnitudeL = constrain(magnitudeL, 0, barHeight);
    display.drawLine(i * 2, barHeight, i * 2, barHeight - magnitudeL, WHITE);

    int magnitudeR = vRealR[i] / AMPLITUDE;
    magnitudeR = constrain(magnitudeR, 0, barHeight);
    display.drawLine(i * 2, barHeight + 1, i * 2, barHeight + 1 + magnitudeR, WHITE);
  }

  display.display();
}