// ══ CONFIGURACIÓN — modificar estos valores ══
#include <WiFi.h>
#include <HTTPClient.h>
#include <driver/i2s.h>
#include <ArduinoJson.h>

// ── WiFi ─────────────────────────────────
const char* WIFI_SSID  = "TU_WIFI_SSID";
const char* WIFI_PASS  = "TU_WIFI_PASSWORD";
const char* SERVER_URL = "http://192.168.1.100:5000/translate";

// ── Pines I2S Micrófono INMP441 ──────────
#define MIC_SCK  26   // BCLK
#define MIC_WS   25   // LRCLK
#define MIC_SD   32   // Data IN

// ── Pines I2S Amplificador MAX98357A ─────
#define AMP_BCLK 27   // BCLK
#define AMP_LRC  14   // LRCLK
#define AMP_DIN  13   // Data OUT → DIN amp

// ── UI ───────────────────────────────────
#define BTN_PIN   0    // Botón grabar (PULLUP)
#define LED_RED   2    // Grabando
#define LED_GREEN 4    // Procesando
#define LED_BLUE  5    // Reproduciendo

// ── Audio ────────────────────────────────
#define SAMPLE_RATE     16000
#define MAX_RECORD_SEC  5
#define BUFFER_SAMPLES  (SAMPLE_RATE * MAX_RECORD_SEC)
#define BUFFER_BYTES    (BUFFER_SAMPLES * 2)

// ══ FILTRO DE VOZ — Butterworth paso-banda 300–3400Hz ══
struct BiquadFilter {
  float b0, b1, b2, a1, a2;
  float x1, x2, y1, y2;
};
BiquadFilter hpf, lpf; // High-pass 300Hz + Low-pass 3400Hz

void initVoiceFilter() {
  // ── HPF 300Hz @ 16kHz (Q=0.707 Butterworth) ──
  float w0 = 2*M_PI*300.0f/16000.0f;
  float alpha = sinf(w0)/(2*0.7071f);
  float c = cosf(w0), a0 = 1+alpha;
  hpf.b0 = (1+c)/(2*a0);  hpf.b1 = -(1+c)/a0;
  hpf.b2 = hpf.b0;
  hpf.a1 = -2*c/a0;   hpf.a2 = (1-alpha)/a0;

  // ── LPF 3400Hz @ 16kHz ──
  w0 = 2*M_PI*3400.0f/16000.0f;
  alpha = sinf(w0)/(2*0.7071f);
  c = cosf(w0); a0 = 1+alpha;
  lpf.b0 = (1-c)/(2*a0);  lpf.b1 = (1-c)/a0;
  lpf.b2 = lpf.b0;
  lpf.a1 = -2*c/a0;   lpf.a2 = (1-alpha)/a0;
}

inline float biquad(BiquadFilter& f, float x) {
  float y = f.b0*x + f.b1*f.x1 + f.b2*f.x2
              - f.a1*f.y1 - f.a2*f.y2;
  f.x2=f.x1; f.x1=x; f.y2=f.y1; f.y1=y;
  return y;
}

inline int16_t applyVoiceFilter(int16_t s) {
  float y = biquad(lpf, biquad(hpf, (float)s));
  return (y>32767)?32767:(y<-32768)?-32768:(int16_t)y;
}

// ══ GRABACIÓN con filtro aplicado ══
void recordChunk() {
  int32_t raw[256]; size_t br=0;
  i2s_read(I2S_NUM_0, raw, sizeof(raw), &br, 10);
  int n = br/sizeof(int32_t);
  for(int i=0; i<n && samplesRec<BUFFER_SAMPLES; i++) {
    // INMP441: dato 24b en MSB del int32 → shift para int16
    int16_t s = (int16_t)(raw[i] >> 16);
    audioBuf[samplesRec++] = applyVoiceFilter(s);
  }
}

// ══ REPRODUCIR audio TTS por I2S (MAX98357A) ══
void playAudioStream(const char* audioUrl) {
  HTTPClient http;
  http.begin(audioUrl);
  if(http.GET() != 200) { http.end(); return; }

  WiFiClient* stream = http.getStreamPtr();
  uint8_t skip[44]; int sk=0;           // Saltar WAV header
  while(sk<44) if(stream->available()) skip[sk++]=stream->read();

  int16_t buf[512*2]; // mono → stereo
  int remaining = http.getSize()-44;

  while(remaining>0 && stream->connected()) {
    int16_t mono[256]; int got=0;
    while(got<512 && remaining>0 && stream->available()) {
      mono[got/2] = stream->read() | (stream->read()<<8);
      got+=2; remaining-=2;
    }
    int n=got/2;
    // Duplicar mono → stereo para MAX98357A
    for(int i=0;i<n;i++){buf[i*2]=mono[i];buf[i*2+1]=mono[i];}
    size_t w; i2s_write(I2S_NUM_1, buf, n*4, &w, portMAX_DELAY);
  }
  i2s_zero_dma_buffer(I2S_NUM_1);
  http.end();
}

// ══ LOOP PRINCIPAL ══
void loop() {
  bool btn = (digitalRead(BTN_PIN) == LOW);

  if(btn && !btnWas) {       // Botón presionado
    playBeep(660, 80);
    startRecording();
  }
  if(!btn && btnWas) {       // Botón soltado
    stopRecording();
    playBeep(440, 80);
    digitalWrite(LED_GREEN, HIGH);
    if(sendAndTranslate())    // Enviar al servidor
      blinkLED(LED_GREEN, 3);
    else
      blinkLED(LED_RED, 3);
    digitalWrite(LED_GREEN, LOW);
  }
  btnWas = btn;
  if(isRecording) recordChunk();
  delay(1);
}