/*
  ESP32 Sound Board “Brain” — ESP-IDF I2S version (no <I2S.h> dependency)
  - 12 debounced buttons triggering short audio beeps via I2S amp (e.g., MAX98357A)
  - 16x2 I2C LCD status display
  - Notes:
    * Buttons to GND (active LOW). Use external 10k pull-ups on GPIO35/36/39.
    * Bootstrap pins (0/2/12/15) must idle at safe levels; don’t hold buttons during reset.
    * LCD moved to SDA=22, SCL=23 (since your map uses GPIO21 for a button).
*/

#include <Arduino.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include "driver/i2s.h"
#include <math.h>

// ------------------------- User-configurable: Verify these -------------------------
const int BUTTON_PINS[12] = {
  12,  // Button 1
  13,  // Button 2
  15,  // Button 3  (BOOT-strap pin)
  2,   // Button 4  (assumed; BOOT-strap pin)
  17,  // Button 5
  21,  // Button 6  (default I2C SDA; we're moving I2C off this to 22/23)
  35,  // Button 7  (input-only; needs external pull-up)
  36,  // Button 8  (input-only; needs external pull-up)
  39,  // Button 9  (input-only; needs external pull-up)
  0,   // Button 10 (assumed; BOOT-strap pin)
  3,   // Button 11 (UART0 RX)
  4    // Button 12
};

// I2C pins and LCD
const int I2C_SDA = 22;
const int I2C_SCL = 23;
const uint8_t LCD_ADDR = 0x27;  // try 0x3F if blank
LiquidCrystal_I2C lcd(LCD_ADDR, 16, 2);

// I2S pins for MAX98357A-style amplifier
struct {
  int BCLK = 26;  // Bit clock
  int LRCK = 25;  // Word select (LRCLK/WS)
  int DIN  = 27;  // Data out to amp
} I2S_PINS;

// Audio settings
const uint32_t SAMPLE_RATE = 22050;
const int BITS_PER_SAMPLE = 16;
const int BEEP_MS = 120;
const float BEEP_FREQS[12] = {
  440.0, 466.16, 493.88, 523.25,
  554.37, 587.33, 622.25, 659.25,
  698.46, 739.99, 783.99, 830.61
};

// Debounce
const unsigned long DEBOUNCE_MS = 25;

// ------------------------- Internals -------------------------
unsigned long lastChange[12] = {0};
bool lastStableState[12];
bool lastReadState[12];

bool isInputOnly(int pin) { return (pin >= 34 && pin <= 39); }

// ------------------------- I2S (ESP-IDF driver) -------------------------
bool setupI2S() {
  i2s_config_t i2s_config = {
    .mode = (i2s_mode_t)(I2S_MODE_MASTER | I2S_MODE_TX),
    .sample_rate = SAMPLE_RATE,
    .bits_per_sample = I2S_BITS_PER_SAMPLE_16BIT,
    .channel_format = I2S_CHANNEL_FMT_RIGHT_LEFT,
#if ESP_IDF_VERSION >= ESP_IDF_VERSION_VAL(4, 0, 0)
    .communication_format = I2S_COMM_FORMAT_STAND_I2S,
#else
    .communication_format = (i2s_comm_format_t)(I2S_COMM_FORMAT_I2S | I2S_COMM_FORMAT_I2S_MSB),
#endif
    .intr_alloc_flags = 0,
    .dma_buf_count = 6,
    .dma_buf_len = 256,
    .use_apll = false,
    .tx_desc_auto_clear = true,
    .fixed_mclk = 0
  };

  i2s_pin_config_t pin_config = {
    .bck_io_num = I2S_PINS.BCLK,
    .ws_io_num = I2S_PINS.LRCK,
    .data_out_num = I2S_PINS.DIN,
    .data_in_num = I2S_PIN_NO_CHANGE
  };

  if (i2s_driver_install(I2S_NUM_0, &i2s_config, 0, NULL) != ESP_OK) return false;
  if (i2s_set_pin(I2S_NUM_0, &pin_config) != ESP_OK) return false;
  if (i2s_set_clk(I2S_NUM_0, SAMPLE_RATE, I2S_BITS_PER_SAMPLE_16BIT, I2S_CHANNEL_STEREO) != ESP_OK) return false;
  return true;
}

// Generate and play a short sine beep on both channels
void playBeep(float freqHz, int ms) {
  const uint32_t totalSamples = (uint32_t)((SAMPLE_RATE * ms) / 1000.0f);
  const float twoPiFOverFs = 2.0f * 3.14159265f * freqHz / SAMPLE_RATE;

  for (uint32_t n = 0; n < totalSamples; n++) {
    float s = sinf(twoPiFOverFs * n);
    int16_t sample = (int16_t)(s * 3000);  // modest amplitude
    // Stereo frame: Left then Right (16-bit each)
    size_t bw;
    i2s_write(I2S_NUM_0, (const void*)&sample, sizeof(sample), &bw, portMAX_DELAY);
    i2s_write(I2S_NUM_0, (const void*)&sample, sizeof(sample), &bw, portMAX_DELAY);
  }
}

// ------------------------- Buttons/LCD -------------------------
void setupButtons() {
  for (int i = 0; i < 12; i++) {
    int pin = BUTTON_PINS[i];
    if (isInputOnly(pin)) {
      pinMode(pin, INPUT); // needs external pull-up
    } else {
      pinMode(pin, INPUT_PULLUP);
    }
    bool r = digitalRead(pin);
    lastStableState[i] = r;
    lastReadState[i]   = r;
    lastChange[i]      = millis();
  }
}

bool edgePressed(int idx, bool newStable) {
  // Active LOW: pressed when HIGH -> LOW
  return (lastStableState[idx] == HIGH && newStable == LOW);
}

void reportButtonOnLCD(int idx) {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Button ");
  lcd.print(idx + 1);
  lcd.print(" pressed");
  lcd.setCursor(0, 1);
  lcd.print("Beep ");
  lcd.print((int)BEEP_FREQS[idx]);
  lcd.print(" Hz");
}

// ------------------------- Arduino lifecycle -------------------------
void setup() {
  Serial.begin(115200);
  delay(100);

  Wire.begin(I2C_SDA, I2C_SCL);
  lcd.init();
  lcd.backlight();
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Sound Board v1");
  lcd.setCursor(0, 1);
  lcd.print("Init...");

  setupButtons();

  if (!setupI2S()) {
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("I2S init failed");
    lcd.setCursor(0, 1);
    lcd.print("Check wiring/pins");
  } else {
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Ready...");
  }
}

void loop() {
  unsigned long now = millis();

  for (int i = 0; i < 12; i++) {
    int pin = BUTTON_PINS[i];
    bool r = digitalRead(pin);

    if (r != lastReadState[i]) {
      lastReadState[i] = r;
      lastChange[i] = now;
    }

    if ((now - lastChange[i]) >= DEBOUNCE_MS) {
      if (r != lastStableState[i]) {
        bool wasPressed = edgePressed(i, r);
        lastStableState[i] = r;
        if (wasPressed) {
          reportButtonOnLCD(i);
          playBeep(BEEP_FREQS[i], BEEP_MS);
          delay(60);
        }
      }
    }
  }
}