#include <Wire.h>
// usare o il SSD1306 o il SSH1106
#include <Adafruit_SSD1306.h>
//#include <Adafruit_SH1106.h>
#include <Adafruit_GFX.h>
// librerie per il WiFi e l'ESP-NOW
//#include <esp_now.h>
//#include <WiFi.h>

// parametri OLED
#define OLED_RESET 4
#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels
// per SSH1106: se nn funziona la risoluzione provare
//#define SH1106_LCDWIDTH 128
//#define SH1106_LCDHEIGHT 64
Adafruit_SSD1306 lcd(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
//Adafruit_SH1106 lcd(OLED_RESET);
byte address = 0x3c;

// parametri MACCHINA A STATI MENU
int state = 0;
boolean changedState = true;
int subState = 1; // parte da PLAY e non da MENU

// parametri monitoraggio BATTERIA
float batteryLevel;

// parametri per il TIMER non bloccante
unsigned long current = 0;
unsigned long dTime = 1000;


// parametri per il ROTARY ENCODER
int encPinA = 19; // CLK pin
int encPinB = 18; // DT pin
int encBtn = 2; // SW pin
int encPinVal;
bool pressedAndReleased;
bool state_SW;

// parametri per il DFPLAYER
int pListCont = 1;
int trackCont = 1;
int globalVol = 15;

// imposto il MAC address del RICEVITORE, nel mio caso 30:C6:F7:1F:B3:0C
uint8_t broadcastAddress[] = {0x30, 0xC6, 0xF7, 0x1F, 0xB3, 0x0C};

// Creo la struttura dati, deve essere UGUALE alla struttura del trasmittente
typedef struct struct_message {
    char cmd[5];
    int p1;
    int p2;
} struct_message;

// Creo un'istanza della struttura dati per poterci memorizzare i dati
struct_message myData;

// Creo una variabile che memorizza il risultato dell'errore INVIO
//esp_err_t result;

// creo la variabile INFO del ricevitore
//esp_now_peer_info_t peerInfo;

// creo la variabile che misura il segnale
//int32_t RSSI;

// funzione che verrà registrata come Callback ad ogni INVIO
/*
void OnDataSent(const uint8_t *mac_addr, esp_now_send_status_t status) {
  Serial.println();
  Serial.print("Last Packet Send Status: ");
  Serial.println(status == ESP_NOW_SEND_SUCCESS ? "Delivery Success" : "Delivery Fail");
}
*/

// immagine della Madonna del Castello
const unsigned char madonna [] = {
  0x00, 0x00, 0x00, 0x01, 0xfe, 0x3f, 0x0d, 0xc7, 0xcf, 0x8f, 0x7f, 0xff, 0xf8, 0x06, 0xcb, 0xff, 
  0x82, 0x00, 0x00, 0x01, 0xff, 0xff, 0x0e, 0x87, 0x83, 0x33, 0xbf, 0xff, 0xfe, 0x01, 0xa7, 0xbf, 
  0x03, 0x00, 0x00, 0x04, 0xbf, 0xff, 0x0f, 0x83, 0x87, 0xf3, 0x9f, 0xff, 0xff, 0x03, 0xca, 0x79, 
  0x02, 0x00, 0x00, 0x0d, 0x1e, 0xef, 0x8f, 0x83, 0xc7, 0x33, 0x9f, 0xff, 0xff, 0x87, 0xb0, 0xf3, 
  0x00, 0x00, 0x00, 0x08, 0x0e, 0x65, 0x83, 0x23, 0xc7, 0x01, 0x1f, 0xff, 0xff, 0xcd, 0x6b, 0xe3, 
  0xc0, 0x00, 0x02, 0x1a, 0x1c, 0x67, 0x03, 0x80, 0xc7, 0x01, 0x1f, 0xff, 0xff, 0xe6, 0xf6, 0xc7, 
  0x00, 0x00, 0x02, 0x39, 0x98, 0x07, 0x83, 0x80, 0xa7, 0x03, 0x1f, 0xff, 0xff, 0xf5, 0xef, 0x1c, 
  0x00, 0x00, 0x02, 0x38, 0xb8, 0x03, 0x83, 0x00, 0xe6, 0x13, 0x1f, 0xff, 0xff, 0xf8, 0xde, 0x38, 
  0x00, 0x00, 0x06, 0x7f, 0xf9, 0x83, 0xc7, 0x88, 0xe6, 0x19, 0x1f, 0xff, 0xff, 0xfc, 0x08, 0x60, 
  0x00, 0x00, 0x08, 0x7f, 0x99, 0x80, 0xe3, 0x90, 0x87, 0xb3, 0x9f, 0xff, 0xff, 0xfe, 0x03, 0xc3, 
  0x00, 0x00, 0x07, 0xfb, 0xc3, 0xc0, 0xe3, 0x21, 0x07, 0x17, 0x1d, 0xff, 0xff, 0xfe, 0x07, 0x8f, 
  0x00, 0x00, 0x07, 0xf9, 0x82, 0x80, 0xe3, 0x99, 0x07, 0x87, 0xbf, 0xff, 0xff, 0xff, 0x0b, 0x1a, 
  0x00, 0x04, 0x86, 0xe4, 0x02, 0x80, 0xe7, 0xc1, 0x0f, 0x87, 0x3f, 0xff, 0xff, 0xff, 0x8e, 0x64, 
  0x00, 0x00, 0x0e, 0x67, 0x83, 0x0c, 0x7f, 0xc0, 0x1f, 0x0e, 0x7f, 0xff, 0xff, 0xff, 0x88, 0xe3, 
  0x00, 0x01, 0x4e, 0x47, 0xc3, 0xc8, 0x73, 0xe0, 0x7c, 0x04, 0xff, 0xff, 0xff, 0xff, 0xc3, 0x6f, 
  0x00, 0x00, 0x0c, 0x01, 0xe3, 0x80, 0x43, 0x83, 0xfc, 0x40, 0xff, 0xff, 0xff, 0xff, 0xe6, 0x1e, 
  0x00, 0x01, 0x0c, 0x00, 0x73, 0xc0, 0x47, 0x80, 0x80, 0x18, 0xff, 0xff, 0xff, 0xff, 0xe4, 0x19, 
  0x00, 0x00, 0x0c, 0xc0, 0x39, 0xe0, 0x05, 0x80, 0x08, 0x38, 0xff, 0xff, 0xff, 0xff, 0xf0, 0x36, 
  0x03, 0x01, 0x0c, 0x80, 0x79, 0xf0, 0x0c, 0x04, 0x0c, 0x10, 0xff, 0xff, 0xff, 0xff, 0xfa, 0xf9, 
  0x01, 0x80, 0x40, 0xc0, 0x39, 0xf8, 0xd0, 0x06, 0x08, 0x00, 0xff, 0xff, 0xff, 0xff, 0xf9, 0x77, 
  0x00, 0x20, 0x61, 0xc0, 0x14, 0xf0, 0x00, 0x00, 0x00, 0x03, 0xff, 0xff, 0xff, 0xff, 0xfc, 0xdc, 
  0x00, 0x00, 0x61, 0xd2, 0x34, 0xf0, 0x01, 0x00, 0x27, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfd, 0x22, 
  0x01, 0x80, 0x41, 0xe0, 0x10, 0xe0, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0x01, 
  0x01, 0x80, 0xe0, 0xe0, 0x11, 0xe0, 0x80, 0xf0, 0x07, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0x07, 
  0x00, 0x01, 0xf0, 0xe0, 0x01, 0x80, 0x80, 0x00, 0x00, 0x3f, 0xff, 0xff, 0xff, 0xff, 0xfe, 0x08, 
  0x00, 0x00, 0x78, 0x68, 0x02, 0x00, 0x00, 0x00, 0x00, 0x0f, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00, 
  0x00, 0x00, 0x0e, 0x34, 0x10, 0x60, 0x00, 0x00, 0x00, 0x06, 0x7f, 0xff, 0xff, 0xff, 0xff, 0x00, 
  0x00, 0x00, 0x0f, 0x72, 0x80, 0x40, 0x00, 0x7f, 0xf8, 0x02, 0x3f, 0xff, 0xff, 0xff, 0xff, 0x00, 
  0x00, 0x30, 0x0f, 0x20, 0x00, 0x0c, 0x03, 0xff, 0xff, 0xc0, 0x1f, 0xff, 0xff, 0xff, 0xff, 0x83, 
  0x00, 0x20, 0x03, 0x9c, 0x10, 0x38, 0x0f, 0xff, 0xff, 0xfc, 0x00, 0x3f, 0xff, 0xff, 0xff, 0x80, 
  0x00, 0x28, 0x12, 0x0c, 0x18, 0xe1, 0xe7, 0xff, 0xff, 0xff, 0x00, 0x1f, 0xff, 0xff, 0xff, 0x80, 
  0x00, 0x22, 0x42, 0x6c, 0x01, 0x87, 0xff, 0xfe, 0x40, 0x7f, 0x80, 0x1f, 0xff, 0xff, 0xff, 0x80, 
  0x00, 0x28, 0x02, 0x38, 0x02, 0x1f, 0xff, 0x10, 0x00, 0x0f, 0xe0, 0x1f, 0xff, 0xff, 0xff, 0xc3, 
  0x00, 0x3c, 0x00, 0x20, 0x0c, 0x7f, 0xe0, 0x00, 0x00, 0x03, 0xf8, 0x1b, 0xff, 0xff, 0xff, 0xc0, 
  0x00, 0x1e, 0x00, 0x00, 0x10, 0xff, 0x00, 0x00, 0x00, 0x01, 0xfc, 0x0f, 0xff, 0xff, 0xff, 0xc3, 
  0x00, 0x0b, 0x00, 0x00, 0x23, 0xfc, 0x00, 0x00, 0x00, 0x00, 0xfe, 0x07, 0xff, 0xff, 0xff, 0xc0, 
  0x00, 0x07, 0xe0, 0x00, 0x43, 0xf8, 0x00, 0x00, 0x00, 0x00, 0x7f, 0x07, 0xff, 0xff, 0xff, 0xc3, 
  0x00, 0x00, 0xe0, 0x00, 0x07, 0xf0, 0x00, 0x00, 0x3f, 0xc0, 0x0f, 0x83, 0xdf, 0xff, 0xff, 0xe1, 
  0x00, 0x00, 0xc0, 0x00, 0x0f, 0x20, 0x00, 0x03, 0xff, 0xfc, 0x1f, 0xc1, 0xff, 0xff, 0xff, 0xc3, 
  0x00, 0x0c, 0x41, 0x80, 0x1e, 0x00, 0x00, 0x0f, 0xc0, 0x07, 0x07, 0xe0, 0x7b, 0xff, 0xff, 0xe0, 
  0x00, 0x0e, 0x00, 0x00, 0x3f, 0x00, 0x00, 0x1e, 0x00, 0x00, 0x43, 0xf0, 0x3f, 0xff, 0xff, 0xe0, 
  0x00, 0x0f, 0xc0, 0x08, 0x3c, 0x00, 0x00, 0x3e, 0x00, 0x00, 0x01, 0xf8, 0x3f, 0xff, 0xff, 0xe0, 
  0x00, 0x0c, 0xe0, 0x20, 0x70, 0x00, 0x00, 0x78, 0x00, 0x00, 0x01, 0xf8, 0x3f, 0xff, 0xff, 0xe0, 
  0x00, 0x06, 0xe0, 0x20, 0xf0, 0x00, 0x00, 0xe0, 0x00, 0x00, 0x00, 0xfc, 0xff, 0xff, 0xff, 0xe1, 
  0x00, 0x06, 0x40, 0x40, 0xe0, 0x00, 0x00, 0xe0, 0x3f, 0x80, 0x00, 0xfc, 0x67, 0xff, 0xff, 0xe0, 
  0x00, 0x0e, 0x43, 0x00, 0xc0, 0x00, 0x00, 0x80, 0xff, 0xe0, 0x00, 0x6e, 0x3f, 0xff, 0xff, 0xf3, 
  0x00, 0x0f, 0x22, 0x00, 0xc0, 0x00, 0x01, 0x91, 0xfe, 0x38, 0x00, 0x2f, 0x0f, 0xff, 0xff, 0xf0, 
  0x00, 0x0c, 0x20, 0x01, 0xc0, 0x00, 0x01, 0xb2, 0x72, 0x10, 0x00, 0x21, 0x8f, 0xff, 0xff, 0xf0, 
  0x00, 0x0a, 0x67, 0x01, 0xc0, 0x00, 0x01, 0xf6, 0x4a, 0x60, 0x00, 0x30, 0xcf, 0xff, 0xff, 0xf0, 
  0x00, 0x0b, 0x4e, 0x01, 0xc3, 0xe0, 0x00, 0xee, 0x6e, 0xc0, 0x00, 0x16, 0x4f, 0xff, 0xff, 0xf0, 
  0x00, 0x09, 0xfe, 0x01, 0x9f, 0xfc, 0x00, 0x9c, 0x3f, 0x00, 0x00, 0x16, 0x2f, 0xff, 0xff, 0xf0, 
  0x00, 0x09, 0xfc, 0x01, 0xff, 0xff, 0x00, 0x1e, 0x1c, 0x00, 0x00, 0x02, 0x23, 0xff, 0xff, 0xf0, 
  0x00, 0x09, 0xf8, 0x01, 0xfc, 0xff, 0x80, 0x0f, 0xf0, 0x00, 0x00, 0x09, 0x13, 0xff, 0xff, 0xf0, 
  0x00, 0x0b, 0xf8, 0x01, 0xd9, 0xc3, 0xc0, 0x07, 0xc0, 0x00, 0x00, 0x09, 0x13, 0xff, 0xff, 0xf0, 
  0x00, 0x0f, 0x78, 0x00, 0xc2, 0x3f, 0xc0, 0x01, 0x00, 0x00, 0x00, 0x08, 0x12, 0x7f, 0xff, 0xf8, 
  0x00, 0x03, 0xe0, 0x00, 0xe4, 0xf3, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x0c, 0x10, 0x7f, 0xff, 0xf8, 
  0x00, 0x01, 0x00, 0x00, 0x69, 0xe0, 0xf0, 0x00, 0x00, 0x00, 0x00, 0x0c, 0x00, 0x7f, 0xff, 0xf8, 
  0x00, 0x03, 0x88, 0x00, 0x73, 0xc0, 0xf0, 0x00, 0x00, 0x00, 0x00, 0x0c, 0x20, 0x7f, 0xff, 0xf8, 
  0x00, 0x0f, 0x80, 0x00, 0x1e, 0xc6, 0xd8, 0x00, 0x00, 0x00, 0x00, 0x0c, 0x10, 0x7f, 0xff, 0xf8, 
  0x00, 0x03, 0x00, 0x00, 0x1c, 0x6f, 0x98, 0x00, 0x00, 0x00, 0x00, 0x0c, 0x02, 0x3f, 0xff, 0xf8, 
  0x00, 0x02, 0x00, 0x00, 0x06, 0x3e, 0x1c, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00, 0x3f, 0xff, 0xf8, 
  0x00, 0x07, 0x00, 0x00, 0x02, 0x1c, 0x1c, 0x00, 0x00, 0x00, 0x00, 0x02, 0x00, 0x1f, 0xff, 0xf9, 
  0x00, 0x07, 0x00, 0x00, 0x00, 0xf2, 0x1c, 0x00, 0x00, 0x00, 0x00, 0x02, 0x00, 0x3f, 0xff, 0xf8, 
  0x00, 0x03, 0x80, 0x00, 0x01, 0x98, 0x1c, 0x00, 0x00, 0x00, 0x00, 0x06, 0x10, 0x1f, 0xff, 0xf8, 
};

void setup() {
  // inizializzo la seriale
  Serial.begin(9600);

  // imposto l'encoder rotativo
  pinMode (encPinA, INPUT);
  pinMode (encPinB, INPUT);
  pinMode(encBtn, INPUT_PULLUP);
  pressedAndReleased = false;

  // inizializzo il protocollo I2C e connetto il device
  Wire.begin();
  Wire.beginTransmission(address);
  byte error = Wire.endTransmission();

  // inizializzo il Diplay SSD1306
  // SSD1306_SWITCHCAPVCC = generate display voltage from 3.3V internally
  if(!lcd.begin(SSD1306_SWITCHCAPVCC, address)) { // Address 0x3D for 128x64
    Serial.println(F("SSD1306 allocation failed"));
    for(;;); // Don't proceed, loop forever
  }
  // pulisco lo schermo
  lcd.setTextColor(SSD1306_WHITE);
  lcd.clearDisplay();

  // per display SSH1106
  //lcd.begin(SH1106_SWITCHCAPVCC, address);  // initialize with the I2C addr 0x3D (for the 128x64)
  //lcd.setTextColor(WHITE);
  //lcd.clearDisplay();

  // stampa splashscreeen madonna
  lcd.drawBitmap(0, 0, madonna, 128, 64, WHITE);
  lcd.display();
  delay(1000);

  // inizializzo il timer per l'avvio
  current = millis();

}

void loop() {
  switch (state) {
    case 0:
      checkConnection();
    break;
    case 10:
      choicePlaylist();
    break;
    case 20:
      choiceTrack();
    break;
    case 30:
      menuPlayStop();
    break;
    case 40:
      menuSetVolume();
    break;
  }
}

void checkConnection(){
  // verifica la comunicazione con la base, se comunica allora passa allo stato successivo
  // altrimenti passa allo stato 99 di errore e servirà spegnere e riaccendere
  // ............ faccio le verifiche e intanto passa il tempo
  // se è passato il tempo necessario ed è connesso passo alla fase successiva

  /*
  // setto il dispositivo come WiFi Station
  WiFi.mode(WIFI_STA);

  // Inizializzo l'ESP-NOW
  if (esp_now_init() != ESP_OK) {
    Serial.println("Error initializing ESP-NOW");
    return;
  }

  // Registro la funzione di CallBack
  esp_now_register_send_cb(OnDataSent);
  
  // Registro il PEER / RICEVITORE
  memcpy(peerInfo.peer_addr, broadcastAddress, 6);
  peerInfo.channel = 0;  
  peerInfo.encrypt = false;
  
  // Associo il PEER alla comunicazione ESP
  if (esp_now_add_peer(&peerInfo) != ESP_OK){
    Serial.println("Failed to add peer");
    return;
  }
  // calcolo il segnale
  RSSI = WiFi.RSSI(i);
  */

  if (changedState) {
    batteryLevel = map(analogRead(33), 0.0f, 4095.0f, 0, 100);
    lcd.clearDisplay();
    lcd.setTextSize(1);
    lcd.setCursor(0,0);
    lcd.print("Device INFO");
    lcd.setCursor(0,24);
    lcd.print("Battery:");
    lcd.setCursor(50, 16);
    lcd.setTextSize(2);
    lcd.print((int)batteryLevel);
    lcd.print("%");
    lcd.setTextSize(1);
    lcd.setCursor(0, 48);
    lcd.print("Signal:");
    lcd.setTextSize(2);
    lcd.setCursor(50, 40);
    //lcd.print(RSSI);
    lcd.display();
    changedState = false;
  }
  if (millis() - current > dTime) {
    state = 10;
    changedState = true;
  }
  
}

void choicePlaylist() {
  // se è appena cambiato lo stato della macchina
  // mostro sul menu il messaggio di scelta
  if (changedState) {
    printPlayListOLED();
    changedState = false;
  }
  else {
    encPinVal = digitalRead(encPinA);
    if (encPinVal == LOW) { // check if knob is rotating
      // if pin A state changed before pin B, rotation is clockwise
      if (digitalRead(encPinB)) {
        if (pListCont < 99) {
          pListCont++;
        }
        else {
          pListCont = 1;
        }

      } else {
        if (pListCont > 1) {
          pListCont--;
        }
        else {
          pListCont = 99;
        }
      }
      printPlayListOLED();
      delay(80);
      
    }

    // check if button is pressed (pin SW)
    if ((digitalRead(encBtn) == LOW) && (pressedAndReleased)) {
      state_SW = !state_SW;
      pressedAndReleased = false;
      // passo allo stato successivo
      state = 20;
      changedState = true;
    } else if ((digitalRead(encBtn) == HIGH) && (!pressedAndReleased)) {
      pressedAndReleased = true;
    }
  }

}

void printPlayListOLED() {
    lcd.clearDisplay();
    lcd.setCursor(0,0);
    lcd.setTextSize(2);
    lcd.print("PlayList:");
    lcd.setTextSize(1);
    lcd.setCursor(0,56);
    lcd.print("Click = OK");
    lcd.setTextSize(2);
    if (pListCont < 10) {
      lcd.setCursor(32, 24);
    }
    else {
      lcd.setCursor(25,24);
    }
    lcd.print("< ");
    lcd.print(pListCont);
    lcd.print(" >");
    lcd.display();
}

void choiceTrack() {
  // se è appena cambiato lo stato della macchina
  // mostro sul menu il messaggio di scelta
  if (changedState) {
    printTrackOLED();
    changedState = false;
  }
  else {
    encPinVal = digitalRead(encPinA);
    if (encPinVal == LOW) { // check if knob is rotating
      // if pin A state changed before pin B, rotation is clockwise
      if (digitalRead(encPinB)) {
        if (trackCont < 99) {
          trackCont++;
        }
        else {
          trackCont = 1;
        }

      } else {
        if (trackCont > 1) {
          trackCont--;
        }
        else {
          trackCont = 99;
        }
      }
      printTrackOLED();
      delay(80);
      
    }

    // check if button is pressed (pin SW)
    if ((digitalRead(encBtn) == LOW) && (pressedAndReleased)) {
      state_SW = !state_SW;
      pressedAndReleased = false;
      // passo allo stato successivo
      state = 30;
      changedState = true;
    } else if ((digitalRead(encBtn) == HIGH) && (!pressedAndReleased)) {
      pressedAndReleased = true;
    }
  }

}

void printTrackOLED() {
    lcd.clearDisplay();
    lcd.setCursor(0,0);
    lcd.setTextSize(2);
    lcd.print("Track n.: ");
    lcd.setTextSize(1);
    lcd.setCursor(0,56);
    lcd.print("Click = OK");
    lcd.setTextSize(2);
    if (trackCont < 10) {
      lcd.setCursor(32, 24);
    }
    else {
      lcd.setCursor(25,24);
    }
    lcd.print("< ");
    lcd.print(trackCont);
    lcd.print(" >");
    lcd.display();
}

void menuPlayStop() {
  // se è appena cambiato lo stato della macchina
  // mostro sul menu il messaggio di scelta
  if (changedState) {
    printMenuOLED();
    changedState = false;
  } else {
    encPinVal = digitalRead(encPinA);
    if (encPinVal == LOW) { // check if knob is rotating
      // if pin A state changed before pin B, rotation is clockwise
      if (digitalRead(encPinB)) {
        if (subState < 5) {
          // destra
          subState++;
        }
        else {
          subState = 0;
        }

      } else {
        // sinistra
        if (subState > 0) {
          subState--;
        }
        else {
          subState = 5;
        }
      }
      printMenuOLED();
      delay(80);
    }

    // check if button is pressed (pin SW)
    if ((digitalRead(encBtn) == LOW) && (pressedAndReleased)) {
      state_SW = !state_SW;
      pressedAndReleased = false;
      // eseguo la funzione in base al SubStato selezionato
      // es: se sono in substato 0 passo al menu principale, substato 1 vado in Play, ecc
      switch (subState) {
        case 0:
          // ritorno al menu di scelta Playlist e Track
          state = 10;
          changedState = true;
        break;
        case 1:
          // mando il segnale di PLAY della PlayList e Track
          strcpy(myData.cmd, "PLAY");
          myData.p1 = pListCont;
          myData.p2 = trackCont;
          // invio il comando tramite WiFi
          //result = esp_now_send(broadcastAddress, (uint8_t *) &myData, sizeof(myData));
        break;
        case 2:
          // mando il segnale di STOP
          strcpy(myData.cmd, "STOP");
          myData.p1 = 0;
          myData.p2 = 0;
          // invio il comando tramite WiFi
          //result = esp_now_send(broadcastAddress, (uint8_t *) &myData, sizeof(myData));
        break;
        case 3:
          // sposto il puntatore alla TRACCIA SUCCESSIVA
          if (trackCont < 99) {
            trackCont++;
          } else {
            trackCont = 1;
          }
          changedState = true;
          // invio il comando di PLAY alla nuova traccia
          strcpy(myData.cmd, "PLAY");
          myData.p1 = pListCont;
          myData.p2 = trackCont;
          // invio il comando tramite WiFi
          //result = esp_now_send(broadcastAddress, (uint8_t *) &myData, sizeof(myData));
        break;
        case 4:
          // sposto il puntatore alla TRACCIA PRECEDENTE
          if (trackCont > 1) {
            trackCont--;
          } else {
            trackCont = 99;
          }
          changedState = true;
          // invio il comando di PLAY alla nuova traccia
          strcpy(myData.cmd, "PLAY");
          myData.p1 = pListCont;
          myData.p2 = trackCont;
          // invio il comando tramite WiFi
          //result = esp_now_send(broadcastAddress, (uint8_t *) &myData, sizeof(myData));
        break;
        case 5:
          // entro nel menu del VOLUME
          state = 40;
          changedState = true;
        break;
      }
    } else if ((digitalRead(encBtn) == HIGH) && (!pressedAndReleased)) {
      pressedAndReleased = true;
    }
  }
}

void printMenuOLED() {
    lcd.clearDisplay();
    lcd.setCursor(0,0);
    lcd.setTextSize(1);
    lcd.print("Playlist: ");
    lcd.print(pListCont);
    lcd.setCursor(0,8);
    lcd.print("Track n.: ");
    lcd.print(trackCont);
    lcd.setTextSize(2);

    // stampo il subMenu corretto in base al valore di Sub State
    switch (subState) {
      case 0:
        lcd.setCursor(15,28);
        lcd.print("< MENU >");
      break;
      case 1:
        lcd.setCursor(15,28);
        lcd.print("< PLAY >");

      break;
      case 2:
        lcd.setCursor(15,28);
        lcd.print("< STOP >");
      break;
      case 3:
        lcd.setCursor(15,28);
        lcd.print("< NEXT >");
      break;
      case 4:
        lcd.setCursor(15,28);
        lcd.print("< PREV >");
      break;
      case 5:
        lcd.setCursor(15,28);
        lcd.print("< VOL. >");
      break;
    }

    lcd.setTextSize(1);
    lcd.setCursor(0,56);
    lcd.print("Click = OK");
    lcd.display();
}

void menuSetVolume() {
  // se è appena cambiato lo stato della macchina
  // mostro sul menu il messaggio di scelta
  if (changedState) {
    printVolumeOLED();
    changedState = false;
  }
  else {
    encPinVal = digitalRead(encPinA);
    if (encPinVal == LOW) { // check if knob is rotating
      // if pin A state changed before pin B, rotation is clockwise
      if (digitalRead(encPinB)) {
        if (globalVol < 30) {
          globalVol += 3;
        }

      } else {
        if (globalVol > 1) {
          globalVol -= 3;
        }

      }

      // invio il comando di VOLUME
      strcpy(myData.cmd, "VOLU");
      myData.p1 = globalVol;
      myData.p2 = 0;
      // invio il comando tramite WiFi
      //result = esp_now_send(broadcastAddress, (uint8_t *) &myData, sizeof(myData));
      printVolumeOLED();
      delay(80);
      
    }

    // check if button is pressed (pin SW)
    if ((digitalRead(encBtn) == LOW) && (pressedAndReleased)) {
      state_SW = !state_SW;
      pressedAndReleased = false;
      // passo allo stato precedente, MENU STOP PLAY
      state = 30;
      changedState = true;
    } else if ((digitalRead(encBtn) == HIGH) && (!pressedAndReleased)) {
      pressedAndReleased = true;
    }
  }

}

void printVolumeOLED() {
    lcd.clearDisplay();
    lcd.setCursor(0,0);
    lcd.setTextSize(2);
    lcd.print("Volume ");
    lcd.print((int)(globalVol / 0.3));
    if (globalVol > 0) {
      lcd.setCursor(0,24);
      lcd.print("<");
    }
    // stampo la barra del volume
    drawProgressbar(20, 24, 80, 16, globalVol / 0.3);

    if (globalVol < 30) {
      lcd.setCursor(110, 24);
      lcd.print(">");
    }

    lcd.setTextSize(1);
    lcd.setCursor(0,56);
    lcd.print("Click = OK");
    lcd.display();
}

void drawProgressbar(int x,int y, int width,int height, int progress)
{
   progress = progress > 100 ? 100 : progress; // set the progress value to 100
   progress = progress < 0 ? 0 :progress; // start the counting to 0-100
   float bar = ((float)(width-1) / 100) * progress;
   lcd.drawRect(x, y, width, height, WHITE);
   lcd.fillRect(x+2, y+2, bar-2 , height-4, WHITE); // initailize the graphics fillRect(int x, int y, int width, int height)
}