#include <LiquidCrystal.h>

#define menuLength 4
#define pinBtnUp 2
#define pinBtnDwn 3

LiquidCrystal lcd(9,8,7,6,5,4);

bool menuChange = 0;
unsigned menuVal = 0;
unsigned char RxdataCnt = 0;
unsigned long time = 0;
unsigned int counter = 0;
float analogVal; // letura analogico-digitale potenziometro su A0

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);

  pinMode (pinBtnUp, INPUT_PULLUP); // alla push
  pinMode (pinBtnDwn, INPUT_PULLUP); // alla push
  attachInterrupt(digitalPinToInterrupt(pinBtnUp), myISRup, FALLING);
  attachInterrupt(digitalPinToInterrupt(pinBtnDwn), myISRdwn, FALLING);

  lcd.begin(16,2);

  menuChange = 1;
  
}

void loop() {
  // put your main code here, to run repeatedly:
  if (menuChange == 1) {
    changeMenuText();
  }
  updateVal();

  //Serial.print(" INIT LCD ");

}


void myISRup(void) {  // interrupt service routine
  static unsigned long last_interrupt_time = 0;
  unsigned long interrupt_time = millis();

  // Per gestire il bounce del pulsante non accetto azioni per 150ms, 
  // non funziona con i semplici delay all'interno degli interrupt

  if (interrupt_time - last_interrupt_time > 150) {
    if (++menuVal >= menuLength) {
       menuVal = 0;
    }
    menuChange =1;
    counter++;

  }
  last_interrupt_time = interrupt_time;
}

void myISRdwn(void) {  // interrupt service routine
  static unsigned long last_interrupt_time = 0;
  unsigned long interrupt_time = millis();

  // Per gestire il bounce del pulsante non accetto azioni per 150ms, 
  // non funziona con i semplici delay all'interno degli interrupt

  if (interrupt_time - last_interrupt_time > 150) {
    if (--menuVal > menuLength) {
    menuVal = menuLength-1;
    }
    menuChange =1;
    counter++;

  }
  last_interrupt_time = interrupt_time;
}


void changeMenuText(void) { //parte fissa del display alla i-esima posizione
  lcd.clear();
  switch(menuVal) {
    case 0:
      lcd.setCursor(3,0);
      lcd.print("Voltometro");
      lcd.setCursor(15,0);
      lcd.print(menuVal);
      lcd.setCursor(0,1);
      lcd.print("Tensione: ");
      lcd.setCursor(14,1);
      lcd.print("V");
      Serial.print(menuVal, DEC);
      break;
    case 1:
      lcd.setCursor(3,0);
      lcd.print("Cronometro");
      lcd.setCursor(15,0);
      lcd.print(menuVal);
      lcd.setCursor(0,1);
      lcd.print("Up-Time: ");
      Serial.print(menuVal, DEC);
      break;
    case 2:
      lcd.setCursor(1,0);
      lcd.print("Dati Seriale");
      lcd.setCursor(15,0);
      lcd.print(menuVal);
      Serial.print(menuVal, DEC);
      break;
    case 3:
      lcd.setCursor(2,0);
      lcd.print("Contatore");
      lcd.setCursor(15,0);
      lcd.print(menuVal);
      Serial.print(menuVal, DEC);
      break;
  }
  menuChange = 0;
  delay(400);
}

void updateVal(void) { //senza variare il contenuto della schermata, aggiorno i valori variabili rilevati/forniti
  switch(menuVal) {
    case 0:
      lcd.setCursor(10,1);
      analogVal = ((float)analogRead(A0)/1024)*5;
      lcd.print(analogVal);
      break;
    case 1:
      time = millis() / 1000;
      lcd.setCursor(9,1);
      lcd.print(time);
      lcd.print("sec.");
      break;
    case 2:
      char incomingByte;
      if (Serial.available() > 0) {
        incomingByte = Serial.read();
        lcd.setCursor(RxdataCnt++,1);
        lcd.print(incomingByte);
        delay(300);
        if (RxdataCnt >= 16) {
          RxdataCnt = 0;
        }
        lcd.print(" ");
      }
      break;
    case 3:
      lcd.setCursor(0,1);
      lcd.print(counter);
      break;
    
  }
}