#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 20 , 4); 

// Generally, you should use "unsigned long" for variables that hold time
// The value will quickly become too large for an int to store
unsigned long previousMillis = 0;  // will store last time LED was updated
unsigned long currentMillis = 0;


// constants won't change:
const long interval = 1000;  // interval at which to blink (milliseconds)

const int buttonUpPin = 4;  // the number of the pushbutton pin
const int buttonDownPin = 5;  // the number of the pushbutton pin
const int buttonEscPin = 3;  // the number of the pushbutton pin
const int buttonEnterPin = 2;  // the number of the pushbutton pin
const byte ledPin = 13;

int upFlag = 0;
int downFlag = 0;
int escFlag = 0;
int enterFlag = 0;
int menuFlag = 0;
int displayMenuFlag = 0;

int buttonState;            // the current reading from the input pin
int lastButtonState = LOW;  // the previous reading from the input pin

// the following variables are unsigned longs because the time, measured in
// milliseconds, will quickly become a bigger number than can be stored in an int.
unsigned long lastDebounceTime = 0;  // the last time the output pin was toggled
unsigned long debounceDelay = 50; 

void setup()
{
  lcd.init();
  Serial.begin(115200);
  lcd.begin(20, 4);
  pinMode(ledPin, OUTPUT);
  pinMode(buttonUpPin, INPUT_PULLUP);
  pinMode(buttonDownPin, INPUT_PULLUP);
  pinMode(buttonEscPin, INPUT_PULLUP);
  pinMode(buttonEnterPin, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(buttonDownPin), myDown, FALLING);
  attachInterrupt(digitalPinToInterrupt(buttonUpPin), myUp, FALLING);
  attachInterrupt(digitalPinToInterrupt(buttonEscPin), myEsc, FALLING);
  attachInterrupt(digitalPinToInterrupt(buttonEnterPin), myEnter, FALLING);
}

int myTimer(int previous, int interval) {
  unsigned long currentMillis = millis();

  if (currentMillis - previousMillis >= interval) {
    // save the last time you blinked the LED
    previousMillis = currentMillis;
    return 1;
  }
  return 0;
}

void displayTime(int time){
  lcd.setCursor(0, 0);
  lcd.print("     ");
  lcd.setCursor(0, 0);
  lcd.print(time / 1000);
}

void displayMenu(){
  lcd.setCursor(0, 0);
  lcd.print("CHOICE 1");
  lcd.setCursor(0, 1);
  lcd.print("CHOICE 2");
  lcd.setCursor(0, 2);
  lcd.print("CHOICE 3");
  lcd.setCursor(0, 3);
  lcd.print("CHOICE 4");
}


void  displayFlag(){
  lcd.setCursor(0, 0);
  lcd.print("     ");
  lcd.setCursor(0, 0);
  if (upFlag) {
    lcd.print("UP");
    upFlag = 0;
  }
  if (downFlag) {
    lcd.print("DOWN");
    downFlag = 0;
  }
  if (escFlag) {
    lcd.print("ESC");
    menuFlag = 1;
    escFlag = 0;
  }
  if (enterFlag) {
    lcd.print("ENTER");
    enterFlag = 0;
  }
}

void myDown(){
  downFlag = 1;
}

void myUp(){
  upFlag = 1;
}

void myEsc(){
  escFlag = 1;
}

void myEnter(){
  enterFlag = 1;
}

int displayMenu(){
  if 
}

void loop() {
  currentMillis = millis();

  // Check state :
  // on regarde si un flag est checké
  // soit RUN et on est dans un programme
  // soit MENU et on est en train de faire une séléction
  // 
  if (isMenu()){
    displayMenu();
  }
  else if(isRun()){
    runProgram();
  }
  else
  {
    displayError();
  }

  if (menuFlag && !displayMenuFlag) {
    displayMenuFlag = 0;
 }
  // if (digitalRead(buttonDownPin)) {
  //   downFlag = 1;
  //   displayFlag();
  // }
  // if (digitalRead(buttonUpPin)) {
  //   upFlag = 1;
  //   displayFlag();
  // }

  if (upFlag || downFlag || escFlag || enterFlag) {
    displayFlag();
  }
  if (myTimer(previousMillis, interval) && !menuFlag) {
    // if the LED is off turn it on and vice-versa:
      displayTime(currentMillis);
  }
}