#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

// Button pins
#define UP     2
#define DOWN   3
#define LEFT   4
#define RIGHT  5
#define OK     6
#define LED    7

String menuItems[] = {"Timer", "Stop Timer", "WiFi Mode"};
int menuIndex = 0;

enum State { MENU, SET_HOUR, SET_MIN, SET_SEC };
State currentState = MENU;

int hour = 0, minute = 0, second = 0;
unsigned long timerStart = 0;
unsigned long timerDuration = 0;
bool timerRunning = false;
bool showCountdown = true;

unsigned long lastInteraction = 0;
const unsigned long HIDE_INTERVAL = 180000; // 3 minutes

void setup() {
  lcd.init();
  lcd.backlight();

  pinMode(UP, INPUT_PULLUP);
  pinMode(DOWN, INPUT_PULLUP);
  pinMode(LEFT, INPUT_PULLUP);
  pinMode(RIGHT, INPUT_PULLUP);
  pinMode(OK, INPUT_PULLUP);
  pinMode(LED, OUTPUT);

  lcd.setCursor(0, 0);
  lcd.print("LED Menu System");
  delay(1000);
  lcd.clear();
  showMenu();
}

void loop() {
  handleButtons();
  handleTimer();
  handleCountdownDisplay();
}

void handleButtons() {
  if (currentState == MENU) {
    if (digitalRead(UP) == LOW) {
      menuIndex = (menuIndex - 1 + 3) % 3;
      showMenu();
      delay(200);
    }

    if (digitalRead(DOWN) == LOW) {
      menuIndex = (menuIndex + 1) % 3;
      showMenu();
      delay(200);
    }

    if (digitalRead(OK) == LOW) {
      lastInteraction = millis();
      if (menuItems[menuIndex] == "Timer") {
        hour = 0; minute = 0; second = 0;
        currentState = SET_HOUR;
        delay(200);
        showSetTime("Hour", hour);
      } else if (menuItems[menuIndex] == "Stop Timer") {
        digitalWrite(LED, LOW);
        timerRunning = false;
        lcd.clear();
        lcd.setCursor(0, 0);
        lcd.print("Timer Stopped");
        delay(1000);
        showMenu();
      } else if (menuItems[menuIndex] == "WiFi Mode") {
        lcd.clear();
        lcd.setCursor(0, 0);
        lcd.print("WiFi Mode On");
        delay(1000);
        showMenu();
      }
    }
  } else {
    handleSetTime();
  }
}

void showMenu() {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print(">");
  lcd.print(menuItems[menuIndex]);
  currentState = MENU;
}

void handleSetTime() {
  int *currentValue;
  String label;
  State nextState;

  if (currentState == SET_HOUR) {
    currentValue = &hour;
    label = "Hour";
    nextState = SET_MIN;
  } else if (currentState == SET_MIN) {
    currentValue = &minute;
    label = "Minute";
    nextState = SET_SEC;
  } else {
    currentValue = &second;
    label = "Second";
    nextState = MENU;
  }

  if (digitalRead(UP) == LOW) {
    (*currentValue)++;
    showSetTime(label, *currentValue);
    delay(200);
  }

  if (digitalRead(DOWN) == LOW) {
    if (*currentValue > 0) (*currentValue)--;
    showSetTime(label, *currentValue);
    delay(200);
  }

  if (digitalRead(OK) == LOW) {
    delay(200);
    if (currentState == SET_SEC) {
      timerDuration = (unsigned long)hour * 3600000UL +
                      (unsigned long)minute * 60000UL +
                      (unsigned long)second * 1000UL;
      timerStart = millis();
      timerRunning = true;
      digitalWrite(LED, HIGH);
      showCountdown = true;
      lastInteraction = millis();
      showMenu(); // Return to menu
    } else {
      currentState = nextState;
      showSetTime(nextState == SET_MIN ? "Minute" : "Second", *currentValue);
    }
  }
}

void showSetTime(String label, int value) {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Set ");
  lcd.print(label);
  lcd.setCursor(0, 1);
  lcd.print("Value: ");
  lcd.print(value);
  lcd.print("   ");
}

void handleTimer() {
  if (timerRunning && millis() - timerStart >= timerDuration) {
    digitalWrite(LED, LOW);
    timerRunning = false;
    showCountdown = false;
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Timer Done");
    delay(1500);
    showMenu();
  }
}

void handleCountdownDisplay() {
  if (timerRunning && showCountdown) {
    unsigned long remaining = timerDuration - (millis() - timerStart);
    unsigned int rem_h = remaining / 3600000UL;
    unsigned int rem_m = (remaining % 3600000UL) / 60000UL;
    unsigned int rem_s = (remaining % 60000UL) / 1000UL;

    lcd.setCursor(0, 1);
    lcd.print("T:");
    if (rem_h < 10) lcd.print("0");
    lcd.print(rem_h);
    lcd.print(":");
    if (rem_m < 10) lcd.print("0");
    lcd.print(rem_m);
    lcd.print(":");
    if (rem_s < 10) lcd.print("0");
    lcd.print(rem_s);

    if (digitalRead(OK) == LOW) {
      showCountdown = false;
      lcd.setCursor(0, 1);
      lcd.print("                ");
      lastInteraction = millis();
      delay(200);
    }
  }

  // Redisplay countdown after inactivity
  if (!showCountdown && timerRunning && (millis() - lastInteraction > HIDE_INTERVAL)) {
    showCountdown = true;
  }
}