#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

const int numOfScreens = 5;
const char* screens[numOfScreens] = {"Time", "Schedule", "Set Time", "Test1", "Test2"};

int currentScreen = 0;

const int numOfInputs = 5;
//          key functions=         up,down, +, -, select
const int inputPins[numOfInputs] = {2, 4, 18, 19, 15};
int inputState[numOfInputs];
int lastInputState[numOfInputs] = {LOW, LOW, LOW, LOW, LOW};
bool inputFlags[numOfInputs] = {LOW, LOW, LOW, LOW, LOW};
long lastDebounceTime[numOfInputs] = {0, 0, 0, 0, 0};
long debounceDelay = 15;

long lastKeyPressTime = 0;
long sleepDelay = 15000; // 15 seconds
bool sleepMode = false;
bool keyPressed = false;

void setup() {
  for (int i = 0; i < numOfInputs; i++) {
    pinMode(inputPins[i], INPUT);
    digitalWrite(inputPins[i], HIGH); // pull-up 20k
  }
  Serial.begin(9600);
  lcd.begin(16, 2);
  lcd.init();
  lcd.backlight();

  handle_screens();
}

void loop() {
  setInputFlags();
  resolveInputFlags();
  sleep();
}

void setInputFlags() {
  for (int i = 0; i < numOfInputs; i++) {
    int reading = digitalRead(inputPins[i]);

    if (reading != lastInputState[i]) {
      lastDebounceTime[i] = millis();
    }

    if ((millis() - lastDebounceTime[i]) > debounceDelay) {
      if (reading != inputState[i]) {
        inputState[i] = reading;
        if (inputState[i] == HIGH) {
          inputFlags[i] = HIGH;
          lastKeyPressTime = millis(); // Update last key press time
        }
      }
    }

    lastInputState[i] = reading;
  }
}

void sleep() {
  unsigned long currentTime = millis();

  if ((currentTime - lastKeyPressTime) > sleepDelay && !sleepMode) {
    Serial.println("Sleeping");
    sleepMode = true;
    keyPressed = false;
    lcd.noBacklight();
  } else if (sleepMode && (currentTime - lastKeyPressTime) < sleepDelay) {
    Serial.println("Wake up");
    sleepMode = false;
    keyPressed = true;
    lcd.backlight();
  }
}

void resolveInputFlags() {
  for (int i = 0; i < numOfInputs; i++) {

    if (inputFlags[i] == HIGH) {
      if (!sleepMode) {
        inputAction(i);
        inputFlags[i] = LOW;
        handle_screens();
      }
      inputFlags[i] = LOW;
    }
  }
}

void inputAction(int input) {
  if (input == 0) {
    if (currentScreen == 0) {
      currentScreen = numOfScreens - 1;
    } else {
      currentScreen--;
    }
  } else if (input == 1) {
    if (currentScreen == numOfScreens - 1) {
      currentScreen = 0;
    } else {
      currentScreen++;
    }
  } else if (input == 2) {

  } else if (input == 3) {

  }
}


void time_screen() {
  lcd.clear();
  lcd.print(currentScreen);
  lcd.setCursor(0, 1);
  lcd.print("time");
}

void schedule_screen() {
  lcd.clear();
  lcd.print(currentScreen);
  lcd.setCursor(0, 1);
  lcd.print("schedule");
}

void error_screen() {
  lcd.clear();
  lcd.print(currentScreen);
  lcd.setCursor(0, 1);
  lcd.print("hello");
}

void printScreen() {
  lcd.clear();
  lcd.print(screens[currentScreen]);
}

void handle_screens() {
  if (currentScreen < 0) {
    currentScreen = numOfScreens - 1;
  } else if (currentScreen >= numOfScreens) {
    currentScreen = 0;
  }

  printScreen();

  switch (currentScreen) {
    case 0:
      Serial.println("Time Screen");
      time_screen();

      break;
    case 1:
      Serial.println("Schedule Screen");
      schedule_screen();
      break;
    case 2:
      Serial.println("scr 3");
      break;
    case 3:
      Serial.println("scr 4");
      break;
    case 4:
      Serial.println("scr 5");
      break;

    default:
      break;
  }
}