#include <Wire.h>
#include <RTClib.h>
#include <LiquidCrystal.h>
#include <Servo.h>

// LCD: RS, E, D4, D5, D6, D7
LiquidCrystal lcd(7, 8, 9, 10, 11, 12);

// RTC module
RTC_DS1307 rtc;

// Servo motor
Servo feederServo;

// Push buttons
const int BUTTON_HOUR = 2;
const int BUTTON_MINUTE = 3;
const int BUTTON_OK = 4;
const int BUTTON_FEED = 5;

// Servo signal pin
const int SERVO_PIN = 6;

// Feeding schedule: default 08:00
int feedHour = 8;
int feedMinute = 0;

bool scheduleConfirmed = false;
int lastFedDate = -1;

// Servo positions
const int CLOSED_ANGLE = 0;
const int OPEN_ANGLE = 90;

// Button debounce variables
const int buttonPins[] = {2, 3, 4, 5};
bool lastReading[4] = {HIGH, HIGH, HIGH, HIGH};
bool stableState[4] = {HIGH, HIGH, HIGH, HIGH};
unsigned long lastChange[4] = {0, 0, 0, 0};

bool buttonPressed(int index) {
  bool reading = digitalRead(buttonPins[index]);

  if (reading != lastReading[index]) {
    lastChange[index] = millis();
    lastReading[index] = reading;
  }

  if (millis() - lastChange[index] > 40) {
    if (reading != stableState[index]) {
      stableState[index] = reading;

      if (stableState[index] == LOW) {
        return true;
      }
    }
  }

  return false;
}

// Dispense food
void feedPet() {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Feeding Pet...");

  feederServo.write(OPEN_ANGLE);
  delay(1000);

  feederServo.write(CLOSED_ANGLE);

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Food Dispensed!");
  delay(1000);
}

// Display current time and schedule
void displayStatus(DateTime now) {
  lcd.setCursor(0, 0);
  lcd.print("Time ");

  if (now.hour() < 10) lcd.print("0");
  lcd.print(now.hour());
  lcd.print(":");

  if (now.minute() < 10) lcd.print("0");
  lcd.print(now.minute());

  lcd.print("       ");

  lcd.setCursor(0, 1);

  if (!scheduleConfirmed) {
    lcd.print("Set ");

    if (feedHour < 10) lcd.print("0");
    lcd.print(feedHour);
    lcd.print(":");

    if (feedMinute < 10) lcd.print("0");
    lcd.print(feedMinute);

    lcd.print(" Press OK");
  } else {
    lcd.print("Feed ");

    if (feedHour < 10) lcd.print("0");
    lcd.print(feedHour);
    lcd.print(":");

    if (feedMinute < 10) lcd.print("0");
    lcd.print(feedMinute);

    lcd.print("       ");
  }
}

void setup() {
  Serial.begin(9600);
  Wire.begin();

  // Initialize standard 16-pin LCD
  lcd.begin(16, 2);
  lcd.clear();
  lcd.print("Pet Feeder");
  lcd.setCursor(0, 1);
  lcd.print("Starting...");

  // Initialize servo
  feederServo.attach(SERVO_PIN);
  feederServo.write(CLOSED_ANGLE);

  // Configure buttons
  for (int i = 0; i < 4; i++) {
    pinMode(buttonPins[i], INPUT_PULLUP);
  }

  delay(1500);

  // Initialize RTC
  if (!rtc.begin()) {
    lcd.clear();
    lcd.print("RTC Not Found!");
    while (true) {
      delay(100);
    }
  }

  // Set RTC if it is not running
  if (!rtc.isrunning()) {
    rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
  }

  lcd.clear();
}

void loop() {
  DateTime now = rtc.now();

  // Button 1: Increase feeding hour
  if (buttonPressed(0)) {
    feedHour = (feedHour + 1) % 24;
    scheduleConfirmed = false;
  }

  // Button 2: Increase feeding minute
  if (buttonPressed(1)) {
    feedMinute = (feedMinute + 1) % 60;
    scheduleConfirmed = false;
  }

  // Button 3: Confirm schedule
  if (buttonPressed(2)) {
    scheduleConfirmed = true;
    lcd.clear();
    lcd.print("Schedule Saved");
    delay(700);
  }

  // Button 4: Manual feeding
  if (buttonPressed(3)) {
    feedPet();
  }

  // Feed once per day at the selected time
  int today = now.year() * 10000
            + now.month() * 100
            + now.day();

  if (scheduleConfirmed &&
      now.hour() == feedHour &&
      now.minute() == feedMinute &&
      lastFedDate != today) {

    feedPet();
    lastFedDate = today;
  }

  displayStatus(now);
  delay(50);
}