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

// Pin definitions
const int menuButtonPin = 2;
const int upButtonPin = 3;
const int downButtonPin = 4;
const int backButtonPin = 5;
const int setButtonPin = 6;
const int relayPin = 7;

// Create LCD and RTC objects
LiquidCrystal_I2C lcd(0x27, 20, 4);
RTC_DS3231 rtc;

struct AlarmEvent {
  uint8_t hour;
  uint8_t minute;
};

AlarmEvent alarms[10];  // Array to store 10 alarm events

int currentMenu = 0;  // 0: Time, 1: Alarm Settings
int selectedAlarm = 0;  // Index of selected alarm event
bool isSettingTime = true;
bool settingHour = true;  // Toggle between hour and minute settings

// Variables to hold the last displayed information
String lastDisplay = "";
int lastAlarm = -1;

// Buzzer control variables
bool buzzerOn = false;
unsigned long buzzerStartTime = 0;
const unsigned long buzzerDuration = 5000;  // Buzzer duration in milliseconds

// Add a new variable to store the alarm duration
unsigned long alarmDuration = 10000; // 10 seconds
unsigned long alarmStartTime = 0;

// Settings menu variables
int menuOption = 0; // Tracks the current selected menu option
int lastMenuOption = -1; // Tracks the last selected menu option to prevent unnecessary redraws
bool inMenu = false; // Tracks if we're in the menu screen
bool inSettings = false; // Tracks if we're in the settings screen

// Variables to track the last button states
bool lastUpButtonState = LOW;
bool lastDownButtonState = LOW;
bool lastMenuButtonState = LOW;
bool lastBackButtonState = LOW;
bool lastSetButtonState = LOW;

byte customChar[] = {
  B10000,
  B11000,
  B11100,
  B11110,
  B11110,
  B11100,
  B11000,
  B10000
};

void setup() {
  pinMode(menuButtonPin, INPUT_PULLUP);
  pinMode(upButtonPin, INPUT_PULLUP);
  pinMode(downButtonPin, INPUT_PULLUP);
  pinMode(backButtonPin, INPUT_PULLUP);
  pinMode(setButtonPin, INPUT_PULLUP);
  pinMode(relayPin, OUTPUT);

  digitalWrite(relayPin, LOW);

  lcd.init();
  lcd.backlight();

  if (!rtc.begin()) {
    lcd.clear();
    lcd.print("RTC not found!");
    while (1);
  }

  // Load alarms from EEPROM
  for (int i = 0; i < 10; i++) {
    alarms[i].hour = EEPROM.read(i * 2);
    alarms[i].minute = EEPROM.read(i * 2 + 1);
  }

  interface(); // Display the initial interface
}

void loop() {
  bool menuButton = digitalRead(menuButtonPin);
  bool upButton = digitalRead(upButtonPin);
  bool downButton = digitalRead(downButtonPin);
  bool backButton = digitalRead(backButtonPin);
  bool setButton = digitalRead(setButtonPin);

  // Handle the main menu button
  if (menuButton == LOW && lastMenuButtonState == HIGH && !inMenu) {
    inMenu = true;
    displayMenu();
  }
  lastMenuButtonState = menuButton;

  if (inMenu && upButton == LOW && lastUpButtonState == HIGH) {
    menuOption = (menuOption > 0) ? menuOption - 1 : 3; // Move up in menu
    displayMenuOptions();
  }
  lastUpButtonState = upButton;

  if (inMenu && downButton == LOW && lastDownButtonState == HIGH) {
    menuOption = (menuOption < 3) ? menuOption + 1 : 0; // Move down in menu
    displayMenuOptions();
  }
  lastDownButtonState = downButton;

  if (inMenu && setButton == LOW && lastSetButtonState == HIGH) {
    inSettings = true;
    executeOption(menuOption);
  }
  lastSetButtonState = setButton;

  if (inMenu && backButton == LOW && lastBackButtonState == HIGH) {
    inMenu = false;
    inSettings = false;
    interface(); // Go back to the main interface
  }
  lastBackButtonState = backButton;

  // Display time and date
  if (!inMenu) {
    DateTime now = rtc.now();
    
    // Title on the 1st line
    lcd.setCursor(0, 0);
    lcd.print(" PISD  BELL  SYSTEM");

    // Date on the 2nd line
    lcd.setCursor(0, 1);
    lcd.print("Date: ");
    lcd.print(formatDate(now));

    // Time on the 3rd line
    lcd.setCursor(0, 2);
    lcd.print("Time: ");
    lcd.print(format12Hour(now.hour()) + ":" + formatTime(now.minute()) + (now.hour() < 12 ? " AM" : " PM"));

    // Note on the 4th line
    lcd.setCursor(0, 3);
    lcd.print("Press M for Settings");
  }
}

void interface() {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("  PISD BELL SYSTEM");
  lcd.setCursor(0, 1);
  lcd.print("Date: ");
  lcd.setCursor(0, 2);
  lcd.print("Time: ");
  lcd.setCursor(0, 3);
  lcd.print("Press M for Settings");
}

void displayMenu() {
  lcd.clear();
  lastMenuOption = -1; // Force a redraw of the menu
  displayMenuOptions();
}

void displayMenuOptions() {
  if (menuOption != lastMenuOption) {
    lcd.clear();
    if (menuOption == 0) {
      pointerOne();
    } else if (menuOption == 1) {
      pointerTwo();
    } else if (menuOption == 2) {
      pointerThree();
    } else if (menuOption == 3) {
      pointerFour();
    }

    lcd.setCursor(1, 0);
    lcd.print("Set Date");
    lcd.setCursor(1, 1);
    lcd.print("Set Time");
    lcd.setCursor(1, 2);
    lcd.print("Adjust Bell");
    lcd.setCursor(1, 3);
    lcd.print("Reset Defaults");

    lastMenuOption = menuOption; // Update lastMenuOption to current
  }
}

void executeOption(int option) {
  lcd.clear();
  switch (option) {
    case 0:
      setDate();
      break;
    case 1:
      setTime();
      break;
    case 2:
      adjustBellTime();
      break;
    case 3:
      resetDefaults();
      break;
  }
  inSettings = false;
  displayMenu();
}

void pointerOne() {
  lcd.createChar(0, customChar);
  lcd.setCursor(0, 0);
  lcd.write(0);
}

void pointerTwo() {
  lcd.createChar(0, customChar);
  lcd.setCursor(0, 1);
  lcd.write(0);
}

void pointerThree() {
  lcd.createChar(0, customChar);
  lcd.setCursor(0, 2);
  lcd.write(0);
}

void pointerFour() {
  lcd.createChar(0, customChar);
  lcd.setCursor(0, 3);
  lcd.write(0);
}

// Helper function to format time with leading zeros
String formatTime(int value) {
  return (value < 10) ? "0" + String(value) : String(value);
}

// Helper function to convert 24-hour format to 12-hour format
String format12Hour(int hour) {
  int hr = hour % 12;
  return hr == 0 ? "12" : String(hr);
}

// Helper function to format date
String formatDate(DateTime now) {
  return String(now.day()) + "/" + String(now.month()) + "/" + String(now.year());
}

void setDate() {
  int day, month, year;
  bool confirmed = false;

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Set Date:");

  // Input the day
  day = getUserInput("Day:", rtc.now().day()); // Use current day as default
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Set Date:");
  lcd.setCursor(0, 1);
  lcd.print("Day: ");
  lcd.print(day);

  // Confirm day
  confirmed = false;
  while (!confirmed) {
    lcd.setCursor(0, 2);
    lcd.print("Press OK to Save");
    if (digitalRead(setButtonPin) == LOW) {
      confirmed = true;
      delay(200); // Debounce delay
    }
  }

  // Input the month
  month = getUserInput("Month:", rtc.now().month()); // Use current month as default
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Set Date:");
  lcd.setCursor(0, 1);
  lcd.print("Month: ");
  lcd.print(month);

  // Confirm month
  confirmed = false;
  while (!confirmed) {
    lcd.setCursor(0, 2);
    lcd.print("Press OK to Save");
    if (digitalRead(setButtonPin) == LOW) {
      confirmed = true;
      delay(200); // Debounce delay
    }
  }

  // Input the year
  year = getUserInput("Year:", rtc.now().year()); // Use current year as default
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Set Date:");
  lcd.setCursor(0, 1);
  lcd.print("Year: ");
  lcd.print(year);

  // Confirm year
  confirmed = false;
  while (!confirmed) {
    lcd.setCursor(0, 2);
    lcd.print("Press OK to Save");
    if (digitalRead(setButtonPin) == LOW) {
      confirmed = true;
      delay(200); // Debounce delay
    }
  }

  // Save the date
  rtc.adjust(DateTime(year, month, day, rtc.now().hour(), rtc.now().minute(), 0));

  lcd.clear();
  lcd.print("Date set.");
  delay(1000);  // Pause to let the user read the message
}

void setTime() {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Set Time:");

  // Input hour and minute
  int hour = getUserInput("Hour:", rtc.now().hour()); // Use current hour as default
  int minute = getUserInput("Minute:", rtc.now().minute()); // Use current minute as default
  
  rtc.adjust(DateTime(rtc.now().year(), rtc.now().month(), rtc.now().day(), hour, minute, 0));
  
  lcd.clear();
  lcd.print("Time set.");
  delay(1000);  // Pause to let the user read the message
}

void adjustBellTime() {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Set Bell Time:");
  
  // Input bell time in seconds
  unsigned long bellTime = getUserInput("Seconds:", 10);  // Provide a default duration
  alarmDuration = bellTime * 1000;  // Convert to milliseconds
  
  lcd.clear();
  lcd.print("Bell time set.");
  delay(1000);  // Pause to let the user read the message
}

void resetDefaults() {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Resetting...");
  
  // Reset alarms in EEPROM
  for (int i = 0; i < 10; i++) {
    EEPROM.write(i * 2, 0);       // Default alarm hour 0
    EEPROM.write(i * 2 + 1, 0);   // Default alarm minute 0
  }

  // Reset bell duration
  alarmDuration = 10000; // 10 seconds
  
  lcd.clear();
  lcd.print("Defaults reset.");
  delay(1000);  // Pause to let the user read the message
}

int getUserInput(String prompt, int defaultValue) {
  int value = defaultValue;
  bool inputAdjusted = false;
  
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print(prompt);
  
  while (!inputAdjusted) {
    lcd.setCursor(0, 1);
    lcd.print("Value: ");
    lcd.print(value);

    if (digitalRead(upButtonPin) == LOW) {
      value++;
      delay(200); // Debounce delay
    } else if (digitalRead(downButtonPin) == LOW) {
      value--;
      delay(200); // Debounce delay
    }

    // Ensure value stays within valid range for day, month, or year
    if (prompt.startsWith("Day:")) {
      if (value > 31) value = 1; // Wrap around for day
      if (value < 1) value = 31; // Wrap around for day
    } else if (prompt.startsWith("Month:")) {
      if (value > 12) value = 1; // Wrap around for month
      if (value < 1) value = 12; // Wrap around for month
    } else if (prompt.startsWith("Year:")) {
      if (value < 2000) value = 2000; // Minimum year
      if (value > 2100) value = 2100; // Maximum year
    }

    if (digitalRead(setButtonPin) == LOW) {
      inputAdjusted = true;
      delay(200); // Debounce delay
    }
  }

  return value;
}