#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <RTClib.h>
#include <Keypad.h>
#include <SD.h>

#define BUZZER_PIN 8
#define SD_CS_PIN 10  // Chip select pin for SD card

LiquidCrystal_I2C lcd(0x27, 16, 2);  // Initialize LCD with address 0x27
RTC_DS1307 rtc;                      // Initialize DS1307 RTC

// Keypad setup
const byte ROWS = 4; // Four rows
const byte COLS = 4; // Four columns
char keys[ROWS][COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};
byte rowPins[ROWS] = {9, 8, 7, 6}; // Connect to row pinouts
byte colPins[COLS] = {5, 4, 3, 2}; // Connect to column pinouts
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

File dataFile;

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

  // Initialize LCD
  lcd.begin(16, 2);
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("Smart Fridge 2.0");

  // Initialize RTC
  if (!rtc.begin()) {
    Serial.println("RTC Error");
    lcd.setCursor(0, 1);
    lcd.print("RTC Error!");
    while (1);  // Stop if RTC is not found
  }
  if (!rtc.isrunning()) {
    rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));  // Set time to compile time
  }

  // Initialize SD card
  if (!SD.begin(SD_CS_PIN)) {
    Serial.println("SD Card Initialization Failed!");
    lcd.setCursor(0, 1);
    lcd.print("SD Error!");
    delay(5000);
    lcd.clear();
    return;  // Allow program to run even if SD card fails
  } else {
    Serial.println("SD Card Initialized.");
  }

  // Open or create the data file
  dataFile = SD.open("fridge.csv", FILE_WRITE);
  if (dataFile) {
    Serial.println("Successfully opened fridge.csv.");
    if (dataFile.size() == 0) {
      dataFile.println("ID,ExpiryDate,Location");
      Serial.println("Added headers to fridge.csv.");
    }
    dataFile.close();
  } else {
    Serial.println("Error opening fridge.csv during setup.");
    lcd.setCursor(0, 1);
    lcd.print("File Error!");
    delay(5000);
    lcd.clear();
  }

  pinMode(BUZZER_PIN, OUTPUT);  // Configure buzzer pin

  lcd.setCursor(0, 0);
  lcd.print("Smart Fridge Ready");
  delay(2000);
  lcd.clear();
}
void loop() {
  lcd.setCursor(0, 0);
  lcd.print("Enter Item ID...");
  String inputID = getInput("ID:");

  if (inputID != "") {
    if (isDuplicateID(inputID)) {
      lcd.clear();
      lcd.print("Item Exists!");
      activateBuzzer();
      delay(2000);
      return;
    }

    lcd.clear();
    lcd.print("Enter Exp Date");
    lcd.setCursor(0, 1);
    lcd.print("DDMMYY:");

    String expiryDateStr = getInput("Date:");
    DateTime expiryDate = parseExpiryDate(expiryDateStr);

    if (expiryDate.unixtime() == 0 || !isValidDate(expiryDate)) {
      lcd.clear();
      lcd.print("Invalid Date!");
      activateBuzzer();
    } else {
      lcd.clear();
      lcd.print("Enter Location:");
      String location = getInput("Loc:");

      addItemToCSV(inputID, expiryDate, location);   // Add item to the CSV file
      checkExpirations();                           // Check for items nearing expiration
    }
  }

  delay(1000);
}

bool isDuplicateID(String id) {
  dataFile = SD.open("fridge.csv", FILE_READ);
  if (dataFile) {
    while (dataFile.available()) {
      String line = dataFile.readStringUntil('\n');
      if (line.startsWith("ID")) continue;  // Skip header line

      int firstComma = line.indexOf(',');
      String existingID = line.substring(0, firstComma);

      if (existingID == id) {
        dataFile.close();
        return true;
      }
    }
    dataFile.close();
  } else {
    Serial.println("Error reading fridge.csv");
    lcd.clear();
    lcd.print("Read Error!");
    delay(2000);
  }
  return false;
}

String getInput(String prompt) {
  String input = "";
  char key;
  lcd.setCursor(0, 1);
  lcd.print("Press # to end");

  while (true) {
    key = keypad.getKey();
    if (key) {
      if (key == '#') {
        return input; // End input on '#'
      } else if (key == '*') {
        input = ""; // Reset input on '*'
        lcd.setCursor(0, 1);
        lcd.print(prompt + "        ");
      } else {
        input += key; // Append key to the input
        lcd.setCursor(0, 1);
        lcd.print(prompt + input);
      }
    }
  }
}

DateTime parseExpiryDate(String dateStr) {
  // Parse expiry date in DDMMYY format
  if (dateStr.length() != 6) return DateTime(2000, 1, 1, 0, 0, 0);

  int day = dateStr.substring(0, 2).toInt();
  int month = dateStr.substring(2, 4).toInt();
  int year = 2000 + dateStr.substring(4, 6).toInt();  // Assuming year is YY format (e.g., 23 -> 2023)

  if (day < 1 || day > 31 || month < 1 || month > 12) return DateTime(2000, 1, 1, 0, 0, 0);

  return DateTime(year, month, day, 0, 0, 0);
}

bool isValidDate(DateTime date) {
  DateTime placeholder(2000, 1, 1, 0, 0, 0);
  if (date == placeholder) return false;

  DateTime now = rtc.now();
  return date >= now;  // Date must be today or in the future
}

void addItemToCSV(String id, DateTime expiryDate, String location) {
  String expiryDateStr = String(expiryDate.year()) + "-" + String(expiryDate.month()) + "-" + String(expiryDate.day());

  dataFile = SD.open("fridge.csv", FILE_WRITE);
  if (dataFile) {
    dataFile.println(id + "," + expiryDateStr + "," + location);
    dataFile.close();

    lcd.clear();
    lcd.print("Added: " + id);
    lcd.setCursor(0, 1);
    lcd.print("Loc: " + location);
    delay(2000);
  } else {
    Serial.println("Error writing to fridge.csv");
    lcd.clear();
    lcd.print("Write Error!");
    delay(2000);
  }
}

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

  dataFile = SD.open("fridge.csv", FILE_READ);
  if (dataFile) {
    while (dataFile.available()) {
      String line = dataFile.readStringUntil('\n');
      if (line.startsWith("ID")) continue;  // Skip header line

      int firstComma = line.indexOf(',');
      int secondComma = line.indexOf(',', firstComma + 1);

      String id = line.substring(0, firstComma);
      String expiryDateStr = line.substring(firstComma + 1, secondComma);
      DateTime expiryDate = parseExpiryDateFromString(expiryDateStr);

      if ((expiryDate - now).days() <= 1) {
        lcd.clear();
        lcd.print(id);
        lcd.setCursor(0, 1);
        lcd.print("Expires Soon!");
        activateBuzzer();
        delay(2000);
      }
    }
    dataFile.close();
  } else {
    Serial.println("Error reading fridge.csv");
  }
}

DateTime parseExpiryDateFromString(String dateStr) {
  int firstDash = dateStr.indexOf('-');
  int secondDash = dateStr.indexOf('-', firstDash + 1);

  int year = dateStr.substring(0, firstDash).toInt();
  int month = dateStr.substring(firstDash + 1, secondDash).toInt();
  int day = dateStr.substring(secondDash + 1).toInt();

  return DateTime(year, month, day);
}

void activateBuzzer() {
  digitalWrite(BUZZER_PIN, HIGH);
  delay(2000);
  digitalWrite(BUZZER_PIN, LOW);
}