#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <Encoder.h>

// Constants for encoder
const int encoderPinA = 2;
const int encoderPinB = 3;
const int encoderButtonPin = 4;
const int buzzerPin = 13;

// OLED display configuration
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

// Encoder instance
Encoder myEnc(encoderPinA, encoderPinB);

// Variables for alarm
unsigned long alarmTime = 0;
bool alarmSet = false;
bool alarmActive = false;
int alarmMinutes = 1;  // Default alarm time 1 minute
bool buttonPressed = false;
unsigned long buttonPressStartTime = 0;
const unsigned long longPressDuration = 3000; // 1 second

// Previous state for encoder
long lastEncoderPosition = -999;
unsigned long lastDebounceTime = 0;
const unsigned long debounceDelay = 50;

void setup() {
  pinMode(encoderButtonPin, INPUT_PULLUP);
  pinMode(buzzerPin, OUTPUT);
  digitalWrite(buzzerPin, LOW);

  // Initialize the OLED display
  if (!display.begin(SSD1306_PAGEADDR, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for (;;);
  }

  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 10);
  display.print("Set Alarm");
  display.display();
}

void loop() {
  // Read encoder position
  long newEncoderPosition = myEnc.read() / 4;  // Adjust sensitivity if necessary
  if (newEncoderPosition != lastEncoderPosition) {
    lastEncoderPosition = newEncoderPosition;
    alarmMinutes = newEncoderPosition;
    if (alarmMinutes < 1) {
      alarmMinutes = 1;
      myEnc.write(4);  // Set to 1 minute (4 * 0.25 steps)
    }
    displayAlarmTime();
  }

  // Read encoder button state
  bool buttonState = digitalRead(encoderButtonPin);
  if (buttonState == LOW && !buttonPressed) {
    buttonPressed = true;
    buttonPressStartTime = millis();
  } else if (buttonState == HIGH && buttonPressed) {
    unsigned long buttonPressDuration = millis() - buttonPressStartTime;
    if (buttonPressDuration >= longPressDuration) {
      resetSettings();
    } else {
      if (!alarmSet) {
        alarmSet = true;
        alarmTime = millis() + alarmMinutes * 60000;  // Set alarm time in future
        displayAlarmTime();
      } else {
        alarmActive = true;
      }
    }
    buttonPressed = false;
  }

  // Check if alarm time is reached
  if (alarmActive && millis() >= alarmTime) {
    alarmActive = false;
  }

  if (alarmActive) {
    digitalWrite(buzzerPin, HIGH);  // Turn on buzzer for alarm
    unsigned long remainingTime = alarmTime - millis();
    displayRemainingTime(remainingTime);
  } else {
    digitalWrite(buzzerPin, LOW);  // Turn off buzzer if alarm is not set
  }
}

void displayAlarmTime() {
  display.clearDisplay();
  display.setCursor(0, 0);
  display.print("Set Alarm in: ");
  display.print(alarmMinutes);
  display.print(" min");

  if (alarmSet) {
    display.setCursor(0, 20);
    display.print("Alarm Set");
  } else {
    display.setCursor(0, 20);
    display.print("Alarm Not Set");
  }

  display.display();
}

void displayRemainingTime(unsigned long remainingTime) {
  display.clearDisplay();
  display.setCursor(0, 0);
  display.print("Alarm in: ");
  display.print(remainingTime / 60000);  // Convert milliseconds to minutes
  display.print(" min ");
  display.print((remainingTime % 60000) / 1000);  // Remaining seconds
  display.print(" sec");

  display.display();
}

void resetSettings() {
  alarmSet = false;
  alarmActive = false;
  alarmTime = 0;
  alarmMinutes = 1;
  lastEncoderPosition = -999;
  display.clearDisplay();
  display.setCursor(0, 0);
  display.print("Settings Reset");
  display.display();
}