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

// LCD: 16x2 I2C
LiquidCrystal_I2C lcd(0x27, 16, 2);

// Pin Definitions
const int greenLED = 2;
const int yellowLED = 3;
const int redLED = 4;
const int buzzer = 5;
const int button = 6;
const int waterSensor = A0;

// Alarm State
bool fullAlarmActive = false;
bool fullAlarmAcknowledged = false;
bool emptyAlarmActive = false;
int previousLevel = -1;

void setup() {
  pinMode(greenLED, OUTPUT);
  pinMode(yellowLED, OUTPUT);
  pinMode(redLED, OUTPUT);
  pinMode(buzzer, OUTPUT);
  pinMode(button, INPUT_PULLUP);  // Active LOW

  lcd.begin(16, 2);
  lcd.backlight();
  lcd.print("Water Level Init");
  delay(1500);
  lcd.clear();

  Serial.begin(9600);
}

void loop() {
  int waterLevel = analogRead(waterSensor);
  bool buttonPressed = digitalRead(button) == LOW;

  Serial.println(waterLevel);

  lcd.setCursor(0, 0);
  lcd.print("Level: ");
  lcd.print(waterLevel);
  lcd.print("    ");

  // Reset LEDs every loop
  digitalWrite(greenLED, LOW);
  digitalWrite(yellowLED, LOW);
  digitalWrite(redLED, LOW);

  // -------- FULL ALARM HANDLING --------
  if (waterLevel == 1023 && !fullAlarmAcknowledged) {
    fullAlarmActive = true;
  }

  // Wait for user button press to stop full alarm
  if (fullAlarmActive) {
    lcd.setCursor(0, 1);
    lcd.print("Status: FULL!!! ");

    // Siren effect
    for (int i = 1000; i <= 2000; i += 200) {
      tone(buzzer, i);
      delay(40);
    }
    for (int i = 2000; i >= 1000; i -= 200) {
      tone(buzzer, i);
      delay(40);
    }

    // Wait for button press
    if (buttonPressed) {
      fullAlarmActive = false;
      fullAlarmAcknowledged = true;
      noTone(buzzer);
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("Full Acknowledged");
      delay(1000);
      lcd.clear();
    }

    return;  // Skip rest
  }

  // After leaving FULL state (i.e. water < 1023), reset acknowledge
  if (previousLevel == 1023 && waterLevel < 1023) {
    fullAlarmAcknowledged = false;
  }

  // -------- EMPTY ALARM HANDLING --------
  if (waterLevel == 0) {
    emptyAlarmActive = true;
    digitalWrite(greenLED, HIGH);
    lcd.setCursor(0, 1);
    lcd.print("Status: EMPTY    ");

    // Beep beep
    tone(buzzer, 500);
    delay(200);
    noTone(buzzer);
    delay(200);

    previousLevel = waterLevel;
    return;  // Skip rest
  }

  // If water goes above 0, turn off empty alarm
  if (waterLevel > 0 && emptyAlarmActive) {
    emptyAlarmActive = false;
  }

  // -------- NORMAL RANGE DISPLAY --------
  lcd.setCursor(0, 1);

  if (waterLevel <= 340) {
    digitalWrite(greenLED, HIGH);
    lcd.print("Status: LOW     ");
  } else if (waterLevel <= 681) {
    digitalWrite(yellowLED, HIGH);
    lcd.print("Status: MEDIUM  ");
  } else if (waterLevel <= 1022) {
    digitalWrite(redLED, HIGH);
    lcd.print("Status: HIGH    ");
  }

  noTone(buzzer);
  previousLevel = waterLevel;
  delay(300);
}