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


#define PIN_TRIG 5
#define PIN_ECHO 18
#define ON_LED 0
#define ALERT_LED 17
#define TANK_HEIGHT_CM 300 // total height of the tank in cm
#define BUZZER_ALARM 23
#define BUZZER_DURATION_MS 5000 // Duration to keep the buzzer on in ms


// LCD i2c address for 16x2
LiquidCrystal_I2C lcd(0x27, 16, 2);


const int DHT_PIN = 33;


DHTesp dhtSensor;


unsigned long buzzerStartTime = 0; // Store the time when the buzzer was turned on
bool buzzerActive = false; // To track the buzzer state
bool warningOrNormalDetected = false; // To track if warning or normal level was detected
unsigned long lastBlinkTime = 0; // Timer for LED blinking
bool isLedOn = false; // To track the LED state


void setup() {
  Serial.begin(115200); // Baud rate of ESP32


  pinMode(PIN_TRIG, OUTPUT);
  pinMode(PIN_ECHO, INPUT);
  pinMode(ON_LED, OUTPUT);
  pinMode(ALERT_LED, OUTPUT);
  pinMode(BUZZER_ALARM, OUTPUT);


  digitalWrite(ON_LED, HIGH); // Ensure ON_LED is always on
  digitalWrite(ALERT_LED, LOW); // Ensure ALERT_LED is initially off
  digitalWrite(BUZZER_ALARM, LOW); // Ensure Buzzer is initially off


  dhtSensor.setup(DHT_PIN, DHTesp::DHT22);


  lcd.init(); // Initialize LCD
  lcd.backlight(); // Turn on the backlight


  displayMsg("System Initializing", "Please Wait...");
}


void displayMsg(String message1, String message2) {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print(message1);
  lcd.setCursor(0, 1);
  lcd.print(message2);
  delay(3000); // Display for 3 seconds
}


int measureWaterLvl() {
  digitalWrite(PIN_TRIG, LOW);
  delayMicroseconds(2);
  digitalWrite(PIN_TRIG, HIGH);
  delayMicroseconds(10);
  digitalWrite(PIN_TRIG, LOW);


  int duration = pulseIn(PIN_ECHO, HIGH);
  Serial.print("Duration: "); // Debugging line
  Serial.println(duration);    // Debugging line
  return duration * 0.0343 / 2; // Convert duration to distance in cm
}


int calcWaterLevel(int distanceCM) {
  return distanceCM; // Calculate water level (refer code bfore)
}


void handleCriticalLevel() {
  digitalWrite(ALERT_LED, HIGH);
  if (!buzzerActive && warningOrNormalDetected) {
    digitalWrite(BUZZER_ALARM, HIGH);
    tone(BUZZER_ALARM, 1000);
    buzzerStartTime = millis();
    buzzerActive = true; // Set buzzer as active
    warningOrNormalDetected = false; // Reset warning/normal detection flag
  }
}


void handleWarningLevel() {
  unsigned long currentMillis = millis();
 
  if (currentMillis - lastBlinkTime >= 2000) { // Check if 2 seconds have passed
    lastBlinkTime = currentMillis; // Reset the timer
    isLedOn = !isLedOn; // Toggle the LED state
    digitalWrite(ALERT_LED, isLedOn ? HIGH : LOW); // Blink the LED
  }


  handleNormalLevel(); // Ensure buzzer off
}


void handleNormalLevel() {
  digitalWrite(ALERT_LED, LOW); // Ensure ALERT_LED is off
  digitalWrite(BUZZER_ALARM, LOW); // Ensure Buzzer is off
  noTone(BUZZER_ALARM); // Ensure Buzzer is off
  buzzerActive = false; // Set buzzer as inactive
  warningOrNormalDetected = true; // Set warning/normal detection flag
}


void checkBuzzer() {
  if (buzzerActive && (millis() - buzzerStartTime >= BUZZER_DURATION_MS)) { // Duration to keep buzzer on
    noTone(BUZZER_ALARM); // Turn off the Buzzer
    buzzerActive = false; // Set buzzer as inactive
  }
}


String waterLvlStatus(int waterLevel) {
  if (waterLevel <= 30) { // Critical low level
    return "CRITICAL";
  } else if (waterLevel <= 70) { // Warning level
    return "WARNING";
  } else {
    return "NORMAL";
  }
}


String tempStatus(float temperature) {
  if (temperature < 5.0 || temperature > 45.0) {
    return "WARNING";
  } else {
    return "NORMAL";
  }
}


String humStatus(float humidity) {
  if (humidity < 20.0 || humidity > 80.0) {
    return "WARNING";
  } else {
    return "NORMAL";
  }
}


void displayLCD(int waterLevel, float temperature, float humidity) {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("WaterLvl: ");
  lcd.print(waterLevel);
  lcd.print("cm");
  lcd.setCursor(0, 1);
  lcd.print("Status: ");
  lcd.print(waterLvlStatus(waterLevel));
  delay(1500); // Wait 2 seconds


  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Temp: ");
  lcd.print(temperature, 1);
  lcd.print("degC");
  lcd.setCursor(0, 1);
  lcd.print("Status: ");
  lcd.print(tempStatus(temperature));
  delay(1500); // Wait 2 seconds


  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Hum: ");
  lcd.print(humidity, 1);
  lcd.print(" %RH");
  lcd.setCursor(0, 1);
  lcd.print("Status: ");
  lcd.print(humStatus(humidity));
  delay(1500); // Wait 2 seconds
}


void loop() {
  unsigned long startMillis = millis(); // Start the measurement cycle


  while (millis() - startMillis < 60000) { // Run for 1 minute
    int distanceCM = measureWaterLvl();
    int waterLevel = calcWaterLevel(distanceCM);


    // Read temperature and humidity
    TempAndHumidity data = dhtSensor.getTempAndHumidity();
    float temperature = data.temperature;
    float humidity = data.humidity;


    displayLCD(waterLevel, temperature, humidity);


    // Handle alarm and LED
    if (waterLevel <= 30) { // Critical low level
      handleCriticalLevel();
    } else if (waterLevel <= 70) { // Warning level
      handleWarningLevel();
    } else { // Normal level
      handleNormalLevel();
    }


    checkBuzzer();


    delay(1000); // Short delay to allow other tasks to run smoothly
  }
}