#include <LiquidCrystal.h>
#include <NewPing.h>
#include <DHT.h>

// Constants
#define MAX_DISTANCE 197        // Maximum sensor distance in cm
#define MEDIAN_SAMPLE 5         // Number of samples for median filter
#define DEBOUNCE_DELAY 70       // Button debounce delay
#define MIN_MEASUREMENT_INTERVAL 100  // Minimum time between ultrasonic measurements in milliseconds

#define GREEN_LED_PIN 8
#define YELLOW_LED_PIN 9
#define RED_LED_PIN 10

#define TRIGGER_PIN  7
#define ECHO_PIN     7
#define BUTTON_PIN   13
#define RELAY_PIN    A1
#define LCDPOWER_PIN A3
#define DHT_PIN      6
#define DHT_TYPE     DHT22

// Initialize objects
NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE);
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
DHT dht(DHT_PIN, DHT_TYPE);

// Variables
volatile bool buttonState = LOW;
bool previousButtonState = LOW;
unsigned long lastDebounceTime = 0;
unsigned long lastDisplayUpdateTime = 0;
unsigned int distance;
int waterLevel = 0; // This will store the water level in centimeters
byte waterLevelPercent = 0;
bool pumpFlag = false;
unsigned long lastMeasurementTime = 0; // Last time ultrasonic measurement was performed

void setup() {
  pinMode(BUTTON_PIN, INPUT);
  pinMode(LCDPOWER_PIN, OUTPUT);
  pinMode(RELAY_PIN, OUTPUT);

  pinMode(GREEN_LED_PIN, OUTPUT);
  pinMode(YELLOW_LED_PIN, OUTPUT);
  pinMode(RED_LED_PIN, OUTPUT);

  Serial.begin(9600);
  lcd.begin(16, 2);
  dht.begin();
}

void loop() {
  buttonState = digitalRead(BUTTON_PIN);
  unsigned long currentMillis = millis();

  // Button debounce
  if (currentMillis - lastDebounceTime > DEBOUNCE_DELAY) {
    if (buttonState != previousButtonState) {
      if (buttonState == LOW) {
        buttonPressed();
      }
      lastDebounceTime = currentMillis;
    }
  }
  previousButtonState = buttonState;

  // Perform ultrasonic measurement if MIN_MEASUREMENT_INTERVAL has passed
  if (currentMillis - lastMeasurementTime >= MIN_MEASUREMENT_INTERVAL) {
    lastMeasurementTime = currentMillis;
    checkWaterLevel();
  }

  // Periodic tasks
  if (currentMillis - lastDisplayUpdateTime > 1000) {
    updateDisplay();
    controlRelay();
    updateLEDs(); // Update the LED status based on the water level
    lastDisplayUpdateTime = currentMillis;
  }
}

void buttonPressed() {
  analogWrite(LCDPOWER_PIN, 255); // Ensure LCD backlight is on
  lcd.clear();
  lcd.print(F("Button Pressed!"));
  delay(2000); // Display message for 2 seconds
}

void updateDisplay() {
  float temperature = dht.readTemperature();
  if (!isnan(temperature)) {
    lcd.setCursor(0, 0);
    lcd.print(F("Temp: "));
    lcd.print(temperature,1);
    lcd.print(F(" C   "));
  }

  lcd.setCursor(0, 1);
  lcd.print(F("Water: "));
  lcd.print(waterLevelPercent);
  lcd.print(F("%  "));
  drawWaterLevelGraph(waterLevelPercent);
}

void drawWaterLevelGraph(int percentage) {
  int blocks = percentage / 20; // 5 blocks max for 0-100%
  lcd.setCursor(11, 1);
  for (int i = 0; i < 5; i++) {
    lcd.write(i < blocks ? 255 : 32); // Full block for water, space for empty
  }
}

void checkWaterLevel() {
  unsigned int currentDistance = sonar.ping_cm(); // Perform ultrasonic measurement

  // Ensure the measurement is within valid range and interval
  if (currentDistance > 0 && currentDistance <= MAX_DISTANCE) {
    distance = currentDistance; // Update the distance variable
    waterLevel = MAX_DISTANCE - distance; // Calculate water level
    waterLevelPercent = map(waterLevel, 0, MAX_DISTANCE, 0, 100); // Calculate water level percentage
    Serial.println("Water level measured: " + String(waterLevelPercent) + "%");
  } else {
    Serial.println("Invalid measurement or interval exceeded.");
  }
}

void controlRelay() {
  // Turn on the relay when water level is below 12%
  if (waterLevelPercent < 12) {
    digitalWrite(RELAY_PIN, HIGH);
  } else {
    digitalWrite(RELAY_PIN, LOW);
  }
}

void updateLEDs() {
  if (waterLevelPercent >= 75) {
    // High water level - Green LED on
    digitalWrite(GREEN_LED_PIN, HIGH);
    digitalWrite(YELLOW_LED_PIN, LOW);
    digitalWrite(RED_LED_PIN, LOW);
  } else if (waterLevelPercent >= 25 && waterLevelPercent < 75) {
    // Medium water level - Yellow LED on
    digitalWrite(GREEN_LED_PIN, LOW);
    digitalWrite(YELLOW_LED_PIN, HIGH);
    digitalWrite(RED_LED_PIN, LOW);
  } else {
    // Low water level - Red LED on
    digitalWrite(GREEN_LED_PIN, LOW);
    digitalWrite(YELLOW_LED_PIN, LOW);
    digitalWrite(RED_LED_PIN, HIGH);
  }
}