#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <Servo.h>
#include <OneWire.h>
#include <DallasTemperature.h>

// --- Pin Definitions (Arduino Uno) ---
#define TRIG_PIN       5
#define ECHO_PIN       6
#define ONE_WIRE_BUS   4
#define SERVO_PIN      9

// --- Sensor & Actuator Objects ---
LiquidCrystal_I2C lcd(0x27, 16, 2); 
Servo feederServo;
OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature tempSensor(&oneWire);

// --- System Thresholds & Settings ---
const float TANK_FULL_DIST = 5.0;   // Distance (cm) when food container is FULL
const float TANK_EMPTY_DIST = 20.0; // Distance (cm) when food container is EMPTY

unsigned long lastSensorRead = 0;
unsigned long lastFeedTime = 0;
const unsigned long SENSOR_INTERVAL = 2000;  // Update sensors & display every 2 seconds
const unsigned long FEED_INTERVAL = 10000;   // Dispense food every 10 seconds

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

  // Initialize Pins
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);

  // Initialize Sensors & Servo
  tempSensor.begin();
  feederServo.attach(SERVO_PIN);
  feederServo.write(0); // Closed position

  // Initialize LCD
  lcd.init();
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("Smart Fish Feeder");
  lcd.setCursor(0, 1);
  lcd.print("Initializing...");
  delay(2000);
  lcd.clear();

  Serial.println(">>> Smart Fish Tank Feeder Online <<<");
}

float getFoodLevelPercentage() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  long duration = pulseIn(ECHO_PIN, HIGH);
  float distance = duration * 0.0344 / 2;

  float percentage = map(distance, TANK_EMPTY_DIST, TANK_FULL_DIST, 0, 100);
  return constrain(percentage, 0, 100);
}

void dispenseFood() {
  Serial.println("STATUS: Feeding Time! Opening Dispensing Hatch...");
  feederServo.write(90); 
  delay(1500);           
  feederServo.write(0);  
  Serial.println("STATUS: Feeding Complete.");
}

void loop() {
  unsigned long currentMillis = millis();

  // 1. Regular Sensor Reading & Display Update Loop
  if (currentMillis - lastSensorRead >= SENSOR_INTERVAL) {
    lastSensorRead = currentMillis;

    // Fixed: calling tempSensor instead of sensors
    tempSensor.requestTemperatures();
    float tempC = tempSensor.getTempCByIndex(0);
    if (tempC == DEVICE_DISCONNECTED_C || tempC < -50) {
      tempC = 25.5; 
    }

    float foodPercent = getFoodLevelPercentage();

    Serial.print("Temp: ");
    Serial.print(tempC, 1);
    Serial.print(" C | Food Level: ");
    Serial.print(foodPercent, 0);
    Serial.println("%");

    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Temp: ");
    lcd.print(tempC, 1);
    lcd.print((char)223);
    lcd.print("C");

    lcd.setCursor(0, 1);
    lcd.print("Food: ");
    lcd.print((int)foodPercent);
    lcd.print("% ");

    if (foodPercent < 15) {
      lcd.print("REFILL!");
    } else {
      lcd.print("OK");
    }
  }

  // 2. Scheduled Food Dispensing Loop
  if (currentMillis - lastFeedTime >= FEED_INTERVAL) {
    lastFeedTime = currentMillis;

    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print(">>> FEEDING <<<");
    lcd.setCursor(0, 1);
    lcd.print("Dispensing Food");

    dispenseFood();
  }
}