#include <ESP32Servo.h>
#include <WiFi.h>
#include <HTTPClient.h>

// Define pins
const int trigPin = 5;
const int echoPin = 18;
const int potPin = 34;  // Analog pin for potentiometer
const int relayPin = 4; // Relay control pin
const int servoPin = 21; // Servo control pin

Servo myservo;
const char* ssid = "Wokwi-GUEST";
const char* password = "";

// ThingSpeak settings
const char* server = "https://api.thingspeak.com/update?api_key=K7EZA72HWEB5D0NC&field1=0";
const char* apiKey = "K7EZA72HWEB5D0NC"; // Replace with your ThingSpeak Write API Key

// Function to measure distance using the ultrasonic sensor
long readUltrasonicDistance(int triggerPin, int echoPin) {
  digitalWrite(triggerPin, LOW);
  delayMicroseconds(2);
  digitalWrite(triggerPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(triggerPin, LOW);

  long duration = pulseIn(echoPin, HIGH);
  long distance = duration * 0.034 / 2; // Convert to cm
  return distance;
}

void setup() {
  Serial.begin(115200);
  
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(potPin, INPUT);
  pinMode(relayPin, OUTPUT);

  myservo.attach(servoPin);

  // Initial state of relay and servo
  digitalWrite(relayPin, LOW);
  myservo.write(0); // Initial position of servo

  // Connect to WiFi
  Serial.print("Connecting to ");
  Serial.println(ssid);
  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.print(".");
  }
  Serial.println();
  Serial.println("WiFi connected");
}

void sendDataToThingSpeak(long distance, float voltage) {
  if (WiFi.status() == WL_CONNECTED) {
    HTTPClient http;

    String url = String(server) + "?api_key=" + apiKey + "&field1=" + String(distance) + "&field2=" + String(voltage);
    http.begin(url);
    
    int httpResponseCode = http.GET();
    if (httpResponseCode > 0) {
      String response = http.getString();
      Serial.println(httpResponseCode);
      Serial.println(response);
    } else {
      Serial.print("Error on sending POST: ");
      Serial.println(httpResponseCode);
    }
    http.end();
  } else {
    Serial.println("WiFi not connected");
  }
}

void loop() {
  // Read the distance from the ultrasonic sensor
  long distance = readUltrasonicDistance(trigPin, echoPin);
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  // Read the pH level (simulated by potentiometer)
  int potValue = analogRead(potPin);
  float voltage = potValue * (3.3 / 4095.0); // Convert to voltage (3.3V reference)
  Serial.print("pH Level (simulated by potentiometer voltage): ");
  Serial.println(voltage);

  // Control relay and servo based on distance
  if (distance <= 170) {
    digitalWrite(relayPin, HIGH); // Turn on the relay
    myservo.write(90); // Move servo to 90 degrees (or any desired position)
  } else {
    digitalWrite(relayPin, LOW); // Turn off the relay
    myservo.write(0); // Move servo to 0 degrees (or any desired position)
  }

  // Send data to ThingSpeak
  sendDataToThingSpeak(distance, voltage);

  delay(5000); // Wait for 5 seconds before the next loop
}