#include <WiFi.h>
#include <HTTPClient.h>
#include <Wire.h>
#include <Adafruit_GFX.h> 
#include <Adafruit_SSD1306.h> 

#define OLED_RESET -1
Adafruit_SSD1306 display(OLED_RESET);

const char* ssid = "Wokwi-GUEST";
const char* password = "";
const char* server = "api.thingspeak.com";
const char* apiKey = "O2F74M0OCOAUNNW0"; 

#define TRIG_PIN 2
#define ECHO_PIN 4

void setup() {
  Serial.begin(115200);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);

  if(!(display.begin(SSD1306_SWITCHCAPVCC, 0x3C))){
    Serial.println("failed");
  };
  display.display();
  delay(2000); 

  WiFi.begin(ssid, password);

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

  Serial.println("Connected to WiFi");
}

void loop() {
 
  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 * 0.0343 / 2; 

  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  display.clearDisplay(); // Clear the display buffer
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0,0);
  display.println("Distance: ");
  display.setTextSize(2);
  display.println(distance);
  display.setTextSize(1);
  display.println("cm");
  display.display(); 

  sendDataToThingSpeak(distance);


  delay(10000); 
}

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

   
    String url = "http://";
    url += server;
    url += "/update?api_key=";
    url += apiKey;
    url += "&field1=";
    url += String(distance);
    Serial.print("Sending data to ThingSpeak: ");
    http.begin(url); 
    int httpResponseCode = http.GET(); 

    if (httpResponseCode > 0) {
    
      Serial.println("CONNECTION SENT  WITH HTTP CODE");
      Serial.println(httpResponseCode);
    } else {
      Serial.print("Error sending data to ThingSpeak. HTTP error code: ");
      Serial.println(httpResponseCode);
    }

    http.end(); 
  }
}