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

const char* ssid = "Wokwi-GUEST";
const char* password = "";
const char* server = "api.thingspeak.com";
const char* apiKey = "0NDCO11WCJYJETJL"; // Obtain your API key from ThingSpeak

#define TRIG_PIN 2
#define ECHO_PIN 3

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels
#define OLED_RESET    -1 // Reset pin # (or -1 if sharing Arduino reset pin)

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

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

  WiFi.begin(ssid, password);

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

  Serial.println("Connected to WiFi");

  // Initialize the OLED display
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { // Address 0x3C for 128x64
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }

  // Clear the display buffer
  display.clearDisplay();
}

void loop() {
  // Send a pulse to the trigger pin to start the measurement
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  // Measure the duration of the pulse on the echo pin
  long duration = pulseIn(ECHO_PIN, HIGH);

  // Calculate the distance based on the duration
  // Speed of sound at sea level is 343 meters/second or 0.0343 cm/microsecond
  float distance = duration * 0.0343 / 2; // Divide by 2 because it's a round trip

  // Print the distance to the serial monitor
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  // Print the distance to the OLED display
  display.clearDisplay();
  display.setTextSize(1);      
  display.setTextColor(SSD1306_WHITE); 
  display.setCursor(0,0);     
  display.print("Distance: ");
  display.print(distance);
  display.println(" cm");
  display.display();

  // Send data to ThingSpeak
  sendDataToThingSpeak(distance);

  // Wait before taking the next measurement
  delay(10000); // Adjust delay as needed
}

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

    // Construct the URL for ThingSpeak
    String url = "http://";
    url += server;
    url += "/update?api_key=";
    url += apiKey;
    url += "&field1=";
    url += String(distance);

    Serial.print("Sending data to ThingSpeak: ");
    Serial.println(url);

    http.begin(url); // Initialize HTTP connection
    int httpResponseCode = http.GET(); // Send HTTP GET request

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

    http.end(); // Close HTTP connection
  }
}