#include <WiFi.h>
#include "ThingSpeak.h"

// Pin configuration
const int echoPin = 13;   
const int trigPin = 15;   

unsigned long lastSendTime = 0;
const unsigned long sendInterval = 20000;

// WiFi credentials
const char* WIFI_NAME = "Wokwi-GUEST";
const char* WIFI_PASSWORD = "";

// ThingSpeak channel details
const int myChannelNumber = 2436303;
const char* myApiKey = "WUVRTGPUOPHQL7N6";
const char* server = "api.thingspeak.com";

WiFiClient client;

void setup() {
  Serial.begin(115200);

  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  
  // Connect to WiFi
  WiFi.begin(WIFI_NAME, WIFI_PASSWORD);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.println("Wifi not connected");
  }
  Serial.println("Wifi connected !");
  Serial.println("Local IP: " + String(WiFi.localIP()));

  // Set WiFi mode to STA (station) mode
  WiFi.mode(WIFI_STA);

  // Initialize ThingSpeak client
  ThingSpeak.begin(client);
}

void loop() {
  
  int distance = measuredistance();

  // Send data to ThingSpeak if the interval has passed
  unsigned long currentTime = millis();
  if (currentTime - lastSendTime >= sendInterval) {
    sendToThingSpeak(distance);
    lastSendTime = currentTime;  // Update the last send time
  }
 
  // Print temperature and humidity to serial monitor
  Serial.println("dist: " + String(distance) + " cm");
  

  

  // Delay for 10 seconds before the next iteration
  delay(10000);
}

int measuredistance(){
  // Trigger ultrasonic sensor to send a pulse
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Measure the time taken for the pulse to return
  int duration = pulseIn(echoPin, HIGH);
  int dis = duration * 0.034 / 2;

  return dis;
}

void sendToThingSpeak(int distance) {
  ThingSpeak.setField(1, distance);

  int status = ThingSpeak.writeFields(myChannelNumber, myApiKey);

  if (status == 200) {
    Serial.println("Data sent to ThingSpeak successfully.");
  } else {
    Serial.println("Error sending data to ThingSpeak. Status code: " + String(status));
  }
}