/**
 *
 */
#include <WiFi.h>
#include <ThingSpeak.h>

const int TRIG_PIN = 2;
const int ECHO_PIN = 4; 
const int YELLOW_LED = 13;
const int GREEN_LED = 14;
const int RED_LED = 12;
const char* WIFI_NAME = "Wokwi-GUEST";
const char* WIFI_PASSWORD = "";
const int myChannelNumber = 2313788;
const char* myApiKey = "1K40ID5WLHJCF46Y";
const char* server = "api.thingspeak.com";

WiFiClient client;

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

  pinMode(YELLOW_LED, OUTPUT);
  pinMode(GREEN_LED, OUTPUT);
  pinMode(RED_LED, OUTPUT);

  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);

  digitalWrite(TRIG_PIN, LOW);

  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()));
  WiFi.mode(WIFI_STA);
  ThingSpeak.begin(client);
}

void loop() {

  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  double distanceCM = pulseIn(ECHO_PIN, HIGH) * 0.017;

  if(distanceCM < 28) {

    digitalWrite(RED_LED, HIGH);
    digitalWrite(GREEN_LED, LOW);
    digitalWrite(YELLOW_LED, LOW);
  } else if(distanceCM >= 28 && distanceCM < 40) {

    digitalWrite(RED_LED, LOW);
    digitalWrite(GREEN_LED, HIGH);
    digitalWrite(YELLOW_LED, LOW);
  } else {

    digitalWrite(RED_LED, LOW);
    digitalWrite(GREEN_LED, LOW);
    digitalWrite(YELLOW_LED, HIGH);
  }
  
  ThingSpeak.setField(1, String(distanceCM, 2));
  
  int res = ThingSpeak.writeFields(myChannelNumber, myApiKey);
  
  Serial.println("Distance: " + String(distanceCM, 2) + " cm");
  
  if(res == 200) {
    Serial.println("Data published successfully");
  } else {
    Serial.println("Publish error: " + String(res));
  }

  delay(9000);
}