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

#define SSID "Wokwi-GUEST"
#define SSID_PASSWORD ""

#define MQTT_SERVER "broker.hivemq.com"
#define MQTT_PORT 1883

#define MQTT_TOPIC "sensor/gps"

WiFiClient espClient;
PubSubClient client(espClient);

const int ledPin = 4;

// Starting point
float latitude = 44.403050;
float longitude = 8.971959;

// 10 m/s movement diagonally → sqrt(2)/2 * 10 m in lat & lon
const float METERS_TO_DEGREES = 0.00008983; // approx for latitude/longitude
const float step = 10.0 * METERS_TO_DEGREES / sqrt(2);  // diagonal

void setup_wifi() {
  WiFi.begin(SSID, SSID_PASSWORD);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
  }
}

void reconnect() {
  while (!client.connected()) {
    String clientId = "ESP32Client-" + String(random(0xffff), HEX);
    if (client.connect(clientId.c_str())) {
      Serial.println("Connected!");
    } else {
      delay(5000);
      Serial.println("Reconnecting...");
    }
  }
}

void setup() {
  Serial.begin(115200);
  pinMode(ledPin, OUTPUT);
  setup_wifi();
  client.setServer(MQTT_SERVER, MQTT_PORT);
  Serial.println("MQTT server is connected!");
}

void loop() {
  if (!client.connected()) {
    reconnect();
  }
  client.loop();

  // Update GPS position diagonally
  latitude += step;
  longitude += step;

  String payload = String("{\"gps\":{\"latitude\":") + String(latitude, 7) +
                   ",\"longitude\":" + String(longitude, 7) + "}}";

  Serial.println(payload);
  client.publish(MQTT_TOPIC, payload.c_str());

  digitalWrite(ledPin, HIGH);
  delay(1000);
}