#include <WiFi.h>
#include <PubSubClient.h>
#include <DHT.h>
#include <ArduinoJson.h>

const char* WIFI_SSID = "YourNetwork";
const char* WIFI_PASS = "YourPassword";
const char* TB_HOST   = "mqtt.thingsboard.cloud";
const int   TB_PORT   = 1883;
const char* TB_TOKEN  = "YOUR_ACCESS_TOKEN";  // ThingsBoard device token
const char* TB_TELEM  = "v1/devices/me/telemetry";
const char* TB_ATTR   = "v1/devices/me/attributes";

#define DHT_PIN 4
#define LDR_PIN 34  // ADC1 pin — safe to use with Wi-Fi

DHT dht(DHT_PIN, DHT22);
WiFiClient   wifiClient;
PubSubClient mqtt(wifiClient);
unsigned long lastSend = 0;
const long INTERVAL = 15000;

void connectMQTT() {
  while (!mqtt.connected()) {
    Serial.print("Connecting to ThingsBoard...");
    // ThingsBoard: username = token, password = empty string
    if (mqtt.connect("esp32-weather-01", TB_TOKEN, "")) {
      Serial.println(" Connected!");
      // Publish device attributes (static info) once on connect
      StaticJsonDocument<128> attr;
      attr["firmware"] = "v1.0.2";
      attr["location"] = "Kigali-Lab01";
      attr["sensor"]   = "DHT22+LDR";
      char attrBuf[128];
      serializeJson(attr, attrBuf);
      mqtt.publish(TB_ATTR, attrBuf);
    } else {
      Serial.print(" Failed rc="); Serial.print(mqtt.state());
      Serial.println(" retry in 5s");
      delay(5000);
    }
  }
}

void setup() {
  Serial.begin(115200);
  dht.begin();
  analogSetAttenuation(ADC_11DB);  // Full 0–3.3 V ADC range on ESP32
  WiFi.begin(WIFI_SSID, WIFI_PASS);
  while (WiFi.status() != WL_CONNECTED) delay(500);
  Serial.println("Wi-Fi: " + WiFi.localIP().toString());
  mqtt.setServer(TB_HOST, TB_PORT);
  connectMQTT();
}

void loop() {
  if (!mqtt.connected()) connectMQTT();
  mqtt.loop();
  if (millis() - lastSend >= INTERVAL) {
    lastSend = millis();
    float temp = dht.readTemperature();
    float hum  = dht.readHumidity();
    int   ldr  = analogRead(LDR_PIN);
    if (!isnan(temp) && !isnan(hum)) {
      StaticJsonDocument<128> doc;
      doc["temperature"] = round(temp * 10) / 10.0;
      doc["humidity"]    = round(hum  * 10) / 10.0;
      doc["light"]       = ldr;
      doc["rssi"]        = WiFi.RSSI();  // Wi-Fi signal strength
      char payload[128];
      serializeJson(doc, payload);
      mqtt.publish(TB_TELEM, payload);
      Serial.println(payload);
    }
  }
}