#ifndef BME680_H
#define BME680_H

#include "Adafruit_BME680.h"
#include "mqtt.h"

class BME680 {

  Adafruit_BME680 bme; // NOLINT(*-interfaces-global-init)

  unsigned long last = 0UL;

public:

  const String name;

  unsigned long intervalMs;

  explicit BME680(String  name, const unsigned long interval_ms = 5000) : name(std::move(name)), intervalMs(interval_ms) {
    //
  }

  void setup() {
    if (bme.begin()) {
      Log.printf("BME680 \"%s\": Initialized.\n", name.c_str());
    } else {
      Log.printf("BME680 \"%s\": Failed to initialize.\n", name.c_str());
    }
    bme.setTemperatureOversampling(BME680_OS_8X);
    bme.setHumidityOversampling(BME680_OS_2X);
    bme.setPressureOversampling(BME680_OS_4X);
    bme.setIIRFilterSize(BME680_FILTER_SIZE_3);
    bme.setGasHeater(320, 150);
  }

  void loop() {
    const auto now = max(1UL, millis());
    if (last == 0 || now - last >= intervalMs) {
      if (bme.beginReading() == 0) {
        Log.printf("BME680 \"%s\": Failed to request reading.\n", name.c_str());
        setup();
      }
      last = now;
    }
    if (bme.remainingReadingMillis() == 0) {
      if (bme.endReading()) {
        const auto humidityAbsolute = calculateHumidityAbsolute(bme.temperature, bme.humidity);
        mqttPublishValue(name + "/temperature", bme.temperature, "TEMPERATURE_C");
        mqttPublishValue(name + "/pressure", bme.pressure / 100.0, "PRESSURE_HPA");
        mqttPublishValue(name + "/humidity/relative", bme.humidity, "HUMIDITY_RELATIVE_PERCENT");
        mqttPublishValue(name + "/humidity/absolute", humidityAbsolute, "HUMIDITY_ABSOLUTE_MGL");
        mqttPublishValue(name + "/gas", bme.gas_resistance, "RESISTANCE_OHMS");
        mqttPublishValue(name + "/altitude", bme.readAltitude(1013.25), "ALTITUDE_M");
      } else {
        Log.printf("BME680 \"%s\": Failed to complete reading\n", name.c_str());
        setup();
      }
    }

  }

  static double calculateHumidityAbsolute(const double temperature, const double humidityRelative) {
    constexpr auto A = 6.112;
    constexpr auto m = 17.67;
    constexpr auto Tn = 243.5;
    constexpr auto Mw = 18.01534;
    constexpr auto R = 8.314462618;
    const auto Tk = temperature + 273.15;
    const auto P_sat = A * exp((m * temperature) / (temperature + Tn));
    const auto P_act = P_sat * (humidityRelative / 100.0);
    return (P_act * Mw) / (R * Tk);
  }

};

#endif