Rewrite sun component calculations (#1661)

esphome/components/sun/sun.h

@@ -8,85 +8,72 @@
 namespace esphome {
 namespace sun {
 
+namespace internal {
+
+/* Usually, ESPHome uses single-precision floating point values
+ * because those tend to be accurate enough and are more efficient.
+ *
+ * However, some of the data in this class has to be quite accurate, so double is
+ * used everywhere.
+ */
+using num_t = double;
+struct GeoLocation {
+  num_t latitude;
+  num_t longitude;
+
+  num_t latitude_rad() const;
+  num_t longitude_rad() const;
+};
+
+struct Moment {
+  time::ESPTime dt;
+
+  num_t jd() const;
+  num_t jde() const;
+};
+
+struct EquatorialCoordinate {
+  num_t right_ascension;
+  num_t declination;
+
+  num_t right_ascension_rad() const;
+  num_t declination_rad() const;
+};
+
+struct HorizontalCoordinate {
+  num_t elevation;
+  num_t azimuth;
+
+  num_t elevation_rad() const;
+  num_t azimuth_rad() const;
+};
+
+}  // namespace internal
+
 class Sun {
  public:
   void set_time(time::RealTimeClock *time) { time_ = time; }
   time::RealTimeClock *get_time() const { return time_; }
-  void set_latitude(double latitude) { latitude_ = latitude; }
-  void set_longitude(double longitude) { longitude_ = longitude; }
+  void set_latitude(double latitude) { location_.latitude = latitude; }
+  void set_longitude(double longitude) { location_.longitude = longitude; }
 
-  optional<time::ESPTime> sunrise(double elevation = 0.0);
-  optional<time::ESPTime> sunset(double elevation = 0.0);
+  optional<time::ESPTime> sunrise(double elevation);
+  optional<time::ESPTime> sunset(double elevation);
 
   double elevation();
   double azimuth();
 
  protected:
-  double current_sun_time_() { return this->calc_sun_time_(this->time_->utcnow()); }
-
-  /** Calculate the declination of the sun in rad.
-   *
-   * See https://en.wikipedia.org/wiki/Position_of_the_Sun#Declination_of_the_Sun_as_seen_from_Earth
-   *
-   * Accuracy: ±0.2°
-   *
-   * @param sun_time The day of the year, 1 means January 1st. See calc_sun_time_.
-   * @return Sun declination in degrees
-   */
-  double sun_declination_(double sun_time);
-
-  double elevation_ratio_(double sun_time);
-
-  /** Calculate the hour angle based on the sun time of day in hours.
-   *
-   * Positive in morning, 0 at noon, negative in afternoon.
-   *
-   * @param sun_time Sun time, see calc_sun_time_.
-   * @return Hour angle in rad.
-   */
-  double hour_angle_(double sun_time);
-
-  double elevation_(double sun_time);
-
-  double elevation_rad_(double sun_time);
-
-  double zenith_rad_(double sun_time);
-
-  double azimuth_rad_(double sun_time);
-
-  double azimuth_(double sun_time);
-
-  /** Return the sun time given by the time_ object.
-   *
-   * Sun time is defined as doubleing point day of year.
-   * Integer part encodes the day of the year (1=January 1st)
-   * Decimal part encodes time of day (1/24 = 1 hour)
-   */
-  double calc_sun_time_(const time::ESPTime &time);
-
-  uint32_t calc_epoch_(time::ESPTime base, double sun_time);
-
-  /** Calculate the sun time of day
-   *
-   * @param day_of_year
-   * @param elevation
-   * @param rising
-   * @return
-   */
-  double sun_time_for_elevation_(int32_t day_of_year, double elevation, bool rising);
-
-  double latitude_rad_();
+  internal::HorizontalCoordinate calc_coords_();
+  optional<time::ESPTime> calc_event_(bool rising, double zenith);
 
   time::RealTimeClock *time_;
-  /// Latitude in degrees, range: -90 to 90.
-  double latitude_;
-  /// Longitude in degrees, range: -180 to 180.
-  double longitude_;
+  internal::GeoLocation location_;
 };
 
 class SunTrigger : public Trigger<>, public PollingComponent, public Parented<Sun> {
  public:
-  SunTrigger() : PollingComponent(1000) {}
+  SunTrigger() : PollingComponent(60000) {}
 
   void set_sunrise(bool sunrise) { sunrise_ = sunrise; }
   void set_elevation(double elevation) { elevation_ = elevation; }