Display current UV for Météo France results

app/src/main/java/wangdaye/com/geometricweather/weather/converters/CommonConverter.java

@@ -10,6 +10,7 @@
 
 import wangdaye.com.geometricweather.R;
 import wangdaye.com.geometricweather.common.basic.models.weather.AirQuality;
+import wangdaye.com.geometricweather.common.basic.models.weather.UV;
 import wangdaye.com.geometricweather.common.basic.models.weather.Wind;
 
 public class CommonConverter {
@@ -122,4 +123,27 @@ public static boolean isDaylight(Date sunrise, Date sunset, Date current) {
 
         return sunriseTime < currentTime && currentTime < sunsetTime;
     }
+
+    public static UV getCurrentUV(int dayMaxUV, Date currentDate, Date sunriseDate, Date sunsetDate) {
+        if (currentDate == null || sunriseDate == null || sunsetDate == null || sunriseDate.after(sunsetDate))
+            return new UV(null, null, null);
+
+        // You can visualize formula here: https://www.desmos.com/calculator/lna7dco4zi
+        Calendar calendar = Calendar.getInstance();
+        calendar.setTime(currentDate);
+        float currentTime = calendar.get(Calendar.HOUR_OF_DAY) + calendar.get(Calendar.MINUTE) / 60f; // Approximating to the minute is enough
+
+        calendar.setTime(sunriseDate);
+        float sunRiseTime = calendar.get(Calendar.HOUR_OF_DAY) + calendar.get(Calendar.MINUTE) / 60f; // b in desmos graph
+
+        calendar.setTime(sunsetDate);
+        float sunSetTime = calendar.get(Calendar.HOUR_OF_DAY) + calendar.get(Calendar.MINUTE) / 60f; // c in desmos graph
+
+        float sunlightDuration = sunSetTime - sunRiseTime; // d in desmos graph
+
+        float sunRiseOffset = (float) -Math.PI * sunRiseTime / sunlightDuration; // o in desmos graph
+        double currentUV = dayMaxUV * Math.sin(Math.PI / sunlightDuration * currentTime + sunRiseOffset); // dayMaxUV = a in desmos graph
+
+        return new UV(Math.toIntExact(Math.round(currentUV)), null, null);
+    }
 }

app/src/main/java/wangdaye/com/geometricweather/weather/converters/MfResultConverter.java

@@ -206,7 +206,7 @@ public static WeatherService.WeatherResultWrapper convert(Context context,
                                     currentResult.observation.wind.speed * 3.6f,
                                     CommonConverter.getWindLevel(context, currentResult.observation.wind.speed * 3.6f)
                             ),
-                            new UV(null, null, null),
+                            getCurrentUV(new Date(), forecastResult.dailyForecasts),
                             getAirQuality(new Date(), aqiAtmoAuraResult),
                             null,
                             null,
@@ -461,6 +461,17 @@ private static Float getSnowCumul(MfForecastResult.Forecast.Snow snow) {
         return null;
     }
 
+    private static UV getCurrentUV(Date currentDate, List<MfForecastResult.DailyForecast> dailyForecasts) {
+        if (dailyForecasts == null || dailyForecasts.isEmpty())
+            return new UV(null, null, null);
+
+        MfForecastResult.DailyForecast todayForecast = dailyForecasts.get(0);
+        if (todayForecast == null || todayForecast.sun.rise == null || todayForecast.sun.set == null)
+            return new UV(null, null, null);
+
+        return CommonConverter.getCurrentUV(todayForecast.uv, currentDate, new Date(todayForecast.sun.rise * 1000), new Date(todayForecast.sun.set * 1000));
+    }
+
     private static Precipitation getHourlyPrecipitation(MfForecastResult.Forecast hourlyForecast) {
         Float rainCumul = getRainCumul(hourlyForecast.rain);
         Float snowCumul = getSnowCumul(hourlyForecast.snow);