HomeMonitor/Weather/Service/Models/WeatherUpdate.cs

using ChrisKaczor.HomeMonitor.Weather.Models;
using ChrisKaczor.HomeMonitor.Weather.Service.Data;
using DecimalMath;
using JetBrains.Annotations;
using MathNet.Numerics;
using System.Linq;

namespace ChrisKaczor.HomeMonitor.Weather.Service.Models;

[PublicAPI]
public class WeatherUpdate : WeatherUpdateBase
{
    private readonly Database _database;

    public WeatherUpdate(WeatherMessage weatherMessage, Database database)
    {
        _database = database;

        Type = weatherMessage.Type;
        Message = weatherMessage.Message;
        Timestamp = weatherMessage.Timestamp;
        WindDirection = weatherMessage.WindDirection;
        WindSpeed = weatherMessage.WindSpeed;
        Humidity = weatherMessage.Humidity;
        Rain = weatherMessage.Rain;
        Pressure = weatherMessage.Pressure;
        Temperature = weatherMessage.HumidityTemperature;
        LightLevel = weatherMessage.LightLevel;
        Latitude = weatherMessage.Latitude;
        Longitude = weatherMessage.Longitude;
        Altitude = weatherMessage.Altitude;
        SatelliteCount = weatherMessage.SatelliteCount;
        GpsTimestamp = weatherMessage.GpsTimestamp;

        CalculateHeatIndex();
        CalculateWindChill();
        CalculateDewPoint();
        CalculatePressureTrend();
        CalculateRainLastHour();
    }

    private void CalculateRainLastHour()
    {
        RainLastHour = _database.GetReadingValueSum(WeatherValueType.Rain, Timestamp.AddHours(-1), Timestamp).Result;
    }

    private void CalculateWindChill()
    {
        var temperatureInF = Temperature;
        var windSpeedInMph = WindSpeed;

        if (temperatureInF.IsBetween(-45, 45) && windSpeedInMph.IsBetween(3, 60))
        {
            WindChill = 35.74m + 0.6215m * temperatureInF - 35.75m * DecimalEx.Pow(windSpeedInMph, 0.16m) + 0.4275m * temperatureInF * DecimalEx.Pow(windSpeedInMph, 0.16m);
        }
    }

    private void CalculateDewPoint()
    {
        var relativeHumidity = Humidity;
        var temperatureInF = Temperature;

        var temperatureInC = (temperatureInF - 32.0m) * 5.0m / 9.0m;

        var vaporPressure = relativeHumidity * 0.01m * 6.112m * DecimalEx.Exp(17.62m * temperatureInC / (temperatureInC + 243.12m));
        var numerator = 243.12m * DecimalEx.Log(vaporPressure) - 440.1m;
        var denominator = 19.43m - DecimalEx.Log(vaporPressure);
        var dewPointInC = numerator / denominator;

        DewPoint = dewPointInC * 9.0m / 5.0m + 32.0m;
    }

    private void CalculatePressureTrend()
    {
        var pressureData = _database
            .GetReadingValueHistory(WeatherValueType.Pressure, Timestamp.AddHours(-3), Timestamp).Result.ToList();

        var xData = pressureData.Select(p => (double)p.Timestamp.ToUnixTimeSeconds()).ToArray();
        var yData = pressureData.Select(p => (double)p.Value / 100.0).ToArray();

        var lineFunction = Fit.LineFunc(xData, yData);

        PressureDifferenceThreeHour = (decimal)(lineFunction(xData.Last()) - lineFunction(xData[0]));
    }

    private void CalculateHeatIndex()
    {
        var temperature = Temperature;
        var humidity = Humidity;

        if (temperature > 80 && humidity > 40)
        {
            HeatIndex = -42.379m + 2.04901523m * temperature + 10.14333127m * humidity -
                        .22475541m * temperature * humidity - .00683783m * temperature * temperature -
                        .05481717m * humidity * humidity + .00122874m * temperature * temperature * humidity +
                        .00085282m * temperature * humidity * humidity -
                        .00000199m * temperature * temperature * humidity * humidity;
        }
    }
}