242 lines
10 KiB
JavaScript
242 lines
10 KiB
JavaScript
import {queryHourly, getCoords, queryCurrent} from './influx.mjs';
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import {getCelestialCurrent} from './celestial.mjs';
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import {getWeatherCondition} from './openweather.mjs';
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import {localDateStr} from './config.mjs';
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import {uvLabel} from './openmeteo.mjs';
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export let lastForecast = { ts: 0, slots: [], summary: null }
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export const forecastTTL = 5 * 60 * 60_000
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function estimateUV(sunElevation, cloudFraction) {
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if (sunElevation <= 0) return 0;
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const clearSkyUV = Math.sin((sunElevation * Math.PI) / 180) * 12;
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return Math.round(clearSkyUV * (1 - cloudFraction * 0.75) * 10) / 10;
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}
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function linearTrend(values) {
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const n = values.length;
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if (n < 2) return 0;
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const xMean = (n - 1) / 2;
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const yMean = values.reduce((a, b) => a + b, 0) / n;
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const num = values.reduce((s, v, i) => s + (i - xMean) * (v - yMean), 0);
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const den = values.reduce((s, _, i) => s + (i - xMean) ** 2, 0);
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return den === 0 ? 0 : num / den;
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}
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function dewPoint(tempC, humidity) {
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const a = 17.27, b = 237.7;
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const gamma = (a * tempC) / (b + tempC) + Math.log(humidity / 100);
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return (b * gamma) / (a - gamma);
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}
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function heatIndex(tempC, humidity) {
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const T = tempC * 9 / 5 + 32;
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if (T < 80) return tempC;
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const HI =
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-42.379 + 2.04901523 * T + 10.14333127 * humidity
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- 0.22475541 * T * humidity - 0.00683783 * T * T
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- 0.05481717 * humidity * humidity + 0.00122874 * T * T * humidity
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+ 0.00085282 * T * humidity * humidity - 0.00000199 * T * T * humidity * humidity;
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return (HI - 32) * 5 / 9;
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}
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function vaporPressureDeficit(tempC, humidity) {
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const svp = 0.6108 * Math.exp((17.27 * tempC) / (tempC + 237.3));
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return Math.round(svp * (1 - humidity / 100) * 1000) / 1000;
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}
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function absoluteHumidity(tempC, humidity) {
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const svp = 0.6108 * Math.exp((17.27 * tempC) / (tempC + 237.3));
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return Math.round((humidity / 100 * svp * 2165) / (tempC + 273.15) * 1000) / 1000;
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}
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function pressureRule(trend3h, currentHpa) {
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if (trend3h < -2.0) return { label: 'Storm likely', code: 211, precipChance: 0.85 };
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if (trend3h < -0.8) return { label: 'Rain likely', code: 501, precipChance: 0.65 };
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if (trend3h < -0.3) return { label: 'Cloudy', code: 803, precipChance: 0.35 };
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if (trend3h > 1.5) return { label: 'Clearing', code: 801, precipChance: 0.05 };
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if (trend3h > 0.3) return { label: 'Improving', code: 800, precipChance: 0.10 };
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if (currentHpa < 1000) return { label: 'Unsettled', code: 802, precipChance: 0.30 };
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if (currentHpa < 1013) return { label: 'Partly cloudy', code: 802, precipChance: 0.15 };
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return { label: 'Fair', code: 800, precipChance: 0.05 };
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}
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function solarTempDelta(sunElevation, cloudFraction) {
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if (sunElevation <= 0) return 0;
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return Math.sin((sunElevation * Math.PI) / 180) * (1 - cloudFraction) * 6;
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}
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function nocturnalCooling(cloudFraction) {
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return (1 - cloudFraction) * 1.5;
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}
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function forecastHumidity(absHumidity, forecastTempC) {
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const svp = 0.6108 * Math.exp((17.27 * forecastTempC) / (forecastTempC + 237.3));
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const rh = (absHumidity * (forecastTempC + 273.15)) / (svp * 2165) * 100;
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return Math.min(100, Math.max(0, Math.round(rh * 10) / 10));
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}
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function estimateClouds(humidity, pressureTrend) {
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let base = humidity / 100 * 0.8;
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if (pressureTrend < -0.3) base = Math.min(1, base + 0.2);
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if (pressureTrend > 0.3) base = Math.max(0, base - 0.15);
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return Math.round(base * 100) / 100;
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}
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function forecastWind(currentWind, pressureTrend) {
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const boost = pressureTrend < -1 ? 1.3 : pressureTrend < -0.5 ? 1.1 : 1.0;
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return Math.round(currentWind * boost * 10) / 10;
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}
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export async function get24HourForecast(currentSensors) {
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const now = new Date();
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const sixAgo = new Date(now - 6 * 3600 * 1000);
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const coords = await getCoords();
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const history = await queryHourly(sixAgo, now);
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const pressures = history.map(r => r.pressure_hpa).filter(Number.isFinite);
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const temps = history.map(r => r.temperature).filter(Number.isFinite);
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const humidities = history.map(r => r.humidity).filter(Number.isFinite);
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const winds = history.map(r => r.wind_speed).filter(Number.isFinite);
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const pressureTrend = linearTrend(pressures);
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const tempTrend = linearTrend(temps);
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const humidityTrend = linearTrend(humidities);
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const pressure3h = pressureTrend * 3;
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const seedTemp = currentSensors.temperature ?? temps.at(-1) ?? 20;
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const seedHumidity = currentSensors.humidity ?? humidities.at(-1) ?? 60;
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const seedPressure = currentSensors.pressure_hpa ?? pressures.at(-1) ?? 1013;
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const seedWind = currentSensors.wind_speed ?? winds.at(-1) ?? 0;
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const seedAbsHum = currentSensors.humidity_abs ?? absoluteHumidity(seedTemp, seedHumidity);
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const weather = pressureRule(pressure3h, seedPressure);
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const slots = Array.from({ length: 24 }, (_, i) => {
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const time = new Date(now.getTime() + (i + 1) * 3600 * 1000);
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time.setMinutes(0, 0, 0);
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const pressureDamping = Math.exp(-i * 0.08);
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const pressure = seedPressure + pressureTrend * (i + 1) * pressureDamping;
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const clouds = estimateClouds(seedHumidity + humidityTrend * i, pressureTrend);
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const bgTemp = seedTemp + tempTrend * (i + 1);
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const temperature = Math.round(bgTemp * 10) / 10;
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const humidity = forecastHumidity(seedAbsHum, temperature);
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const wind_speed = forecastWind(seedWind, pressureTrend);
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const uv_index = estimateUV(celestial.sun_elevation ?? 0, clouds);
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const celestial = getCelestialCurrent(coords.latitude, coords.longitude, time);
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const snapshot = {
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time,
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temperature,
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humidity,
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humidity_abs: absoluteHumidity(temperature, humidity),
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dew_point: Math.round(dewPoint(temperature, humidity) * 100) / 100,
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heat_index: Math.round(heatIndex(temperature, humidity) * 100) / 100,
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vapor_pressure_deficit: vaporPressureDeficit(temperature, humidity),
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pressure_hpa: Math.round(pressure * 100) / 100,
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wind_speed,
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clouds,
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precipitation_chance: Math.round(weather.precipChance * (1 - i * 0.02) * 100),
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uv_index,
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uv_index_label: uvLabel(uv_index),
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...celestial
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};
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Object.assign(snapshot, getWeatherCondition(snapshot));
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return snapshot;
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});
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for (const slot of slots) {
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if (slot.sunrise && slot.sunset) {
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const t = slot.time instanceof Date ? slot.time.getTime() : new Date(slot.time).getTime();
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const rise = slot.sunrise instanceof Date ? slot.sunrise.getTime() : new Date(slot.sunrise).getTime();
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const set = slot.sunset instanceof Date ? slot.sunset.getTime() : new Date(slot.sunset).getTime();
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slot.daytime = t >= rise && t < set;
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} else {
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slot.daytime = (slot.sun_elevation ?? 0) > 0;
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}
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const solar = solarTempDelta(slot.sun_elevation ?? 0, slot.clouds);
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const cool = slot.daytime ? 0 : nocturnalCooling(slot.clouds);
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slot.temperature = Math.round((slot.temperature + solar - cool) * 10) / 10;
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slot.humidity = forecastHumidity(seedAbsHum, slot.temperature);
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slot.dew_point = Math.round(dewPoint(slot.temperature, slot.humidity) * 100) / 100;
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slot.heat_index = Math.round(heatIndex(slot.temperature, slot.humidity) * 100) / 100;
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slot.vapor_pressure_deficit = vaporPressureDeficit(slot.temperature, slot.humidity);
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slot.humidity_abs = absoluteHumidity(slot.temperature, slot.humidity);
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}
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return slots;
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}
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// Group slots into local-time day buckets, summarise each as daytime-only
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function groupByLocalDay(slots) {
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const days = {}
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for (const slot of slots) {
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const key = localDateStr(new Date(slot.time))
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if (!days[key]) days[key] = []
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days[key].push(slot)
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}
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return days
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}
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function summarise(slots) {
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if (!slots.length) return null
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// Use only daytime slots for representative label/stats, fallback to all if none
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const daytime = slots.filter(s => s.daytime)
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const source = daytime.length ? daytime : slots
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const temps = source.map(s => s.temperature).filter(Number.isFinite)
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const precips = source.map(s => s.precipitation_chance).filter(Number.isFinite)
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const winds = source.map(s => s.wind_speed).filter(Number.isFinite)
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const gusts = source.map(s => s.wind_gusts).filter(Number.isFinite)
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const uvs = source.map(s => s.uv_index).filter(Number.isFinite)
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const solar = source.map(s => s.solar_wm2).filter(Number.isFinite)
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// Min/max temp uses ALL slots for the full day range
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const allTemps = slots.map(s => s.temperature).filter(Number.isFinite)
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const labelCount = {}
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for (const s of source) labelCount[s.label] = (labelCount[s.label] || 0) + 1
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const label = Object.entries(labelCount).sort((a, b) => b[1] - a[1])[0][0]
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const dominant = source.find(s => s.label === label)
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return {
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time: slots[0].time,
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label: dominant.label,
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code: dominant.code,
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icon: dominant.icon,
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temperature: Math.max(...temps),
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temperature_max: Math.max(...allTemps),
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temperature_min: Math.min(...allTemps),
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precipitation_chance: Math.round(Math.max(...precips)),
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wind_speed: Math.round(Math.max(...winds) * 10) / 10,
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wind_gusts: gusts.length ? Math.round(Math.max(...gusts) * 10) / 10 : null,
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uv_index: uvs.length ? Math.max(...uvs) : null,
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uv_index_label: dominant.uv_index_label ?? null,
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solar_wm2: solar.length ? Math.round(solar.reduce((a, b) => a + b, 0) / solar.length * 10) / 10 : null,
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sunrise: slots.find(s => s.sunrise)?.sunrise ?? null,
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sunset: slots.find(s => s.sunset)?.sunset ?? null,
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humidity: Math.round(source.map(s => s.humidity).filter(Number.isFinite).reduce((a, b) => a + b, 0) / source.length * 10) / 10,
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pressure_hpa: Math.round(source.map(s => s.pressure_hpa).filter(Number.isFinite).reduce((a, b) => a + b, 0) / source.length * 10) / 10,
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}
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}
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export async function getForecast() {
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if (Date.now() - lastForecast.ts < forecastTTL) return lastForecast;
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const sensors = await queryCurrent().catch(() => null)
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if (!sensors) return lastForecast
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const slots = await get24HourForecast(sensors).catch(() => null)
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if (!slots) return lastForecast
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// Summarise today's local-day slots only
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const days = groupByLocalDay(slots)
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const todayKey = localDateStr(new Date())
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const todaySlots = days[todayKey] ?? slots
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lastForecast = { ts: Date.now(), slots, summary: summarise(todaySlots) }
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return lastForecast
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}
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