feat: add Open-Meteo weather forecast

lib/forecast-api.ts

@@ -0,0 +1,68 @@
+import type { DailyForecast, HourlyForecast, RawForecastSeries, RawWeatherForecast, WeatherForecast } from "@/types/forecast";
+
+function asArray(value: unknown): unknown[] {
+  return Array.isArray(value) ? value : [];
+}
+
+function readString(series: RawForecastSeries, key: keyof RawForecastSeries, index: number) {
+  const value = asArray(series[key])[index];
+  return typeof value === "string" && value ? value : null;
+}
+
+function readNumber(series: RawForecastSeries, key: keyof RawForecastSeries, index: number) {
+  const value = asArray(series[key])[index];
+  return typeof value === "number" && Number.isFinite(value) ? value : null;
+}
+
+function normalizeHourlyForecast(series: RawForecastSeries = {}): HourlyForecast[] {
+  return asArray(series.time).flatMap((_, index) => {
+    const time = readString(series, "time", index);
+    if (!time) return [];
+    return [{
+      time,
+      temperature: readNumber(series, "temperature_2m", index),
+      feelsLike: readNumber(series, "apparent_temperature", index),
+      precipitationProbability: readNumber(series, "precipitation_probability", index),
+      precipitation: readNumber(series, "precipitation", index),
+      weatherCode: readNumber(series, "weather_code", index),
+      windSpeed: readNumber(series, "wind_speed_10m", index),
+    }];
+  });
+}
+
+function normalizeDailyForecast(series: RawForecastSeries = {}): DailyForecast[] {
+  return asArray(series.time).flatMap((_, index) => {
+    const date = readString(series, "time", index);
+    if (!date) return [];
+    return [{
+      date,
+      temperatureMax: readNumber(series, "temperature_2m_max", index),
+      temperatureMin: readNumber(series, "temperature_2m_min", index),
+      precipitationProbability: readNumber(series, "precipitation_probability_max", index),
+      precipitation: readNumber(series, "precipitation_sum", index),
+      weatherCode: readNumber(series, "weather_code", index),
+      sunrise: readString(series, "sunrise", index),
+      sunset: readString(series, "sunset", index),
+    }];
+  });
+}
+
+function normalizeForecast(raw: RawWeatherForecast): WeatherForecast {
+  const latitude = Number(raw.latitude);
+  const longitude = Number(raw.longitude);
+  if (!Number.isFinite(latitude) || !Number.isFinite(longitude)) throw new Error("Forecast service returned invalid coordinates.");
+  return {
+    latitude,
+    longitude,
+    timezone: typeof raw.timezone === "string" ? raw.timezone : "Europe/Warsaw",
+    hourly: normalizeHourlyForecast(raw.hourly),
+    daily: normalizeDailyForecast(raw.daily),
+  };
+}
+
+export async function fetchForecast(latitude: number, longitude: number, signal?: AbortSignal) {
+  const params = new URLSearchParams({ latitude: String(latitude), longitude: String(longitude) });
+  const response = await fetch(`/api/forecast?${params}`, { signal });
+  if (!response.ok) throw new Error("Unable to load forecast.");
+  return normalizeForecast(await response.json() as RawWeatherForecast);
+}

lib/forecast-utils.ts

@@ -0,0 +1,28 @@
+import type { Language, TranslationKey } from "@/lib/i18n";
+import { translate } from "@/lib/i18n";
+
+export function getForecastConditionKey(code: number | null): TranslationKey {
+  if (code === 0) return "forecast.condition.clear";
+  if (code === 1 || code === 2) return "forecast.condition.partlyCloudy";
+  if (code === 3) return "forecast.condition.cloudy";
+  if (code === 45 || code === 48) return "forecast.condition.fog";
+  if (code !== null && code >= 51 && code <= 57) return "forecast.condition.drizzle";
+  if (code !== null && ((code >= 61 && code <= 67) || (code >= 80 && code <= 82))) return "forecast.condition.rain";
+  if (code !== null && ((code >= 71 && code <= 77) || code === 85 || code === 86)) return "forecast.condition.snow";
+  if (code !== null && code >= 95) return "forecast.condition.thunderstorm";
+  return "forecast.condition.unknown";
+}
+
+export function getForecastCondition(code: number | null, language: Language) {
+  return translate(language, getForecastConditionKey(code));
+}
+
+export function formatForecastTemperature(value: number | null, language: Language) {
+  if (value === null) return "—";
+  return `${new Intl.NumberFormat(language === "pl" ? "pl-PL" : "en-GB", { maximumFractionDigits: 0 }).format(value)}°`;
+}
+
+export function formatForecastRainfall(value: number | null, language: Language) {
+  if (value === null) return "—";
+  return `${new Intl.NumberFormat(language === "pl" ? "pl-PL" : "en-GB", { maximumFractionDigits: 1 }).format(value)} mm`;
+}

lib/i18n.tsx

@@ -66,6 +66,25 @@ const translations = {
     "weather.windDirectionDetail": "Kierunek napływu wiatru",
     "weather.rainfallDetail": "Suma opadu z pomiaru IMGW",
     "weather.temperatureDetail": "Temperatura powietrza",
+    "forecast.label": "Prognoza modelowa",
+    "forecast.title": "Najbliższe godziny i dni",
+    "forecast.description": "Prognoza dla {location}. Bieżący pomiar powyżej pochodzi ze stacji IMGW, a poniższe wartości są prognozą modelową.",
+    "forecast.hourly": "Najbliższe 24 godziny",
+    "forecast.daily": "Prognoza 7-dniowa",
+    "forecast.today": "Dzisiaj",
+    "forecast.source": "Źródło prognozy:",
+    "forecast.error": "Nie udało się pobrać prognozy Open-Meteo.",
+    "forecast.emptyTitle": "Brak prognozy",
+    "forecast.emptyDescription": "Open-Meteo nie zwróciło teraz kompletnej prognozy dla tej lokalizacji.",
+    "forecast.condition.clear": "Bezchmurnie",
+    "forecast.condition.partlyCloudy": "Częściowe zachmurzenie",
+    "forecast.condition.cloudy": "Pochmurno",
+    "forecast.condition.fog": "Mgła",
+    "forecast.condition.drizzle": "Mżawka",
+    "forecast.condition.rain": "Opady deszczu",
+    "forecast.condition.snow": "Opady śniegu",
+    "forecast.condition.thunderstorm": "Burza",
+    "forecast.condition.unknown": "Brak opisu",
     "stations.emptyTitle": "Brak pasujących stacji",
     "station.all": "Wszystkie stacje",
     "station.label": "Stacja {name}",
@@ -176,6 +195,25 @@ const translations = {
     "weather.windDirectionDetail": "Direction the wind is coming from",
     "weather.rainfallDetail": "Total rainfall from the IMGW reading",
     "weather.temperatureDetail": "Air temperature",
+    "forecast.label": "Model forecast",
+    "forecast.title": "Upcoming hours and days",
+    "forecast.description": "Forecast for {location}. The current reading above comes from an IMGW station. The values below are a model forecast.",
+    "forecast.hourly": "Next 24 hours",
+    "forecast.daily": "7-day forecast",
+    "forecast.today": "Today",
+    "forecast.source": "Forecast source:",
+    "forecast.error": "Unable to load the Open-Meteo forecast.",
+    "forecast.emptyTitle": "Forecast unavailable",
+    "forecast.emptyDescription": "Open-Meteo did not return a complete forecast for this location.",
+    "forecast.condition.clear": "Clear sky",
+    "forecast.condition.partlyCloudy": "Partly cloudy",
+    "forecast.condition.cloudy": "Cloudy",
+    "forecast.condition.fog": "Fog",
+    "forecast.condition.drizzle": "Drizzle",
+    "forecast.condition.rain": "Rain",
+    "forecast.condition.snow": "Snow",
+    "forecast.condition.thunderstorm": "Thunderstorm",
+    "forecast.condition.unknown": "Description unavailable",
     "stations.emptyTitle": "No matching stations",
     "station.all": "All stations",
     "station.label": "Station {name}",

lib/location-utils.ts

@@ -59,6 +59,8 @@ export function findNearestSynopStation(location: LocationSearchResult, stations
   return {
     name: location.name,
     province: location.province,
+    latitude: location.latitude,
+    longitude: location.longitude,
     stationId: nearest.station.id,
     stationName: nearest.station.name,
     distanceKm: Math.round(nearest.distanceKm),