/**
 * The one shape the UI understands.
 *
 * Every provider returns wildly different JSON. Each adapter in ./providers
 * translates its provider's response into these types, so the UI never has
 * to know which provider it is talking to.
 *
 * Rules every adapter follows:
 *   - Units are metric: °C, km/h, hPa, km, mm.
 *   - Times are ISO-8601 instants in UTC ("2026-10-21T23:00:00.000Z").
 *     The UI formats them in the location's time zone.
 *   - A reading the provider doesn't offer is `null`, and the UI hides it.
 */

export type ProviderId = "openweather" | "weatherapi" | "tomorrow" | "openmeteo";

/** A deliberately small set of conditions — one per pixel icon. */
export type Condition = "clear" | "clouds" | "rain" | "storm" | "snow" | "fog";

export interface Place {
  name: string;
  region?: string;
  country?: string;
  lat: number;
  lon: number;
}

export interface CurrentWeather {
  time: string;
  tempC: number;
  feelsLikeC: number;
  condition: Condition;
  description: string; // human words, e.g. "light rain"
  isDay: boolean;
  humidity: number; // %
  windKph: number;
  gustKph: number | null;
  windDeg: number | null; // direction the wind blows FROM, 0 = north
  pressureHpa: number | null;
  dewPointC: number | null;
  visibilityKm: number | null;
  uvIndex: number | null;
  cloudCover: number | null; // %
  precipMm: number | null; // in the last hour
}

export interface HourlyForecast {
  time: string; // start of the hour (or 3-hour block)
  tempC: number;
  feelsLikeC: number | null;
  condition: Condition;
  isDay: boolean;
  precipChance: number | null; // %
  precipMm: number | null;
  windKph: number;
  gustKph: number | null;
  windDeg: number | null;
  humidity: number | null;
  uvIndex: number | null;
}

export interface DailyForecast {
  time: string; // any instant inside that local day (midday where possible)
  highC: number;
  lowC: number;
  condition: Condition;
  summary: string | null; // provider's own one-liner, if it has one
  precipChance: number | null;
  precipMm: number | null;
  windKph: number | null; // daily max
  gustKph: number | null;
  windDeg: number | null;
  uvIndexMax: number | null;
  humidity: number | null; // daily average
  sunrise: string | null;
  sunset: string | null;
}

export type AlertSeverity = "extreme" | "severe" | "moderate" | "minor" | "unknown";

export interface WeatherAlert {
  title: string;
  severity: AlertSeverity;
  source: string; // who issued it, e.g. "NWS Twin Cities/Chanhassen MN"
  starts: string | null;
  ends: string | null;
  description: string;
  instruction: string | null;
}

export interface AirQuality {
  usAqi: number; // US EPA scale, 0–500
  pm25: number | null; // µg/m³
  pm10: number | null;
  ozone: number | null;
  no2: number | null;
}

/** What one provider adapter returns. */
export interface ProviderForecast {
  current: CurrentWeather;
  hourly: HourlyForecast[];
  daily: DailyForecast[];
  hourlyStepHours: 1 | 3;
  timeZone: string | null; // IANA name, if the provider tells us
  alerts: WeatherAlert[];
}

/** What /api/weather returns: the provider's forecast plus extras from other sources. */
export interface WeatherReport extends ProviderForecast {
  provider: ProviderId;
  timeZone: string | null;
  airQuality: AirQuality | null;
  alertSource: string | null;
  fetchedAt: string;
}

/** The contract each provider adapter fulfils. */
export interface WeatherProvider {
  id: ProviderId;
  label: string;
  /** Name of the env var holding its key, or null if no key is needed. */
  envKey: string | null;
  /** Forecast horizon available on the configured tier. */
  limits(): { forecastDays: number; hourlyStepHours: 1 | 3 };
  getForecast(lat: number, lon: number): Promise<ProviderForecast>;
}

/** Configured provider metadata exposed to the browser (never includes keys). */
export interface ProviderInfo {
  id: ProviderId;
  label: string;
  forecastDays: number;
  hourlyStepHours: 1 | 3;
}

/** Map overlays the radar panel can show. */
export interface RadarFrame {
  time: string;
  url: string; // Leaflet tile template with {z}/{x}/{y}
}