import { Injectable, Logger } from '@nestjs/common';
import { Cron } from '@nestjs/schedule';
import { BROADCAST_ADDR } from '../mesh/codec.js';
import { MeshService } from '../mesh/mesh.service.js';

/** Open-Meteo `current` block fields we use (free API, no key). */
export interface CurrentWeather {
  temperature_2m: number;
  apparent_temperature: number;
  relative_humidity_2m: number;
  wind_speed_10m: number;
  weather_code: number;
}

// WMO weather interpretation codes (the common ones); unknown → `code <n>`
const WMO_CODES: Record<number, string> = {
  0: 'clear',
  1: 'mainly clear',
  2: 'partly cloudy',
  3: 'overcast',
  45: 'fog',
  48: 'freezing fog',
  51: 'light drizzle',
  53: 'drizzle',
  55: 'heavy drizzle',
  61: 'light rain',
  63: 'rain',
  65: 'heavy rain',
  71: 'light snow',
  73: 'snow',
  75: 'heavy snow',
  80: 'light rain showers',
  81: 'rain showers',
  82: 'violent rain showers',
  95: 'thunderstorm',
};

@Injectable()
export class WeatherService {
  private readonly logger = new Logger(WeatherService.name);
  // read at construction, like MeshService's env config
  private readonly lat = parseFloat(process.env.WEATHER_LAT ?? '51.2465');
  private readonly lon = parseFloat(process.env.WEATHER_LON ?? '22.5684');
  private readonly city = process.env.WEATHER_CITY ?? 'Lublin';

  constructor(private readonly mesh: MeshService) {}

  /** Fetch current conditions from Open-Meteo; throws on HTTP/parse failure. */
  async fetchWeather(): Promise<CurrentWeather> {
    const url =
      `https://api.open-meteo.com/v1/forecast?latitude=${this.lat}` +
      `&longitude=${this.lon}` +
      `&current=temperature_2m,apparent_temperature,relative_humidity_2m,wind_speed_10m,weather_code`;
    const res = await fetch(url);
    if (!res.ok) throw new Error(`open-meteo HTTP ${res.status}`);
    const json = (await res.json()) as { current: CurrentWeather };
    return json.current;
  }

  /** One short line, e.g. `Lublin weather: 18°C (feels 17), partly cloudy, humidity 65%, wind 12 km/h`. */
  formatReport(current: CurrentWeather): string {
    const desc =
      WMO_CODES[current.weather_code] ?? `code ${current.weather_code}`;
    return `${this.city} weather: ${Math.round(current.temperature_2m)}°C (feels ${Math.round(
      current.apparent_temperature,
    )}), ${desc}, humidity ${Math.round(current.relative_humidity_2m)}%, wind ${Math.round(
      current.wind_speed_10m,
    )} km/h`;
  }

  /** Hourly cron: fetch → format → broadcast on the pinned send channel. Never throws — a failed report must not crash the app. */
  @Cron(process.env.WEATHER_CRON || '0 * * * *')
  async report(): Promise<void> {
    try {
      const current = await this.fetchWeather();
      await this.mesh.sendText(BROADCAST_ADDR, this.formatReport(current));
    } catch (err) {
      this.logger.warn(`[weather] report failed: ${(err as Error).message}`);
    }
  }
}