import { steam2ToSteam64 } from './steam';

export interface SteamSummary {
  avatarUrl: string;
  personaName: string | null;
}

// Steam's generic "no avatar set" question-mark image — used whenever a
// player has no avatar, or the lookup fails for any reason.
export const DEFAULT_AVATAR_URL =
  'https://steamcdn-a.akamaihd.net/steamcommunity/public/images/avatars/fe/fef49e7fa7e1997310d705b2a6158ff8dc1cdfeb_full.jpg';

/**
 * Fetches avatar + persona name from Steam's GetPlayerSummaries endpoint.
 * Always resolves to a usable avatarUrl (falls back to the default
 * question-mark image on any failure — including a missing STEAM_API_KEY)
 * rather than null, so callers don't need their own fallback logic.
 *
 * Cached for an hour via Next's extended fetch() — avatars rarely change,
 * and this keeps calls well within Steam's rate limits without needing a
 * separate DB cache table.
 */
export async function getSteamSummary(steamId64: string): Promise<SteamSummary> {
  const apiKey = process.env.STEAM_API_KEY;
  if (!apiKey) {
    return { avatarUrl: DEFAULT_AVATAR_URL, personaName: null };
  }

  try {
    const res = await fetch(
      `https://api.steampowered.com/ISteamUser/GetPlayerSummaries/v0002/?key=${apiKey}&steamids=${steamId64}`,
      { next: { revalidate: 3600 } },
    );
    if (!res.ok) {
      return { avatarUrl: DEFAULT_AVATAR_URL, personaName: null };
    }

    const data = await res.json();
    const player = data?.response?.players?.[0];

    return {
      avatarUrl: player?.avatarfull || DEFAULT_AVATAR_URL,
      personaName: player?.personaname ?? null,
    };
  } catch {
    return { avatarUrl: DEFAULT_AVATAR_URL, personaName: null };
  }
}

/**
 * Same as getSteamSummary, but for many players in one go — Steam's
 * GetPlayerSummaries accepts up to 100 comma-separated steamids per call,
 * so fetching a list of players (e.g. "who was online at this point in
 * time") is one HTTP call per 100 players rather than one per player.
 * Returns a map keyed by SteamID64; missing entries mean "use the default
 * avatar" at the call site.
 */
export async function getSteamSummariesBatch(
  steamId64List: string[],
): Promise<Map<string, SteamSummary>> {
  const result = new Map<string, SteamSummary>();
  const apiKey = process.env.STEAM_API_KEY;
  if (!apiKey || steamId64List.length === 0) {
    return result;
  }

  const chunks: string[][] = [];
  for (let i = 0; i < steamId64List.length; i += 100) {
    chunks.push(steamId64List.slice(i, i + 100));
  }

  await Promise.all(
    chunks.map(async (chunk) => {
      try {
        const res = await fetch(
          `https://api.steampowered.com/ISteamUser/GetPlayerSummaries/v0002/?key=${apiKey}&steamids=${chunk.join(',')}`,
          { next: { revalidate: 3600 } },
        );
        if (!res.ok) return;

        const data = await res.json();
        const players = data?.response?.players ?? [];
        for (const player of players) {
          result.set(player.steamid, {
            avatarUrl: player.avatarfull || DEFAULT_AVATAR_URL,
            personaName: player.personaname ?? null,
          });
        }
      } catch {
        // this chunk's players just fall back to the default avatar downstream
      }
    }),
  );

  return result;
}

/**
 * Attaches avatarUrl to any list of objects that have a `steamid` (Steam2
 * format) field — the shared enrichment step used everywhere a list of
 * players gets rendered, so every list in the app shows avatars
 * consistently without duplicating the batch-fetch/fallback logic per call
 * site.
 */
export async function attachAvatars<T extends { steamid: string }>(
  players: T[],
): Promise<(T & { avatarUrl: string })[]> {
  const steam64ByPlayer = new Map<string, string>();
  for (const p of players) {
    const id64 = steam2ToSteam64(p.steamid);
    if (id64) steam64ByPlayer.set(p.steamid, id64);
  }

  const avatars = await getSteamSummariesBatch([...steam64ByPlayer.values()]);

  return players.map((p) => {
    const id64 = steam64ByPlayer.get(p.steamid);
    const avatarUrl = (id64 && avatars.get(id64)?.avatarUrl) || DEFAULT_AVATAR_URL;
    return { ...p, avatarUrl };
  });
}