import type { FetchedStandingsRecord, StandingsSyncAdapter } from "./types";
import {
  flattenEspnStandings,
  parseConferenceRank,
  sortByWinLoss,
  statsMap,
  type EspnStandingsResponse,
} from "./espn";

const NBA_STANDINGS_URL =
  "https://site.api.espn.com/apis/v2/sports/basketball/nba/standings";

export class NbaStandingsAdapter implements StandingsSyncAdapter {
  async fetchStandings(): Promise<FetchedStandingsRecord[]> {
    const response = await fetch(NBA_STANDINGS_URL);
    if (!response.ok) {
      throw new Error(`NBA standings API returned ${response.status}: ${response.statusText}`);
    }

    const json = (await response.json()) as EspnStandingsResponse;
    const flattened = flattenEspnStandings(json);

    if (flattened.length === 0) {
      throw new Error("NBA standings API returned no entries — response shape may have changed");
    }

    // Pre-build statsMap once per entry so the sort doesn't rebuild it on every comparison.
    const withSm = flattened.map(({ entry, conference, division }) => ({
      entry,
      conference,
      division,
      sm: statsMap(entry.stats),
    }));

    const sorted = [...withSm].toSorted(sortByWinLoss);

    return sorted.map(({ entry, conference, division, sm }, leagueIdx): FetchedStandingsRecord => {
      const wins = sm.get("wins")?.value ?? 0;
      const losses = sm.get("losses")?.value ?? 0;

      // Fall back to computing win% from wins/losses if ESPN omits the stat.
      const winPctStat = sm.get("winPercent")?.value ?? sm.get("winPct")?.value;
      const winPct = winPctStat ?? (wins + losses > 0 ? wins / (wins + losses) : 0);

      const gamesBehind = sm.get("gamesBehind")?.value;
      const streak = sm.get("streak")?.displayValue ?? sm.get("streakSummary")?.displayValue;
      const lastTen =
        sm.get("Last Ten Games")?.displayValue ?? sm.get("L10")?.displayValue ?? undefined;
      const homeRecord = sm.get("Home")?.displayValue ?? undefined;
      const awayRecord = sm.get("Road")?.displayValue ?? undefined;

      return {
        teamName: entry.team.displayName,
        externalTeamId: entry.team.id,
        wins: Math.round(wins),
        losses: Math.round(losses),
        winPct,
        gamesPlayed: Math.round(wins) + Math.round(losses),
        gamesBack: gamesBehind,
        conference,
        division: division || undefined,
        conferenceRank: parseConferenceRank(sm),
        leagueRank: leagueIdx + 1,
        streak,
        lastTen,
        homeRecord,
        awayRecord,
      };
    });
  }
}