/**
 * LeagueStandingsPresenter - Pure data transformer
 * Transforms API response to view model without DI dependencies.
 */

import { apiClient, type LeagueStandingsViewModel as ApiLeagueStandingsViewModel } from '@/lib/apiClient';

export interface LeagueStandingsEntryViewModel {
  driverId: string;
  driverName: string;
  position: number;
  points: number;
  wins: number;
  podiums: number;
  races: number;
  avatarUrl?: string | undefined;
}

export interface LeagueStandingsViewModel {
  leagueId: string;
  standings: LeagueStandingsEntryViewModel[];
  totalDrivers: number;
}

export interface ILeagueStandingsPresenter {
  present(leagueId: string): Promise<void>;
  getViewModel(): LeagueStandingsViewModel | null;
  reset(): void;
}

/**
 * Transform API response to view model
 */
function transformApiResponse(leagueId: string, apiResponse: ApiLeagueStandingsViewModel): LeagueStandingsViewModel {
  const standings: LeagueStandingsEntryViewModel[] = apiResponse.standings.map((entry) => {
    const viewModel: LeagueStandingsEntryViewModel = {
      driverId: entry.driverId,
      driverName: entry.driver?.name ?? 'Unknown Driver',
      position: entry.position,
      points: entry.points,
      wins: entry.wins,
      podiums: entry.podiums,
      races: entry.races,
    };
    if (entry.driver?.avatarUrl) {
      viewModel.avatarUrl = entry.driver.avatarUrl;
    }
    return viewModel;
  });

  return {
    leagueId,
    standings,
    totalDrivers: standings.length,
  };
}

export class LeagueStandingsPresenter implements ILeagueStandingsPresenter {
  private viewModel: LeagueStandingsViewModel | null = null;

  reset(): void {
    this.viewModel = null;
  }

  async present(leagueId: string): Promise<void> {
    const apiResponse = await apiClient.leagues.getStandings(leagueId);
    this.viewModel = transformApiResponse(leagueId, apiResponse);
  }

  getViewModel(): LeagueStandingsViewModel | null {
    return this.viewModel;
  }
}

/**
 * Convenience function to fetch and transform standings
 */
export async function fetchLeagueStandings(leagueId: string): Promise<LeagueStandingsViewModel> {
  const apiResponse = await apiClient.leagues.getStandings(leagueId);
  return transformApiResponse(leagueId, apiResponse);
}