import type { Logger, UseCaseOutputPort } from '@core/shared/application';
import { Result } from '@core/shared/application/Result';
import type { ApplicationErrorCode } from '@core/shared/errors/ApplicationErrorCode';
import type { Driver } from '../../domain/entities/Driver';
import type { Team } from '../../domain/entities/Team';
import type { IDriverRepository } from '../../domain/repositories/IDriverRepository';
import type { IDriverStatsService } from '../../domain/services/IDriverStatsService';
import type { IRankingService } from '../../domain/services/IRankingService';
import { SkillLevelService, type SkillLevel } from '../../domain/services/SkillLevelService';

export type GetDriversLeaderboardInput = {
  leagueId?: string;
  seasonId?: string;
};

export interface DriverLeaderboardItem {
  driver: Driver;
  team?: Team;
  rating: number;
  skillLevel: SkillLevel;
  racesCompleted: number;
  wins: number;
  podiums: number;
  isActive: boolean;
  rank: number;
  avatarUrl?: string;
}

export interface GetDriversLeaderboardResult {
  items: DriverLeaderboardItem[];
  totalRaces: number;
  totalWins: number;
  activeCount: number;
}

export type GetDriversLeaderboardErrorCode =
  | 'LEAGUE_NOT_FOUND'
  | 'SEASON_NOT_FOUND'
  | 'REPOSITORY_ERROR';

/**
 * Use Case for retrieving driver leaderboard data.
 * Returns a Result containing the domain leaderboard model.
 */
export class GetDriversLeaderboardUseCase {
  constructor(
    private readonly driverRepository: IDriverRepository,
    private readonly rankingService: IRankingService,
    private readonly driverStatsService: IDriverStatsService,
    private readonly getDriverAvatar: (driverId: string) => Promise<string | undefined>,
    private readonly logger: Logger,
    private readonly output: UseCaseOutputPort<GetDriversLeaderboardResult>,
  ) {}

  async execute(
    input: GetDriversLeaderboardInput,
  ): Promise<
    Result<
      void,
      ApplicationErrorCode<GetDriversLeaderboardErrorCode, { message: string }>
    >
  > {
    this.logger.debug('Executing GetDriversLeaderboardUseCase', { input });

    try {
      const drivers = await this.driverRepository.findAll();
      const rankings = this.rankingService.getAllDriverRankings();

      const avatarUrls: Record<string, string | undefined> = {};

      for (const driver of drivers) {
        avatarUrls[driver.id] = await this.getDriverAvatar(driver.id);
      }

      // TODO maps way too much data, should just create Domain Objects

      const items: DriverLeaderboardItem[] = drivers.map(driver => {
        const ranking = rankings.find(r => r.driverId === driver.id);
        const stats = this.driverStatsService.getDriverStats(driver.id);
        const rating = ranking?.rating ?? 0;
        const racesCompleted = stats?.totalRaces ?? 0;
        const skillLevel: SkillLevel = SkillLevelService.getSkillLevel(rating);
        const avatarUrl = avatarUrls[driver.id];

        return {
          driver,
          rating,
          skillLevel,
          racesCompleted,
          wins: stats?.wins ?? 0,
          podiums: stats?.podiums ?? 0,
          isActive: racesCompleted > 0,
          rank: ranking?.overallRank ?? 0,
          ...(avatarUrl !== undefined ? { avatarUrl } : {}),
        };
      });

      const totalRaces = items.reduce((sum, d) => sum + d.racesCompleted, 0);
      const totalWins = items.reduce((sum, d) => sum + d.wins, 0);
      const activeCount = items.filter(d => d.isActive).length;

      const result: GetDriversLeaderboardResult = {
        items: items.sort((a, b) => b.rating - a.rating),
        totalRaces,
        totalWins,
        activeCount,
      };

      this.logger.debug('Successfully computed drivers leaderboard');

      this.output.present(result);

      return Result.ok(undefined);
    } catch (error) {
      const err = error instanceof Error ? error : new Error(String(error));

      this.logger.error('Error executing GetDriversLeaderboardUseCase', err);

      return Result.err({
        code: 'REPOSITORY_ERROR',
        details: { message: err.message ?? 'Unknown error occurred' },
      });
    }
  }
}