import type {
  ILeagueMembershipRepository,
} from '@gridpilot/racing/domain/repositories/ILeagueMembershipRepository';
import type {
  LeagueMembership,
  MembershipRole,
  MembershipStatus,
} from '@gridpilot/racing/domain/entities/LeagueMembership';

export interface JoinLeagueCommand {
  leagueId: string;
  driverId: string;
}

export class JoinLeagueUseCase {
  constructor(private readonly membershipRepository: ILeagueMembershipRepository) {}

  /**
   * Joins a driver to a league as an active member.
   *
   * Mirrors the behavior of the legacy joinLeague function:
   * - Throws when membership already exists for this league/driver.
   * - Creates a new active membership with role "member" and current timestamp.
   */
  async execute(command: JoinLeagueCommand): Promise<LeagueMembership> {
    const { leagueId, driverId } = command;

    const existing = await this.membershipRepository.getMembership(leagueId, driverId);
    if (existing) {
      throw new Error('Already a member or have a pending request');
    }

    const membership: LeagueMembership = {
      leagueId,
      driverId,
      role: 'member' as MembershipRole,
      status: 'active' as MembershipStatus,
      joinedAt: new Date(),
    };

    return this.membershipRepository.saveMembership(membership);
  }
}