class DataStitchingService {
  constructor({ usersRepository }) {
    this.usersRepository = usersRepository;
  }

  async populateBetsWithUsers(bets) {
    if (!bets || bets.length === 0) return [];

    const userIds = new Set();
    bets.forEach((bet) => {
      bet.participants.forEach((p) => userIds.add(p.user));
      if (bet.winner) {
        userIds.add(bet.winner);
      }
    });

    if (userIds.size === 0)
      return bets.map((b) => (typeof b.toJSON === 'function' ? b.toJSON() : b));

    const users = await this.usersRepository.findAll({
      where: { id: Array.from(userIds) },
    });
    const userMap = new Map(
      users.map((u) => [u.id, typeof u.toJSON === 'function' ? u.toJSON() : u])
    );

    return bets.map((bet) => {
      const betJson = typeof bet.toJSON === 'function' ? bet.toJSON() : bet;
      betJson.participants = betJson.participants.map((p) => ({
        ...p,
        user: userMap.get(p.user) || null,
      }));
      if (betJson.winner) {
        betJson.winner = userMap.get(betJson.winner) || null;
      }
      return betJson;
    });
  }
}

module.exports = DataStitchingService;