package service

import (
	"context"
	"errors"

	"google.golang.org/protobuf/types/known/emptypb"

	"datarush/internal/user/middleware"
	pb "datarush/pkg/api/user"
)

type UserRepository interface {
	GetProfile(ctx context.Context, userID string) (*pb.User, error)
	RegisterForCompetition(ctx context.Context, userID, competitionID string) error
	UnregisterFromCompetition(ctx context.Context, userID, competitionID string) error
	ListUserCompetitions(ctx context.Context, userID string) ([]string, error)
}

type UserService struct {
	repo UserRepository
}

func NewUserService(repo UserRepository) *UserService {
	return &UserService{repo: repo}
}

func (s *UserService) GetProfile(ctx context.Context, req *pb.GetProfileRequest) (*pb.User, error) {
	return s.repo.GetProfile(ctx, req.UserId)
}

func (s *UserService) RegisterForCompetition(
	ctx context.Context,
	req *pb.RegisterForCompetitionRequest,
) (*emptypb.Empty, error) {
	userID, ok := ctx.Value(middleware.UserIDKey{}).(string)
	if !ok {
		return nil, errors.New("user ID not found in context")
	}

	err := s.repo.RegisterForCompetition(ctx, userID, req.CompetitionId)
	return &emptypb.Empty{}, err
}

func (s *UserService) UnregisterFromCompetition(
	ctx context.Context,
	req *pb.UnregisterFromCompetitionRequest,
) (*emptypb.Empty, error) {
	userID, ok := ctx.Value(middleware.UserIDKey{}).(string)
	if !ok {
		return nil, errors.New("user ID not found in context")
	}

	err := s.repo.UnregisterFromCompetition(ctx, userID, req.CompetitionId)
	return &emptypb.Empty{}, err
}

func (s *UserService) ListUserCompetitions(
	ctx context.Context,
	req *pb.ListUserCompetitionsRequest,
) (*pb.ListUserCompetitionsResponse, error) {
	competitionIDs, err := s.repo.ListUserCompetitions(ctx, req.UserId)
	if err != nil {
		return nil, err
	}
	return &pb.ListUserCompetitionsResponse{CompetitionIds: competitionIDs}, nil
}