ds-galo/backend/internal/social/service.go

package social

import (
	"context"
	"errors"
	"strings"

	"shared-album/internal/auth"
	"shared-album/internal/httpx"
	"shared-album/internal/models"
	"shared-album/internal/roles"
	"shared-album/internal/sse"
)

type AlbumAccess interface {
	Access(ctx context.Context, albumID, userID string) (*models.Album, string, error)
}

type PhotoLookup interface {
	GetByID(ctx context.Context, id, viewerID string) (*models.Photo, error)
}

type Notifier interface {
	Create(ctx context.Context, userID, typ string, payload map[string]any) error
}

type Service struct {
	store  Repository
	albums AlbumAccess
	photos PhotoLookup
	hub    *sse.Hub
	notify Notifier
}

func NewService(store Repository, albums AlbumAccess, photos PhotoLookup, hub *sse.Hub, notify Notifier) *Service {
	return &Service{store: store, albums: albums, photos: photos, hub: hub, notify: notify}
}

func (s *Service) requireComment(ctx context.Context, photo *models.Photo, userID string) (string, error) {
	_, role, err := s.albums.Access(ctx, photo.AlbumID, userID)
	if err != nil {
		return "", err
	}
	if !roles.CanComment(role) {
		return "", httpx.Forbidden("forbidden", "you do not have permission to interact with photos")
	}
	return role, nil
}

func (s *Service) AddLike(ctx context.Context, photoID, userID string) error {
	photo, err := s.photos.GetByID(ctx, photoID, userID)
	if err != nil {
		if errors.Is(err, ErrNotFound) {
			return httpx.NotFound("photo_not_found", "photo not found")
		}
		return err
	}
	if _, err := s.requireComment(ctx, photo, userID); err != nil {
		return err
	}
	if err := s.store.Like(ctx, photoID, userID); err != nil {
		return err
	}
	s.hub.Publish(photo.AlbumID, "like.added", map[string]string{
		"photo_id": photoID, "album_id": photo.AlbumID, "user_id": userID,
	})
	if s.notify != nil && photo.UploaderID != userID {
		_ = s.notify.Create(ctx, photo.UploaderID, "like.added", map[string]any{
			"photo_id": photoID, "album_id": photo.AlbumID, "user_id": userID,
		})
	}
	return nil
}

func (s *Service) RemoveLike(ctx context.Context, photoID, userID string) error {
	photo, err := s.photos.GetByID(ctx, photoID, userID)
	if err != nil {
		if errors.Is(err, ErrNotFound) {
			return httpx.NotFound("photo_not_found", "photo not found")
		}
		return err
	}
	if _, err := s.requireComment(ctx, photo, userID); err != nil {
		return err
	}
	if err := s.store.Unlike(ctx, photoID, userID); err != nil {
		return err
	}
	s.hub.Publish(photo.AlbumID, "like.removed", map[string]string{
		"photo_id": photoID, "album_id": photo.AlbumID, "user_id": userID,
	})
	return nil
}

func (s *Service) AddComment(ctx context.Context, photoID, userID, text string) (*models.Comment, error) {
	text = strings.TrimSpace(text)
	if text == "" {
		return nil, httpx.BadRequest("invalid_text", "comment text is required")
	}
	photo, err := s.photos.GetByID(ctx, photoID, userID)
	if err != nil {
		if errors.Is(err, ErrNotFound) {
			return nil, httpx.NotFound("photo_not_found", "photo not found")
		}
		return nil, err
	}
	if _, err := s.requireComment(ctx, photo, userID); err != nil {
		return nil, err
	}
	c := &models.Comment{
		ID:      auth.NewID(),
		PhotoID: photoID,
		UserID:  userID,
		Text:    text,
	}
	if err := s.store.CreateComment(ctx, c); err != nil {
		return nil, err
	}
	list, err := s.store.ListComments(ctx, photoID)
	if err == nil {
		for _, item := range list {
			if item.ID == c.ID {
				c.User = item.User
				break
			}
		}
	}
	s.hub.Publish(photo.AlbumID, "comment.created", c)
	if s.notify != nil && photo.UploaderID != userID {
		_ = s.notify.Create(ctx, photo.UploaderID, "comment.created", map[string]any{
			"photo_id": photoID, "album_id": photo.AlbumID, "user_id": userID, "comment_id": c.ID,
		})
	}
	return c, nil
}

func (s *Service) ListComments(ctx context.Context, photoID, userID string) ([]models.Comment, error) {
	photo, err := s.photos.GetByID(ctx, photoID, userID)
	if err != nil {
		if errors.Is(err, ErrNotFound) {
			return nil, httpx.NotFound("photo_not_found", "photo not found")
		}
		return nil, err
	}
	if _, _, err := s.albums.Access(ctx, photo.AlbumID, userID); err != nil {
		return nil, err
	}
	return s.store.ListComments(ctx, photoID)
}

func (s *Service) DeleteComment(ctx context.Context, commentID, userID string) error {
	c, err := s.store.GetComment(ctx, commentID)
	if err != nil {
		if errors.Is(err, ErrNotFound) {
			return httpx.NotFound("comment_not_found", "comment not found")
		}
		return err
	}
	photo, err := s.photos.GetByID(ctx, c.PhotoID, userID)
	if err != nil {
		return err
	}
	_, role, err := s.albums.Access(ctx, photo.AlbumID, userID)
	if err != nil {
		return err
	}
	if c.UserID != userID && !roles.CanDeleteAnyPhoto(role) {
		return httpx.Forbidden("forbidden", "you cannot delete this comment")
	}
	return s.store.DeleteComment(ctx, commentID)
}