first

backend/internal/modules/media/service.go

@@ -0,0 +1,99 @@
+package media
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+
+	"github.com/google/uuid"
+)
+
+var (
+	ErrFileTooLarge    = errors.New("file exceeds the maximum allowed size")
+	ErrUnsupportedType = errors.New("unsupported file type")
+)
+
+// allowedTypes maps accepted MIME types to a safe file extension. Anything
+// not in this list is rejected -- uploads are never trusted to declare
+// their own extension.
+var allowedTypes = map[string]string{
+	"image/jpeg": ".jpg",
+	"image/png":  ".png",
+	"image/webp": ".webp",
+	"image/gif":  ".gif",
+	"video/mp4":  ".mp4",
+	"video/webm": ".webm",
+}
+
+type Service struct {
+	repo        Repository
+	storage     Storage
+	maxSizeByte int64
+}
+
+func NewService(repo Repository, storage Storage, maxSizeBytes int64) *Service {
+	return &Service{repo: repo, storage: storage, maxSizeByte: maxSizeBytes}
+}
+
+func (s *Service) List(ctx context.Context) ([]*Media, error) {
+	return s.repo.List(ctx)
+}
+
+func (s *Service) Get(ctx context.Context, id uuid.UUID) (*Media, error) {
+	return s.repo.FindByID(ctx, id)
+}
+
+func (s *Service) Upload(ctx context.Context, filename string, reader io.Reader, size int64, contentType, altText string) (*Media, error) {
+	if size > s.maxSizeByte {
+		return nil, ErrFileTooLarge
+	}
+	ext, ok := allowedTypes[contentType]
+	if !ok {
+		return nil, ErrUnsupportedType
+	}
+
+	key := uuid.NewString() + ext
+	url, err := s.storage.Save(ctx, key, reader, size, contentType)
+	if err != nil {
+		return nil, fmt.Errorf("save file: %w", err)
+	}
+
+	m := &Media{
+		ID:         uuid.New(),
+		Filename:   filename,
+		StorageKey: key,
+		URL:        url,
+		MimeType:   contentType,
+		SizeBytes:  size,
+		AltText:    altText,
+	}
+	if err := s.repo.Create(ctx, m); err != nil {
+		_ = s.storage.Delete(ctx, key)
+		return nil, fmt.Errorf("save metadata: %w", err)
+	}
+	return m, nil
+}
+
+func (s *Service) UpdateAltText(ctx context.Context, id uuid.UUID, altText string) (*Media, error) {
+	m, err := s.repo.FindByID(ctx, id)
+	if err != nil {
+		return nil, err
+	}
+	m.AltText = altText
+	if err := s.repo.Update(ctx, m); err != nil {
+		return nil, err
+	}
+	return m, nil
+}
+
+func (s *Service) Delete(ctx context.Context, id uuid.UUID) error {
+	m, err := s.repo.FindByID(ctx, id)
+	if err != nil {
+		return err
+	}
+	if err := s.storage.Delete(ctx, m.StorageKey); err != nil {
+		return fmt.Errorf("delete stored file: %w", err)
+	}
+	return s.repo.Delete(ctx, id)
+}