feat: image variants per image

internal/infrastructure/useCases/imageVariantView.go

@@ -0,0 +1,108 @@
+package useCases
+
+import (
+	"RenewCMS/internal/domain/image"
+	"errors"
+	"slices"
+	"strings"
+)
+
+const (
+	svgContentType   = "image/svg+xml"
+	unsupportedSVG   = "svg"
+	causeTooLarge    = "too_large"
+	causeUnsupported = "unsupported_format"
+	causeFailed      = "failed"
+	variantURLQuery  = "?" + image.VariantQueryParameter + "="
+)
+
+type ImageVariantView struct {
+	Variant      image.Variant
+	OutputWidth  int
+	OutputHeight int
+	OutputFormat image.VariantFormat
+	Generated    bool
+	Size         int64
+	URL          string
+}
+
+type ImageVariantList struct {
+	Unsupported string
+	Items       []ImageVariantView
+}
+
+type VariantFailure struct {
+	Name  string
+	Cause string
+}
+
+func isVectorSource(img image.Image) bool {
+	return img.ContentType == svgContentType
+}
+
+func enabledVariants(variants image.VariantRepository) ([]image.Variant, error) {
+	listed, err := variants.List()
+	if err != nil {
+		return nil, err
+	}
+	enabled := make([]image.Variant, 0, len(listed))
+	for _, variant := range listed {
+		if variant.Enabled {
+			enabled = append(enabled, variant)
+		}
+	}
+	slices.SortFunc(enabled, func(a, b image.Variant) int { return strings.Compare(a.Name, b.Name) })
+	return enabled, nil
+}
+
+func currentFiles(files image.VariantFileRepository, storedName string) (map[string]image.VariantFile, error) {
+	rows, err := files.ListBySource(storedName)
+	if err != nil {
+		return nil, err
+	}
+	byVariant := make(map[string]image.VariantFile, len(rows))
+	for _, row := range rows {
+		byVariant[row.VariantName] = row
+	}
+	return byVariant, nil
+}
+
+func isCurrent(variant image.Variant, rows map[string]image.VariantFile) bool {
+	row, found := rows[variant.Name]
+	return found && row.Fingerprint == variant.Settings().Fingerprint()
+}
+
+func viewOf(variant image.Variant, img image.Image, rows map[string]image.VariantFile, encodable []image.VariantFormat) ImageVariantView {
+	width, height := image.OutputSize(img.Width, img.Height, variant.Settings())
+	view := ImageVariantView{
+		Variant:      variant,
+		OutputWidth:  width,
+		OutputHeight: height,
+		OutputFormat: image.OutputFormat(variant.Format, img.ContentType, encodable),
+		URL:          image.PublicPath(image.StoredName(img.Path)) + variantURLQuery + variant.Name,
+	}
+	if isCurrent(variant, rows) {
+		view.Generated = true
+		view.Size = rows[variant.Name].Size
+	}
+	return view
+}
+
+func viewsOf(variants []image.Variant, img image.Image, rows map[string]image.VariantFile, encodable []image.VariantFormat) []ImageVariantView {
+	views := make([]ImageVariantView, 0, len(variants))
+	for _, variant := range variants {
+		views = append(views, viewOf(variant, img, rows, encodable))
+	}
+	return views
+}
+
+func generationCause(err error) string {
+	switch {
+	case errors.Is(err, image.ErrSourceTooLarge):
+		return causeTooLarge
+	case errors.Is(err, image.ErrVariantSourceUnreadable):
+		return causeUnsupported
+	default:
+		return causeFailed
+	}
+}