feat(favicon): add variant support for favicons

- Introduced a new Variant field in GetFavIconRequest to specify icon variants (light/dark).
- Updated GetFavIconFromAlias function to handle the variant when fetching favicons.
- Added WithVariant method in IconURL to manage icon variants effectively.

internal/api/v1/favicon.go

@@ -13,8 +13,9 @@ import (
 )
 
 type GetFavIconRequest struct {
-	URL   string `form:"url" binding:"required_without=Alias"`
-	Alias string `form:"alias" binding:"required_without=URL"`
+	URL     string               `form:"url" binding:"required_without=Alias"`
+	Alias   string               `form:"alias" binding:"required_without=URL"`
+	Variant homepage.IconVariant `form:"variant" binding:"omitempty,oneof=light dark"`
 } //	@name	GetFavIconRequest
 
 // @x-id				"favicon"
@@ -56,7 +57,7 @@ func FavIcon(c *gin.Context) {
 	}
 
 	// try with alias
-	result, err := GetFavIconFromAlias(c.Request.Context(), request.Alias)
+	result, err := GetFavIconFromAlias(c.Request.Context(), request.Alias, request.Variant)
 	if err != nil {
 		homepage.GinFetchError(c, result.StatusCode, err)
 		return
@@ -65,7 +66,7 @@ func FavIcon(c *gin.Context) {
 }
 
 //go:linkname GetFavIconFromAlias v1.GetFavIconFromAlias
-func GetFavIconFromAlias(ctx context.Context, alias string) (homepage.FetchResult, error) {
+func GetFavIconFromAlias(ctx context.Context, alias string, variant homepage.IconVariant) (homepage.FetchResult, error) {
 	// try with route.Icon
 	r, ok := routes.HTTP.Get(alias)
 	if !ok {
@@ -81,7 +82,8 @@ func GetFavIconFromAlias(ctx context.Context, alias string) (homepage.FetchResul
 		if hp.Icon.IconSource == homepage.IconSourceRelative {
 			result, err = homepage.FindIcon(ctx, r, *hp.Icon.FullURL)
 		} else {
-			result, err = homepage.FetchFavIconFromURL(ctx, hp.Icon)
+			icon := hp.Icon.WithVariant(variant)
+			result, err = homepage.FetchFavIconFromURL(ctx, icon)
 		}
 	} else {
 		// try extract from "link[rel=icon]"

internal/homepage/icon_url.go

@@ -23,7 +23,8 @@ type (
 		IsDark   bool    `json:"is_dark"`
 	}
 
-	IconSource string
+	IconSource  string
+	IconVariant string
 )
 
 const (
@@ -33,6 +34,12 @@ const (
 	IconSourceSelfhSt   IconSource = "@selfhst"
 )
 
+const (
+	IconVariantNone  IconVariant = ""
+	IconVariantLight IconVariant = "light"
+	IconVariantDark  IconVariant = "dark"
+)
+
 var ErrInvalidIconURL = gperr.New("invalid icon url")
 
 func NewIconURL(source IconSource, refOrName, format string) *IconURL {
@@ -76,6 +83,28 @@ func (u *IconURL) HasIcon() bool {
 	return HasIcon(u)
 }
 
+func (u *IconURL) WithVariant(variant IconVariant) *IconURL {
+	var extra *IconExtra
+	if u.Extra != nil {
+		extra = &IconExtra{
+			Key:      u.Extra.Key,
+			Ref:      u.Extra.Ref,
+			FileType: u.Extra.FileType,
+		}
+		switch variant {
+		case IconVariantLight:
+			extra.IsLight = true
+		case IconVariantDark:
+			extra.IsDark = true
+		}
+	}
+	return &IconURL{
+		IconSource: u.IconSource,
+		FullURL:    u.FullURL,
+		Extra:      extra,
+	}
+}
+
 // Parse implements strutils.Parser.
 func (u *IconURL) Parse(v string) error {
 	return u.parse(v, true)