Categories, views: Implement viewutil.Chain

categories/views.go

@@ -28,21 +28,12 @@ var (
 	//go:embed *.html
 	fs                           embed.FS
 	m                            = template.Must
-	baseEn, baseRu, listEn, listRu, pageEn, pageRu *template.Template
+	baseEn, baseRu               *template.Template
+	viewListChain, viewPageChain viewutil.Chain
 	categoryTemplatesEn          *template.Template
 	categoryTemplatesRu          *template.Template
 )
 
-func loctmp(meta viewutil.Meta, en *template.Template, ru *template.Template) *template.Template {
-	switch meta.Locale() {
-	case "en":
-		return en
-	case "ru":
-		return ru
-	}
-	panic("aaa")
-}
-
 func prepareViews() {
 	categoryTemplatesEn = template.Must(template.
 		New("category").
@@ -55,10 +46,17 @@ func prepareViews() {
 
 	baseEn = m(viewutil.BaseEn.Clone())
 	baseRu = m(viewutil.BaseRu.Clone())
-	listEn = m(m(baseEn.Clone()).ParseFS(fs, "view_list.html"))
+
-	listRu = m(m(m(baseRu.Clone()).ParseFS(fs, "view_list.html")).Parse(categoriesRu))
+	viewListChain = viewutil.
-	pageEn = m(m(baseEn.Clone()).ParseFS(fs, "view_page.html"))
+		En(
-	pageRu = m(m(m(baseRu.Clone()).ParseFS(fs, "view_page.html")).Parse(categoriesRu))
+			m(m(baseEn.Clone()).ParseFS(fs, "view_list.html"))).
+		Ru(
+			m(m(m(baseRu.Clone()).ParseFS(fs, "view_list.html")).Parse(categoriesRu)))
+	viewPageChain = viewutil.
+		En(
+			m(m(baseEn.Clone()).ParseFS(fs, "view_page.html"))).
+		Ru(
+			m(m(m(baseRu.Clone()).ParseFS(fs, "view_page.html")).Parse(categoriesRu)))
 }
 
 func localizedCatTemplates(meta viewutil.Meta) *template.Template {
@@ -108,7 +106,7 @@ type pageData struct {
 }
 
 func categoryPage(meta viewutil.Meta, catName string) {
-	if err := loctmp(meta, pageEn, pageRu).ExecuteTemplate(meta.W, "page", pageData{
+	if err := viewPageChain.Get(meta).ExecuteTemplate(meta.W, "page", pageData{
 		BaseData: viewutil.BaseData{
 			Meta:          meta,
 			Title:         localizedCatTemplateAsString(meta, "category x", catName),
@@ -129,7 +127,7 @@ type listData struct {
 }
 
 func categoryList(meta viewutil.Meta) {
-	if err := loctmp(meta, listEn, listRu).ExecuteTemplate(meta.W, "page", listData{
+	if err := viewListChain.Get(meta).ExecuteTemplate(meta.W, "page", listData{
 		BaseData: viewutil.BaseData{
 			Meta:          meta,
 			Title:         localizedCatTemplateAsString(meta, "category list heading"),

viewutil/chain.go

@@ -0,0 +1,33 @@
+package viewutil
+
+import "text/template"
+
+// Chain represents a chain of different language versions of the same template.
+type Chain struct {
+	en *template.Template
+	ru *template.Template
+}
+
+// En returns a new Chain. This is the only constructor of the type, so every view is forced to have an English representation.
+func En(en *template.Template) Chain {
+	return Chain{
+		en: en,
+	}
+}
+
+// Ru adds a Russian translation to the Chain.
+func (c Chain) Ru(ru *template.Template) Chain {
+	c.ru = ru
+	return c
+}
+
+// Get returns an appropriate language representation for the given locale in meta.
+func (c Chain) Get(meta Meta) *template.Template {
+	switch meta.Locale() {
+	case "en":
+		return c.en
+	case "ru":
+		return c.ru
+	}
+	panic("unknown language " + meta.Locale())
+}