templates: Add a proper menu and navigation

internal/dis/component/control/static/custom/menu.go

@@ -0,0 +1,47 @@
+package custom
+
+import (
+	"html/template"
+	"net/http"
+
+	"github.com/FAU-CDI/wisski-distillery/internal/dis/component"
+	"github.com/FAU-CDI/wisski-distillery/pkg/mux"
+	"golang.org/x/exp/slices"
+)
+
+// getMenuItems gets a fresh copy of the cached slice of menu items
+func (custom *Custom) Menu(r *http.Request) []component.MenuItem {
+	return custom.menu.Get(func() []component.MenuItem {
+		items := make([]component.MenuItem, 0, len(custom.Dependencies.Routeables))
+		for _, route := range custom.Dependencies.Routeables {
+			routes := route.Routes()
+			if routes.MenuTitle == "" {
+				continue
+			}
+			items = append(items, component.MenuItem{
+				Title:    routes.MenuTitle,
+				Priority: routes.MenuPriority,
+				Path:     template.URL(routes.Prefix),
+			})
+		}
+		slices.SortFunc(items, component.MenuItemSort)
+		return items
+	})
+}
+
+func (custom *Custom) BuildMenu(r *http.Request) []component.MenuItem {
+	// NOTE(twiesing): Don't name this method "Menu", as it will cause
+	// a stack overflow.
+	path := mux.NormalizePath(r.URL.Path)
+
+	// get the static menu items, and then return all the regular ones
+	var items []component.MenuItem
+	for _, m := range custom.Dependencies.Menuable {
+		items = append(items, m.Menu(r)...)
+	}
+	for i, item := range items {
+		items[i].Active = string(item.Path) == path
+	}
+	slices.SortFunc(items, component.MenuItemSort)
+	return items
+}