package cabana

import (
	"net/http"
	"slices"
)

// adminLangPrefix is the only namespace the public bundle serves (D-20).
const adminLangPrefix = "backend::lang."

// langBundle serves GET {prefix}/api/v1/lang: every backend::lang key as CLDR
// forms for the request locale, with the fallback locale's keys underneath.
// A locale query parameter naming a supported admin locale (one of
// Translator.Locales(adminLangPrefix)) replaces the request locale; any other
// value is ignored. meta.locales lists the supported admin locales. It is
// public (the login screen needs it) and never includes another namespace.
func (s *service) langBundle(w http.ResponseWriter, r *http.Request) {
	tr := s.translator()
	locales := tr.Locales(adminLangPrefix)
	if locales == nil {
		locales = []string{}
	}
	locale := schemaLocale(r.Context(), tr)
	if requested := r.URL.Query().Get("locale"); requested != "" && slices.Contains(locales, requested) {
		locale = requested
	}
	data := map[string]map[string]string{}
	if tr != nil {
		locale = tr.Resolved(locale, adminLangPrefix)
		data = tr.Bundle(locale, adminLangPrefix)
	}
	w.Header().Set("Cache-Control", "no-cache")
	WriteData(w, http.StatusOK, data, map[string]any{"locale": locale, "locales": locales})
}