package surf

import (
	"net/http"

	"git.golem15.com/golem15/summercms/modules/bouncer"
	"git.golem15.com/golem15/summercms/modules/towel"
)

// LocaleFromPrincipal overrides the header locale with the authenticated
// principal's PreferredLocale when that value is non-empty.
func LocaleFromPrincipal(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if p, ok := bouncer.User(r.Context()); ok && p.PreferredLocale != "" {
			r = r.WithContext(towel.WithLocale(r.Context(), p.PreferredLocale))
		}
		next.ServeHTTP(w, r)
	})
}