(defn class-names [& args]
  (clojure.string/join " "
    (mapv name
      (reduce (fn [arr arg]
        (cond
          (or (string? arg)
              (symbol? arg)
              (keyword? arg)) (conj arr arg)
          (vector? arg) (vec (concat arr arg))
          (map? arg) (vec (concat arr
                            (reduce-kv (fn [map-arr key value]
                              (if (true? value)
                                (conj map-arr key)
                                map-arr)) [] arg)))
          :else arr)) [] args))))

; (class-names "foo" "bar" :bax { :active true :seleced false })
; -> "foo bar bax active"
; (class-names "foo" "bar" nil)
; -> "foo bar"
; (class-names "foo" "bar" :bax { :active true :seleced false } 'nox { :more-classes-in-map true })
; -> "foo bar bax active nox more-classes-in-map"