Cincy Day of Functional

berlin_clock.clj

(require '[clojure.string :as str])

(ns berlin
  (:require [clojure.test :refer :all]))

(defn render-lights [number-on total-lights]
  (let [on-lights (apply str (repeat number-on "*"))
        format-string (str "%-" total-lights "s")]
    (str/replace
      (format format-string on-lights)
      #" "
      ".")))

(defn second-light [s]
   (render-lights (mod s 2) 1))

(defn hour-lights [h]
  (list
   (render-lights (int (/ h 5)) 4)
   (render-lights (mod h 5) 4)))

(defn minute-lights [m]
  (list
   (render-lights (int (/ m 5)) 11)
   (render-lights (mod m 5) 4)))

(defn berlin-clock [[h m s]]
  (flatten (list
   (second-light s)
   (hour-lights h)
   (minute-lights m))))

(defn parse-time [time-string]
  (map
   (fn [s] (Integer. s))
   (str/split time-string #":")))

(deftest can-make-times
  (is (= '("*" "...." "...." "..........." "....") (berlin-clock (parse-time "00:00:00"))))
  (is (= '("." "**.." "***." "***........" "**..") (berlin-clock (parse-time "13:17:01"))))
  (is (= '("." "****" "***." "***********" "****") (berlin-clock (parse-time "23:59:59"))))
  )
  
(run-tests)