kata from http://codingdojo.org/kata/Tennis/ take winner and game state, return updated game state

tennis.cljc

(ns tennis.tennis)

(def next-score
  {0  15
   15 30
   30 40})

(defn tennis [winner {:keys [score advantage] :as game-state}]
  "kata from http://codingdojo.org/kata/Tennis/
   take winner and game state, return updated game state"
  ;;The scoring system is rather simple:
  (cond
      ;; 3. If both have 40 the players are deuce.
      ;; a. If the game is in deuce
      (= (vals score) [40 40])
      (cond
          ;;, the winner of a ball will have advantage and game ball.
          (nil? advantage)
          (assoc game-state :advantage winner)
          ;; b. If the player with advantage wins the ball he wins the game
          (= advantage winner)
          (assoc game-state :winner winner)
          ;; c. If the player without advantage wins they are back at deuce.
          :else
          (dissoc game-state :advantage))
      ;;2. If you have 40 and you win the ball you win the game, however there are special rules.
      (= (get score winner) 40)
      (assoc game-state :status :win :winner winner)
      ;; 1. Each player can have either of these points in one game 0 15 30 40
      :else
      (update-in game-state [:score winner] next-score)))
[
 (tennis :p1 {:score {:p1 0 :p2 0}})    ;; => {:score {:p1 15, :p2 0}}
 (tennis :p1 {:score {:p1 0 :p2 15}})   ;; => {:score {:p1 15, :p2 15}}
 (tennis :p2 {:score {:p1 15 :p2 30}})  ;; => {:score {:p1 15, :p2 40}}
 (tennis :p2 {:score {:p1 40 :p2 40}})  ;; => {:score {:p1 40, :p2 40}, :advantage :p2}
 (tennis :p1 {:score {:p1 40 :p2 40}    ;; => {:score {:p1 40, :p2 40}, :advantage :p1, :winner :p1}
              :advantage :p1})
 (tennis :p1 {:score {:p1 40 :p2 40}    ;; => {:score {:p1 40, :p2 40}}]
              :advantage :p2})]





(def score-described
  {0 "love"
   15 "fifteen"
   30 "thirty"
   40 "forty"})

(defn running-score [winner  {:keys [score]}]
  (->> winner
      (get score)
      (get score-described)))

[ (running-score :p1 {:score {:p1 0 :p2 0}})
  (running-score :p1 {:score {:p1 0 :p2 15}})
  (running-score :p2 {:score {:p1 15 :p2 30}})
  (running-score :p2 {:score {:p1 40 :p2 40}})
  (running-score :p1 {:score {:p1 40 :p2 40}
                      :advantage :p1})
  (running-score :p1 {:score {:p1 40 :p2 40}
                      :advantage :p2})]