snakes-and-ladders.cljc

(ns s-and-l.main)

#?(:cljs (set! *print-fn* #(.log js/console %)))
#?(:cljs (def log print))
#?(:clj (def log println))
(def max-board-value 100)

(defn roll-dice []
  (-> #?(:cljs (.random js/Math) :clj (java.lang.Math/random))
    (* 100)
    int
    (rem 6)
    (+ 1)))

(def board {03 10, 18 51, 26 04,
            32 62, 37 80, 44 91,
            56 22, 60 89, 97 15})

(defn climb-or-drop-position [current-position]
  (let [next-position (board current-position current-position)]
    (if-not (= current-position next-position)
      (log "And we've been promoted/demoted from " current-position " to " next-position))
    next-position))

(defn get-next-position [current-position dice-value]
  (let [provisional-position (+ current-position dice-value)]
    (if (> provisional-position max-board-value)
      current-position
      (climb-or-drop-position provisional-position))))

(defonce ^:dynamic *player-positions* (atom {}))

(defn create-players [num-players]
  (reset! *player-positions* (zipmap (iterate inc 0) (take num-players (iterate identity 0)))))

(defn game-over? []
  (some #(= max-board-value (second %)) @*player-positions*))

(defn update-player-position [player-number new-position]
  (swap! *player-positions* assoc player-number new-position))

(defn play [player]
  (let [dice-value (roll-dice)]
    (log (str "Player " player " rolled dice to get " dice-value))
    (update-player-position player (get-next-position (@*player-positions* player) dice-value))))

(defn ^:export play-a-game [num-players]
  (let [_ (create-players num-players)]
    (loop [player 0]
      (play player)
      (if (game-over?)
        (log (str "Game over. Player " player " won."))
        (recur (rem (inc player) num-players))))))

(defn -main [& args]
  (let [num-players (str (or (first args) "2"))]
    (play-a-game #?(:cljs (js/parseInt num-players) :clj (java.lang.Integer/parseInt num-players)))))

#?(:cljs (set! *main-cli-fn* -main))