Simple clojure trivia plugin for lazybot

trivia.clj

(ns lazybot.plugins.trivia
  (:use (lazybot registry info))
  (:require [clojure.string :as s]
            [clojure.java.io :as io]))

(use '[incanter.stats :only (levenshtein-distance)])

(def answer (atom ""))
(def buzzer (atom 0))

(defn rand-seq-elem [sequence]
  (let [f (fn [[k old] new]
            [(inc k) (if (zero? (rand-int k)) new old)])]
    (->> sequence (reduce f [1 nil]) second)))

(defn rand-line [filename]
  (with-open [reader (io/reader filename)]
    (rand-seq-elem (line-seq reader))))

(defn start-trivia [x] (reset! answer (second x)) (reset! buzzer (System/currentTimeMillis)) (first x))

(defn end-trivia [] (reset! answer "") (reset! buzzer 0))

(defplugin
  (:hook
    :on-message
    (fn [{:keys [bot com nick message channel] :as com-m}]
      (if-not (empty? @answer)
        (if (.equalsIgnoreCase message @answer)
          (do
            (send-message (assoc com-m :channel "#trivia") (str nick ", you got it right! The answer is: " @answer))
            (end-trivia))
          (if (> (- 1 (/ (levenshtein-distance @answer message) (.length @answer))) 0.50)
            (do
              (send-message (assoc com-m :channel "#trivia") (str nick ", close enough for me! The exact answer is: " @answer))
              (end-trivia))
            (if (> (System/currentTimeMillis) (+ 60000 @buzzer))
              (do
                (send-message (assoc com-m :channel "#trivia") (str "Time's up! Answer: " @answer))
                (end-trivia))))))))
  (:cmd
    "Ask a trivia question!"
    #{"trivia" "t"}
    (fn [com-m] (if (empty? @answer) (send-message com-m (start-trivia
                                      (-> "jquestions" io/resource io/file rand-line (s/split #"`"))))))))