(ns benchmark
  (:import java.lang.System
           java.util.Random)
  (:use compojure
        clojure.contrib.json.write))

(defstruct user-struct :nick :last-seen)
(defstruct message-struct :nick :content :timestamp)

(def room-limit 100)
(def message-log-size 100)

(def users (ref {}))
(def messages (ref []))

(def random (new Random))

;define characters list to use to generate string
(def chars 
   (map char (concat (range 48 58) (range 66 92) (range 97 123))))

;generates 1 random character
(defn random-char [] 
  (nth chars (.nextInt random (count chars))))

; generates random string of length characters
(defn random-string [length]
  (apply str (take length (repeatedly random-char))))

(defn pick [s]
  (nth (seq s)
       (. random nextInt (count s))))

(defn refresh []
  (dosync
   {"users" (keys @users) "messages" @messages}))

(defn add-user []
  (dosync
   (if (= (count @users) room-limit)
     (let [loser (pick (keys @users))]
       (alter users dissoc loser)))
   (let [nick (random-string 10)]
     (alter users assoc nick (struct user-struct nick (System/currentTimeMillis)))
     {"users" (keys @users) "messages" (reverse @messages)})))

          
(defn post-message []
  (dosync
   (let [nick (pick (keys @users))
         msg (random-string 30)]
     (ref-set messages (conj (take (- 100 1) @messages)
                             (struct message-struct nick msg (System/currentTimeMillis))))
     (alter users assoc-in [nick :last-seen] (System/currentTimeMillis))
     "OK")))

(defn out [x]
  "out")

(defn do-bench []
  (let [r (.nextDouble random)]
    (cond (< r 0.8) (out (refresh))
	  (< r 0.9) (out (add-user))
	  (< r 1) (out (post-message)))))
 
(defn hello-world []
  "hello world!")

(defroutes benchmark
  (GET "/hello" (hello-world))
  (ANY "*" (do-bench)))

(add-user)

(run-server {:port 8080}
            "/*" (servlet benchmark))