(ns dialog-app.core
  (:gen-class))


(defn switch-speaker [speaker w]
  (swap! w assoc :who speaker))

(defn switch-to-student [w]
  (switch-speaker :student w))

(defn switch-to-teacher [w]
  (switch-speaker :teacher w))

(defn set-already-met [w]
  (swap! w assoc :already-met true))

(defn set-teacher-continue [w]
  (swap! w assoc :teacher-continue true))

(defn set-start-teaching [w]
  (swap! w assoc :start-teaching true))

(defn unset-teacher-continue [w]
  (swap! w assoc :teacher-continue false))

(def dialog-base
  [{:who :teacher :context :shop :phrase "Hello, I'm Lingo!" :already-met false :update-funcs [set-teacher-continue]}
   {:who :teacher :context :shop :phrase "I will guide you through this!" :teacher-continue true :already-met false :update-funcs [set-already-met set-start-teaching]}
   {:who :teacher :context :shop :phrase "Now I'll teach you how to buy things." :teacher-continue true}])


(def world-state (atom {:who :teacher :context :shop :already-met false :start-teaching false}))

(defn score-attr [[name value] row]
  (if (contains? row name) 1 0))

(defn score [q row]
  (apply + (for [attr (map vector (keys q) (vals q))]
             (score-attr attr row))))

(defn attr-match-or-empty? [[name value] row]
  (or
   (nil? (name row))
   (= (name row) value)))

(defn all-attrs-match-or-empty [q row]
  (for [attr (map vector (keys q) (vals q))]
    (attr-match-or-empty? attr row)))


(defn drop-other-attrs [q row]
  (apply dissoc row (concat (keys q) [:phrase :update-funcs])))

(defn match-func [q row]
  (and
   (every? true? (all-attrs-match-or-empty q row))
   (empty? (drop-other-attrs q row))))

(defn search-base [q]
  (sort-by (comp - first)
           (map
            (fn [row] [((partial score q) row) row])
            (filter (partial match-func q) dialog-base))))


(defn candidates [world-state]
  (let [search-results (search-base @world-state)]
    (take-while
     #(= (ffirst search-results) (first %))
     search-results)))


(defn dialog []
  (let [candidates (candidates world-state)]
    (if (empty? candidates)
      (println "Nothing to say :(")
      (do
        (let [best (second (rand-nth candidates))]
          (println (:phrase best))
          (run! #(% world-state) (:update-funcs best)))))))



(defn -main
  "I don't do a whole lot ... yet."
  [& args]
  (println "Hello, World!"))