(ns microtables-frontend.core
    (:require
      [reagent.core :as r]
      ["mathjs" :as mathjs]))

; to generate random values
;for(let i = 0, s = new Set(); i < 10; i++){ let r = Math.floor(Math.random() * 15)+1, c = a[Math.floor(Math.random() * a.length)], k = `${c}${r}`; if(s.has(k)){ i--; continue; } s.add(k); v.push(`{:row ${r} :col "${c}" :value "${Math.floor(Math.random() * 10000)}"}`); }
(def sample-data [{:row 1 :col "A" :value "59" :view :display}
                  {:row 5 :col "C" :value "269" :view :display}
                  {:row 4 :col "B" :value "7893" :view :display}
                  {:row 2 :col "F" :value "8650" :view :display}
                  {:row 6 :col "D" :value "4065" :view :display}
                  {:row 7 :col "F" :value "5316" :view :display}
                  {:row 12 :col "A" :value "2405" :view :display}
                  {:row 5 :col "B" :value "7863" :view :display}
                  {:row 9 :col "E" :value "3144" :view :display}
                  {:row 10 :col "D" :value "8272" :view :display}
                  {:row 11 :col "D" :value "2495" :view :display}
                  {:row 15 :col "E" :value "8968" :view :display}
                  {:row 7 :col "B" :value "=C5 + D6" :view :display}
                  {:row 8 :col "B" :value "=B7 * 2" :view :display}
                  {:row 7 :col "C" :value "=D1" :view :display}])

(defonce data-atom (r/atom sample-data))

(defn highest [dir data] (apply max (map dir data)))

; COLUMN NAMES
(defn upgrade-letter-code [s]
  (let [l (last s)]
    (cond
      (empty? s) [65]
      (= l 90) (conj (upgrade-letter-code (subvec s 0 (dec (count s)))) 65)
      :else (conj (subvec s 0 (dec (count s))) (inc l)))))
(defn next-letter [lc]
  (apply str (map char (upgrade-letter-code (mapv #(.charCodeAt % 0) lc)))))
(def col-letters (iterate next-letter "A"))


; CHANGE VALUE FUNCTIONS
(defn update-value [c r datum value]
  (if (nil? datum)
    (swap! data-atom conj {:row r :col c :value value})
    (swap! data-atom (fn [d] (map #(if (and (= r (:row %)) (= c (:col %))) (assoc % :value value) %) d)))))
(defn update-display [c r display]
  (println (str "  trying to update " c r " to " display))
  (swap! data-atom (fn [d] (map #(if (and (= r (:row %)) (= c (:col %)) (= (first (:value %)) "=")) (assoc % :display display) %) d))))
(defn toggle-display [c r view-mode]
  (println (str "  toggling " c r " to " view-mode))
  (swap! data-atom (fn [d] (map #(if (and (= r (:row %)) (= c (:col %))) (assoc % :view view-mode) %) d))))

; CALCULATION / FORMULA EVALUATION FUNCTIONS

(defn temp1 [data]
  (let [first-order (group-by #(not= (first (:value %)) "=") data)
        evaluated-cells (map #(keyword (str (:col %) (:row %))) (first-order true))
        non-evaluated-cells (map #(keyword (str (:col %) (:row %))) (first-order false))
        evaluated-values (map :value (first-order true))
        non-evaluated-values (map #(subs (:value %) 1) (first-order false))]
    {:remaining (zipmap non-evaluated-cells non-evaluated-values)
     :evaluated (zipmap evaluated-cells evaluated-values)}))

(def parse-variables (memoize (fn [expression]
                                (js->clj (.getVariables mathjs expression)))))
(def evaluate-expression (memoize (fn [expression variables]
                                    (.evaluate mathjs expression (clj->js variables)))))

(defn temp3 [[k v]]
  (let [w (name k)
        c (re-find #"^[A-Z]+" w)
        r (.parseInt js/window (re-find #"[0-9]+$" w))]
    (do
      (println "looking at cell " c r)
      (update-display c r v)
      )
    )
  )

(defn temp2 [evaluated remaining]
  (if (empty? remaining)
    evaluated
    (let [vars (map #(parse-variables (val %)) remaining)
          remaining-vars (zipmap (keys remaining) vars)
          evaluated-vars (map (fn [x] (map #(let [item (keyword %)]
                                              (cond
                                                (contains? evaluated item) [% (evaluated item)]
                                                (contains? remaining item) [% :not-yet]
                                                :else [% 0]
                                                )) x)) vars)
          parsed (zipmap (keys remaining) evaluated-vars)
          not-ready (group-by (fn [[ k v ]] (some #(= :not-yet (last %)) v)) parsed)
          ;TODO: detect circular references
          prepared (map (fn [[k v]] [k (evaluate-expression (remaining k) (apply hash-map (flatten v)))]) (not-ready nil))
          new-evaluated (reduce conj evaluated prepared)
          still-remaining (apply hash-map (flatten (map #(list (key %) (remaining (key %))) (not-ready true))))]
      ;remaining ; {:B8 B7 * 2, :C7 D1, :B7 C5 + D6}
      ;vars ; ([B7] [D1] [C5 D6])
      ;remaining-vars ; {:B8 [B7], :C7 [D1], :B7 [C5 D6]}
      ;parsed ; {:B8 ([B7 :not-yet]), :C7 ([D1 0]), :B7 ([C5 269] [D6 4065])}
      ;not-ready ; {true [[:B8 ([B7 :not-yet])]], nil [[:C7 ([D1 0])] [:B7 ([C5 269] [D6 4065])]]}
      ;prepared ; ([:C7 0] [:B7 4334])
      ;still-remaining ; {:B8 B7 * 2}
      ;evaluated; TODO: change name, consider putting "data" directly in here
      (recur new-evaluated still-remaining)
      ;new-evaluated
      )
    ))

(def str->rc (memoize (fn [s]
                        (let [c (re-find #"^[A-Z]+" s)
                              r (.parseInt js/window (re-find #"[0-9]+$" s))]
                          {:row r :col c}))))

(defn find-cell [data c r]
  (some #(if (and (= (:col %) c) (= (:row %) r)) %) data))
(defn find-val [data c r]
  (let [l (find-cell data c r)
        v (get l :display (get l :value))]
    (println "found?" c r v l (get l :value) (get l :display))
    (cond
      (nil? v) 0
      (and (string? v) (= (first v) "=")) :not-yet
      :else v)))
(defn copy-display-values' [data display-values]
  (if (empty? display-values)
    data
    (let [v (first display-values)
          r (:row v)
          c (:col v)
          inserted (map #(if (and (= r (:row %)) (= c (:col %)) (= (first (:value %)) "=")) (assoc % :display (:display v)) %) data)]
      (recur inserted (rest display-values)))))
(defn copy-display-values [data display-values]
  (let [removed (map #(-> % (dissoc :vars) (dissoc :refs) (dissoc :found) (dissoc :inputs)) display-values)]
    (into data removed)))

(defn experimental [data]
  (let [remove-old-displays (map #(dissoc % :display) data)
        {has-formula true original-values false} (group-by #(= (first (:value %)) "=") remove-old-displays)
        ;TODO: detect circular references
        variables (map #(assoc % :vars (parse-variables (subs (:value %) 1))) has-formula)
        first-mapped-cell-keys (map (fn [datum] (assoc datum :refs (map str->rc (:vars datum)))) variables)]
    (loop [values original-values mapped-cell-keys first-mapped-cell-keys]
      (let [search-values (map (fn [datum] (assoc datum :found (map #(find-val (concat values mapped-cell-keys) (:col %) (:row %)) (:refs datum)))) mapped-cell-keys)
            {not-ready true ready nil} (group-by (fn [datum] (some #(= :not-yet %) (:found datum))) search-values)
            prepped-for-eval (map (fn [datum] (assoc datum :inputs (apply hash-map (interleave (:vars datum) (:found datum))))) ready)
            evaluated (map (fn [datum] (assoc datum :display (evaluate-expression (subs (:value datum) 1) (:inputs datum)))) prepped-for-eval)
            updated-values (copy-display-values values evaluated)
            ]
        (println)
        (println)
        (println)
        (println "has-formula" has-formula)
        (println "values" values)
        (println "variables" variables)
        (println "mapped-cell-keys" mapped-cell-keys)
        (println "search-values" search-values)
        (println "not ready to eval" not-ready)
        (println "             nil?" (nil? not-ready))
        (println "ready to eval" ready)
        (println "prepped-for-eval" prepped-for-eval)
        (println "evaluated" evaluated)
        (println "updated-values" updated-values)
        (println "done!")
        (println)
        (println "loop    " values "      " mapped-cell-keys)
        (println "")
        (println "recur   " updated-values "    " not-ready)
        (if (nil? not-ready)
          updated-values
          (recur updated-values not-ready)
          )
        ))
    )
  )

;TODO: figure out how to re-evaluate only when the cell modified affects other cells
(defn re-evaluate-data []
  (let [rt (temp1 @data-atom)
        new-data (temp2 (:evaluated rt) (:remaining rt))
        update-results (map temp3 new-data)
        ]
    (do
      (println rt)
      (println new-data)
      (println "updating sheet data with above new data")
      (println update-results)
      (println "done")
      )))


(defn on-enter-cell [c r e]
  (println (str "entering cell " c r))
  (toggle-display c r :value))
(defn on-leave-cell [c r e]
  (println (str "leaving cell " c r))
  (toggle-display c r :display)
  (re-evaluate-data))


;; -------------------------
;; Views

(defn cell [c r data]
  (let [datum (some #(if (and (= c (:col %)) (= r (:row %))) %) data)]
    ^{:key (str c r)} [:td [:input {:value (if (= (get datum :view nil) :value) (get datum :value "") (get datum :display (get datum :value "")))
                                    :on-change #(update-value c r datum (.. % -target -value))
                                    :on-blur (partial on-leave-cell c r)
                                    :on-focus (partial on-enter-cell c r)}]]
    )
  )
(defn row [r cols data]
  ^{:key (str "row-" r)} [:tr
                          (cons
                            ^{:key (str "row-head-" r)} [:th (str r)]
                            (map #(cell % r data) cols))])
(defn header-row [cols]
  ^{:key "header"} [:tr
   (cons
     ^{:key "corner"} [:th]
     (map (fn [c] ^{:key (str "col-head-" c)} [:th c]) cols))])

(defn sheet [data]
  [:table [:tbody
           (let [maxrow (highest :row data)
                 cols (take-while (partial not= (next-letter (highest :col data))) col-letters)]
             (cons
               (header-row cols)
               (map #(row % cols data) (range 1 (inc maxrow)))))
           ]])

(defn app []
  [:div
   [:h3 "Microtables"]
   (do
     (println "hi again")
     (experimental @data-atom)
     "hi again")
   [sheet @data-atom]])

;; -------------------------
;; Initialize app

(defn mount-root []
  (r/render [app] (.getElementById js/document "app")))

(defn init! []
  (mount-root))