(ns microtables-frontend.views.sheet
  (:require
   [microtables-frontend.events :as events]
   [microtables-frontend.utils.coordinates :as coords]
   [re-frame.core :as re-frame]))

;TODO: expand selection/highlight mode
;      - directional controls
;        - arrow keys, enter, tab, shift-enter, shift-tab
;        - enter key triggers editing (?)
;      - special controls
;        - expand selection
;        - move selection
;        - delete selection (neighbouring cells displaced in)
;        - clear selection (cells become blank)
;        - continue selection (intelligent sequence continuation)
;      - common functions (sum, avg, etc)
;        - display numeric answer in menu
;        - offer to put the answer (in formula form) in a cell (to be chosen by clicking)
(defn cell [c r col-idx maxrow data]
  (let [datum (get-in data [c r])
        touch-device? (pos? (.. js/navigator -maxTouchPoints))]
    ^{:key (str c r)} [:td
                       [:input (cond-> {:id (str c r)
                                        :class (if (= (:view datum) :highlighted) "highlighted" "")
                                        :value (if (= (get datum :view nil) :value)
                                                 (get datum :value "")
                                                 (get datum :error (get datum :display (get datum :value ""))));TODO: add "highlight" display mode (possibly just a css class)
                                        :on-change #(re-frame/dispatch [::events/edit-cell-value c r (.. % -target -value)])
                                        :on-focus #(re-frame/dispatch [::events/movement-enter-cell c r])
                                        :on-blur #(re-frame/dispatch [::events/movement-leave-cell c r])
                                        :on-keyPress #(when (= (.. % -which) 13)
                                                        (if (.. % -shiftKey)
                                                          (re-frame/dispatch [::events/press-shift-enter-in-cell c r])
                                                          (re-frame/dispatch [::events/press-enter-in-cell c r])))}
                                 ; column-major tabindex on touch devices so "Next" moves down instead of right
                                 touch-device? (assoc :tab-index (+ (* col-idx maxrow) r)))]]))

(defn row [r cols maxrow data]
  ^{:key (str "row-" r)} [:tr
                          (cons
                           ^{:key (str "row-head-" r)} [:th (str r)]
                           (map-indexed #(cell %2 r %1 maxrow 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
   {:id "main-table"}
   [:tbody
    ;TODO: figure out appropriate starting values for maxrow and maxcol (maybe keep them intentionally small)
    ;TODO: figure out movement (maybe allow scroll overflow)
    (let [maxrow 20;(coords/highest-row data)
          maxcol "G";(coords/highest-col data)
          cols (take-while (partial not= (coords/next-letter maxcol)) coords/col-letters)]
      (cons
       (header-row cols)
       (map #(row % cols maxrow data) (range 1 (inc maxrow)))))]])