;; Books.eeform — one record at a time, the dBASE way: move with |◀ ◀ ▶ ▶|, and New, Edit, Save,
;; Cancel, Delete. The boxes are locked while you browse and open while you edit, so a record can't
;; change by accident; Save and Cancel only light up while there is something to keep or throw away.
;;
;; Press ▶ run. An empty table? Record → Add sample books. The rows live in the books table of the
;; workspace database — (browse books) at the REPL shows the same thing as a grid.

(form "Books" :size (520 380) :on-load bk-load :menu (("Record" ("New" bk-new) ("Edit" bk-edit) ("Save" bk-save) ("Cancel" bk-cancel) ("Delete" bk-delete) ("-") ("Add sample books" bk-samples) ("-") ("Close" bk-close)) ("Go" ("First" bk-first) ("Previous" bk-prev) ("Next" bk-next) ("Last" bk-last)))
  (label lblTitle :text "Title" :at (16 20) :size (80 24))
  (textbox txtTitle :required true :at (100 16) :size (404 28))
  (label lblAuthor :text "Author" :at (16 56) :size (80 24))
  (textbox txtAuthor :at (100 52) :size (404 28))
  (label lblYear :text "Year" :at (16 92) :size (80 24))
  (textbox txtYear :number true :min 0 :max 2100 :at (100 88) :size (88 28))
  (label lblNotes :text "Notes" :at (16 128) :size (80 24))
  (textbox txtNotes :multiline true :at (100 124) :size (404 88))
  (button btnFirst :text "|◀" :at (16 228) :size (44 30) :on-click bk-first)
  (button btnPrev :text "◀" :at (64 228) :size (44 30) :on-click bk-prev)
  (button btnNext :text "▶" :at (112 228) :size (44 30) :on-click bk-next)
  (button btnLast :text "▶|" :at (160 228) :size (44 30) :on-click bk-last)
  (label lblPos :at (216 232) :size (140 24))
  (textbox txtFind :placeholder "find…" :at (364 228) :size (140 30) :on-change bk-find)
  (button btnNew :text "New" :at (16 272) :size (88 30) :on-click bk-new)
  (button btnEdit :text "Edit" :at (112 272) :size (88 30) :on-click bk-edit)
  (button btnSave :text "Save" :submit true :default true :at (208 272) :size (88 30) :on-click bk-save)
  (button btnCancel :text "Cancel" :cancel true :at (304 272) :size (88 30) :on-click bk-cancel)
  (button btnDelete :text "Delete" :at (416 272) :size (88 30) :on-click bk-delete)
  (label lblStatus :at (16 320) :size (488 24)))

(deftable books (title:string author:string year:number notes:string))

;; Where we are: an index into the table in id order, and whether the boxes are being edited.
;; Local: each open copy of Books has its own — open two and move them apart.
(local pos 0)
(local mode "browse")    ;; "browse", "edit" or "new"

(defn bk-all () (records (query books :order "_id")))

(defn bk-load (f)
  (var! "pos" 0)
  (bk-show f))

;; The record at pos into the boxes, then the buttons to match.
(defn bk-show (f)
  (let (rows (bk-all)
        n (length rows))
    (when (>= (var "pos") n) (var! "pos" (max 0 (- n 1))))
    (if (= n 0)
      (do
        (bk-fill nil)
        (ui-set "lblPos" :text "No records"))
      (do
        (bk-fill (nth rows (var "pos")))
        (ui-set "lblPos" :text (str "Record " (+ (var "pos") 1) " of " n))))
    (bk-mode! "browse" n)))

(defn bk-fill (r)
  (ui-set "txtTitle" :value (if r (field-get r :title) ""))
  (ui-set "txtAuthor" :value (if r (field-get r :author) ""))
  (ui-set "txtYear" :value (if r (field-get r :year) ""))
  (ui-set "txtNotes" :value (if r (field-get r :notes) "")))

;; Browsing: the boxes locked, moving allowed. Editing: the other way round.
(defn bk-mode! (mode n)
  (var! "mode" mode)
  (let (editing (not (= mode "browse")))
    (for-each c '("txtTitle" "txtAuthor" "txtYear" "txtNotes" "btnSave" "btnCancel")
      (ui-set c :enabled editing))
    (ui-set "btnNew" :enabled (not editing))
    (ui-set "txtFind" :enabled (not editing))
    (ui-set "btnEdit" :enabled (and (not editing) (> n 0)))
    (ui-set "btnDelete" :enabled (and (not editing) (> n 0)))
    (ui-set "btnFirst" :enabled (and (not editing) (> (var "pos") 0)))
    (ui-set "btnPrev" :enabled (and (not editing) (> (var "pos") 0)))
    (ui-set "btnNext" :enabled (and (not editing) (< (var "pos") (- n 1))))
    (ui-set "btnLast" :enabled (and (not editing) (< (var "pos") (- n 1))))))

;; ── moving ──

(defn bk-first (f) (var! "pos" 0) (bk-show f))
(defn bk-prev (f) (var! "pos" (max 0 (- (var "pos") 1))) (bk-show f))
(defn bk-next (f) (var! "pos" (+ (var "pos") 1)) (bk-show f))
(defn bk-last (f) (var! "pos" (- (length (bk-all)) 1)) (bk-show f))

;; Find: the first record, from the top, whose title or author contains the text.
(defn bk-find (f)
  (let (text (str-lower (str-trim (or (ui-get f "txtFind") "")))
        rows (bk-all))
    (when (not (= text ""))
      (loop (i 0)
        (cond
          (>= i (length rows)) (ui-set "lblStatus" :text (str "Nothing matches \"" text "\""))
          (or (str-contains (str-lower (str (field-get (nth rows i) :title))) text)
              (str-contains (str-lower (str (field-get (nth rows i) :author))) text))
            (do (var! "pos" i) (ui-set "lblStatus" :text "") (bk-show f))
          true (recur (+ i 1)))))))

;; ── changing ──

(defn bk-new (f)
  (bk-fill nil)
  (ui-set "lblPos" :text "New record")
  (ui-set "lblStatus" :text "")
  (bk-mode! "new" 0)
  (ui-focus "txtTitle"))

(defn bk-edit (f)
  (bk-mode! "edit" (length (bk-all)))
  (ui-set "lblStatus" :text "Editing — Save keeps it, Cancel (Esc) throws it away")
  (ui-focus "txtTitle"))

;; Save is :submit, so the :required title and the year's :min/:max are checked before this runs.
(defn bk-save (f)
  (let (title (str-trim (ui-get f "txtTitle"))
        data {:title title :author (str-trim (or (ui-get f "txtAuthor") "")) :year (ui-get f "txtYear") :notes (ui-get f "txtNotes")})
    (if (= (var "mode") "new")
      (do
        (insert books data)
        (var! "pos" (- (length (bk-all)) 1)))
      (update books (record-id (nth (bk-all) (var "pos"))) data))
    (ui-set "lblStatus" :text (str "Saved " title))
    (bk-show f)))

(defn bk-cancel (f)
  (ui-set "lblStatus" :text "")
  (bk-show f))

(defn bk-delete (f)
  (let (rows (bk-all))
    (when (> (length rows) 0)
      (let (r (nth rows (var "pos")))
        (delete books (record-id r))
        (ui-set "lblStatus" :text (str "Deleted " (field-get r :title)))
        (bk-show f)))))

(defn bk-samples (f)
  (insert books {:title "The Mythical Man-Month" :author "Frederick Brooks" :year 1975 :notes "Adding people to a late project makes it later."})
  (insert books {:title "Structure and Interpretation of Computer Programs" :author "Abelson & Sussman" :year 1985 :notes "The wizard book."})
  (insert books {:title "Gödel, Escher, Bach" :author "Douglas Hofstadter" :year 1979 :notes ""})
  (ui-set "lblStatus" :text "Three books added")
  (bk-show f))

(defn bk-close (f) (ui-close))