;; The first three lines of this file were inserted by DrScheme. They record metadata
;; about the language level of this file in a form that our tools can easily process.
#reader(lib "htdp-intermediate-reader.ss" "lang")((modname |22.3|) (read-case-sensitive #t) (teachpacks ((lib "draw.ss" "teachpack" "htdp") (lib "arrow.ss" "teachpack" "htdp") (lib "gui.ss" "teachpack" "htdp"))) (htdp-settings #(#t constructor repeating-decimal #f #t none #f ((lib "draw.ss" "teachpack" "htdp") (lib "arrow.ss" "teachpack" "htdp") (lib "gui.ss" "teachpack" "htdp")))))
;;Model

;build-number : number number -> number
;Given new and previous, multiply previous by 10 and add new to build a new number for display in the calculator.

(define (build-number new previous)
  (+ (* 10 previous) new))

;A cell is either
;1. a number or
;2. a symbol.

;A gui-table is a (listof (listof cell)).


(define pad1 '((1 2 3)
               (4 5 6)
               (7 8 9)
               ("#" 0 "*")))
(define pad2 '((1 2 3 "+")
               (4 5 6 "-")
               (7 8 9 "*")
               (0 "=" "." "/")))


;;View

;pad->gui : string gui-table -> (listof (listof gui-items))
;Given title and a-gui-table, return a (listof (listof gui-items)) that can be used by create-window to create a phone or calculator pad.  pad->gui first creates a message gui-item with the string from title, then a message gui-item repeating the last item entered, and finally an array of button gui-items.

(define (pad->gui title a-gui-table)
  (append (list (list (make-message title))
                (list (make-message "")))
          (map loc->lob a-gui-table)))



;;Controller

;cell->button : cell -> gui-item [button]
;Given acell, create a gui-item [button].

;gen-button : string -> gui-item [button]

;pad-callback : event -> true
;Draws acell (the text associated with the button) into title.

(define (cell->button acell)
  (local ((define (gen-button cell-text)
            (make-button cell-text pad-callback))
          (define (pad-callback event) 
            (draw-text (convert->string acell))))
    (gen-button (convert->string acell))))

;draw-text : string -> true
;Given a-string, draw it into the title and return true.

(define (draw-text a-string)
  (draw-message (list-ref (list-ref phonepad 1) 0) a-string))

;convert->string : X -> string

(define (convert->string a-datum)
  (cond
    [(number? a-datum) (number->string a-datum)]
    [else a-datum]))

;loc->lob : (listof cell)
;[(listof cells) to (listof buttons)] Given aloc, convert them to a lob.

(define (loc->lob aloc)
  (map cell->button aloc))

(define phonepad (pad->gui "Phone" pad1))
(define calcpad (pad->gui "Calculator" pad2))

(create-window phonepad)