#lang racket

(require "tfield.rkt")
(require web-server/servlet
         web-server/servlet-env
         web-server/templates
         xml)


;; TODO: maybe render tfield names as 'class'es instead of 'id's in HTML
;        elements (because the same tfield may be rendered multiple times
;        in the page -- on the saved preview tab, the edit tab, and/or
;        the results tab -- leading to duplicate occurrences of id's)
;       


;; ============================================================================

; render-full/string : tfield/function string -> string
; produces the initial XHTML rendering of the application's main page, as
; a string. The given continuation url string will be appropriately
; embedded somewhere in the page to allow further AJAX requests

(define (render-full/string tf cont-url)
  (define title (tfield-label tf))
  (define text 
    (match (tfield/function-text tf)
      [(? string? s) s]
      [xs (apply string-append (map xexpr->string xs))]))
  (include-template "htdocs/template.html"))
  


;; ============================================================================
;; render form elements for editing

; render*/edit : (listof tfield) (or #f tfield) -> (listof xexpr)
(define (render*/edit tfs parent)
  (map (λ(t) (render/edit t parent)) tfs))

; render/edit : tfield (or #f tfield) -> xexpr
(define (render/edit tf parent)
  (define parent-not-oneof? (not (tfield/oneof? parent)))
  (define parent-not-oneof/listof? (and (not (tfield/oneof? parent))
                                        (not (tfield/listof? parent))))
  (define (input-text-of name value [disabled? #f])
    `(input ([type "text"] [name ,name] [id ,name]
             [value ,value] ,@(if disabled? `([disabled "disabled"]) '()))))
    
  (match tf
    [(tfield/const label name error value)
     (define label? parent-not-oneof/listof?)
     (render-basic/edit name '(tfield-constant) (and label? label)
                   (input-text-of name (format "~a" value) #t) error)]
    [(tfield/boolean label name error value)
     (define label? parent-not-oneof/listof?)
     (render-basic/edit name '(tfield-boolean) 
                   (and label? `(label ([for ,name]) ,label))
                   `(input ([type "checkbox"] [name ,name]
                            [id ,name] ,@(if value `([checked "checked"]) '())))
                   error)]
    [(tfield/number label name error value raw-value)
     (define label? parent-not-oneof/listof?)
     (render-basic/edit name '(tfield-number) (and label? label)
                   (input-text-of name (or raw-value "")) error)]
    [(tfield/symbol label name error value)
     (define label? parent-not-oneof/listof?)
     (render-basic/edit name '(tfield-symbol) (and label? label)
                   (input-text-of name (if value (symbol->string value) "")) 
                   error)]
    [(tfield/string label name error value non-empty?)
     (define label? parent-not-oneof/listof?)
     (render-basic/edit name '(tfield-string) (and label? label) 
                   (input-text-of name (or value "")) error)]
    [(? tfield/struct? _) (render-struct/edit tf parent)]
    [(? tfield/oneof? _)  (render-oneof/edit tf parent)]
    [(? tfield/listof? _) (render-listof/edit tf parent)]
    [(tfield/function title name error text func args result)
     "blah"]
    [_ (error (object-name render/edit)
              (format "somehow got an unknown field type: ~a" tf))]))


; div-wrapper: (listof symbol) -> [(listof xexpr) -> (or xexpr (listof xexpr))]
; produces (λ(inner) `(div ([id [<name>-div"] [class "symbol ..."]) ,@inner)
(define ((div-wrapper name classes) inner)
  `(div ([id ,(format "~a-div" name)]
         [class ,(string-join (map symbol->string classes) " ")])
        ,@(if (xexpr? inner) (list inner) inner)))


; produces a 'nest...' class name based on depth of given tfield or name
(define (nest-level tf/name)
  (format "nest~a" (add1 (remainder (sub1 (depth-of tf/name)) 3))))


; render-basic : (listof symbol) (or #f string) xexpr (or #f xexpr) -> xexpr
(define (render-basic/edit name classes label input-elt error)
  ((div-wrapper name `(tfield tfield-basic ,@classes))
   (list (if label `(span ([class "label"]) ,label) "")
         input-elt
         (if error `(span ([class "error"]) ,error) ""))))
      
; render-listof : tfield/listof (or #f tfield) -> xexpr
(define (render-listof/edit tf parent)
  (match tf
    [(tfield/listof label name error base elts non-empty?)
     ((div-wrapper name `(tfield tfield-listof))
      `(fieldset ([class ,(nest-level tf)])
         (legend ,label)
         ,(if error `(div ([class "error error-listof"]) ,error) "")
         (input ([type "hidden"] [name ,name] [id ,name]
                                 [value ,(format "~a" (length elts))]))
         (ol ([id ,(string-append name "-ol")] [class "tfield-listof sortable"])
             ,@(map (curry render-listof-item/edit tf) elts)
             (li ([class "nosort"])
                 (button ([id ,(string-append name "-addbtn")]
                          [class "addbtn"] [type "button"]) 
                         "Add " ,(tfield-label base))))))]))
     
(define (render-listof-item/edit tf/listof e)
       (define elt-name (tfield-name e))
       `(li ([id ,(string-append elt-name "-li")])
            (div ([class "listof-item"])
                 (div ([class "li-handle"])
                      (span ([class "ui-icon ui-icon-arrowthick-2-n-s"]) ""))
                 (button ([id ,(string-append elt-name "-delbtn")]
                          [class "delbtn"] [type "button"]) "")
                 (div ([class "listof-data"])
                      ,(render/edit e tf/listof))
                 (div ([style "clear: both;"]) ""))))      
                
; render-oneof : tfield/oneof (or #f tfield) -> xexpr
(define (render-oneof/edit tf parent)
  (match tf
    [(tfield/oneof label name error options chosen)
     (define label? (and (not (tfield/oneof? parent))
                         (not (tfield/listof? parent))))
     (define selected-tf (and chosen (list-ref options chosen)))
     (define fieldset? (and selected-tf (or (tfield/struct? selected-tf)
                                            (tfield/listof? selected-tf))))
     (define select-elt (render-select-element/edit tf))
     (define label-span
       `(span ,(if (and label? label)
                   `(label ([for ,name]) ,label " ") "") ,select-elt))
     (cond
       [(not selected-tf)
        (render-basic/edit name '(tfield-oneof) label-span empty error)]
       [fieldset?
        ((div-wrapper name `(tfield tfield-oneof))
         `(fieldset ([class ,(nest-level tf)])
            (legend ,label-span)
            ,(if error `(div ([class "error"]) ,error) "")
            ,(render/edit selected-tf tf)))]
       [else
        (render-basic/edit name '(tfield-oneof) label-span
                      (render/edit selected-tf tf) error)])]))

; render-select-element : tfield/oneof -> xexpr
(define (render-select-element/edit tf/o)
  (define name (tfield-name tf/o))
  (define opts (tfield/oneof-options tf/o))
  (define chosen (tfield/oneof-chosen tf/o))
  `(select ([name ,name] [id ,name] [class "tfield-oneof"])
     (option ([value "-"]
              ,@(if chosen '() '([selected "selected"]))) "-")
     ,@(map (λ(tflabel i)
              `(option ([value ,(number->string i)]
                        ,@(if (and chosen (= i chosen)) 
                              '([selected "selected"]) '())) ,tflabel))
            (map tfield-label opts)
            (build-list (length opts) values))))

; render-struct : tfield/struct (or #f tfield) -> xexpr
(define (render-struct/edit tf parent)
  (match tf
    [(tfield/struct label name error constr args)
     (define arg/content 
       `(ul ([class "tfield-structure"])
           ,@(map (λ(a) `(li ,(render/edit a tf))) args)))
     (define wrapper
       (if (tfield/oneof? parent)
           ((div-wrapper name '(tfield tfield-structure))
            (list (if error `(div ([class "error"]) ,error) "")
                  arg/content))
           ((div-wrapper name '(tfield tfield-structure))
            `(fieldset ([class ,(nest-level name)])
                       ,(if label `(legend ,label) "")
                       ,(if error `(div ([class "error"]) ,error) "")
                       ,arg/content)) ))
     wrapper]))


;; ============================================================================
;; render form elements for display

; colonize : string -> string
; adds ": " to end of given string if it's not ""
(define (colonize str)
  (if (equal? str "") str (string-append str ": ")))

; render*/disp : (listof tfield) (or #f tfield) -> (listof xexpr)
(define (render*/disp tfs parent)
  (map (λ(t) (render/disp t parent)) tfs))


; render-basic/disp : string (listof symbol) (or #f string)
;                           (or xexpr (listof xexpr)) -> xexpr
(define (render-basic/disp name classes label content)
  ((div-wrapper name `(tfield tfield-basic ,@classes))
   (list (if label `(span ([class "label"]) ,(colonize label)) "")
         `(span ,@(if (xexpr? content) (list content) content)))))
      

; render/disp : tfield (or #f tfield) -> xexpr
(define (render/disp tf parent)
  (define parent-not-oneof? (not (tfield/oneof? parent)))
  (define parent-not-oneof/listof? (and (not (tfield/oneof? parent))
                                        (not (tfield/listof? parent))))
  (define parent-not-listof? (not (tfield/listof? parent)))
  
  (match tf
    [(tfield/const label name error value)
     (render-basic/disp name '(tfield-constant) #f label)]
    [(tfield/boolean label name error value)
     (render-basic/disp name '(tfield-boolean) (and parent-not-listof? label)
                        (if value "YES" "NO"))]
    [(tfield/number label name error value raw-value)
     (render-basic/disp name '(tfield-number) (and parent-not-listof? label)
                        (or raw-value "-"))]
    [(tfield/symbol label name error value)
     (render-basic/disp name '(tfield-symbol) (and parent-not-listof? label)
                        (or (and value (symbol->string value)) "-"))]
    [(tfield/string label name error value non-empty?)
     (render-basic/disp name '(tfield-string) (and parent-not-listof? label)
                        (if (equal? value "") "-"
                            (or value "-")))]
    [(tfield/struct label name error constr args)
     ((div-wrapper name '(tfield tfield-structure))
      `(fieldset (legend ,(colonize label))
                 (ul ,@(map (λ(a) `(li ,a)) (render*/disp args tf)))))]
    [(tfield/oneof label name error options chosen)
     (define selected-tf (and chosen (list-ref options chosen)))
     (cond
       [(not selected-tf) 
        ((div-wrapper name `(tfield tfield-oneof))
         `(span "(" ,label " not selected)"))]
       [else 
        ((div-wrapper name `(tfield tfield-oneof))
         (render/disp selected-tf tf))])]
    [(tfield/listof label name error base elts non-empty?)
     ((div-wrapper name `(tfield tfield-listof))
      `(fieldset (legend ,(colonize label))
                 ,(if (empty? elts) 
                      "(empty)"
                      `(ol ,@(map (λ(a) `(li ,a)) (render*/disp elts tf))))))]
    [(tfield/function title name error text func args result)
     `(span ([id ,name]) "")]
    [_ (error (object-name render/disp)
              (format "somehow got an unknown field type: ~a" tf))]))

;; ============================================================================

(provide render-full/string 
         render*/edit
         render/edit
         render-listof-item/edit
         
         render*/disp 
         render/disp)