(module split-screen mzscheme
  (require (lib "match.ss")
           (only (lib "misc.ss" "swindle")  mappend)
           "html.ss"
           "url.ss"
           "../../private/options.ss")
  
  ; These items are common to all split screens
  
  (define left-header-items
    `((VERBATIM (big (big (big (b (a ((href ,url-helpdesk-home)) "PLT Scheme Help Desk"))))))))
  
  (define left-footer-items
    (case (helpdesk-platform)
      [(internal-browser internal-browser-simple)
       '(nbsp)]
      [else
       '(nbsp 
         (VERBATIM (small (small (a ((href "http://www.plt-scheme.org/map.html")) "Site Map"))))
         (VERBATIM (hr ((noshade "1") (size "2") (color "#3a652b"))))
         (VERBATIM (nobr 
                    (small ((class "sansa")) 
                           (a ((href "http://www.plt-scheme.org/")) "PLT")
                           nbsp "|" nbsp 
                           (a ((href "http://www.plt-scheme.org/software/drscheme/")) "DrScheme")
                           nbsp "|" nbsp 
                           (a ((href "http://www.teach-scheme.org/")) "TeachScheme!")
                           nbsp "|" nbsp 
                           (a ((href "http://www.htdp.org/")) "HtDP") nbsp
                           "|" nbsp 
                           (a ((href "http://planet.plt-scheme.org/")) "PLaneT") 
                           nbsp)))
         ; Google Search for PLT Documentation
         #;(VERBATIM (div ((align "center")) 
                          (div ((style "display: inline; margin: 0; white-space: nowrap;")) 
                               ; The Google "Search Documentation" field and button
                               (form ((id "searchbox_010927490648632664335:4yu6uuqr9ia") 
                                      (action "http://www.plt-scheme.org/search/")
                                      (style "display: inline; margin: 0;")) 
                                     (input ((type "hidden") (name "cx") (value "010927490648632664335:4yu6uuqr9ia")))
                                     (input ((type "text") (name "q") (size "16") (style "font-size: 75%;")))
                                     (input ((type "hidden") (name "hq") (value "more:plt")))
                                     (input ((type "hidden") (name "cxq") (value "more:docs")))
                                     (input ((type "submit") (name "sa") (value "Search Documentation") 
                                                             (style "font-size: 75%;")))
                                     (input ((type "hidden") (name "cof") (value "FORID:9")))))
                          nbsp)))]))
  
  
  ; the internal browser makes a "split" screen by having the left items at the top,
  ; and the right items at the bottom
  (define (make-split-page/internal-browser title top-items left-items right-header right-items)
    (html-page
     #:title title
     #:body `(div ,(html-left-items (append #;left-header-items 
                                            left-items left-footer-items))
                  (hr)
                  ,@(html-right-items right-items))))
  
  ; simple version that only shows the contents and no menu
  (define (make-simple-page/internal-browser title top-items left-items right-header right-items)
    (html-page 
     #:title title
     #:body (if (equal? left-items "home")
                `(div (h1 "PLT Help Desk") ,(html-left-items right-items))
                `(div (h1 ,right-header)  
                      ,@(html-right-items right-items)))))
  
  ; an external is capable of displaying a proper split screen
  (define (make-split-page title top-items left-items right-header right-items)
    (html-page
     #:title title
     #:bodies `(,@top-items ,(make-split-screen left-items right-header right-items))))
  
  
  (define (make-split-screen left-items right-header right-items)
    `(table ((height "80%") (width "100%") (align "center") (border "0") (cellspacing "0") (cellpadding "30"))
            (tr ((valign "top")) 
                (td ((height "80%") (width "50%") (align "center") (valign "top") (bgcolor "#74ca56")) 
                    ; LEFT TABLE
                    (table ((align "center") (class "sansa") (border "0") (cellpadding "0") (cellspacing "4")) 
                           #;(tr (td ((align "center"))                                      
                                     (img ((src "http://www.plt-scheme.org/plt-green.jpg") 
                                           (width "133") (height "128") (alt "[icon]")))))
                             ,(html-left-items (append left-header-items left-items left-footer-items)))
                    (td ((height "100%") (width "50%") (align "left") (valign "top"))
                        ; RIGHT TABLE
                        (table ((width "80%") (class "sansa") (align "center") (border "0") 
                                              (cellpadding "0") (cellspacing "0")) 
                               (tr (td (h1 ,right-header)))
                               ;(tr (td (small (small nbsp))))
                               (tr (td (table ((border "0") (cellpadding "3") (cellspacing "0") (width "100%"))
                                              ,@(html-right-items right-items))))))))))
  
  ;;;
  ;;; ITEM FORMATTING
  ;;; (ad hoc markup inherited)
  
  (define (html-left-items items)
    `(tr (td (table ,@(mappend html-left-item items)))))

  (define (html-left-item item)
    (match item
      ['UP                (list '(font ((size "-2")) nbsp))]
      ['--                (list '(tr ((height "4")) (td ((colspan "2")))))]
      [('VERBATIM sxml)   (list `(tr (td ((align "center")) ,sxml)))]
      [(header)           (list `(tr (td  #;((colspan "2")) ,header)))]
      [(header body ...)  (list `(tr (td  #;((colspan "2")) ,header))
                                `(tr (td  ,@body)))]
      [other              (list other)]))
  
  (define (html-right-items items)
    (mappend html-right-item items))
  
  (define (html-right-item item)
    (match item
      ['--                      (list '(tr ((height "4")) (td ((colspan "2")))))]
      [('VERBATIM item)         item]
      [(body ...)               (list body)]))
  

  (provide make-split-screen
           make-split-page
           make-split-page/internal-browser
           make-simple-page/internal-browser)
  
)