#lang scheme/base

(require (for-syntax scheme/base)
         scheme/unit
         scheme/class
         scheme/gui/base
         scheme/runtime-path
         "sig.ss"
         "../decorated-editor-snip.ss"
         string-constants)

(define-runtime-path semicolon-bitmap-path '(lib "icons/semicolon.gif"))
(provide comment-box@)

(define-unit comment-box@
  
  (import [prefix text: framework:text^]
          [prefix scheme: framework:scheme^]
          [prefix keymap: framework:keymap^])
  (export (rename framework:comment-box^
                  (-snip% snip%)))
  
  (define snipclass%
    (class decorated-editor-snipclass%
      (define/override (make-snip stream-in) (instantiate -snip% ()))
      (super-instantiate ())))
  
  (define snipclass (make-object snipclass%))
  (send snipclass set-version 1)
  (send snipclass set-classname (format "~s" '(lib "comment-snip.ss" "framework")))
  (send (get-the-snip-class-list) add snipclass)
  
  (define bm (make-object bitmap% semicolon-bitmap-path))
  
  (define scheme+copy-self% #f)
  (define (get-scheme+copy-self%)
    (unless scheme+copy-self%
      (set! scheme+copy-self%
            (class scheme:text%
              (inherit copy-self-to)
              (define/override (copy-self)
                (let ([ed (new scheme+copy-self%)])
                  (copy-self-to ed)
                  ed))
              (super-new)
              (inherit set-max-undo-history)
              (set-max-undo-history 'forever))))
    scheme+copy-self%)
  
  (define -snip%
    (class* decorated-editor-snip% (readable-snip<%>)
      (inherit get-editor get-style)
      
      (define/override (make-editor) (new (get-scheme+copy-self%)))
      (define/override (make-snip) (make-object -snip%))
      (define/override (get-corner-bitmap) bm)
      (define/override (get-position) 'left-top)
      
      (define/override (get-text offset num [flattened? #t])
        (let* ([super-res (super get-text offset num flattened?)]
               [replaced (string-append "; " (regexp-replace* "\n" super-res "\n; "))])
          (if (char=? #\newline (string-ref replaced (- (string-length replaced) 1)))
              replaced
              (string-append replaced "\n"))))
      
      
      (define/override (get-menu)
        (let ([menu (make-object popup-menu%)])
          (make-object menu-item% 
            (string-constant convert-to-semicolon-comment)
            menu
            (λ (x y)
              (let ([to-ed (find-containing-editor)])
                (when to-ed
                  (let ([this-pos (find-this-position)])
                    (when this-pos
                      (let ([from-ed (get-editor)])
                        (send to-ed begin-edit-sequence)
                        (send from-ed begin-edit-sequence)
                        (copy-contents-with-semicolons-to-position to-ed from-ed (+ this-pos 1))
                        (send to-ed delete this-pos (+ this-pos 1))
                        (send to-ed end-edit-sequence)
                        (send from-ed end-edit-sequence))))))))
          menu))
      
      (inherit get-admin)
      ;; find-containing-editor : -> (union #f editor)
      (define/private (find-containing-editor)
        (let ([admin (get-admin)])
          (and admin
               (send admin get-editor))))
      
      ;; find-this-position : -> (union #f number)
      (define/private (find-this-position)
        (let ([ed (find-containing-editor)])
          (and ed
               (send ed get-snip-position this))))
      
      ;; copy-contents-with-semicolons-to-position : (is-a? text%) number -> void
      (define/private (copy-contents-with-semicolons-to-position to-ed from-ed pos)
        (let loop ([snip (find-last-snip from-ed)])
          (cond
            [snip 
             (when (or (memq 'hard-newline (send snip get-flags))
                       (memq 'newline (send snip get-flags)))
               (send to-ed insert "; " pos))
             (send to-ed insert (send snip copy) pos)
             (loop (send snip previous))]
            [else 
             (send to-ed insert "; " pos)])))
      
      ;; find-last-snip : editor -> snip
      ;; returns the last snip in the editor
      (define/private (find-last-snip ed)
        (let loop ([snip (send ed find-first-snip)]
                   [acc (send ed find-first-snip)])
          (cond
            [snip (loop (send snip next) snip)]
            [else acc])))
      
      (define/public (read-special source line column position)
        (make-special-comment "comment"))
      (super-instantiate ())
      (inherit set-snipclass)
      (set-snipclass snipclass))))
