;;;;
;;;; w w w - b r o w s e r . s t k l o s     -- A simple WEB browser
;;;;
;;;; Copyright © 1993-1999 Erick Gallesio - I3S-CNRS/ESSI <eg@unice.fr>
;;;; 
;;;; Permission to use, copy, modify, distribute,and license this
;;;; software and its documentation for any purpose is hereby granted,
;;;; provided that existing copyright notices are retained in all
;;;; copies and that this notice is included verbatim in any
;;;; distributions.  No written agreement, license, or royalty fee is
;;;; required for any of the authorized uses.
;;;; This software is provided ``AS IS'' without express or implied
;;;; warranty.
;;;;
;;;;           Author: Erick Gallesio [eg@unice.fr]
;;;;    Creation date: 21-Oct-1996 14:02
;;;; Last file update:  3-Sep-1999 19:56 (eg)
;;;;

(require "Tk-classes")
(require "www")

(import WWW)

(define WWW:browser
  (let ((browser #f)		;; Id of browser (#f if no browser exists)
	(lentry  #f))		;; The labeled entry of the interface
    (lambda args

  ;; URL history management
  ;;
  (define new-url
    (let ((history '())
	  (current -1))
      (lambda  (txt url)
	(case url
	  ((previous) (when (> (length history) 1)
			(set! current (modulo (- current 1) (length history)))
			(www:view-url (Id txt) (list-ref history current))))
	  ((next)     (when (> (length history) 1)
			(set! current (modulo (+ current 1) (length history)))
			(www:view-url (Id txt) (list-ref history current))))
	  ((reload)   (www:view-url (Id txt) (list-ref history current)))
	  (ELSE	      (if (null? history)
			  (begin
			    (set! history (list url))
			    (set! current 0))
			  (unless (string=? (list-ref history current) url)
			    (set! history (append history (list url)))
			    (set! current (- (length history) 1)))))))))
  ;;; Make interface
  ;;;
  (define (make-buttons parent txt)
    (let ((s (make-toolbar parent
	   `(("tb_back.gif"     "Back"    ,(lambda () (new-url (Id txt) 'previous)))
	     2
	     ("tb_forward.gif"  "Forward" ,(lambda () (new-url (Id txt) 'next)))
	     2
	     ("tb_reload.gif"   "Reload"  ,(lambda () (new-url (Id txt) 'reload)))
	     2
	     ("tb_stop.gif"     "Stop Loading" 
	      			          ,(lambda () (set! www:stop-loading #t)))
	     10
	     ("tb_exit.gif"     "Exit"    ,(lambda () (destroy parent)))
	     0
	     ("tb_info.gif"     "Help"    ,(lambda () 
					     (STk:show-help-file "STk-hlp.html"))))
	   :relief "ridge" :border-width 2
	   :release-command (default-release-toolbar txt))))
      s))

  (define (make-location parent txt)
    (let* ((s  (make-toolbar parent '(0)
			     :relief "ridge" :border-width 2
			     :release-command (default-release-toolbar txt)))
	   (f  (toolbar-item s 0))
	   (le (make <Labeled-entry> :parent f :title "Location:" 
		                     :font '(Courier -12))))
      (pack le :fill 'x :expand #t)
      (bind (Id le) "<Return>" (lambda () (www:view-url (Id txt) (value le))))
      ;; Keep a reference on the labeled entry for later bindings
      (set! lentry le)
      s))

  (define (make-interface parent)
    (let* ((txt   (make <Scroll-text> :parent parent :font '(Courier -12)
			:width 100 :height 45))
	   (loc   (make-location parent txt))
	   (f     (make-buttons parent txt))
	   (f1    (make <Frame> :parent parent))
	   (lab	  (make <Label> :parent f1 :anchor "w"))
	   (gauge (make <Gauge> :parent f1 :width 200 :height 10 
			:background "gray40" :foreground "IndianRed4")))
      ;;
      ;; Pack commponents
      (pack f loc :expand #f :fill "x")
      (pack txt   :expand #t :fill "both")
      (pack f1    :expand #f :fill "x")
      (pack lab   :expand #t :fill "x" :side "left")
      (pack gauge :expand #f :side "left" :padx 10)

      ;; Redefinition of WWW hooks
      ;;
      (set! www:hook-formatting 
	    (let ((counter  0)
		  (pos      0))
	      (lambda ()
		(when (= counter 20)
		  (set! pos (modulo (+ pos 5) 105))
		  (set! counter 0)
		  (set! (value gauge) pos)
		  (update))
		(set! counter (+ counter 1)))))

      (set! www:hook-start-loading
	    (lambda ()
	      (slot-set! txt 'cursor "watch")
	      (slot-set! lab 'text "Loading Document ...")
	      (update)))

      (set! www:hook-stop-loading 
	    (lambda ()
	      (let ((msg "Loading Document ... Done."))
		(slot-set! gauge 'value 0)
		(slot-set! lab 'text msg)
		(slot-set! txt 'cursor "top_left_arrow")
		(set! www:stop-loading #f)
		(after 5000 (lambda () 
			      (catch (if (equal? (slot-ref lab 'text) msg)
					 (slot-set! lab 'text ""))))))))
      (set! www:hook-title 
	    (lambda (value)
	      (slot-set! parent 'title value)))

      (set! www:hook-location
	    (lambda (url)
	      (set! (value lentry) url)
	      (new-url txt url)))

      ;; Return the txt widget
      txt))

  ;;;;
  ;;;; STk:browse starts here 
  ;;;;
  (let* ((url    (get-keyword :url args #f))
	 (parent (get-keyword :parent args #f)))

    (unless browser
      (set! browser (make-interface 
		        (or parent 
			    (make <Toplevel> :title "STk Web browser"))))
      (bind browser "<Destroy>" (lambda () (set! browser #f))))

    (when url
      (www:view-url (Id browser) url))
    browser))))

;;;
;;; Misc.
;;; 
(define STk:web-browser WWW:browser) ; for backward compatibility with 3.x versions

(provide "www-browser")