# Simple HTML display library by Stephen Uhler (stephen.uhler@sun.com)
# Copyright (c) 1995 by Sun Microsystems
# Version 0.3 Fri Sep  1 10:47:17 PDT 1995
#
# Modified to support some 8.0 and 8.1 font conventions by Clif Flynt
#        (clif@cflynt.com)
#   Modifications copyright (c) 1998 by Flynt Consulting Services, 
# Version 0.3.1 Jan 10, 1999
#
;# RCSID: $Header: /home/clif.clif/CVS_ROOT/TclXexample/htmllib.tcl,v 1.9 1999/02/01 04:58:02 clif Exp $
#
# See the file "license.terms" for information on usage and redistribution
# of this file, and for a DISCLAIMER OF ALL WARRANTIES.
#
# To use this package,  create a text widget (say, .text)
# and set a variable full of html, (say $html), and issue:
#        HMinit_win .text
#        HMparse_html $html "HMrender .text"
# You also need to supply the routine:
#   proc HMlink_callback {win href} { ...}
#      win:  The name of the text widget
#      href  The name of the link
# which will be called anytime the user "clicks" on a link.
# The supplied version just prints the link to stdout.
# In addition, if you wish to use embedded images, you will need to write
#   proc HMset_image {handle src}
#      handle  an arbitrary handle (not really)
#      src     The name of the image
# Which calls
#        HMgot_image $handle $image
# with the TK image.
#
# To return a "used" text widget to its initialized state, call:
#   HMreset_win .text
# See "sample.tcl" for sample usage
##################################################################
############################################
# mapping of html tags to text tag properties
# properties beginning with "T" map directly to text tags

# These are Defined in HTML 2.0

array set HMtag_map {
        large        {size 18}
        large2        {size 22}
        large3        {size 20}
        large4        {size 18}
        b      {weight bold}
        blockquote        {style i indent 1 Trindent rindent}
        bq                {style i indent 1 Trindent rindent}
        cite   {style i}
        code   {family courier}
        dfn    {style i}        
        dir    {indent 1}
        dl     {indent 1}
        em     {style i}
        h1     {size 24 weight bold}
        h2     {size 22}                
        h3     {size 20}        
        h4     {size 18}
        h5     {size 16}
        h6     {style i}
        i      {style i}
        kbd    {family courier weight bold}
        menu     {indent 1}
        ol     {indent 1}
        pre    {fill 0 family courier Tnowrap nowrap}
        samp   {family courier}                
        strong {weight bold}                
        tt     {family courier}
        u         {Tunderline underline}
        ul     {indent 1}
        var    {style i}        
}

# These are in common(?) use, but not defined in html2.0

array set HMtag_map {
        center {Tcenter center}
        strike {Tstrike strike}
        u           {Tunderline underline}
}

# initial values

set HMtag_map(hmstart) {
        family times   weight medium   style r   size 14
        Tcenter ""   Tlink ""   Tnowrap ""   Tunderline ""   list list
        fill 1   indent "" counter 0 adjust 0
}

# html tags that insert white space

array set HMinsert_map {
        blockquote "\n\n" /blockquote "\n"
        br        "\n"
        dd        "\n" /dd        "\n"
        dl        "\n" /dl        "\n"
        dt        "\n"
        form "\n"        /form "\n"
        h1        "\n\n"        /h1        "\n"
        h2        "\n\n"        /h2        "\n"
        h3        "\n\n"        /h3        "\n"
        h4        "\n"        /h4        "\n"
        h5        "\n"        /h5        "\n"
        h6        "\n"        /h6        "\n"
        li   "\n"
        /dir "\n"
        /ul "\n"
        /ol "\n"
        /menu "\n"
        p        "\n\n"
        pre "\n"        /pre "\n"
}

# tags that are list elements, that support "compact" rendering

array set HMlist_elements {
        ol 1   ul 1   menu 1   dl 1   dir 1
}

;# Default to no font size scaling
set HM_globals(S_adjust_size) 0

############################################
# initialize the window and stack state

proc HMinit_win {win} {
        upvar #0 HM$win var
        
        HMinit_state $win
        $win tag configure underline -underline 1
        $win tag configure center -justify center
        $win tag configure nowrap -wrap none
        $win tag configure rindent -rmargin $var(S_tab)c
        $win tag configure strike -overstrike 1
        $win tag configure mark -foreground red                ;# list markers
        $win tag configure list -spacing1 3p -spacing3 3p                ;# regular lists
        $win tag configure compact -spacing1 0p                ;# compact lists
        $win tag configure link -borderwidth 2 -foreground blue        ;# hypertext links
        HMset_indent $win $var(S_tab)
        $win configure -wrap word

        # configure the text insertion point
        $win mark set $var(S_insert) 1.0

        # for horizontal rules
        set size 1;
        while {[catch "$win tag configure thin -font [list [HMx_font times $size medium r]]" ]} {
          puts "Failed to open horizontal rule $size, trying larger"
          global errorCode errorInfo
          puts "$errorCode -- $errorInfo"
          incr size;
        } 

        $win tag configure hr -relief sunken -borderwidth 2 -wrap none \
                -tabs [winfo width $win]
        bind $win <Configure> {
                %W tag configure hr -tabs %w
                %W tag configure last -spacing3 %h
        }

        # generic link enter callback

        $win tag bind link <1> "HMlink_hit $win %x %y"
}

# set the indent spacing (in cm) for lists
# TK uses a "weird" tabbing model that causes \t to insert a single
# space if the current line position is past the tab setting

proc HMset_indent {win cm} {
        set tabs [expr $cm / 2.0]
        $win configure -tabs ${tabs}c
        foreach i {1 2 3 4 5 6 7 8 9} {
                set tab [expr $i * $cm]
                $win tag configure indent$i -lmargin1 ${tab}c -lmargin2 ${tab}c \
                        -tabs "[expr $tab + $tabs]c [expr $tab + 2*$tabs]c"
        }
}

# reset the state of window - get ready for the next page
# remove all but the font tags, and remove all form state

proc HMreset_win {win} {
        upvar #0 HM$win var
        regsub -all { +[^L ][^ ]*} " [$win tag names] " {} tags
        catch "$win tag delete $tags"
        eval $win mark unset [$win mark names]
        $win delete 0.0 end
        $win tag configure hr -tabs [winfo width $win]

        # configure the text insertion point
        $win mark set $var(S_insert) 1.0

        # remove form state.  If any check/radio buttons still exists, 
        # their variables will be magically re-created, and never get
        # cleaned up.
        catch unset [info globals HM$win.form*]

        HMinit_state $win
        return HM$win
}

# initialize the window's state array
# Parameters beginning with S_ are NOT reset
#  adjust_size:                global font size adjuster
#  unknown:                character to use for unknown entities
#  tab:                        tab stop (in cm)
#  stop:                enabled to stop processing
#  update:                how many tags between update calls
#  tags:                number of tags processed so far
#  symbols:                Symbols to use on un-ordered lists

proc HMinit_state {win} {
        upvar #0 HM$win var
        array set tmp [array get var S_*]
        catch {unset var}
        array set var {
                stop 0
                tags 0
                fill 0
                list list
                S_adjust_size 0
                S_tab 1.0
                S_unknown \xb7
                S_update 10
                S_symbols O*=+-o\xd7\xb0>:\xb7
                S_insert Insert
        }

        array set var [array get tmp]
}

# alter the parameters of the text state
# this allows an application to over-ride the default settings
# it is called as: HMset_state -param value -param value ...

array set HMparam_map {
        -update S_update
        -tab S_tab
        -unknown S_unknown
        -stop S_stop
        -size S_adjust_size
        -symbols S_symbols
    -insert S_insert
}

proc HMset_state {win args} {
        upvar #0 HM$win var
        global HMparam_map
        set bad 0
        if {[catch {array set params $args}]} {return 0}
        foreach i [array names params] {
                incr bad [catch {set var($HMparam_map($i)) $params($i)}]
        }
        return [expr $bad == 0]
}

proc HMinsert_FromMap { win text id } {
        global HMtag_map HMinsert_map HMlist_elements
        upvar #0 HM$win var

        # insert white space (with current font)
        # adding white space can get a bit tricky.  This isn't quite right
        set bad [catch {$win insert $var(S_insert) $HMinsert_map($id) "space $var(font)"}]

        if {!$bad && [lindex $var(fill) end]} {
                set text [string trimleft $text]
        }
}        

############################################
# manage the display of html

# HMrender gets called for every html tag
#   win:   The name of the text widget to render into
#   tag:   The html tag (in arbitrary case)
#   not:   a "/" or the empty string
#   param: The un-interpreted parameter list
#   text:  The plain text until the next html tag

proc HMrender {win tag not param text} {
        upvar #0 HM$win var
        if {$var(stop)} return
        global HMtag_map HMinsert_map HMlist_elements
        set tag [string tolower $tag]
        set text [HMmap_esc $text]

        # manage compact rendering of lists
        if {[info exists HMlist_elements($tag)]} {
                set list "list [expr {[HMextract_param $param compact] ? "compact" : "list"}]"
        } else {
                set list ""
        }

        # Allow text to be diverted to a different window (for tables)
        # this is not currently used
        if {[info exists var(divert)]} {
                set win $var(divert)
                upvar #0 HM$win var
        }

        # adjust (push or pop) tag state
        catch {HMstack $win $not "$HMtag_map($tag) $list"}

        HMinsert_FromMap $win $text $not$tag

        # to fill or not to fill
        if {[lindex $var(fill) end]} {
                set text [HMzap_white $text]
        }

        # generic mark hook
        catch {HMmark $not$tag $win $param text} err

        # do any special tag processing
        catch {HMtag_$not$tag $win $param text} msg


        # add the text with proper tags

        set tags [HMcurrent_tags $win]
        $win insert $var(S_insert) $text $tags

        # We need to do an update every so often to insure interactive response.
        # This can cause us to re-enter the event loop, and cause recursive
        # invocations of HMrender, so we need to be careful.
        if {!([incr var(tags)] % $var(S_update))} {
                update
        }
}

# html tags requiring special processing
# Procs of the form HMtag_<tag> or HMtag_</tag> get called just before
# the text for this tag is displayed.  These procs are called inside a 
# "catch" so it is OK to fail.
#   win:   The name of the text widget to render into
#   param: The un-interpreted parameter list
#   text:  A pass-by-reference name of the plain text until the next html tag
#          Tag commands may change this to affect what text will be inserted
#          next.

# A pair of pseudo tags are added automatically as the 1st and last html
# tags in the document.  The default is <HMstart> and </HMstart>.
# Append enough blank space at the end of the text widget while
# rendering so HMgoto can place the target near the top of the page,
# then remove the extra space when done rendering.

proc HMtag_hmstart {win param text} {
        upvar #0 HM$win var
        $win mark gravity $var(S_insert) left
        $win insert end "\n " last
        $win mark gravity $var(S_insert) right
}

proc HMtag_/hmstart {win param text} {
        $win delete last.first end
}

# put the document title in the window banner, and remove the title text
# from the document

proc HMtag_title {win param text} {
        upvar $text data
        wm title [winfo toplevel $win] $data
        set data ""
}

proc HMtag_hr {win param text} {
        upvar #0 HM$win var
        $win insert $var(S_insert) "\n" space "\n" thin "\t" "thin hr" "\n" thin
}

# list element tags

proc HMtag_ol {win param text} {
        upvar #0 HM$win var
        set var(count$var(level)) 0
}

proc HMtag_ul {win param text} {
        upvar #0 HM$win var
        catch {unset var(count$var(level))}
}

proc HMtag_menu {win param text} {
        upvar #0 HM$win var
        set var(menu) ->
        set var(compact) 1
}

proc HMtag_/menu {win param text} {
        upvar #0 HM$win var
        catch {unset var(menu)}
        catch {unset var(compact)}
}
        
proc HMtag_dt {win param text} {
        upvar #0 HM$win var
        upvar $text data
        set level $var(level)
        incr level -1
        $win insert $var(S_insert) "$data" \
                "hi [lindex $var(list) end] indent$level $var(font)"
        set data {}
}

proc HMtag_li {win param text} {
        upvar #0 HM$win var
        set level $var(level)
        incr level -1
        set x [string index $var(S_symbols)+-+-+-+-" $level]
        catch {set x [incr var(count$level)]}
        catch {set x $var(menu)}
        $win insert $var(S_insert) \t$x\t "mark [lindex $var(list) end] indent$level $var(font)"
}

# Manage hypertext "anchor" links.  A link can be either a source (href)
# a destination (name) or both.  If its a source, register it via a callback,
# and set its default behavior.  If its a destination, check to see if we need
# to go there now, as a result of a previous HMgoto request.  If so, schedule
# it to happen with the closing </a> tag, so we can highlight the text up to
# the </a>.

proc HMtag_a {win param text} {
        upvar #0 HM$win var

        # a source

        if {[HMextract_param $param href]} {
                set var(Tref) [list L:$href]
                HMstack $win "" "Tlink link"
                HMlink_setup $win $href
        }

        # a destination

        if {[HMextract_param $param name]} {
                set var(Tname) [list N:$name]
                HMstack $win "" "Tanchor anchor"
                $win mark set N:$name "$var(S_insert) - 1 chars"
                $win mark gravity N:$name left
                if {[info exists var(goto)] && $var(goto) == $name} {
                        unset var(goto)
                        set var(going) $name
                }
        }
}

# The application should call here with the fragment name
# to cause the display to go to this spot.
# If the target exists, go there (and do the callback),
# otherwise schedule the goto to happen when we see the reference.

proc HMgoto {win where {callback HMwent_to}} {
        upvar #0 HM$win var
        if {[regexp N:$where [$win mark names]]} {
                $win see N:$where
                update
                eval $callback $win [list $where]
                return 1
        } else {
                set var(goto) $where
                return 0
        }
}

# We actually got to the spot, so highlight it!
# This should/could be replaced by the application
# We'll flash it orange a couple of times.

proc HMwent_to {win where {count 0} {color orange}} {
        upvar #0 HM$win var
        if {$count > 5} return
        catch {$win tag configure N:$where -foreground $color}
        update
        after 200 [list HMwent_to $win $where [incr count] \
                                [expr {$color=="orange" ? "" : "orange"}]]
}

proc HMtag_/a {win param text} {
        upvar #0 HM$win var
        if {[info exists var(Tref)]} {
                unset var(Tref)
                HMstack $win / "Tlink link"
        }

        # goto this link, then invoke the call-back.

        if {[info exists var(going)]} {
                $win yview N:$var(going)
                update
                HMwent_to $win $var(going)
                unset var(going)
        }

        if {[info exists var(Tname)]} {
                unset var(Tname)
                HMstack $win / "Tanchor anchor"
        }
}

#           Inline Images
# This interface is subject to change
# Most of the work is getting around a limitation of TK that prevents
# setting the size of a label to a widthxheight in pixels
#
# Images have the following parameters:
#    align:  top,middle,bottom
#    alt:    alternate text
#    ismap:  A clickable image map
#    src:    The URL link
# Netscape supports (and so do we)
#    width:  A width hint (in pixels)
#    height:  A height hint (in pixels)
#    border: The size of the window border

proc HMtag_img {win param text} {
        upvar #0 HM$win var

        # get alignment
        array set align_map {top top    middle center    bottom bottom}
        set align bottom                ;# The spec isn't clear what the default should be
        HMextract_param $param align
        catch {set align $align_map([string tolower $align])}

        # get alternate text
        set alt "<image>"
        HMextract_param $param alt
        set alt [HMmap_esc $alt]

        set speed 0
        HMextract_param $param speed

        # get the border width
        set border 1
        HMextract_param $param border

        # see if we have an image size hint
        # If so, make a frame the "hint" size to put the label in
        # otherwise just make the label
        set item $win.$var(tags)
        # catch {destroy $item}
        if {[HMextract_param $param width] && [HMextract_param $param height]} {
                frame $item -width $width -height $height
                pack propagate $item 0
                set label $item.label
                label $label
                pack $label -expand 1 -fill both
        } else {
                set label $item
                label $label 
        }

        $label configure -relief ridge -fg orange -text $alt
        catch {$label configure -bd $border}
        $win window create $var(S_insert) -align $align -window $item -pady 2 -padx 2

        # add in all the current tags (this is overkill)
        set tags [HMcurrent_tags $win]
        foreach tag $tags {
                $win tag add $tag $item
        }

        # set imagemap callbacks
        if {[HMextract_param $param ismap]} {
                # regsub -all {[^L]*L:([^ ]*).*}  $tags {\1} link
                set link [lindex $tags [lsearch -glob $tags L:*]]
                regsub L: $link {} link
                global HMevents
                regsub -all {%} $link {%%} link2
                foreach i [array names HMevents] {
                        bind $label <$i> "catch \{%W configure $HMevents($i)\}"
                }
                bind $label <1> "+HMlink_callback $win $link2?%x,%y"
        } 

        # now callback to the application
        set src ""
        HMextract_param $param src
        HMset_image $win $label $src $speed
        return $label        ;# used by the forms package for input_image types
}

# The app needs to supply one of these
proc HMset_image {win handle src} {
        HMgot_image $handle "can't get\n$src"
}

# When the image is available, the application should call back here.
# If we have the image, put it in the label, otherwise display the error
# message.  If we don't get a callback, the "alt" text remains.
# if we have a clickable image, arrange for a callback

proc HMgot_image {win image_error} {
        # if we're in a frame turn on geometry propogation
        if {[winfo name $win] == "label"} {
                pack propagate [winfo parent $win] 1
        }
        if {[catch {$win configure -image $image_error}]} {
                $win configure -image {}
                $win configure -text $image_error
        }
}

# Sample hypertext link callback routine - should be replaced by app
# This proc is called once for each <A> tag.
# Applications can overwrite this procedure, as required, or
# replace the HMevents array
#   win:   The name of the text widget to render into
#   href:  The HREF link for this <a> tag.

array set HMevents {
        Enter        {-borderwidth 2 -relief raised }
        Leave        {-borderwidth 2 -relief flat }
        1                {-borderwidth 2 -relief sunken}
        ButtonRelease-1        {-borderwidth 2 -relief raised}
}

# We need to escape any %'s in the href tag name so the bind command
# doesn't try to substitute them.

proc HMlink_setup {win href} {
        global HMevents
        regsub -all {%} $href {%%} href2
        foreach i [array names HMevents] {
                eval {$win tag bind  L:$href <$i>} \
                        \{$win tag configure \{L:$href2\} $HMevents($i)\}
        }
}

# generic link-hit callback
# This gets called upon button hits on hypertext links
# Applications are expected to supply ther own HMlink_callback routine
#   win:   The name of the text widget to render into
#   x,y:   The cursor position at the "click"

proc HMlink_hit {win x y} {
        set tags [$win tag names @$x,$y]
        set link [lindex $tags [lsearch -glob $tags L:*]]
        # regsub -all {[^L]*L:([^ ]*).*}  $tags {\1} link
        regsub L: $link {} link
        HMlink_callback $win $link
}

# replace this!
#   win:   The name of the text widget to render into
#   href:  The HREF link for this <a> tag.

proc HMlink_callback {win href} {
        puts "Got hit on $win, link $href"
}

# extract a value from parameter list (this needs a re-do)
# returns "1" if the keyword is found, "0" otherwise
#   param:  A parameter list.  It should alredy have been processed to
#           remove any entity references
#   key:    The parameter name
#   val:    The variable to put the value into (use key as default)

proc HMextract_param {param key {val ""}} {

        if {$val == ""} {
                upvar $key result
        } else {
                upvar $val result
        }
    set ws "    \n\r"
 
    # look for name=value combinations.  Either (') or (") are valid delimeters
    if {
      [regsub -nocase [format {.*%s[%s]*=[%s]*"([^"]*).*} $key $ws $ws] $param {\1} value] ||
      [regsub -nocase [format {.*%s[%s]*=[%s]*'([^']*).*} $key $ws $ws] $param {\1} value] ||
      [regsub -nocase [format {.*%s[%s]*=[%s]*([^%s]+).*} $key $ws $ws $ws] $param {\1} value] } {
        set result $value
        return 1
    }

        # now look for valueless names
        # I should strip out name=value pairs, so we don't end up with "name"
        # inside the "value" part of some other key word - some day
        
        set bad \[^a-zA-Z\]+
        if {[regexp -nocase  "$bad$key$bad" -$param-]} {
                return 1
        } else {
                return 0
        }
}

# These next two routines manage the display state of the page.

# Push or pop tags to/from stack.
# Each orthogonal text property has its own stack, stored as a list.
# The current (most recent) tag is the last item on the list.
# Push is {} for pushing and {/} for popping

proc HMstack {win push list} {
        upvar #0 HM$win var
        array set tags $list
        if {$push == ""} {
                foreach tag [array names tags] {
                        lappend var($tag) $tags($tag)
                }
        } else {
                foreach tag [array names tags] {
                        # set cnt [regsub { *[^ ]+$} $var($tag) {} var($tag)]
                        set var($tag) [lreplace $var($tag) end end]
                }
        }
}

# extract set of current text tags
# tags starting with T map directly to text tags, all others are
# handled specially.  There is an application callback, HMset_font
# to allow the application to do font error handling

proc HMcurrent_tags {win} {
        upvar #0 HM$win var
        set font font
        foreach i {family size weight style} {
                set $i [lindex $var($i) end]
                append font :[set $i]
        }
        set xfont [HMx_font $family $size $weight $style $var(S_adjust_size)]
        HMset_font $win $font $xfont
        set indent [llength $var(indent)]
        incr indent -1
        lappend tags $font indent$indent
        foreach tag [array names var T*] {
                lappend tags [lindex $var($tag) end]        ;# test
        }
        set var(font) $font
        set var(xfont) [$win tag cget $font -font]
        set var(level) $indent
        return $tags
}

# allow the application to do do better font management
# by overriding this procedure

proc HMset_font {win tag font} {
        set fail [catch {$win tag configure $tag -font $font} msg]
        if {$fail} {
            global errorCode errorInfo
            puts "setFontFail: FONT: $font TAG: $tag\n$errorCode: $errorInfo"
            set lvl [info level]
            incr lvl -1;
            puts "called from: '[info level $lvl]'"
        }
}

# Set a global to adjust the size of all text displayed.
#  This may be a positive or negative value.
#  It allows all the text on a set of HTML windows to be scaled.

proc HM_setFontAdjust {newAdjustSize} {
        global HM_globals
        set HM_globals(S_adjust_size) $newAdjustSize
}

# generate an X font name
proc HMx_font {family size weight {style {}} {adjust_size 0}} {
        global tcl_version HM_globals

#  puts "FAMILY: $family - $size $weight $style $adjust_size"
        if {[string match $family ""]} {set family times}


        set size [expr $size + $HM_globals(S_adjust_size)]
        set size [expr $size + $adjust_size]
        
        if {$tcl_version < 8.0} {
            return "-*-$family-$weight-$style-normal-*-*-${size}0-*-*-*-*-*-*"
        } else {
                if {[string match $weight "medium"]} {
                set weight "normal"
                }
            return "$family $size $weight"
            }
}

# Optimize HMrender (hee hee)
# This is experimental

proc HMoptimize {} {
        regsub -all "\n\[         \]*#\[^\n\]*" [info body HMrender] {} body
        regsub -all ";\[         \]*#\[^\n]*" $body {} body
        regsub -all "\n\n+" $body \n body
        proc HMrender {win tag not param text} $body
}
############################################
# Turn HTML into TCL commands
#   html    A string containing an html document
#   cmd                A command to run for each html tag found
#   start        The name of the dummy html start/stop tags

proc HMparse_html {html {cmd HMtest_parse} {start hmstart}} {
        regsub -all \{ $html {\&ob;} html
        regsub -all \} $html {\&cb;} html
        regsub -all {\\} $html {\&#92\;} html
        set w " \t\r\n"        ;# white space
        proc HMcl x {return "\[$x\]"}
        set exp <(/?)([HMcl ^$w>]+)[HMcl $w]*([HMcl ^>]*)>
        set sub "\}\n$cmd {\\2} {\\1} {\\3} \{"
        regsub -all $exp $html $sub html
         eval "$cmd {$start} {} {} \{ $html \}"
        eval "$cmd {$start} / {} {}"
}

proc HMtest_parse {command tag slash text_after_tag} {
        puts "==> $command $tag $slash $text_after_tag"
}

# Convert multiple white space into a single space

proc HMzap_white {data} {
        regsub -all "\[ \t\r\n\]+" $data " " data
        return $data
}

# find HTML escape characters of the form &xxx;

proc HMmap_esc {text} {
        if {![regexp & $text]} {return $text}
        regsub -all {([][$\\])} $text {\\\1} new
        regsub -all {&#([0-9][0-9]?[0-9]?);?} \
                $new {[format %c [scan \1 %d tmp;set tmp]]} new
        regsub -all {&([a-zA-Z]+);?} $new {[HMdo_map \1]} new
        return [subst $new]
}

# convert an HTML escape sequence into character

proc HMdo_map {text {unknown ?}} {
        global HMesc_map
        set result $unknown
        catch {set result $HMesc_map($text)}
        return $result
}

# table of escape characters (ISO latin-1 esc's are in a different table)

array set HMesc_map {
   lt <   gt >   amp &   quot \"   copy \xa9
   reg \xae   ob \x7b   cb \x7d   nbsp \xa0
}
#############################################################
# ISO Latin-1 escape codes

array set HMesc_map {
        #92 \x5c
        nbsp \xa0 iexcl \xa1 cent \xa2 pound \xa3 curren \xa4
        yen \xa5 brvbar \xa6 sect \xa7 uml \xa8 copy \xa9
        ordf \xaa laquo \xab not \xac shy \xad reg \xae
        hibar \xaf deg \xb0 plusmn \xb1 sup2 \xb2 sup3 \xb3
        acute \xb4 micro \xb5 para \xb6 middot \xb7 cedil \xb8
        sup1 \xb9 ordm \xba raquo \xbb frac14 \xbc frac12 \xbd
        frac34 \xbe iquest \xbf Agrave \xc0 Aacute \xc1 Acirc \xc2
        Atilde \xc3 Auml \xc4 Aring \xc5 AElig \xc6 Ccedil \xc7
        Egrave \xc8 Eacute \xc9 Ecirc \xca Euml \xcb Igrave \xcc
        Iacute \xcd Icirc \xce Iuml \xcf ETH \xd0 Ntilde \xd1
        Ograve \xd2 Oacute \xd3 Ocirc \xd4 Otilde \xd5 Ouml \xd6
        times \xd7 Oslash \xd8 Ugrave \xd9 Uacute \xda Ucirc \xdb
        Uuml \xdc Yacute \xdd THORN \xde szlig \xdf agrave \xe0
        aacute \xe1 acirc \xe2 atilde \xe3 auml \xe4 aring \xe5
        aelig \xe6 ccedil \xe7 egrave \xe8 eacute \xe9 ecirc \xea
        euml \xeb igrave \xec iacute \xed icirc \xee iuml \xef
        eth \xf0 ntilde \xf1 ograve \xf2 oacute \xf3 ocirc \xf4
        otilde \xf5 ouml \xf6 divide \xf7 oslash \xf8 ugrave \xf9
        uacute \xfa ucirc \xfb uuml \xfc yacute \xfd thorn \xfe
        yuml \xff
}

##########################################################
# html forms management commands

# As each form element is located, it is created and rendered.  Additional
# state is stored in a form specific global variable to be processed at
# the end of the form, including the "reset" and "submit" options.
# Remember, there can be multiple forms existing on multiple pages.  When
# HTML tables are added, a single form could be spread out over multiple
# text widgets, which makes it impractical to hang the form state off the
# HM$win structure.  We don't need to check for the existance of required
# parameters, we just "fail" and get caught in HMrender

# This causes line breaks to be preserved in the inital values
# of text areas
array set HMtag_map {
        textarea    {fill 0}
}

##########################################################
# html isindex tag.  Although not strictly forms, they're close enough
# to be in this file

# is-index forms
# make a frame with a label, entry, and submit button

proc HMtag_isindex {win param text} {
        upvar #0 HM$win var

        set item $win.$var(tags)
        if {[winfo exists $item]} {
                destroy $item
        }
        frame $item -relief ridge -bd 3
        set prompt "Enter search keywords here"
        HMextract_param $param prompt
        label $item.label -text [HMmap_esc $prompt] -font $var(xfont)
        entry $item.entry
        bind $item.entry <Return> "$item.submit invoke"
        button $item.submit -text search -font $var(xfont) -command \
                [format {HMsubmit_index %s {%s} [HMmap_reply [%s get]]} \
                $win $param $item.entry]
        pack $item.label -side top
        pack $item.entry $item.submit -side left

        # insert window into text widget

        $win insert $var(S_insert) \n isindex
        HMwin_install $win $item
        $win insert $var(S_insert) \n isindex
        bind $item <Visibility> {focus %W.entry}
}

# This is called when the isindex form is submitted.
# The default version calls HMlink_callback.  Isindex tags should either
# be deprecated, or fully supported (e.g. they need an href parameter)

proc HMsubmit_index {win param text} {
        HMlink_callback $win ?$text
}

# initialize form state.  All of the state for this form is kept
# in a global array whose name is stored in the form_id field of
# the main window array.
# Parameters: ACTION, METHOD, ENCTYPE

proc HMtag_form {win param text} {
        upvar #0 HM$win var

        # create a global array for the form
        set id HM$win.form$var(tags)
        upvar #0 $id form

        # missing /form tag, simulate it
        if {[info exists var(form_id)]} {
                puts "Missing end-form tag !!!! $var(form_id)"
                HMtag_/form $win {} {}
        }
        catch {unset form}
        set var(form_id) $id

        set form(param) $param                ;# form initial parameter list
        set form(reset) ""                        ;# command to reset the form
        set form(reset_button) ""        ;# list of all reset buttons
        set form(submit) ""                        ;# command to submit the form
        set form(submit_button) ""        ;# list of all submit buttons
}

# Where we're done try to get all of the state into the widgets so
# we can free up the form structure here.  Unfortunately, we can't!

proc HMtag_/form {win param text} {
        upvar #0 HM$win var
        upvar #0 $var(form_id) form

        # make submit button entries for all radio buttons
        foreach name [array names form radio_*] {
                regsub radio_ $name {} name
                lappend form(submit) [list $name \$form(radio_$name)]
        }

        # process the reset button(s)

        foreach item $form(reset_button) {
                $item configure -command $form(reset)
        }

        # no submit button - add one
        if {$form(submit_button) == ""} {
                HMinput_submit $win {}
        }

        # process the "submit" command(s)
        # each submit button could have its own name,value pair

        foreach item $form(submit_button) {
                set submit $form(submit)
                catch {lappend submit $form(submit_$item)}
                $item configure -command  \
                                [list HMsubmit_button $win $var(form_id) $form(param) \
                                $submit]
        }

        # unset all unused fields here
        unset form(reset) form(submit) form(reset_button) form(submit_button)
        unset var(form_id)
}

###################################################################
# handle form input items
# each item type is handled in a separate procedure
# Each "type" procedure needs to:
# - create the window
# - initialize it
# - add the "submit" and "reset" commands onto the proper Q's
#   "submit" is subst'd
#   "reset" is eval'd

proc HMtag_input {win param text} {
        upvar #0 HM$win var

        set type text        ;# the default
        HMextract_param $param type
        set type [string tolower $type]
        if {[catch {HMinput_$type $win $param} err]} {
                puts stderr $err
        }
}

# input type=text
# parameters NAME (reqd), MAXLENGTH, SIZE, VALUE

proc HMinput_text {win param {show {}}} {
        upvar #0 HM$win var
        upvar #0 $var(form_id) form

        # make the entry
        HMextract_param $param name                ;# required
        set item $win.input_text,$var(tags)
        set size 20; HMextract_param $param size
        set maxlength 0; HMextract_param $param maxlength
        entry $item -width $size -show $show

        # set the initial value
        set value ""; HMextract_param $param value
        $item insert 0 $value
                
        # insert the entry
        HMwin_install $win $item

        # set the "reset" and "submit" commands
        append form(reset) ";$item delete 0 end;$item insert 0 [list $value]"
        lappend form(submit) [list $name "\[$item get]"]

        # handle the maximum length (broken - no way to cleanup bindtags state)
        if {$maxlength} {
                bindtags $item "[bindtags $item] max$maxlength"
                bind max$maxlength <KeyPress> "%W delete $maxlength end"
        }
}

# password fields - same as text, only don't show data
# parameters NAME (reqd), MAXLENGTH, SIZE, VALUE

proc HMinput_password {win param} {
        HMinput_text $win $param *
}

# checkbuttons are missing a "get" option, so we must use a global
# variable to store the value.
# Parameters NAME, VALUE, (reqd), CHECKED

proc HMinput_checkbox {win param} {
        upvar #0 HM$win var
        upvar #0 $var(form_id) form

        HMextract_param $param name
        HMextract_param $param value

        # Set the global variable, don't use the "form" alias as it is not
        # defined in the global scope of the button
        set variable $var(form_id)(check_$var(tags))        
        set item $win.input_checkbutton,$var(tags)
        checkbutton $item -variable $variable -off {} -on $value -text "  "
        if {[HMextract_param $param checked]} {
                $item select
                append form(reset) ";$item select"
        } else {
                append form(reset) ";$item deselect"
        }

        HMwin_install $win $item
        lappend form(submit) [list $name \$form(check_$var(tags))]
}

# radio buttons.  These are like check buttons, but only one can be selected

proc HMinput_radio {win param} {
        upvar #0 HM$win var
        upvar #0 $var(form_id) form

        HMextract_param $param name
        HMextract_param $param value

        set first [expr ![info exists form(radio_$name)]]
        set variable $var(form_id)(radio_$name)
        set variable $var(form_id)(radio_$name)
        set item $win.input_radiobutton,$var(tags)
        radiobutton $item -variable $variable -value $value -text " "

        HMwin_install $win $item

        if {$first || [HMextract_param $param checked]} {
                $item select
                append form(reset) ";$item select"
        } else {
                append form(reset) ";$item deselect"
        }

        # do the "submit" actions in /form so we only end up with 1 per button grouping
        # contributing to the submission
}

# hidden fields, just append to the "submit" data
# params: NAME, VALUE (reqd)

proc HMinput_hidden {win param} {
        upvar #0 HM$win var
        upvar #0 $var(form_id) form
        HMextract_param $param name
        HMextract_param $param value
        lappend form(submit) [list $name $value]
}

# handle input images.  The spec isn't very clear on these, so I'm not
# sure its quite right
# Use std image tag, only set up our own callbacks
#  (e.g. make sure ismap isn't set)
# params: NAME, SRC (reqd) ALIGN

proc HMinput_image {win param} {
        upvar #0 HM$win var
        upvar #0 $var(form_id) form
        HMextract_param $param name
        set name                ;# barf if no name is specified
        set item [HMtag_img $win $param {}]
        $item configure -relief raised -bd 2 -bg blue

        # make a dummy "submit" button, and invoke it to send the form.
        # We have to get the %x,%y in the value somehow, so calculate it during
        # binding, and save it in the form array for later processing

        set submit $win.dummy_submit,$var(tags)
        if {[winfo exists $submit]} {
                destroy $submit
        }
        button $submit        -takefocus 0;# this never gets mapped!
        lappend form(submit_button) $submit
        set form(submit_$submit) [list $name $name.\$form(X).\$form(Y)]
        
        $item configure -takefocus 1
        bind $item <FocusIn> "catch \{$win see $item\}"
        bind $item <1> "$item configure -relief sunken"
        bind $item <Return> "
                set $var(form_id)(X) 0
                set $var(form_id)(Y) 0
                $submit invoke        
        "
        bind $item <ButtonRelease-1> "
                set $var(form_id)(X) %x
                set $var(form_id)(Y) %y
                $item configure -relief raised
                $submit invoke        
        "
}

# Set up the reset button.  Wait for the /form to attach
# the -command option.  There could be more that 1 reset button
# params VALUE

proc HMinput_reset {win param} {
        upvar #0 HM$win var
        upvar #0 $var(form_id) form

        set value reset
        HMextract_param $param value

        set item $win.input_reset,$var(tags)
        button $item -text [HMmap_esc $value]
        HMwin_install $win $item
        lappend form(reset_button) $item
}

# Set up the submit button.  Wait for the /form to attach
# the -command option.  There could be more that 1 submit button
# params: NAME, VALUE

proc HMinput_submit {win param} {
        upvar #0 HM$win var
        upvar #0 $var(form_id) form

        HMextract_param $param name
        set value submit
        HMextract_param $param value
        set item $win.input_submit,$var(tags)
        button $item -text [HMmap_esc $value] -fg blue
        HMwin_install $win $item
        lappend form(submit_button) $item
        # need to tie the "name=value" to this button
        # save the pair and do it when we finish the submit button
        catch {set form(submit_$item) [list $name $value]}
}

#########################################################################
# selection items
# They all go into a list box.  We don't what to do with the listbox until
# we know how many items end up in it.  Gather up the data for the "options"
# and finish up in the /select tag
# params: NAME (reqd), MULTIPLE, SIZE 

proc HMtag_select {win param text} {
        upvar #0 HM$win var
        upvar #0 $var(form_id) form

        HMextract_param $param name
        set size 5;  HMextract_param $param size
        set form(select_size) $size
        set form(select_name) $name
        set form(select_values) ""                ;# list of values to submit
        if {[HMextract_param $param multiple]} {
                set mode multiple
        } else {
                set mode single
        }
        set item $win.select,$var(tags)
    frame $item
    set form(select_frame) $item
        listbox $item.list -selectmode $mode -width 0 -exportselection 0
        HMwin_install $win $item
}

# select options
# The values returned in the query may be different from those
# displayed in the listbox, so we need to keep a separate list of
# query values.
#  form(select_default) - contains the default query value
#  form(select_frame) - name of the listbox's containing frame
#  form(select_values)  - list of query values
# params: VALUE, SELECTED

proc HMtag_option {win param text} {
        upvar #0 HM$win var
        upvar #0 $var(form_id) form
        upvar $text data
        set frame $form(select_frame)

        # set default option (or options)
        if {[HMextract_param $param selected]} {
        lappend form(select_default) [$form(select_frame).list size]
    }
    set value [string trimright $data " \n"]
    $frame.list insert end $value
        HMextract_param $param value
        lappend form(select_values) $value
        set data ""
}
 
# do most of the work here!
# if SIZE>1, make the listbox.  Otherwise make a "drop-down"
# listbox with a label in it
# If the # of items > size, add a scroll bar
# This should probably be broken up into callbacks to make it
# easier to override the "look".

proc HMtag_/select {win param text} {
        upvar #0 HM$win var
        upvar #0 $var(form_id) form
        set frame $form(select_frame)
        set size $form(select_size)
        set items [$frame.list size]

        # set the defaults and reset button
        append form(reset) ";$frame.list selection clear 0  $items"
        if {[info exists form(select_default)]} {
                foreach i $form(select_default) {
                        $frame.list selection set $i
                        append form(reset) ";$frame.list selection set $i"
                }
        } else {
                $frame.list selection set 0
                append form(reset) ";$frame.list selection set 0"
        }

        # set up the submit button. This is the general case.  For single
        # selections we could be smarter

        for {set i 0} {$i < $size} {incr i} {
                set value [format {[expr {[%s selection includes %s] ? {%s} : {}}]} \
                                $frame.list $i [lindex $form(select_values) $i]]
                lappend form(submit) [list $form(select_name) $value]
        }
        
        # show the listbox - no scroll bar

        if {$size > 1 && $items <= $size} {
                $frame.list configure -height $items
                pack $frame.list

        # Listbox with scrollbar

        } elseif {$size > 1} {
                scrollbar $frame.scroll -command "$frame.list yview"  \
                                -orient v -takefocus 0
                $frame.list configure -height $size \
                        -yscrollcommand "$frame.scroll set"
                pack $frame.list $frame.scroll -side right -fill y

        # This is a joke!

        } else {
                scrollbar $frame.scroll -command "$frame.list yview"  \
                        -orient h -takefocus 0
                $frame.list configure -height 1 \
                        -yscrollcommand "$frame.scroll set"
                pack $frame.list $frame.scroll -side top -fill x
        }

        # cleanup

        foreach i [array names form select_*] {
                unset form($i)
        }
}

# do a text area (multi-line text)
# params: COLS, NAME, ROWS (all reqd, but default rows and cols anyway)

proc HMtag_textarea {win param text} {
        upvar #0 HM$win var
        upvar #0 $var(form_id) form
        upvar $text data

        set rows 5; HMextract_param $param rows
        set cols 30; HMextract_param $param cols
        HMextract_param $param name
        set item $win.textarea,$var(tags)
        frame $item
        text $item.text -width $cols -height $rows -wrap none \
                        -yscrollcommand "$item.scroll set" -padx 3 -pady 3
        scrollbar $item.scroll -command "$item.text yview"  -orient v
        $item.text insert 1.0 $data
        HMwin_install $win $item
        pack $item.text $item.scroll -side right -fill y
        lappend form(submit) [list $name "\[$item.text get 0.0 end]"]
        append form(reset) ";$item.text delete 1.0 end; \
                        $item.text insert 1.0 [list $data]"
        set data ""
}

# procedure to install windows into the text widget
# - win:  name of the text widget
# - item: name of widget to install

proc HMwin_install {win item} {
        upvar #0 HM$win var
        $win window create $var(S_insert) -window $item -align bottom
        $win tag add indent$var(level) $item
        set focus [expr {[winfo class $item] != "Frame"}]
        $item configure -takefocus $focus
        bind $item <FocusIn> "$win see $item"
}

#####################################################################
# Assemble and submit the query
# each list element in "stuff" is a name/value pair
# - The names are the NAME parameters of the various fields
# - The values get run through "subst" to extract the values
# - We do the user callback with the list of name value pairs

proc HMsubmit_button {win form_id param stuff} {
        upvar #0 HM$win var
        upvar #0 $form_id form
        set query ""
        foreach pair $stuff {
                set value [subst [lindex $pair 1]]
                if {$value != ""} {
                        set item [lindex $pair 0]
                        lappend query $item $value
                }
        }
        # this is the user callback.
        HMsubmit_form $win $param $query
}

# sample user callback for form submission
# should be replaced by the application
# Sample version generates a string suitable for http

proc HMsubmit_form {win param query} {
        set result ""
        set sep ""
        foreach i $query {
                append result  $sep [HMmap_reply $i]
                if {$sep != "="} {set sep =} {set sep &}
        }
        puts $result
}

# do x-www-urlencoded character mapping
# The spec says: "non-alphanumeric characters are replaced by '%HH'"
 
set HMalphanumeric        a-zA-Z0-9        ;# definition of alphanumeric character class
for {set i 1} {$i <= 256} {incr i} {
    set c [format %c $i]
    if {![string match \[$HMalphanumeric\] $c]} {
        set HMform_map($c) %[format %.2x $i]
    }
}

# These are handled specially
array set HMform_map {
    " " +   \n %0d%0a
}

# 1 leave alphanumerics characters alone
# 2 Convert every other character to an array lookup
# 3 Escape constructs that are "special" to the tcl parser
# 4 "subst" the result, doing all the array substitutions
 
proc HMmap_reply {string} {
    global HMform_map HMalphanumeric
    regsub -all \[^$HMalphanumeric\] $string {$HMform_map(&)} string
    regsub -all \n $string {\\n} string
    regsub -all \t $string {\\t} string
    regsub -all {[][{})\\]\)} $string {\\&} string
    return [subst $string]
}

# convert a x-www-urlencoded string int a a list of name/value pairs

# 1  convert a=b&c=d... to {a} {b} {c} {d}...
# 2, convert + to  " "
# 3, convert %xx to char equiv

proc HMcgiDecode {data} {
        set data [split $data "&="]
        foreach i $data {
                lappend result [cgiMap $i]
        }
        return $result
}

proc HMcgiMap {data} {
        regsub -all {\+} $data " " data
        
        if {[regexp % $data]} {
                regsub -all {([][$\\])} $data {\\\1} data
                regsub -all {%([0-9a-fA-F][0-9a-fA-F])} $data  {[format %c 0x\1]} data
                return [subst $data]
        } else {
                return $data
        }
}

# There is a bug in the tcl library focus routines that prevents focus
# from every reaching an un-viewable window.  Use our *own*
# version of the library routine, until the bug is fixed, make sure we
# over-ride the library version, and not the otherway around

auto_load tkFocusOK
proc tkFocusOK w {
    set code [catch {$w cget -takefocus} value]
    if {($code == 0) && ($value != "")} {
    if {$value == 0} {
        return 0
    } elseif {$value == 1} {
        return 1
    } else {
        set value [uplevel #0 $value $w]
        if {$value != ""} {
        return $value
        }
    }
    }
    set code [catch {$w cget -state} value]
    if {($code == 0) && ($value == "disabled")} {
    return 0
    }
    regexp Key|Focus "[bind $w] [bind [winfo class $w]]"
}