##+##########################################################################
#
# Hypertext HelpSystem.tcl -- A help system based on wiki 1194 and tile
# by Keith Vetter, May 2007
#
 
package require tile 0.7.8
interp alias {} ::button {} ::ttk::button
set haveTile078 1
 
namespace eval ::Help {
    variable W                                  ;# Various widgets
    variable pages                              ;# All the help pages
    variable alias                              ;# Alias to help pages
    variable state
    variable font {Helvetica 10}
 
    array unset pages
    array unset alias
    array unset state
    array set state {history {} seen {} current {} all {} allTOC {} haveTOC 0}
    array set W {top .helpSystem main "" tree ""}
    array set alias {index Index previous Previous back Back search Search
        history History next Next}
}
 
## BON HELP
##+##########################################################################
#
# Help Section
#
# Based on https://wiki.tcl-lang.org/1194
#
#  AddPage title aliases text  -- register a hypertext page
#  Help ?title?                -- bring up a toplevel showing the specified page
#                                 or a index of titles, if not specified
#
# Hypertext pages are in a subset of Wiki format:
#   indented lines come in fixed font without evaluation;
#   blank lines break paragraphs
#   a line starting with "   * " gets a bullet
#   a line starting with "   - " gets a dash
#   a line starting with "   1 " will be a numbered list
#    repeating the initial *,- or "1" will indent the list
#   a line starting with "   | " will be an indented block paragraph (one level only)
#
#   text enclosed by '''<text>''' is embolden
#   text enclosed by ''<text>'' is italics
#   all lines without leading blanks are displayed without explicit
#      linebreak (but possibly word-wrapped)
#   a link is the title of another page in brackets (see examples at
#      end). Links are displayed underlined and blue (or purple if they
#      have been visited before), and change the cursor to a pointing
#      hand. Clicking on a link of course brings up that page.
#
# In addition, you get "Index", "Search" (case-insensitive regexp in
# titles and full text), "History", and "Back" links at the bottom of
# pages.
 
 
##+##########################################################################
#
# ::Help::Help -- initializes and creates the help dialog
#
proc ::Help::Help {{title ""}} {
    variable W
 
    if {![winfo exists $W(top)]} {
        ::Help::DoDisplay $W(top)
    }
 
    raise $W(top)
    ::Help::Show $title
}
##+##########################################################################
#
# ::Help::ReadHelpFiles -- reads "help.txt" in the packages directory
# and creates all the help pages.
#
proc ::Help::ReadHelpFiles {dir} {
    set fname [file join $dir help.txt]
    set fin [open $fname r]
    set data [read $fin] ; list
    close $fin
 
    regsub -all -line {^-+$} $data \x01 data
    regsub -all -line {^\#.*$\n} $data {} data
    foreach section [split $data \x01] {
        set n [regexp -line {^title:\s*(.*)$} $section => title]
        if {! $n} {
            WARN "Bad help section\n'[string range $section 0 400]'"
            continue
        }
        set aliases {}
        foreach {. alias} [regexp -all -line -inline {^alias:\s*(.*)$} $section] {
            lappend aliases $alias
        }
 
        regsub -all -line {^(title:|alias:).*$\n} $section {} section
        ::Help::AddPage $title $aliases $section
    }
    ::Help::BuildTOC
}
##+##########################################################################
#
# ::Help::AddPage -- Adds another page to the help system
#
proc ::Help::AddPage {title aliases body} {
    variable pages
    variable state
    variable alias
 
    set title [string trim $title]
    set body [string trim $body "\n"]
    regsub -all {\\\n} $body {} body            ;# Remove escaped lines
    regsub -all {[ \t]+\n} $body "\n" body      ;# Remove trailing spaces
    regsub -all {([^\n])\n([^\s])} $body {\1 \2} body ;# Unwrap paragraphs
 
    set pages($title) $body
 
    lappend aliases [string tolower $title]
    foreach name $aliases { set alias([string tolower $name]) $title }
 
    if {[lsearch $state(all) $title] == -1} {
        set state(all) [lsort [lappend state(all) $title]]
    }
}
##+##########################################################################
#
# ::Help::DoDisplay -- Creates our help display. If we have tile 0.7.8 then
# we will also have a TOC pane.
#
proc ::Help::DoDisplay {TOP} {
    variable state
 
    destroy $TOP
    toplevel $TOP
    wm title $TOP "Help"
    wm transient $TOP .
 
    frame $TOP.bottom -bd 2 -relief ridge
    button $TOP.b -text "Dismiss" -command [list destroy $TOP]
    pack $TOP.bottom -side bottom -fill both
    pack $TOP.b -side bottom -expand 1 -pady 10 -in $TOP.bottom
 
    set P $TOP.p
    if {$::haveTile078} {                       ;# Need tags on treeview
        set state(haveTOC) 1
        ::ttk::panedwindow $P -orient horizontal
 
        pack $P -side top -fill both -expand 1
        frame $P.toc -relief ridge
        frame $P.help -bd 2 -relief ridge
 
        $P add $P.toc
        $P add $P.help
        ::Help::CreateTOC $P.toc
        ::Help::CreateHelp $P.help
    } else {
        set state(haveTOC) 0
        frame $P
        pack $P -side top -fill both -expand 1
        ::Help::CreateHelp $P
    }

    bind $TOP <Map> [list apply { TOP {
        bind $TOP <Map> {}
        CenterWindow $TOP 
    }} $TOP]
 
}
##+##########################################################################
#
# ::Help::CreateTOC -- Creates a TOC display from tile's treeview widget
#
proc ::Help::CreateTOC {TOC} {
    variable W
 
    set W(tree) $TOC.tree
    scrollbar $TOC.sby -orient vert -command "$W(tree) yview"
    #scrollbar $TOC.sbx -orient hori -command "$W(tree) xview"
 
    ::ttk::treeview $W(tree) -padding {0 0 0 0} -selectmode browse \
        -yscrollcommand "$TOC.sby set" ;#$ -xscrollcommand "$TOC.sbx set"
 
    grid $W(tree) $TOC.sby -sticky news
    #grid $TOC.sbx -sticky ew
    grid rowconfigure $TOC 0 -weight 1
    grid columnconfigure $TOC 0 -weight 1
 
    $W(tree) heading #0 -text "Table of Contents"
    $W(tree) tag configure link -foreground blue
    # NB. binding to buttonpress sometimes "misses" clicks
    #$W(tree) tag bind link <ButtonPress> ::Help::ButtonPress
    bind $W(tree) <<TreeviewSelect>> ::Help::TreeviewSelection
    ::Help::BuildTOC
}
##+##########################################################################
#
# ::Help::CreateHelp -- Creates our main help widget
#
proc ::Help::CreateHelp {w} {
    variable W
    variable font
 
    set W(main) $w.t
    text $w.t -border 5 -relief flat -wrap word -state disabled -width 60 \
        -yscrollcommand "$w.s set" -padx 5 -font $font
    scrollbar $w.s -orient vert -command "$w.t yview"
    pack $w.s -fill y -side right
    pack $w.t -fill both -expand 1 -side left
 
    $w.t tag config link -foreground blue -underline 1
    $w.t tag config seen -foreground purple4 -underline 1
    $w.t tag bind link <Enter> "$w.t config -cursor hand2"
    $w.t tag bind link <Leave> "$w.t config -cursor {}"
    $w.t tag bind link <1> "::Help::Click $w.t %x %y"
    $w.t tag config hdr -font {Times 18 bold}
    $w.t tag config fix -font \
        "[font actual [$w.t cget -font]] -family Courier"
    $w.t tag config bold -font \
        "[font actual [$w.t cget -font]] -weight bold"
    $w.t tag config italic -font \
        "[font actual [$w.t cget -font]] -slant italic"
 
    set l1 [font measure $font "   "]
    set l2 [font measure $font "   \u2022   "]
    set l3 [font measure $font "       \u2013   "]
    set l3 [expr {$l2 + ($l2 - $l1)}]
    $w.t tag config bullet -lmargin1 $l1 -lmargin2 $l2
    $w.t tag config number -lmargin1 $l1 -lmargin2 $l2
    $w.t tag config dash -lmargin1 $l1 -lmargin2 $l2
    $w.t tag config bar -lmargin1 $l2 -lmargin2 $l2
 
    bind $w.t <n> [list ::Help::Next $w.t 1]
    bind $w.t <p> [list ::Help::Next $w.t -1]
    bind $w.t <b> [list ::Help::Back $w.t]
    bind $w.t <Key-space> [bind Text <Key-Next>]
 
    # Create the bitmap for our bullet
    if {0 && [lsearch [image names] ::img::bullet] == -1} {
        image create bitmap ::img::bullet -data {
            #define bullet_width  11
            #define bullet_height 9
            static char bullet_bits[] = {
                0x00,0x00, 0x00,0x00, 0x70,0x00, 0xf8,0x00, 0xf8,0x00,
                0xf8,0x00, 0x70,0x00, 0x00,0x00, 0x00,0x00
            };
        }
    }
}
##+##########################################################################
#
# ::Help::Click -- Handles clicking a link on the help page
#
proc ::Help::Click {w x y} {
    set range [$w tag prevrange link "[$w index @$x,$y] + 1 char"]
    if {[llength $range]} {::Help::Show [eval $w get $range]}
}
##+##########################################################################
#
# ::Help::Back -- Goes back in help history
#
proc ::Help::Back {w} {
    variable state
 
    set l [llength $state(history)]
    if {$l <= 1} return
    set last [lindex $state(history) [expr {$l-2}]]
    set history [lrange $state(history) 0 [expr {$l-3}]]
    ::Help::Show $last
}
##+##########################################################################
#
# ::Help::Next -- Goes to next help page
#
proc ::Help::Next {w dir} {
    variable state
 
    set what $state(all)
    if {$state(allTOC) ne {}} {set what $state(allTOC)} ;# TOC order if we can
 
    set n [lsearch -exact $what $state(current)]
    set n [expr {($n + $dir) % [llength $what]}]
    set next [lindex $what $n]
    ::Help::Show $next
}
##+##########################################################################
#
# ::Help::Listpage -- Puts up a help page with a bunch of links (all or history)
#
proc ::Help::Listpage {w llist} {
    foreach i $llist {$w insert end \n; ::Help::Showlink $w $i}
}
##+##########################################################################
#
# ::Help::Search -- Creates search help page
#
proc ::Help::Search {w} {
    $w insert end "\nSearch phrase:      "
    entry $w.e -textvar ::Help::state(search)
    $w window create end -window $w.e
    focus $w.e
    $w.e select range 0 end
    bind $w.e <Return> "::Help::DoSearch $w"
    button $w.b -text Search! -command "::Help::DoSearch $w"
    $w window create end -window $w.b
}
##+##########################################################################
#
# ::Help::DoSearch -- Does actual help search
#
proc ::Help::DoSearch {w} {
    variable pages
    variable state
 
    $w config -state normal
    $w insert end "\n\nSearch results for '$state(search)':\n"
    foreach i $state(all) {
        if {[regexp -nocase $state(search) $i]} { ;# Found in title
            $w insert end \n
            ::Help::Showlink $w $i
        } elseif {[regexp -nocase -indices -- $state(search) $pages($i) pos]} {
            set p1 [expr {[lindex $pos 0]-20}]
            set p2 [expr {[lindex $pos 1]+20}]
            regsub -all \n [string range $pages($i) $p1 $p2] " " context
            $w insert end \n
            ::Help::Showlink $w $i
            $w insert end " - ...$context..."
        }
    }
    $w config -state disabled
}
##+##########################################################################
#
# ::Help::Showlink -- Displays link specially
#
proc ::Help::Showlink {w link {tag {}}} {
    variable state
 
    set tag [concat $tag link]
    set title [::Help::FindPage $link]
    if {[lsearch -exact $state(seen) $title] > -1} {
        lappend tag seen
    }
    $w insert end $link $tag
}
##+##########################################################################
#
# ::Help::FindPage -- Finds actual pages given a possible alias
#
proc ::Help::FindPage {title} {
    variable pages
    variable alias
 
    if {[info exists pages($title)]} { return $title }
    set title2 [string tolower $title]
    if {[info exists alias($title2)]} { return $alias($title2) }
    return "ERROR!"
}
##+##########################################################################
#
# ::Help::Show -- Shows help or meta-help page
#
proc ::Help::Show {title} {
    variable pages
    variable alias
    variable state
    variable W
 
    set w $W(main)
    set title [::Help::FindPage $title]
 
    if {[lsearch -exact $state(seen) $title] == -1} {lappend state(seen) $title}
    $w config -state normal
    $w delete 1.0 end
    $w insert end $title hdr "\n"
    set next 0                                  ;# Some pages have no next page
    switch -- $title {
        Back    { ::Help::Back $w; return}
        History { ::Help::Listpage $w $state(history)}
        Next    { ::Help::Next $w 1; return}
        Previous { ::Help::Next $w -1; return}
        Index   { ::Help::Listpage $w $state(all)}
        Search  { ::Help::Search $w}
        default { ::Help::ShowPage $w $title ; set next 1 }
    }
 
    # Add bottom of the page links
    $w insert end \n------\n {}
    if {! $state(haveTOC) && [info exists alias(toc)]} {
        $w insert end TOC link " - " {}
    }
    $w insert end Index link " - " {} Search link
    if {$next} {
        $w insert end " - " {} Previous link " - " {} Next link
    }
    if {[llength $state(history)]} {
        $w insert end " - " {} History link " - " {} Back link
    }
 
    $w insert end \n
    lappend state(history) $title
    $w config -state disabled
 
    set state(current) $title
}
##+##########################################################################
#
# ::Help::ShowPage -- Shows a text help page, doing wiki type transforms
#
proc ::Help::ShowPage {w title} {
    variable pages
 
    set endash \u2013
    set emdash \u2014
    set bullet \u2022
 
    $w insert end \n                            ;# Space down from the title
    if {! [info exists pages($title)]} {
        set lines [list "This help page is missing."]
    } else {
        set lines [split $pages($title) \n]
    }
 
    foreach line $lines {
        set tag {}
        set op1 ""
        if {[regexp {^ +([1*-|]+)\s*(.*)} $line -> op txt]} {
            set op1 [string index $op 0]
            set lvl [expr {[string length $op] - 1}]
            set indent [string repeat "     " $lvl]
            if {$op1 eq "1"} {                  ;# Number
                if {! [info exists number($lvl)]} { set number($lvl) 0 }
                set tag number
                incr number($lvl)
                $w insert end "$indent $number($lvl)" $tag
            } elseif {$op1 eq "*"} {            ;# Bullet
                set tag bullet
                $w insert end "$indent $bullet " $tag
            } elseif {$op1 eq "-"} {            ;# Dash
                set tag dash
                $w insert end "$indent $endash " $tag
            } elseif {$op1 eq "|"} {            ;# Bar
                set tag bar
            }
            set line $txt
        } elseif {[string match " *" $line]} {  ;# Line beginning w/ a space
            $w insert end $line\n fix
            unset -nocomplain number
            continue
        }
        if {$op1 ne "1"} {unset -nocomplain number}
 
        while {1} {                             ;# Look for markups
            set link0 [set bold0 [set ital0 $line]]
            set n1 [regexp {^(.*?)[[](.*?)[]](.*$)} $line -> link0 link link1]
            set n2 [regexp {^(.*?)'''(.*?)'''(\s*.*$)} $line -> bold0 bold bold1]
            set n3 [regexp {^(.*?)''(.*?)''(\s*.*$)} $line -> ital0 ital ital1]
            if {$n1 == 0 && $n2 == 0 && $n3 == 0} break
 
            set len1 [expr {$n1 ? [string length $link0] : 9999}]
            set len2 [expr {$n2 ? [string length $bold0] : 9999}]
            set len3 [expr {$n3 ? [string length $ital0] : 9999}]
 
            if {$len1 < $len3} {
                $w insert end $link0 $tag
                ::Help::Showlink $w $link $tag
                set line $link1
            } elseif {$len2 <= $len3} {
                $w insert end $bold0 $tag $bold [concat $tag bold]
                set line $bold1
            } else {
                $w insert end $ital0 $tag $ital [concat $tag italic]
                set line $ital1
            }
        }
        $w insert end "$line\n" $tag
    }
}
##+##########################################################################
#
# ::Help::BuildTOC -- Fills in our TOC widget based on a TOC page
#
proc ::Help::BuildTOC {} {
    variable W
    variable pages
    variable state
 
    set state(allTOC) {}                        ;# All pages in TOC ordering
    if {! [winfo exists $W(tree)]} return
    set tocData $pages([::Help::FindPage toc])
 
    $W(tree) delete [$W(tree) child {}]
    unset -nocomplain parent
    set parent() {}
 
    regsub -all {'{2,}} $tocData {} tocData
    foreach line [split $tocData \n] {
        set n [regexp {^\s*(-+)\s*(.*)} $line => dashes txt]
        if {! $n} continue
 
        set isLink [regexp {^\[(.*)\]$} $txt => txt]
        set pDashes [string range $dashes 1 end]
        set parent($dashes) [$W(tree) insert $parent($pDashes) end -text $txt]
        if {$isLink} {
            $W(tree) item $parent($dashes) -tag link
 
            set ptitle [::Help::FindPage $txt]
            if {[lsearch $state(allTOC) $ptitle] == -1} {
                lappend state(allTOC) $ptitle
            }
        }
    }
}
##+##########################################################################
#
# ::Help::ButtonPress -- Handles clicking on a TOC link
# !!! Sometimes misses clicks, so we're using TreeviewSelection instead
#
proc ::Help::ButtonPress {} {
    variable W
 
    set id [$W(tree) selection]
    set title [$W(tree) item $id -text]
    ::Help::Show $title
}
##+##########################################################################
#
# ::Help::TreeviewSelection -- Handles clicking on any item in the TOC
#
proc ::Help::TreeviewSelection {} {
    variable W
 
    set id [$W(tree) selection]
    set title [$W(tree) item $id -text]
    set tag [$W(tree) item $id -tag]
    if {$tag eq "link"} {
        ::Help::Show $title
    } else {                                    ;# Make all children visible
        set last [lindex [$W(tree) children $id] end]
        if {$last ne {} && [$W(tree) item $id -open]} {
            $W(tree) see $last
        }
    }
}
proc CenterWindow {w} {
    wm withdraw $w
    set x [expr [winfo screenwidth $w]/2 - [winfo reqwidth $w]/2 \
               - [winfo vrootx [winfo parent $w]]]
    set y [expr [winfo screenheight $w]/2 - [winfo reqheight $w]/2 \
               - [winfo vrooty [winfo parent $w]]]
    wm geom $w +$x+$y
    wm deiconify $w
}
 
################################################################
#
# Debugging routines
#
 
##+##########################################################################
#
# ::Help::Reset -- (for testing), resets all help info
#
proc ::Help::Reset {} {
    variable W
    variable state
    variable pages
    variable alias
 
    array unset pages
    array unset state
    array set state {history {} seen {} current {} all {} allTOC {}}
    array unset alias
 
    foreach title {Back History Next Previous Index Search} {
        set alias([string tolower $title]) $title
    }
 
    destroy $W(top)
}
##+##########################################################################
#
# ::Help::Sanity -- Checks for missing help links
#
proc ::Help::Sanity {} {
    variable state
 
    set missing {}
    foreach page $state(all) {
        set m [::Help::CheckLinks $page]
        if {$m ne {}} {
            puts "$page: $m"
            set missing [concat $missing $m]
        }
    }
    return $missing
}
##+##########################################################################
#
# ::Help::CheckLinks -- Checks one page for missing help links
#
proc ::Help::CheckLinks {title} {
    variable pages
    variable alias
 
    set missing {}
    set title [::Help::FindPage $title]
    foreach {. link} [regexp -all -inline {\[(.*?)\]} $pages($title)] {
        if {! [info exists alias([string tolower $link])]} {
            lappend missing $link
        }
    }
    return $missing
}

proc WIKIFIX {txt} {
    regsub -all {\n } $txt "\n" txt
    return $txt

}
## EON HELP
 
################################################################
 
################################################################
 
::Help::AddPage "Table of Contents" TOC [WIKIFIX {
    - [Welcome to the Help System]
    - [What's New]
    - Formatting
      -- [Basic Formatting]
      -- [Aliases]
      -- [Lists]
    - [Creating the TOC]
    - [To Do]
}]
::Help::AddPage "Welcome to the Help System" overview [WIKIFIX {
This is a simple hypertext help system.
 
It's based on ''A Little Hypertext System'' so it includes:
  * Hyperlinks to other help pages
  * Simple searching ability
  * History
  * Simple wiki formatting
 
This new version also includes (see [What's New])
  * [Table of Contents]
  * Hypertext [aliases]
  * [Multi-level Lists]
  11. numeric lists
  ** bullet lists
  -- dash list
  * '''Bold text'''
  * ''Italic text''
  }]
::Help::AddPage "What's New" "" [WIKIFIX {
Here are some features of this help system not found in the previous version:
    * Table of Content
    * Bullets
    * Multiple levels of indentation
      -- like this
      -- ''and this''
      --- '''and even this'''
    * Aliases
    -- So this link [Welcome to the Help System]
    -- is the same as this link [Overview]
 
}]
::Help::AddPage "Basic Formatting" "Formatting" [WIKIFIX {
The formatting code for the help pages follows much like the
tcler's wiki.
'''Links, lists, bold, italics, unformatted''' are
all done the same way.

   | You can also have block paragraphs by prefixing the first line 
with a " | ". It will wrap the text and indent all the lines. Only
one level of indentation can be requested.
 
[Aliases] and [multi-level lists] are only slightly more complicated.
 
}]
::Help::AddPage "Aliases" {alias} [WIKIFIX {
''Aliases'' allow the same page to be referenced by different names.
So this link [Welcome to the Help System]
is the same as this link [Overview].
}]
::Help::AddPage "Multi-level Lists" "lists" [WIKIFIX {
   1. numbered list
   1. numbered list
   11. numbered list
   11. numbered list
   1. numbered list
   1. numbered list
 
   * bullet list
   ** nested bullet list
   ** nested bullet list
   * bullet list
 
    - dash lists
    -- nested dashed list
    -- nested dashed list
    - dash lists
 
}]
::Help::AddPage "Creating the TOC" "" [WIKIFIX {
The '''Table of Content''' is a just a help page with the
name (or [alias]) '''TOC''' which gets displayed in a
tile treeview widget. You can also view the [TOC] as a
normal help page.
 
Each line of the TOC help page that begins with a dash becomes
a node in the treeview. The level of indentation dictates the
tree structure.
}]
 
::Help::AddPage "To Do" {} [WIKIFIX {
  1. Visual clues in TOC about what is a link (don't know treeview well enough to do this)
  1. Mouse buttons 4 & 5 do history back and forward like Firefox and IE
  1. Image support--not hard, I just haven't needed it
  1. msgcat support
  1. read help data from separate file (actually this is done, but for simplicity I omitted here)
}]
 
################################################################
::Help::Help overview
 
return