#!/usr/bin/env wish

set active_transform 0

# Remove empty items at the beginning and the end of a list.
proc ltrim {list} {
    set first [lsearch -not -exact $list {}]
    set last [lsearch -not -exact [lreverse $list] {}]
    return [
        if {$first == -1} {
            list
        } else {
            lrange $list $first end-$last
        }
    ]
}

# Trim indentation in multiline quoted text.
proc undent {msg {whitespaceChars " "}} {
    set msgLines [split $msg "\n"]
    set maxLength [string length $msg]

    set regExp [subst -nocommands {([$whitespaceChars]*)[^$whitespaceChars]}]

    set indent [
        tcl::mathfunc::min {*}[
            lmap x $msgLines {
                if {[regexp $regExp $x match whitespace]} {
                    string length $whitespace
                } else {
                    lindex $maxLength
                }
            }
        ]
    ]

    join [ltrim [lmap x $msgLines {string range $x $indent end}]] "\n"
}

proc oneline {text} {
  return [regsub -all \n+ $text " "]
}

proc wordcount {text} {
  set lines [expr [llength [split $text \n]] - 1]
  set words [llength [regexp -all -inline {\S+} $text]]
  set len [string length $text]

  lappend out $lines
  lappend out $words
  lappend out $len
  return $out
}

proc dedent {text} {
  return [undent $text]
}

proc markdown_quote {text} {
  set text [string trim $text]
  return [string cat "> " [regsub -all \n $text "\n> "]]
}

proc identity {text} { return $text }

lappend transforms [list {None} identity]
lappend transforms [list {One line} oneline]
lappend transforms [list {Line/Word/Char} wordcount]
lappend transforms [list {Dedent} dedent]
lappend transforms [list {Markdown Quote} markdown_quote]

wm geometry . 750x650
wm title . "Text Tools"
wm resizable . false false

text .content
text .output
listbox .transform

foreach {elem} $transforms {
  .transform insert end [lindex $elem 0]
}
.transform selection set $active_transform

grid .transform -row 1 -column 1 -rowspan 2
grid .content -row 1 -column 2
grid .output -row 2 -column 2

focus .content

proc update_output {} {
  global active_transform
  global transforms

  set text [.content get 1.0 end]

  set tf [lindex $transforms $active_transform]
  set out [[lindex $tf 1] $text]
  .output replace 1.0 end $out
}

bind .content <KeyRelease> update_output
bind . <Escape> exit

proc select_transform {args} {
  global active_transform
  set active_transform [.transform curselection]
  update_output
}

bind .transform <Button-1> select_transform

update