use Tk;
use warnings;
use strict;
use Template;

my ( $file, $title, $maketitle, $author );
my ( $type, $fontSizeCheckButton, $geometry );
my ( $pdftex, $paper, $font, $fontSize );
my ( @spinbox, $spinbox, $sizeSpin, $i );
my ( $frameIncludes, $margin, %margin, $includes, %includes );
my ( $contents, $frontmatter, $backmatter, $mainmatter, $citeExample);
$i = 0;

my $mw = MainWindow -> new;
$mw -> bind('<Key-Escape>' => sub { exit } ); # use escape key to exit

# **************** M A I N   D E T A I L S  F R A M E ****************

my $frameMain = $mw -> Frame(    -label => 'MAIN DETAILS',
                               -borderwidth => 2,
                                    -relief => 'groove')
                              -> pack(-side => 'top',
                                      -fill => 'x');

$frameMain -> Label(              -text => 'LaTeX filename')
                              -> pack(-side => 'left');

my $entryFile =
$frameMain -> Entry(      -textvariable => \$file)
                              -> pack(-side => 'left',
                                      -fill => 'x',
                                    -expand => 1);
$entryFile -> insert('end', "default.tex");
$entryFile -> focus;

$frameMain -> Label(              -text => 'Title')
                              -> pack(-side => 'left');

my $entryTitle =
$frameMain -> Entry(      -textvariable => \$title)
                              -> pack(-side => 'left',
                                      -fill => 'x',
                                    -expand => 1);

$frameMain -> Label(              -text => 'Author')
                              -> pack(-side => 'left');

my $entryAuthor =
$frameMain -> Entry(      -textvariable => \$author)
                              -> pack(-side => 'left',
                                      -fill => 'x',
                                    -expand => 1);

# ***************  D O C U M E N T   C L A S S *****************
my $frameDocClass = $mw -> Frame(       -label => 'DOCUMENT CLASS',
                                  -borderwidth => 2,
                                       -relief => 'groove')
                                 -> pack(-side => 'top',
                                         -fill => 'x');

my  $frameType = $frameDocClass -> Frame(-label => 'TYPE',
                                   -borderwidth => 2,
                                        -relief => 'groove');

my $framePaper = $frameDocClass -> Frame(-label => 'PAPER (uncheck = default)',
                                   -borderwidth => 2,
                                        -relief => 'groove');

my  $frameFont = $frameDocClass -> Frame(-label => 'FONT SIZE',
                                   -borderwidth => 2,
                                        -relief => 'groove');




$frameDocClass -> Checkbutton(        -text => 'use pdf',
                                  -variable => \$pdftex,
                                   -onvalue => "pdftex, ",
                                  -offvalue => "",
                            ) -> pack(-side => 'left');

foreach (qw/article book report/) {
    $frameType -> Radiobutton(        -text => $_,
                                     -value => $_,
                                  -variable => \$type)
                              -> pack(-side => 'left'); }

foreach (qw/a4paper letter/) {
    $framePaper -> Radiobutton(       -text => $_,
                                     -value => $_.", ",
                                  -variable => \$paper)
                              -> pack(-side => 'left'); }

$frameFont -> Checkbutton(            -text => 'customize',
                                  -variable => \$fontSizeCheckButton,
                                   -onvalue => "on",
                                  -offvalue => "off",
                                   -command => sub {
                                   if ($fontSizeCheckButton eq "on") {
                                       $sizeSpin -> configure(-state => 'normal') } else {
                                       $sizeSpin -> configure(-state => 'disabled') }
                                      }
                            ) -> pack(-side => 'left');

$frameFont -> Label (                 -text => '')
                              -> pack(-side => 'left');

$sizeSpin =
$frameFont -> Spinbox(               -width => 6,
                                      -from => 10,
                                        -to => 14,
                              -textvariable => \$fontSize,
                                     -state => 'disabled')
                              -> pack(-side => 'left');

# ************************ G E O M E T R Y ***************************

my $frameGeometry = $mw -> Frame;
$frameGeometry = $mw -> Frame(       -label => 'GEOMETRY',
                               -borderwidth => 2,
                                    -relief => 'groove')
                              -> pack(-side => 'top',
                                      -fill => 'x');

$frameGeometry -> Checkbutton(        -text => 'customize',
                                  -variable => \$geometry,
                                   -onvalue => "on",
                                  -offvalue => "off",
                                   -command => sub {
                                   foreach (@spinbox) {
                                       if ($geometry eq "on") {
                                           $_ -> configure(-state => 'normal') } else {
                                           $_ -> configure(-state => 'disabled') }
                                       }
                                   }
                            ) -> pack(-side => 'left');

foreach (qw/left right top bottom/) {
$frameGeometry -> Label (             -text => $_)
                              -> pack(-side => 'left');
$spinbox[$i] =
$frameGeometry -> Spinbox(            -text => 0,
                              -textvariable => \$margin{$_},
                                     -state => 'disable',
                                     -width => 6,
                                 -increment => .1,
                                      -from => 0,
                                        -to => 100)
 -> pack(-side => "left"); $i++ }


# ********************* I N C L U D E S ******************************

$frameIncludes = $mw -> Frame;
$frameIncludes = $mw -> Frame(       -label => 'INCLUDES',
                               -borderwidth => 2,
                                    -relief => 'groove')
                              -> pack(-side => 'top',
                                      -fill => 'x');

foreach (qw/graphicx contents bibliography titledParagraph pdfBookmarks/) {
    $frameIncludes -> Checkbutton(    -text => $_,
                                  -variable => \$includes{$_},
                                   -onvalue => 1,
                                  -offvalue => "")
                              -> pack(-side => 'left');}

$mw -> Button(-text => 'Execute',  -command => \&execute )
                              -> pack(-side => 'bottom');


$frameMain -> pack();
$frameDocClass -> pack;
    $frameType -> pack(-side=>'left');
   $framePaper -> pack(-side=>'left');
    $frameFont -> pack(-side=>'left');
$frameGeometry -> pack;
$frameIncludes -> pack;

MainLoop;

sub execute {
    &load_template_vars;
    &execute_template;
}

sub load_template_vars {
    if ( $title ) {
        $title = "\\title{"."$title"."}\n";
        $maketitle = "\\maketitle\n";
    }

    if ( $author ) {
        $author = "\\author{"."$author"."}\n";
    }

    $geometry = "\\usepackage[left = $margin{left}cm, right = $margin{right}cm, top = $margin{top}cm, bottom = $margin{bottom}cm]{geometry}\n" if $geometry;

    $includes{pdfBookmarks} = "\\usepackage[bookmarks, colorlinks, plainpages=false, pdfpagelabels]{hyperref}\n"
    if $includes{pdfBookmarks};

    $includes{graphicx} = "\\usepackage[pdftex]{graphicx}\n" if $includes{graphicx};
    $includes{titledParagraph} = '\\makeatletter
\\renewcommand\\paragraph{\\@startsection{paragraph}{4}{\\z@}%
                                    {-3.25ex \\@plus-1ex \\@minus-.2ex}%
                                    {0.5ex \\@plus0.2ex}%
                                    {\\normalfont\\large\\bfseries}}
\\makeatother'."\n" if $includes{titledParagraph};
    if ( $includes{contents} ) {
        $frontmatter = "\\frontmatter\n";
        $mainmatter = "\\mainmatter\n";
        $backmatter = "\\backmatter\n";
        $contents = "\\tableofcontents\n";
    }

    if ( $includes{bibliography} ) {
        $citeExample = "% Here is a Reference Example ~\\cite{example}\n";
        $includes{bibliography} = "\\addcontentsline{toc}{section}{Bibliography}
\\begin{thebibliography}{99}
\\bibitem{example} This is an example
\\end{thebibliography}\n";
   }
}

sub execute_template {
    my $config = {
        INTERPOLATE  => 1,               # expand "$var" in plain text
        POST_CHOMP   => 1,               # cleanup whitespaces
        EVAL_PERL    => 1,               # evaluate Perl code blocks
    };

    my $tt    = Template->new($config);
    my $input = 'latex.tt';
    my $vars  = {
        title        => $title,
        maketitle    => $maketitle,
        author       => $author,
        pdftex       => $pdftex,
        fontSize     => $fontSize,
        paper        => $paper,
        type         => $type,
        geometry     => $geometry,
        pdfBookmarks => $includes{pdfBookmarks},
        graphicx     => $includes{graphicx},
        titlepar     => $includes{titledParagraph},
        contents     => $contents,
        frontmatter  => $frontmatter,
        mainmatter   => $mainmatter,
        backmatter   => $backmatter,
        cite         => $citeExample,
        bibliography => $includes{bibliography}

    };

    $tt->process($input, $vars, $file)
        || die $tt->error( );
    exit
}