=head1 NAME

Templer::Plugin::FileGlob - A plugin to expand file globs.

=cut

=head1 SYNOPSIS

The following is a good example use of this plugin

  title: Images of cats
  images: file_glob( img/candid*.jpg )
  ----
  <li>
  <!-- tmpl_loop name='images' -->
    <li><img src="<!-- tmpl_var name='file' -->" width="<!-- tmpl_var name='width' -->" height="<!-- tmpl_var name='height' -->"  alt="Animal &amp; Pet Photography, Edinburgh" /></li>
  <!-- /tmpl_loop -->
  </ul>

=cut

=head1 DESCRIPTION

This plugin operates on file-patterns and populates loops refering
to the specified pattern.

The intended use-case is inline-gallery generation, but more uses
would surely be discovered.

For each loop created there will be the variables:

=over 8

=item file

The name of the file.

=item height

The height of the image, if the file is an image and L<Image::Size> is available.

=item width

The width of the image, if the file is an image and L<Image::Size> is available.

=item contents

The content of the file if the file is not an image and not a templer input file.

=item dirname

The directory part of the file name.

=item basename

The basename of the file (without extension).

=item extension

The extension (everything after the last period) of the file name.

=back

If matching files are templer input files then all templer variables are also
populated.

=cut

=head1 LICENSE

This module is free software; you can redistribute it and/or modify it
under the terms of either:

a) the GNU General Public License as published by the Free Software
Foundation; either version 2, or (at your option) any later version,
or

b) the Perl "Artistic License".

=cut

=head1 AUTHOR

Steve Kemp <steve@steve.org.uk>

=cut

=head1 COPYRIGHT AND LICENSE

Copyright (C) 2012-2018 Steve Kemp <steve@steve.org.uk>.

This library is free software. You can modify and or distribute it under
the same terms as Perl itself.

=cut

=head1 METHODS

=cut


use strict;
use warnings;


package Templer::Plugin::FileGlob;

use Cwd;
use File::Basename;


=head2

Constructor.  No arguments are required/supported.

=cut

sub new
{
    my ( $proto, %supplied ) = (@_);
    my $class = ref($proto) || $proto;

    my $self = {};
    bless( $self, $class );
    return $self;
}



=head2 expand_variables

This is the method which is called by the L<Templer::Plugin::Factory>
to expand the variables contained in a L<Templer::Site::Page> object.

Variables are written in the file in the form "key: value", and are
internally stored within the Page object as a hash.

This method iterates over each key & value and updates any that
seem to refer to file-globs.

=cut

sub expand_variables
{
    my ( $self, $site, $page, $data ) = (@_);

    #
    #  Get the page-variables in the template.
    #
    my %hash = %$data;

    #
    #  Look for a value of "file_glob" in each key.
    #
    foreach my $key ( keys %hash )
    {
        if ( $hash{ $key } =~ /^file_glob\((.*)\)/ )
        {

            #
            #  Populate an array of hash-refs referring to files which match
            #  a particular glob.
            #
            #  Could be used for many things, will be used for image-gallaries.
            #

            #
            #  Get the pattern and strip leading/trailing quotes and whitespace.
            #
            my $pattern = $1;
            $pattern =~ s/['"]//g;
            $pattern =~ s/^\s+|\s+$//g;

            #
            #  Make sure we're relative to the directory containing
            # the actual input-page.
            #
            #  This way globs will match what the author expected.
            #
            my $dirName = $page->source();
            if ( $dirName =~ /^(.*)\/(.*)$/ )
            {
                $dirName = $1;
            }
            my $pwd = Cwd::cwd();
            chdir( $dirName . "/" );

            #
            #  The value we'll set the variable to.
            #
            my $ref;

            #
            #  The suffix of files that are Templer input-files.
            #
            my $suffix = $site->{ suffix };


            #
            #  Run the glob.
            #
            foreach my $file ( glob($pattern) )
            {

                #
                # The page dependency also includes the matching filename now.
                #
                if ( $file =~ m{^/} )
                {
                    $page->add_dependency($file);
                }
                else
                {
                    $page->add_dependency( $dirName . "/" . $file );
                }

                #
                # Data reference - moved here so we can add height/width if the
                # glob refers to an image, and if we have Image::Size installed.
                #
                my %meta = ( file => $file );

                #
                # Populate filename parts.
                #
                my ( $basename, $dirname, $extension ) = fileparse($file);
                ( $meta{ 'dirname' }  = $dirname ) =~ s{/$}{};
                ( $meta{ 'basename' } = $basename ) =~ s{(.*)\.([^.]*)$}{$1};
                $meta{ 'extension' } = $2;

                #
                # If the file is an image AND we have Image::Size
                # then populate the height/width too.
                #
                if ( $file =~ /\.(jpe?g|png|gif)$/i )
                {
                    my $module = "use Image::Size;";
                    ## no critic (Eval)
                    eval($module);
                    ## use critic
                    if ( !$@ )
                    {
                        if ( -e $file )
                        {
                            ( $meta{ 'width' }, $meta{ 'height' } ) =
                              imgsize($file);
                        }
                        else
                        {
                            print
                              "WARNING: Attempting to invoke Image::Size on a file that doesn't exist: $file\n";
                        }
                    }
                }
                elsif ( ($suffix) && ( $file =~ /$suffix$/i ) )
                {

                    #
                    # If the file is a Templer input file
                    # then populate templer variables
                    #
                    my $pageClass = ref $page;
                    my $globPage = $pageClass->new( file => $file );
                    while ( my ( $k, $v ) = each %{ $globPage } )
                    {
                        $meta{ $k } = $v;
                    }
                }
                else
                {

                    #
                    #  If it isn't an image we'll make the content available
                    #
                    if ( open( my $handle, "<:utf8", $file ) )
                    {
                        binmode( $handle, ":utf8" );
                        while ( my $line = <$handle> )
                        {
                            $meta{ 'contents' } .= $line;
                        }
                        close($handle);
                    }
                }

                push( @$ref, \%meta );
            }

            #
            #  If we found at least one file then we'll update
            # the variable value to refer to the populated structure.
            #
            if ($ref)
            {
                $hash{ $key } = $ref;
            }
            else
            {
                print
                  "WARNING: pattern '$pattern' matched zero files for page " .
                  $page->source() . "\n";
                delete $hash{ $key };
            }

            #
            #  Restore the PWD.
            #
            chdir($pwd);
        }
    }

    return ( \%hash );
}


#
#  Register the plugin.
#
Templer::Plugin::Factory->new()->register_plugin("Templer::Plugin::FileGlob");