package paginate;

use vars qw( $prev_link $link_list $next_link $prev_url $next_url
	     $curr_number $curr_url $curr_link $skip $page $pages 
	     $curr_path %template $abort);

use CGI qw/param url/;
use POSIX;

# Grab the templates at start
sub start { 
  while (<DATA>) {
    last if /^(__END__)?$/;
    my($ct, $comp, $txt) = /^(\S+)\s(\S+)\s(.*)$/;
    $txt =~ s/\\n/\n/mg;
    $template{$ct}{$comp} = $txt;
  }

  return 1;
}

# Count total stories & calculate # of stories to skip at filter time.
sub filter {
  my ($pkg, $files_ref) = @_;

  # How many pages in total?  Only count pages we're going to render.
  my $num_files = 0;
  for(keys(%$files_ref)) {
    ($_ =~ m|^$blosxom::datadir/$blosxom::path_info|) && $num_files++;
  }
  # Round up (ceil)
  $pages = ceil($num_files / $blosxom::num_entries);

  # Make sure the page number param is in the valid range;
  ($page) = (param("page") =~ /(\d+)/); $page ||= 1;

  # Determine number of entries to skip
  $skip = $blosxom::num_entries * ($page-1);
}

# Build previous & next links, as well as a list of available pages.
sub head {
  my($pkg, $path, $head_ref) = @_;

  # Set the current path
  $curr_path = $path;

  #
  # If we're rendering a page in the current flavour, don't paginate.
  # Abort! Abort! Abort!
  #
  if($curr_path =~ /\.$blosxom::flavour$/) {
    $abort = 1;
    return undef;
  }

  # Provide a previous page link, if needed.
  $prev_link = "";
  if ($page > 1) {
    param("page" => $page - 1);
    $prev_url = url(-path_info=>1,-query=>1);
    $prev_link = fill_template('paginate_prev_link');
  }

  # Construct a list of links to each page
  my @list = ();
  push @list, fill_template('paginate_list_start');
  for $curr_number (1..$pages) {
    param("page" => $curr_number);
    $curr_url = url(-path_info=>1,-query=>1);
    push @list, fill_template( ($curr_number eq $page) ? 
			       'paginate_list_curr_item' : 
			       'paginate_list_item' );
    push @list, fill_template('paginate_list_join')
      if (($curr_number+1) <= $pages);
  }
  push @list, fill_template('paginate_list_end');
  $link_list = join '', @list;

  # Provide a next page link, if needed.
  $next_link = "";
  if ($pages > $page) {
    param("page" => $page + 1);
    $next_url = url(-path_info=>1,-query=>1);
    $next_link = fill_template('paginate_next_link');
  }

  return undef;
}

# Perform skipping behavior, if necessary, to display chosen page
sub sort {
  ($abort) && return undef;

  return sub {
    my($files_ref) = @_;

    # Sort entries as normal (TODO: consult other plugins here?)
    my @sorted = sort { $files_ref->{$b} <=> $files_ref->{$a} } keys %$files_ref;

    my @relevant = ();

    for(@sorted) {
      ($_ =~ m|^$blosxom::datadir/$blosxom::path_info|) && push(@relevant,$_);
    }

    # Return the sorted entries, skipping the proper amount
    return @relevant[$skip .. scalar(@sorted) - 1];
  };
}

# Inspired by blosxom's template handling - load and fill template all in one
sub fill_template {
  my ($chunk) = @_;
  my $fh = new FileHandle;
  my $tmpl = undef;

  do {
    $tmpl = join '', <$fh> if $fh->open("< $blosxom::datadir/$curr_path$chunk.$blosxom::flavour");
  } while ($path =~ s/(\/*[^\/]*)$// and $1);

  $tmpl = join '', ($template{$blosxom::flavour}{$chunk} || $template{error}{$chunk} || '')
    if (!defined $tmpl);

  $tmpl =~ s/(\$[\w:]+)/$1 . "||''"/gee;

  return $tmpl;
}

1;

__DATA__
html paginate_prev_link <a href="$prev_url">&lt;&lt; prev</a>
html paginate_next_link <a href="$next_url">next &gt;&gt;</a>
html paginate_list_start [ 
html paginate_list_join  | 
html paginate_list_item <a href="$curr_url">$curr_number</a>
html paginate_list_curr_item <b>$curr_number</b>
html paginate_list_end  ] 
__END__

=head1 NAME

Blosxom Plug-in: paginate

=head1 DESCRIPTION

Provide a simple page navigation capability in a Blosxom blog, allowing a
reader to flip through ranges of stories with a previous link, next link,
and a list of available pages.  Page length is defined by the C<$num_entries>
setting in the main blosxom config.

The following variables are available for display in Blosxom templates:

=over 4

=item * $paginate::prev_link

Contains link to previous page, is empty if a this link is not valid.

=item * $paginate::link_list

Contains the entire list of links to available pages.

=item * $paginate::next_link

Contains link to next page, is empty if a this link is not valid.

=back

The display of previous, next, and page
links is customizable via flavoured templates (each with a .$flavour 
extension):

=over 4

=item * paginate_prev_link

Used to build a previous page link.

Default: <a href="$prev_url">&lt;&lt;- prev</a>

=item * paginate_next_link

Used to build a next page link.

Default: <a href="$next_url">next -&gt;&gt;</a>

=item * paginate_list_start

Placed at the start of the page list.

Default: " [ "

=item * paginate_list_join

Placed in between page list items.

Default: " | "

=item * paginate_list_item

Used to display page list items other than the current page.

Default: <a href="$curr_url">$curr_number</a>

=item * paginate_list_curr_item

Used to display the current page in the list.

Default: <b>$curr_number</b>

=item * paginate_list_end 

Placed at the end of the page list.

Default: " ] "

=back

By default, these templates construct simple links to blog pages.  In
customizing these templates, many other forms of page navigation are
possible.  For example, with a little bit of Javascript, the prev/next
links can become buttons and the page list can become a drop-down selector.
An example of this is included with the distribution archive for this
plugin.

=head1 VERSION

v0.03

=head1 AUTHOR

l.m.orchard <deus_x@pobox.com> http://www.decafbad.com

Bugfixes by Rob Flickenger <rob@nocat.net> http://nocat.net/~rob/

=head1 SEE ALSO

Paginate: http://www.decafbad.com/twiki/bin/view/Main/BlosxomPaginate

Blosxom Home/Docs/Licensing: http://www.raelity.org/apps/blosxom/

Blosxom Plugin Docs: http://www.raelity.org/apps/blosxom/plugin.shtml

=head1 CHANGES

v0.03: Use POSIX::ceil instead of int() and only count relevant articles in sort phase.  This fixes page count and subcategory pagination issues.

=head1 LICENSE

This Blosxom Plug-in is Copyright 2003, l.m.orchard 

Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the "Software"),
to deal in the Software without restriction, including without limitation
the rights to use, copy, modify, merge, publish, distribute, sublicense,
and/or sell copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.