package Apache::PageKit::Content;

# $Id: Content.pm,v 1.46 2004/05/03 13:48:29 borisz Exp $

use strict;

use vars qw($CONTENT $PKIT_VIEW $COMPONENT_ID_DIR $PAGE_ID $INCLUDE_MTIMES);

sub new {
  my $class = shift;
  my $self = { @_ };
  bless $self, $class;
  return $self;
}

sub generate_template {
  my ($content, $page_id, $component_id, $pkit_view, $input_param_obj, $component_params) = @_;

  unless(exists $INC{'XML/LibXSLT.pm'}){
    eval {
      require XML::LibXSLT;
    };
    if ($@) {
      die "Cannot find template file $pkit_view/$component_id.tmpl or XML::LibXSLT is required to process $content->{content_dir}/$component_id.xml";
    }
  }

  $CONTENT = $content;
  $PKIT_VIEW = $pkit_view;
  $PAGE_ID = $page_id;
  ($COMPONENT_ID_DIR = $component_id) =~ s![^/]*$!!;
  $INCLUDE_MTIMES = $content->{include_mtimes};

  # XSLT file
  my $xml_file = "$content->{content_dir}/$component_id.xml";
  unless(-f $xml_file){
    die "Cannot find xml file $content->{content_dir}/$component_id.xml or
      template file $pkit_view/$component_id.tmpl";
  }

#  my $xml_mtime = (stat($xml_file))[9];
#  $INCLUDE_MTIMES->{$xml_file} = $xml_mtime;

  my $parser = XML::LibXML->new( ext_ent_handler => \&open_uri );
  # call backs so that we can note the mtimes of dependant files
  $parser->match_callback(\&match_uri);
  $parser->open_callback(\&open_uri);
  $parser->close_callback(\&close_uri);
  $parser->read_callback(\&read_uri);

  my $xp = $parser->parse_file("/$component_id.xml");

  my @pi_nodes = $xp->findnodes("processing-instruction('xml-stylesheet')");
  my @stylesheet_hrefs;
  for my $pi_node (@pi_nodes){
    my $pi_str = $pi_node->getData;
    my ($stylesheet_href) = ($pi_str =~ m!href="([^"]*)"!);
    push @stylesheet_hrefs, $stylesheet_href;
  }

  # for now, just use first stylesheet... we'll add multiple stylesheets later
  unless ($stylesheet_hrefs[0]){
    die qq{must specify <?xml-stylesheet href="file.xsl"?> in $xml_file};
  }
  my $stylesheet_file = $stylesheet_hrefs[0];

#  my $stylesheet_mtime = (stat(_))[9];
#  $INCLUDE_MTIMES->{$stylesheet_file} = $stylesheet_mtime;

  my $stylesheet_parser = XML::LibXML->new();
  my $stylesheet_xp = $stylesheet_parser->parse_file($stylesheet_file);
  # for caching pages including the params info (that way extrenous parameters
  # won't be taken into account when counting)
  # META: do i only need to cache top level params from top level stylesheet?
  for my $node ($stylesheet_xp->findnodes(q{node()[name() = 'xsl:stylesheet']/node()[name() = 'xsl:param']})->get_nodelist){
    my $param_name = $node->getAttribute('name');
    $Apache::PageKit::Content::PAGE_ID_XSL_PARAMS->{$PAGE_ID}->{$param_name} = 1;
  }

  my $xslt = XML::LibXSLT->new();
  my $source = $xp; # we parsed the source xmlfile already
  my $style_doc = $parser->parse_file($stylesheet_file);

  my $stylesheet = $xslt->parse_stylesheet($style_doc);

  my @params = map { $_, $input_param_obj->param($_) } $input_param_obj->param;

  my $results = $stylesheet->transform($source, XML::LibXSLT::xpath_to_string( @params, %$component_params ));

#  my $content_type = $stylesheet->media_type;
#  my $encoding = $stylesheet->output_encoding;

  my $output = $stylesheet->output_string($results);

  return \$output;
}

sub process_template {
  my ($content, $component_id, $template_ref) = @_;

  my $lang_tmpl = {};
  $INCLUDE_MTIMES = {};

  # this pattern is not very accurate, but only as quick check if a run of XPathTemplate is needed
  my $content_pattern = ( $content->{relaxed_parser} eq 'yes' ) ? '<(?:!--)?\s*CONTENT_(VAR|LOOP|IF|UNLESS)\s+' : '<CONTENT_(VAR|LOOP|IF|UNLESS)\s+';
  my $skip_xpath_content = $$template_ref =~ m!$content_pattern!i;
  if( $skip_xpath_content ){
    # XPathTemplate template

    my $xpt = HTML::Template::XPath->new( default_lang   => $content->{default_lang},
				       root_dir       => $content->{content_dir},
                                       relaxed_parser => $content->{relaxed_parser},
                                       template_class => $content->{template_class},
                                      );

    $lang_tmpl = $xpt->process_all_lang(xpt_scalarref => $template_ref,
					xml_filename  => "$component_id.xml");
    my $file_mtimes = $xpt->file_mtimes;
    while (my ($k, $v) = each %$file_mtimes){
      # $v (mtime) can be undef in case where the content came from
      # xpath document function. This is not changed in HTML::Template::XPath
      # since otherwise the H:T:X try to put the file into his mtimes hash
      # over and over
      $content->{include_mtimes}->{$k} = $v if $v;
    }
  } else {
    $lang_tmpl->{$content->{default_lang}} = $template_ref;
  }
  return wantarray ? ( $lang_tmpl, $skip_xpath_content ) : $lang_tmpl;
}

sub _rel2abs {
  my ($rel_uri) = @_;
  if($rel_uri =~ m!\.xml!){
    my $content_dir = $CONTENT->{content_dir};
    if($rel_uri =~ m!^/!){
      return "$content_dir$rel_uri";
    } else {
      # return relative to component_id_dir
      my $abs_uri = "$content_dir/$COMPONENT_ID_DIR$rel_uri";
      while ($abs_uri =~ s![^/]*/\.\./!!) {};
      return $abs_uri;
    }
  } elsif($rel_uri =~ m!\.xsl!){
    my $view_dir = $CONTENT->{view_dir};
    my $stylesheet_file;
    if($rel_uri =~ m!^/!){
      $stylesheet_file = "$view_dir/$PKIT_VIEW$rel_uri";
      unless( -f $stylesheet_file){
	$stylesheet_file = "$view_dir/Default$rel_uri";
      }
    } else {
      # return relative to component_id_dir
      $stylesheet_file = "$view_dir/$PKIT_VIEW/$COMPONENT_ID_DIR$rel_uri";
      while ($stylesheet_file =~ s![^/]*/\.\./!!) {};
      unless( -f $stylesheet_file){
	$stylesheet_file = "$view_dir/Default/$COMPONENT_ID_DIR$rel_uri";
	while ($stylesheet_file =~ s![^/]*/\.\./!!) {};
      }
    }
    die "Stylesheet $stylesheet_file doesn't exist" unless ( -f $stylesheet_file );
    return $stylesheet_file;
  } else {
    die "$rel_uri does not end in .xml or .xsl.  All Content XML files must have
     xml suffix and all View XSLT files must have xsl suffix.";
  }
}

sub match_uri {
  my $uri = shift;
  return $uri !~ /(^\w+:)|(catalog$)/;
}

sub open_uri {
  my $uri = shift;
  my $abs_uri = _rel2abs($uri);
  open my $xml, "$abs_uri" or die "XML file $abs_uri doesn't exist";
  binmode $xml;
  local($/) = undef;
  my $xml_str = <$xml>;
  close $xml;
  my $mtime = (stat(_))[9];
  $INCLUDE_MTIMES->{$abs_uri} = $mtime;

  # we avoid to use any XML::LibXML parser inside the callbackroutines.

  return $xml_str;
}

sub read_uri {
  return substr($_[0], 0, $_[1], "");
}

sub close_uri {}

1;