package WebHACC::Output;
use strict;

require IO::Handle;
use Scalar::Util qw/refaddr/;

my $htescape = sub ($) {
  my $s = $_[0];
  $s =~ s/&/&/g;
  $s =~ s/</&lt;/g;
  $s =~ s/>/&gt;/g;
  $s =~ s/"/&quot;/g;
  $s =~ s{([\x00-\x09\x0B-\x1F\x7F-\xA0\x{FEFF}\x{FFFC}-\x{FFFF}])}{
    sprintf '<var>U+%04X</var>', ord $1;
  }ge;
  return $s;
};

sub new ($) {
  return bless {nav => []}, shift;
} # new

sub input ($;$) {
  if (@_ > 1) {
    if (defined $_[1]) {
      $_[0]->{input} = $_[1];
    } else {
      delete $_[0]->{input};
    }
  }
  
  return $_[0]->{input};
} # input

sub handle ($;$) {
  if (@_ > 1) {
    if (defined $_[1]) {
      $_[0]->{handle} = $_[1];
    } else {
      delete $_[0]->{handle};
    }
  }
  
  return $_[0]->{handle};
} # handle

sub set_utf8 ($) {
  binmode shift->{handle}, ':utf8';
} # set_utf8

sub set_flush ($) {
  shift->{handle}->autoflush (1);
} # set_flush

sub unset_flush ($) {
  shift->{handle}->autoflush (0);
} # unset_flush

sub html ($$) {
  shift->{handle}->print (shift);
} # html

sub text ($$) {
  shift->html ($htescape->(shift));
} # text

sub url ($$%) {
  my ($self, $url, %opt) = @_;
  $self->html (q[<code class=uri>&lt;]);
  $self->link ($url, %opt, url => $url);
  $self->html (q[></code>]);
} # url

sub start_tag ($$%) {
  my ($self, $tag_name, %opt) = @_;
  $self->html ('<' . $htescape->($tag_name)); # escape for safety
  if (exists $opt{id}) {
    my $id = $self->input->id_prefix . $opt{id};
    $self->html (' id="' . $htescape->($id) . '"');
    delete $opt{id};
  }
  for (keys %opt) {    # for safety
    $self->html (' ' . $htescape->($_) . '="' . $htescape->($opt{$_}) . '"');
  }
  $self->html ('>');
} # start_tag

sub end_tag ($$) {
  shift->html ('</' . $htescape->(shift) . '>');
} # end_tag

sub start_section ($%) {
  my ($self, %opt) = @_;
  $self->html ('<div class=section');
  if (defined $opt{id}) {
    my $id = $self->input->id_prefix . $opt{id};
    $self->html (' id="' . $htescape->($id) . '"');
    push @{$self->{nav}}, [$id => $opt{short_title} || $opt{title}] 
        unless $self->input->nested;
  }
  $self->html ('><h2>' . $htescape->($opt{title}) . '</h2>');
} # start_section

sub end_section ($) {
  my $self = shift;
  $self->html ('</div>');
  $self->{handle}->flush;
} # end_section

sub start_code_block ($) {
  shift->html ('<pre><code>');
} # start_code_block

sub end_code_block ($) {
  shift->html ('</code></pre>');
} # end_code_block

sub code ($$;%) {
  my ($self, $content, %opt) = @_;
  $self->start_tag ('code', %opt);
  $self->text ($content);
  $self->html ('</code>');
} # code

sub script ($$;%) {
  my ($self, $content, %opt) = @_;
  $self->start_tag ('script', %opt);
  $self->html ($content);
  $self->html ('</script>');
} # script

sub dt ($$;%) {
  my ($self, $content, %opt) = @_;
  $self->start_tag ('dt', %opt);
  $self->text ($content);
} # dt

sub link ($$%) {
  my ($self, $content, %opt) = @_;
  $self->start_tag ('a', %opt, href => $opt{url});
  $self->text ($content);
  $self->html ('</a>');
} # link

sub xref ($$%) {
  my ($self, $content, %opt) = @_;
  $self->html ('<a href="#' . $htescape->($self->input->id_prefix . $opt{target}) . '">');
  $self->text ($content);
  $self->html ('</a>');
} # xref

sub link_to_webhacc ($$%) {
  my ($self, $content, %opt) = @_;
  $opt{url} = './?uri=' . $self->encode_url_component ($opt{url});
  $self->link ($content, %opt);
} # link_to_webhacc


my $get_node_path = sub ($) {
  my $node = shift;
  my @r;
  while (defined $node) {
    my $rs;
    if ($node->node_type == 1) {
      $rs = $node->node_name;
      $node = $node->parent_node;
    } elsif ($node->node_type == 2) {
      $rs = '@' . $node->node_name;
      $node = $node->owner_element;
    } elsif ($node->node_type == 3) {
      $rs = '"' . $node->data . '"';
      $node = $node->parent_node;
    } elsif ($node->node_type == 9) {
      @r = ('') unless @r;
      $rs = '';
      $node = $node->parent_node;
    } else {
      $rs = '#' . $node->node_type;
      $node = $node->parent_node;
    }
    unshift @r, $rs;
  }
  return join '/', @r;
}; # $get_node_path

sub node_link ($$) {
  my ($self, $node) = @_;
  $self->xref ($get_node_path->($node), target => 'node-' . refaddr $node);
} # node_link

sub nav_list ($) {
  my $self = shift;
  $self->html (q[<ul class="navigation" id="nav-items">]);
  for (@{$self->{nav}}) {
    $self->html (qq[<li><a href="#@{[$htescape->($_->[0])]}">@{[$htescape->($_->[1])]}</a>]);
  }
  $self->html ('</ul>');
} # nav_list


sub encode_url_component ($$) {
  shift;
  require Encode;
  my $s = Encode::encode ('utf8', shift);
  $s =~ s/([^0-9A-Za-z_.~-])/sprintf '%%%02X', ord $1/ge;
  return $s;
} # encode_url_component

1;