#! /usr/bin/perl

use Getopt::Long;
use HTML::Parser;

sub text_handler;
sub comment_handler;
sub default_handler;
sub start_handler;
sub end_handler;
sub body_start;
sub find_tag;
sub nospaces;

$opt_product = "openSUSE";

%help_key_rename = (
  'F2' => 'F3',
  'F3' => 'F4',
  'F4' => 'F2',
);

GetOptions(
  'product=s' => \$opt_product
);

$p = HTML::Parser->new(api_version => 3);

# $p->utf8_mode(1);
$p->unbroken_text(1);

$p->handler(default => "" );
$p->handler(start => \&body_start, "self,tagname,line");

$p->parse_file(shift);

# print "help type = \"$helptype\"\n";


$t .= $_->[1] for @t;

$t =~ s/ +/ /sg;
$t =~ s/\n /\n/sg;
$t =~ s/ \n/\n/sg;
$t =~ s/(\x14.*?\x10)\s*/$1/sg;
$t =~ s/\s*(\x04|$)/$1/sg;
$t =~ s/(&product;|\@product\@)/$opt_product/g;

# FIXME: we need a better solution
$t =~ s/(\bF[234]\b)/$help_key_rename{$1}/sg if $helptype eq 'install';

print $t, "\x00";


if($helptype eq 'boot') {
  $ref{help}++;
  $ref{keytable}++;
  $ref{profile}++;
}

if($helptype eq 'install') {
  $ref{bits}++;
}

for (keys %label) {
  if(!$ref{$_}) {
    $err = 1;
    print STDERR "\"$_\" never referenced\n"
  }
}

for (keys %ref) {
  if(!$label{$_}) {
    $err = 1;
    print STDERR "\"$_\" never defined\n"
  }
}

warn "*** inconsistencies detected ***\n" if $err;



sub text_handler
{
  local $_;

  $_ = shift;
  s/\s+/ /g;

  push @t, [ "", $_ ];
}


sub comment_handler
{
  $helptype = $1 if $_[0] =~ /\bhelp=([a-z]+)/;
}


sub default_handler
{
  my $line = shift;

  die "oops at line $line\n";
}


sub body_start
{
  my ($self, $tag) = @_;

  if($tag eq "body") {
    $self->handler(text => \&text_handler, "text");
    $self->handler(comment => \&comment_handler, "text" );
    $self->handler(default => \&default_handler, "line" );
    $self->handler(start => \&start_handler, "self,tagname,attr,line");
    $self->handler(end => \&end_handler, "self,tagname,line");
  }
}


sub start_handler
{
  my ($self, $tag, $attr, $line) = @_;
  my $l;

  return if $tag eq "hr";
  return if $tag eq "h3";

  if($tag eq "br") {
    push @t, [ "", "\n" ];
  }
  elsif($tag eq "em") {
    push @t, [ "em" ];
  }
  elsif($tag eq "a") {
    $l = $attr->{href};
    $l =~ s/^#//;
    push @t, [ "a", undef, $attr->{name}, $l ];
  }
  else {
    die "line $line: unsupported tag $tag\n";
  }
}


sub end_handler
{
  my ($self, $tag, $line) = @_;
  my ($i, $j);

  return if $tag eq "h3";

  if($tag eq "body") {
    $self->handler(text => "");
    $self->handler(comment => "" );
    $self->handler(default => "" );
    $self->handler(start => "");
    $self->handler(end => "");

    return;
  }

  $i = find_tag $tag, $line;
  die "line $line: no matching opening tag for $tag found\n" unless $i;

  if($tag eq "em") {
    $i = pop @t;
    pop @t;
    push @t, [ "", "\x11$i->[1]\x10" ];
  }
  elsif($tag eq "a") {
    $i = pop @t;
    $j = pop @t;
    if($j->[2]) {
      # name
      die "line $line: label $j->[2] too long (max. 32)\n" if length($j->[2]) > 32;
      die "line $line: label $j->[2] already exists\n" if $label{$j->[2]};
      $label{$j->[2]} = 1;
      push @t, [ "", "\x04\x12$j->[2]\x14$i->[1]\x10" ];
    }
    elsif($j->[3]) {
      # href
      die "line $line: label $j->[3] too long (max. 32)\n" if length($j->[3]) > 32;
      $ref{$j->[3]}++;
      push @t, [ "", "\x12$j->[3]\x13" . nospaces($i->[1]) . "\x10" ];
    }
    else {
      die "line $line: strange tag $tag\n";
    }
  }
  else {
    die "line $line: unexpected tag $tag\n";
  }

}


sub find_tag
{
  my $i = @t - 1;

  return undef if $i < 1;

  return 1 if $t[$i][0] eq "" && $t[$i-1][0] eq $_[0];

  die "line $_[1]: nested tags not supported\n";
}


# \x1f looks like a space but is not a space. This is useful
# to prevent automatic line breaks.
sub nospaces
{
  local $_;

  $_ = shift;
  s/\s/\x1f/g;

  return $_;
}