#! perl -w

## read index.html, and update the templates in all the other files
##
## test comment

use strict;

my $pagetitle_re = qr;<title>.*</title>;sm;
my $title_re = qr;<h2>.*?</h2>;sm;
my $subtitle_re = qr;<h1>.*?</h1>;sm;
my $content_re = qr;(<!--start-of-content-->.*<!--end-of-content-->);sm;
my $keywords_re = qr;(<meta name="keywords" content=".*?" />);sm;
my $linkbox1_re = qr;(<!--start-of-linkbox-1-->.*<!--end-of-linkbox-1-->);sm;
my $linkbox2_re = qr;(<!--start-of-linkbox-2-->.*<!--end-of-linkbox-2-->);sm;
my $linkbox3_re = qr;(<!--start-of-linkbox-3-->.*<!--end-of-linkbox-3-->);sm;
my $all_linkboxes_re = qr;(<!--start-of-linkboxes-->.*<!--end-of-linkboxes-->);sm;

print "Reading template taiji.html ...\n";
open TEMPLATE, "<taiji.html" or die $!;
my $template = do {
  local $/ = undef;
  <TEMPLATE>;
};
close TEMPLATE;

# the title should be the same on all pages
my $global_title;
if ($template =~ m!$title_re!) {
  $global_title = $&;
}
else {
  die "no title in template";
}

sub update_file {
  my $filename=shift;

  print "Processing $filename\n";

  open FILE, "<$filename" or die "$filename: $!";

  my $file = do {
    local $/ = undef;
    <FILE>;
  };

  close FILE;

  my ($subtitle, $content, $linkbox1, $linkbox2, $linkbox3, $keywords);

  if ($file =~ m!$content_re!) {
    $content = $&;
  }
  else {
    die "no content";
  }

  if ($file =~ m!$subtitle_re!) {
    $subtitle = $&;
  }
  else {
    die "no subtitle";
  }

  if ($file =~ m!$keywords_re!) {
    $keywords = $&;
  }
  else {
    die "no keywords";
  }

  if ($file =~ m!$linkbox1_re!) {
    $linkbox1 = $&;
  }
  else {
    #warn "no linkbox1 in $filename";
  }

  if ($file =~ m!$linkbox2_re!) {
    $linkbox2 = $&;
  }
  else {
    #warn "no linkbox2 in $filename";
  }

  if ($file =~ m!$linkbox3_re!) {
    $linkbox3 = $&;
  }
  else {
    #warn "no linkbox3 in $filename";
  }

  #warn "Global title: $global_title";
  #warn "Subtitle: $subtitle";
  #warn "Keywords: $keywords";
  #warn "Content: $content";

  my $newfile = $template;

  $newfile =~ s!$content_re!$content! or die "error replacing content";
  $newfile =~ s!$title_re!$global_title! or die "error replacing title";
  $newfile =~ s!$subtitle_re!$subtitle! or die "error replacing subtitle";
  $newfile =~ s!$keywords_re!$keywords! or die "error replacing keywords";

  if (not defined $linkbox1 and not defined $linkbox2 and not defined $linkbox3) {
    $newfile =~ s,$all_linkboxes_re,<!-- no linkboxes -->,;
  }

  if (defined $linkbox1) {
    $newfile =~ s!$linkbox1_re!$linkbox1! or die "error replacing linkbox1 in $filename";
  }
  if (defined $linkbox2) {
    $newfile =~ s!$linkbox2_re!$linkbox2! or die "error replacing linkbox2 in $filename";
  }
  if (defined $linkbox3) {
    $newfile =~ s!$linkbox3_re!$linkbox3! or die "error replacing linkbox3 in $filename";
  }

  # as well as the above simple things, we update the page's title
  # based on the title and subtitle retrieved from the page.
  my $page_title = "$global_title - $subtitle";
  $page_title =~ s!<[^<>]+>!!g;
  $newfile =~ s!$pagetitle_re!<title>$page_title</title>! or die "error replacing page title";

  open NEWFILE, ">$filename.new" or die "open $filename.new: $!";
  print NEWFILE $newfile;
  close NEWFILE;

  rename($filename, "$filename.old") or die "rename $filename: $!";
  rename("$filename.new", $filename) or die "rename $filename.new: $!";
}

for my $file (glob('*.html')) {
  update_file($file);
}