#! /usr/bin/perl

# $Cambridge: exim/doc/doc-docbook/TidyHTML-spec,v 1.4 2006/04/04 14:03:49 ph10 Exp $

# Script to tidy up the spec HTML files that are generated by xmlto. The
# following changes are made:
#
# 1. Tidy the index.html file by splitting the very long lines.
# 2. Create reverse links from chapter and section titles back to the TOC.
# 3. Tidy the ix01.html file - the actual index - by splitting long lines.
# 4. Insert links from the letter divisions to the top of the Index.
# 5. Turn <div class="literallayout"><p> into <div class="literallayout"> and
#    a matching </p></div> into </div> to get rid of unwanted vertical white
#    space.
# 6. Before each occurrence of </td> insert &nbsp; so that the table's cell
#    is a little bit wider than the text itself.

chdir "spec_html";

$tocref = 1;

# Read in the index.html file. It's really the TOC.

open(IN, "index.html") || die "Failed to open index.html for reading: $!\n";
@toc = <IN>;
close(IN);

# Insert a newline after every > except when it is preceded by 'class="quote"',
# because the whole toc is generated as one humungous line that is hard to
# check. We have to avoid it in the quote case because that puts a space into
# the output, and similarly for the </span> the comes afterwards. Easy way out
# is just not to do it for all </span> occurrences. Unfortunately, Perl does
# not implement lookbehinds where the alternatives are of different lengths, so
# we have to take two passes.


foreach $line (@toc)
  {
  $line =~ s/(?<!class="quote")>\s*/>\n/g;
  $line =~ s/<\/span>\n/<\/span>/g;
  }

# Split the lines so that each one is a separate element in the vector.

for ($i = 0; $i < scalar(@toc); $i++)
  { splice @toc, $i, 1, (split /(?<=\n)/, $toc[$i]); }

# We want to create reverse links from each chapter and section title back to
# the relevant place in the TOC. Scan the TOC for the relevant entries. Add
# an id to each entry, and create tables that remember the file names and the
# new link ids.

foreach $line (@toc)
  {
  if ($line =~ /^<a href="((?:ch|ix)\d+\.html)(#[^"]+)?">/)
    {
    my($chix) = $1;
    my($ss) = $2;
    my($id) = sprintf "%04d", $tocref++;
    $line =~ s/<a/<a id="toc$id"/;
    $backref{"$chix$ss"} = "toc$id";
    push @chlist, $chix;
    }
  }

# Write out the modified index.html file.

open (OUT, ">index.html") || die "Failed to open index.html for writing: $!\n";
print OUT @toc;
close(OUT);

# Now scan each of the other page files and insert the reverse links. While
# we are at it, we tidy up <div class="literallayout"> by removing unwanted
# paragraph marks, which generate unwanted vertical space. We also insert
# &nbsp; before </td> to push table cells apart from each other.

foreach $file (@chlist)
  {
  open(IN, "$file") || die "Failed to open $file for reading: $!\n";
  @text = <IN>;
  close(IN);

  # Insert a newline after certain elements, and split the lines so that each
  # one is a separate element in the vector. This makes it easier to recognize
  # these elements.

  foreach $line (@text)
    {
    $line =~ s/<p>\s*(?!\n)/<p>\n/g;
    $line =~ s/<\/p>\s*(?!\n)/<\/p>\n/g;
    $line =~ s/<\/div>\s*(?!\n)/<\/div>\n/g;
    $line =~ s/<div([^>]*)>(?!\n)/<div$1>\n/g;
    }

  for ($i = 0; $i < scalar(@text); $i++)
    { splice @text, $i, 1, (split /(?<=\n)/, $text[$i]); }

  $thisdiv = 0;

  for ($i = 0; $i < scalar(@text); $i++)
    {
    if ($text[$i] =~ /^(.*?)<a( xmlns="[^"]+")? id="([^"]+)"><\/a>(.+?)<\/h(.*)$/)
      {
      my($pre, $opt, $id, $title, $post) = ($1, $2, $3, $4, $5);

      # Section reference
      my($ref) = $backref{"$file#$id"};

      # If not found, try for a chapter reference
      $ref = $backref{"$file"} if !defined $ref;

      # Adjust the line
      $text[$i]= "$pre<a$opt href=\"index.html#$ref\" id=\"$id\">$title</a></h$post";
      }

    elsif ($text[$i] =~ /^<div [^>]*?class="literallayout">$/ && $text[$i+1] eq "<p>\n")
      {
      $text[++$i] = "";
      $thisdiv = 1;
      }
    elsif ($thisdiv && $text[$i] eq "</p>\n" && $text[$i+1] eq "</div>\n")
      {
      $text[$i] = "";
      $thisdiv = 0;
      }
    elsif ($text[$i] =~ /^\s*<\/td>/)
      {
      $text[$i] = "&nbsp;$text[$i]";
      }
    }

  open(OUT, ">$file") || die "Failed to open $file for writing: $!\n";
  print OUT @text;
  close(OUT);
  }

# Now process the ix01.html file

open(IN, "ix01.html") || die "Failed to open ix01.html for reading: $!\n";
@index = <IN>;
close(IN);

# Insert a newline after every > because the whole index is generated as one
# humungous line that is hard to check. Then split the lines so that each one
# is a separate element in the vector.

foreach $line (@index) { $line =~ s/>\s*/>\n/g; }
for ($i = 0; $i < scalar(@index); $i++)
  { splice @index, $i, 1, (split /(?<=\n)/, $index[$i]); }

# We want to add a list of letters at the top of the index, and link back
# to them from each letter heading. First find the index title and remember
# where to insert the list of letters.

for ($i = 0; $i < scalar(@index); $i++)
  {
  if ($index[$i] =~ /^<\/h2>$/)
    {
    $listindex = $i;
    last;
    }
  }

# Now scan through for the letter headings and build the cross references,
# while also building up the list to insert.

$list = "<h4>\n";
for (; $i < scalar(@index); $i++)
  {
  if ($index[$i] =~ /^(.)<\/h3>$/)
    {
    $letter = $1;
    $index[$i-1] =~ s/^/<a id="${letter}B" href="#${letter}T">/;
    $index[$i] =~ s/$/<\/a>/;
    $list .= "<a id=\"${letter}T\" href=\"#${letter}B\"> $letter</a>\n";
    }
  }

# Now we know which letters we have, we can insert the list.

$list .= "</h4>\n";
splice @index, $listindex, 0, $list;

# Write out the modified index.html file.

open (OUT, ">ix01.html") || die "Failed to open ix01.html for writing: $!\n";
print OUT @index;
close(OUT);


# End