#!/usr/bin/perl

# $Id: gen_help.pl,v 2.2 2004-12-09 08:41:13 pajas Exp $

use strict;
use XML::LibXML;
use Text::Wrap qw(wrap);

if ($ARGV[0]=~'^(-h|--help)?\$') {
  print <<EOF;
Generates help module from RecDescentXML source.

Usage: $0 <source.xml>

EOF
  exit;
}

my $parser=XML::LibXML->new();
$parser->load_ext_dtd(1);
$parser->validation(1);
$parser->keep_blanks(1);
my $doc=$parser->parse_file($ARGV[0]);

my $dom=$doc->getDocumentElement();
my ($rules)=$dom->findnodes('./rules');

my $ruledoc;
my $title;
my @aliases;
my @seealso;
my @usage;
my $desc;


print "# This file was automatically generated from $ARGV[0] on \n# ",scalar(localtime),"\n";
print <<'PREAMB';

package XML::XSH2::Help;
use strict;
use vars qw($HELP %HELP $Apropos);


PREAMB

print "\$HELP=<<'END';\n";
print "\n  Welcome to XSH help\n";
print "  -------------------\n\n";
print "  In this help:\n  [topic] is a cross reference that can be followed using 'help topic'\n\n";
($desc)=$dom->findnodes('./doc/description');
print_description($desc,"  ","  ") if ($desc);
print "\n\n  Within the interactive shell, press <TAB> for auto-completion.\n";
print "END\n\n";

print "\$HELP{'toc'}=[<<'END'];\n";
print "\nHelp items:\n";
print "-----------\n\n";
print "  toc - this page\n\n";
print "  XSH Language Topics:\n\n";
foreach (sort { $a->getAttribute('id') cmp
		$b->getAttribute('id') } 
	 $dom->findnodes("/recdescent-xml/doc/section")) {
  print "    ",$_->getAttribute('id')," - ";
  print wrap("","      ",
	     get_text($_->findnodes("title"))),
	   "\n";
}
print "\n  XSH Commands:\n\n";
print wrap("    ","    ",
	   join ", ", sort map { get_name($_) } 
	   grep {defined($_)} 
	   $dom->findnodes("//rules/rule[\@type='command']")),
	   "\n\n";

print "  XSH Argument Types:\n\n";
print wrap("    ","    ",
	   join ", ", sort map { get_name($_) } 
	   grep {defined($_)} 
	   $dom->findnodes("//rules/rule[\@type='argtype']")),
  "\n\n";

print "  XPath Extension Functions:\n\n";
print wrap("    ","    ",
	   join ", ", sort map { get_name($_) } 
	   grep {defined($_)} 
	   $dom->findnodes("//rules/rule[\@type='function']")),
  "\n\n";
print "END\n\n";


my %apropos;
foreach my $r ($rules->findnodes('./rule')) {
  next unless $r;
  my ($ruledoc)=$r->findnodes('./documentation');
  next unless $ruledoc;
  my $name=get_name($r);

  my ($shortdesc)=$ruledoc->findnodes('./shortdesc');
  $apropos{$name} = get_text($shortdesc) if ($shortdesc);
  $apropos{$name} =~ s/\s+/ /g;

  print "\$HELP{'$name'}=[<<'END'];\n";
  ($title)=$ruledoc->findnodes('./title');
  print get_text($title),"\n\n" if ($title);

  @usage=$ruledoc->findnodes('./usage');
  if (@usage) {
    print "usage:       ";
    foreach (@usage) {
      my $usage=get_text($_);
      $usage=~s/\s+/ /;
      print $usage,"\n             ";
    }
    print "\n";
  }
  @aliases=grep {defined($_)} $r->findnodes('./aliases/alias');
  if (@aliases) {
    print "aliases:     ",join " ",map { get_name($_) } @aliases;
    print "\n\n";
  }
  ($desc)=$ruledoc->findnodes('./description');
  if ($desc) {
    print "description:\n";
    print_description($desc," "x(13)," "x(13));
  }
  @seealso=grep {defined($_)} $ruledoc->findnodes('./see-also/ruleref');
  if (@seealso) {
    print "see also:     ",join " ", map { get_name($_) }# grep {defined($_)}
      map { $_->findnodes('id(@ref)') } @seealso;
    print "\n\n";
  }

  print "END\n\n";

  foreach (@aliases) {
    print "\$HELP{'",get_name($_),"'}=\$HELP{'$name'};\n";
  }
  print "\n";

}

foreach my $sec ($dom->findnodes('/recdescent-xml/doc/section')) {
  my $name=$sec->getAttribute('id');

  print "\$HELP{'$name'}=[<<'END'];\n";
  ($title)=$sec->findnodes('./title');
  if ($title) {
    my $t=get_text($title);
    print $t,"\n";
    print '-' x length($t),"\n\n";
  }

  print_description($sec," "x(2)," "x(2));

  my @commands=$dom->findnodes("//rules/rule[\@type='command' and ".
			       "documentation[contains(\@sections,'$name')]]");
  if (@commands) {
    print "\nRelated help items:\n";
    print wrap("  ","  ",
	       join ", ", sort map { get_name($_) }
	       @commands),
	       "\n\n";
  }
  print "END\n\n";
}

print "\$HELP{'commands'}=\$HELP{'command'};\n";

use Data::Dumper;
print Data::Dumper->Dump([\%apropos],[qw(Apropos)]);

print "\n1;\n__END__\n\n";

exit;

## ================================================

sub strip_space {
  my ($text)=@_;
  $text=~s/^\s*//;
  $text=~s/\s*$//;
  return $text;
}

sub get_name {
  my ($r)=@_;
  return $r->getAttribute('name') ne ""
    ? $r->getAttribute('name')
      : $r->getAttribute('id');
}

sub get_text {
  my ($node,$no_strip)=@_;
  my $text="";
  foreach my $n ($node->childNodes()) {
    if ($n->nodeType() == XML::LibXML::XML_TEXT_NODE ||
	$n->nodeType() == XML::LibXML::XML_CDATA_SECTION_NODE) {
      my $data=$n->getData();
      $data=~s/\t/  /g;
      $text.=$data;
    } elsif ($n->nodeType() == XML::LibXML::XML_ELEMENT_NODE) {
      if ($n->nodeName() eq 'link') {
	$text.="[".get_text($n,1)."]";
      } elsif ($n->nodeName() eq 'xref') {
	$text.="[";
	my ($ref)=$node->findnodes("id('".$n->getAttribute('linkend')."')");
	if ($ref) {
	  $text.=get_name($ref);
	} else {
	  print STDERR "Reference to undefined identifier: ",$n->getAttribute('linkend'),"\n";
	}
	$text.="]";
      } elsif ($n->nodeName() eq 'typeref') {
	foreach (split /\s/,$n->getAttribute('types')) {
	  $text.=join ", ", sort map { get_name($_) } grep {defined($_)} $node->findnodes("//rules/rule[\@type='$_']");
	}
      } elsif ($n->nodeName() eq 'tab') {
	$text.="\t" x $n->getAttribute('count');
      } elsif ($n->nodeName() eq 'literal') {
	$text.="'".get_text($n,1)."'";
      } else {
	$text.=get_text($n);
      }
    }
  }
  return $no_strip ? $text : strip_space($text);
}

sub max { ($_[0] > $_[1]) ? $_[0] : $_[1] }

sub  print_description {
  my ($desc,$indent,$bigindent)=@_;
  foreach my $c ($desc->childNodes()) {
    if ($c->nodeType == XML::LibXML::XML_ELEMENT_NODE) {
      if ($c->nodeName eq 'para') {
	my $t=get_text($c);
	$t=~s/\s+/ /g;
	print wrap($indent,$bigindent,$t),"\n\n";
	$indent=$bigindent;
      } elsif ($c->nodeName eq 'section') {
	my ($title)=$c->findnodes('./title');
	if ($title) {
	  my $t=get_text($title);
	  print $bigindent.$t,"\n";
	  print $bigindent.'-' x length($t),"\n\n";
	}
	print_description($c,$indent."  ",$bigindent."  ");
      } elsif ($c->nodeName eq 'enumerate') {
	my $n=1;
	foreach my $item ($c->findnodes('listitem')) {
	  print_description($item,$indent."  ".($n++).". ",$bigindent."  ");
	}
      } elsif ($c->nodeName eq 'code') {
	local $_ = get_text($c);
	s/\n[ ]*/\n$bigindent/mg;
	s/\\\n/\\\n$bigindent  /g;
	s/\t/  /g;
	print "$bigindent$_\n";
      } elsif ($c->nodeName eq 'example') {
	foreach (map { get_text($_) } $c->findnodes('./title')) {
	  s/\s+/ /g;
	  print wrap("",$bigindent,"Example:"." "x(max(1,length($bigindent)-8))."$_\n");
	}
	unless ($c->findnodes('./title')) {
	  print "Example:";
	}
	print "\n";
	print_description($c,$indent,$bigindent);
	print "\n";
      }
    }
  }
}