#!/usr/bin/perl
## ----------------------------------------------------------------------
## Debian GNU/Linux update-catalog version 0.2
## ----------------------------------------------------------------------
## Copyright (c) 2001-2004 Ardo van Rangelrooij
##
## This is free software; see the GNU General Public Licence version 2
## or later for copying conditions.  There is NO warranty.
## ----------------------------------------------------------------------

## ----------------------------------------------------------------------
use strict;

## ----------------------------------------------------------------------
$0 =~ m|[^/]+$|;

## ----------------------------------------------------------------------
use vars qw( $name );
$name = $&;

## ----------------------------------------------------------------------
use vars qw( $add );
use vars qw( $backup );
use vars qw( $catalog );
use vars qw( @data );
use vars qw( $debug );
use vars qw( $entry );
use vars qw( $quiet );
use vars qw( $remove );
use vars qw( $super );
use vars qw( $template );
use vars qw( $type );

## ----------------------------------------------------------------------
while ( $ARGV[0] =~ m/^--/ )
{
    $_ = shift( @ARGV );
    last if $_ eq '--';
    if ( $_ eq '--add' )
    {
        $add = 1;
    }
    elsif ( $_ eq '--remove' )
    {
        $remove = 1;
    }
    elsif ( $_ eq '--quiet' )
    {
        $quiet = 1;
    }
    elsif ( $_ eq '--super' )
    {
        $super = 1;
    }
    elsif ( $_ eq '--test' )
    {
        $debug = 1;
    }
    elsif ( $_ eq '--help' )
    {
        &help;
	exit -1;
    }
    elsif ( $_ eq '--version' )
    {
        &help;
	exit -1;
    }
    else
    {
        print STDERR "$name: unknown option \`$_'\n";
	&help;
	exit 1;
    }
}

## ----------------------------------------------------------------------
if ( ! @ARGV )
{
    print STDERR "\n";
    &help;
    exit 1;
}

## ----------------------------------------------------------------------
if ( $add || $remove )
{
    if ( $super )
    {
	$catalog = '/etc/sgml/catalog';
    }
    else
    {
	$catalog = shift( @ARGV );
    }
}

## ----------------------------------------------------------------------
if ( ! @ARGV )
{
    print STDERR "\n";
    &help;
    exit 1;
}

## ----------------------------------------------------------------------
$entry = shift( @ARGV );

## ----------------------------------------------------------------------
if ( @ARGV )
{
    print STDERR "$name: too many arguments\n";
    &help;
    exit 1;
}

## ----------------------------------------------------------------------
if ( $add == $remove )
{
    print "Huh? You have to use --add or --remove (not both).\n";
    exit 1;
}

## ----------------------------------------------------------------------
print STDERR "$name: test mode - catalog file will not be updated\n"
    if $debug && ! $quiet;

## ----------------------------------------------------------------------
if ( $add )
{
    print "Adding entry $entry to catalog $catalog...\n"
        unless $quiet;
    
    &read_catalog_without_entry;
    &add_entry;
    &write_catalog;
}
elsif ( $remove )
{
    print "Removing entry $entry from catalog $catalog...\n"
        unless $quiet;
    
    &read_catalog_without_entry;
    &write_catalog;
}

## ----------------------------------------------------------------------
exit 0;

## ----------------------------------------------------------------------
 sub read_catalog_without_entry
{
    if ( -f $catalog )
    {
	print "Reading catalog $catalog and removing entry $entry...\n"
	    if $debug;
	open( CATALOG, "<$catalog" )
	    or die "cannot open catalog $catalog for reading: $!";
	while ( <CATALOG> )
	{
	    chop;
	    push( @data, $_ ) unless m/$entry/;
	}
	close( CATALOG );
    }
    else
    {
	$type = $super ? 'super' : 'centralized';
	$template = "/usr/share/sgml-base/catalog.$type";
	print "Reading template $template...\n"
	    if $debug;
	open( TEMPLATE, "<$template" )
	    or die "cannot open template $template for reading: $!";
	while ( <TEMPLATE> )
	{
	    chop;
	    s|CATALOG|$catalog| if m/CATALOG/;
	    push( @data, $_ );
	}
	close( TEMPLATE );
    }
}

## ----------------------------------------------------------------------
sub add_entry
{
    print "Appending entry $entry...\n" if $debug;
    push( @data, "CATALOG $entry" );
}

## ----------------------------------------------------------------------
sub write_catalog
{
    $backup = $catalog . '.old';
    if ( not $debug )
    {
	if ( -f $catalog )
	{
	    # remove old backup file
	    if ( -f $backup )
	    {
		unlink( $backup )
		    or die "cannot remove backup copy $backup: $!";
	    }
	    rename( $catalog, $backup )
		or die "cannot rename $catalog to $backup: $!";
	}
	open( CATALOG, ">$catalog" )
	    or die "cannot open catalog $catalog for writing: $!";
	for ( @data ) { print CATALOG "$_\n"; };
	close( CATALOG );
    }
    else
    {
	print "Writing new entry to $catalog...\n";
	for ( @data ) { print "$_\n"; };
    }
}

## ----------------------------------------------------------------------
sub help
{
    print STDERR <<END;
Usage:
    $name <options> --add --super <centralized_catalog>
    $name <options> --add <centralized_catalog> <ordinary_catalog>
or
    $name <options> --remove --super <centralized_catalog>
    $name <options> --remove <centralized_catalog> <ordinary_catalog>

Options:
    --quiet         be quiet
    --test          do not modify any files, enables debugging mode
    --version       display version number
    --help          display this text
END
}

## ----------------------------------------------------------------------
sub version
{
    print "Debian $name version 0.2\n";
}

## ----------------------------------------------------------------------