#!/usr/bin/perl -- # -*- Perl -*-

use Getopt::Std;
use Cwd;

$usage = "Usage: $0 file\n";

die $usage if ! getopts('w');

$root = shift @ARGV || die $usage;
if ($root =~ /^(.*)[\/\\]([^\/\\]+)$/) {
    $dir = $1;
    $root = $2;

    $lcldir = cwd();
    chdir ($dir);
    $dir = cwd();
    chdir ($lcldir);
} else {
    $dir = cwd();
}

$startdir = cwd();
$startdir =~ s/\/[^\/]+$//; # drop the last component

%depends_on = ();

@files = ($dir, $root);
while (@files) {
    $fdir = shift @files;
    $file = shift @files;

    chdir($fdir) || die "Cannot cd to $fdir\n";

#    print "Checking $fdir/$file\n";

    open (DSSSL, $file);
    read (DSSSL, $_, -s $file);
    close (DSSSL);

    while (/<!ENTITY.*?>/s) {
	my($ent) = $&;
	$_ = $';
	if ($ent =~ /SYSTEM\s+\"(.*?)\"/is) {
#	    print "System: $1\n";
	    $file = $1;
	} elsif ($ent =~ /PUBLIC\s+\"(.*?)\"\s+\"(.*?)\"/is) {
#	    print "Public: $1 with system $2\n";
	    $file = $2;
	} elsif ($ent =~ /PUBLIC\s+\"(.*?)\"/is) {
#	    print "Public: $1\n";
	    $file = &resolve_pubid($1);
	}	

	if ($file =~ /^(.*)[\/\\]([^\/\\]+)$/) {
	    $dir = $1;
	    $file = $2;

	    $lcldir = cwd();
	    chdir ($dir);
	    $dir = cwd();
	    chdir ($lcldir);
	} else {
	    $dir = cwd();
	}

	push (@files, $dir, $file) if ! exists $depends_on{"$dir/$file"};
	$depends_on{"$dir/$file"} = 1;
    }
}

print "$root depends on\n";
foreach $file (keys %depends_on) {
    if ($file =~ /^$startdir\//) {
	$file = $';
    } elsif ($file =~ /^N:\/share\/dsssl\/docbook\//) {
	$file = "../" . $';
    }

    print "$file\n";
}

sub resolve_pubid {
    my($pubid) = shift;

    if ($pubid eq "-//Norman Walsh//DOCUMENT DSSSL Library//EN") {
	return "n:/share/dsssl/docbook/lib/dblib.133";
    }

    if ($pubid eq "-//Norman Walsh//DOCUMENT DSSSL Library V2//EN") {
	return "n:/share/dsssl/docbook/lib/dblib.dsl";
    }

    if ($pubid eq "ISO 8879:1986//ENTITIES Added Latin 1//EN") {
	return "n:/share/sgml/ISO_8879-1986/entities/iso-lat1.gml";
    }

    if ($pubid eq "ISO 8879-1986//ENTITIES Added Latin 1//EN") {
	return "n:/share/sgml/ISO_8879-1986/entities/iso-lat1.gml";
    }

    if ($pubid eq "ISO 8879:1986//ENTITIES Added Latin 2//EN") {
	return "n:/share/sgml/ISO_8879-1986/entities/iso-lat2.gml";
    }

    if ($pubid eq "ISO 8879-1986//ENTITIES Added Latin 2//EN") {
	return "n:/share/sgml/ISO_8879-1986/entities/iso-lat2.gml";
    }

    if ($pubid eq "ISO 8879:1986//ENTITIES Russian Cyrillic//EN") {
	return "n:/share/sgml/ISO_8879-1986/entities/iso-cyr1.gml";
    }

    if ($pubid eq "ISO 8879-1986//ENTITIES Russian Cyrillic//EN") {
	return "n:/share/sgml/ISO_8879-1986/entities/iso-cyr1.gml";
    }

    die "Cannot resolve \"$pubid\"\n";
}