package xCAT_plugin::dns;
use Getopt::Long;
use Net::DNS;
use xCAT::Table;
use Socket;
use strict;
#This is a rewrite of DNS management using nsupdate rather than direct zone mangling

my $callback;

sub update_named_conf {
    my $ctx = shift;

}
sub get_reverse_zone_for_entity {
    my $ctx = shift;
    my $node = shift;
    my $net;
    if ($ctx->{hoststab} and $ctx->{hoststab}->{$node} and $ctx->{hoststab}->{$node}->[0]->{ip}) {
        $node = $ctx->{hoststab}->{$node}->[0]->{ip};
    }
    my $tvar;
    if ($tvar = inet_aton($node)) { #This is an assignment, we are testing and storing the value in one shot
        $tvar = unpack("N",$tvar);
        foreach my $net (keys %{$ctx->{nets}}) {
            if ($ctx->{nets}->{$net}->{netn} == ($tvar & $ctx->{nets}->{$net}->{mask})) {
                my $maskstr = unpack("B32",pack("N",$ctx->{nets}->{$net}->{mask}));
                my $maskcount = ($maskstr =~ tr/1//);
                $maskcount+=((8-($maskcount%8))%8); #round to the next octet
                my $newmask = 2**$maskcount -1 << (32 - $maskcount);
                my $rev = inet_ntoa(pack("N",($tvar & $newmask)));
                my @zone;
                my @orig=split /\./,$rev;
                while ($maskcount) {
                    $maskcount-=8;
                    unshift(@zone,(shift @orig));
                }
                $rev = join('.',@zone);
                $rev .= '.IN_ADDR.ARPA';
                return $rev;
            }
        }
    }
}

sub process_request {
    my $request = shift;
    my $callback = shift;
    my $ctx = {};
    my @nodes;
    my $hadargs=0;
    my $allnodes;
    my $zapfiles;
    if ($request->{arg}) {
        $hadargs=1;
        @ARGV=@{$request->{arg}};
        if (!GetOptions(
            'a|all' => \$allnodes,
            'n|new' => \$zapfiles,
            )) {
            sendmsg([1,"TODO: makedns Usage message"]);
            return;
        }
    }
        
    if ($request->{node}) { #we have a noderange to process
        @nodes = @{$request->{node}};
    } elsif ($allnodes) {
        #read all nodelist specified nodes
    } else { #legacy behavior, read from /etc/hosts
        sendmsg([1,"TODO: reading from /etc/hosts like old makedns"]);
    }
    my $hoststab = xCAT::Table->new('hosts',-create=>0);
    if ($hoststab) {
        $ctx->{hoststab} = $hoststab->getNodesAttribs(\@nodes,['ip']);
    }
    my $networkstab = xCAT::Table->new('networks',-create=>0);
    unless ($networkstab) { sendmsg([1,'Unable to enumerate networks, try to run makenetworks']); }
    my @networks = $networkstab->getAllAttribs('net','mask');
    foreach (@networks) {
        my $maskn = unpack("N",inet_aton($_->{mask}));
        $ctx->{nets}->{$_->{net}}->{mask} = $maskn;
        $ctx->{nets}->{$_->{net}}->{netn} = unpack("N",inet_aton($_->{net}));
    }
    my $passtab = xCAT::Table->new('passwd');
    my $pent = $passtab->getAttribs({key=>'omapi',username=>'xcat_key'},['password']);
    if ($pent and $pent->{password}) { 
        $ctx->{privkey} = $pent->{password};
    } #do not warn/error here yet, if we can't generate or extract, we'll know later
    my $sitetab = xCAT::Table->new('site');
    my $stab = $sitetab->getAttribs({key=>'domain'},['value']);
    unless ($stab and $stab->{value}) {
        sendmsg([1,"domain not defined in site table"]);
        return;
    }
    $ctx->{domain} = $stab->{value};
    $stab =  $sitetab->getAttribs({key=>'forwarders'},['value']);
    if ($stab and $stab->{value}) {
        my @forwarders = split /[ ,]/,$stab->{value};
        $ctx->{forwarders}=\@forwarders;
    }
    $ctx->{domainstotouch}->{$ctx->{domain}}=1;
    foreach (@nodes) {
           $ctx->{revzones}->{$_} = get_reverse_zone_for_entity($ctx,$_);
           $ctx->{domainstotouch}->{$ctx->{revzones}->{$_}}=1;
    }
    use Data::Dumper;
    if (1) { #TODO: function to detect and return 1 if the master server is DNS SOA for all the zones we care about
        #here, we are examining local files to assure that our key is in named.conf, the zones we care about are there, and that if
        #active directory is in use, allow the domain controllers to update specific zones
        $stab =$sitetab->getAttribs({key=>'directoryprovider'},['value']);
        if ($stab and $stab->{value} and $stab->{value} eq 'activedirectory') {
            $stab =$sitetab->getAttribs({key=>'directoryservers'},['value']);
            if ($stab and $stab->{value} and $stab->{value}) {
                my @dservers = split /[ ,]/,$stab->{value};
                $ctx->{adservers} = \@dservers;
            }
        }
        $stab =$sitetab->getAttribs({key=>'dnsupdaters'},['value']); #allow unsecure updates from these
        if ($stab and $stab->{value} and $stab->{value}) {
                my @nservers = split /[ ,]/,$stab->{value};
                $ctx->{dnsupdaters} = \@nservers;
        }
        if ($zapfiles) { #here, we unlink all the existing files to start fresh
        }
        #We manipulate local namedconf
        update_namedconf($ctx);
    } else {
        unless ($ctx->{privkey}) {
            sendmsg([1,"Unable to update DNS due to lack of credentials in passwd to communicate with remote server"]);
        }
    }
    #now we stick to Net::DNS style updates, with TSIG if possible.  TODO: kerberized (i.e. Windows) DNS server support, maybe needing to use nsupdate -g....
}

sub update_namedconf {
    my $ctx = shift;
    my $namedlocation = '/etc/named.conf';
    my $nameconf;
    my @newnamed;
    my $gotoptions=0;
    my $gotkey=0;
    my %didzones;
    if (-r $namedlocation) {
        my @currnamed=();
        open($nameconf,"<",$namedlocation);
        @currnamed=<$nameconf>;
        close($nameconf);
        my $i = 0;
        for ($i=0;$i<scalar(@currnamed);$i++) {
            my $line = $currnamed[$i];
            if ($line =~ /^options +\{/) {
                $gotoptions=1;
                my $skip=0;
                do {
                    if ($ctx->{forwarders} and $line =~ /forwarders {/) {
                        push @newnamed,"\tforwarders \{";
                        $skip=1;
                        foreach (@{$ctx->{forwarders}}) {
                            push  @newnamed,"\t\t".$_."\n";
                        }
                    } elsif ($skip) {
                        if ($line =~ / };/) {
                            push @newnamed,"\t};";
                            $skip = 0;
                        }
                    } else {
                        push @newnamed,$line;
                    }
                    $i++;
                    $line = $currnamed[$i];
                } while ($line !~ /^\};/);
            } elsif ($line =~ /^zone "([^"]*)" in \{/) {
                my $currzone = $1;
                if ($ctx->{zonestotouch}->{$currzone} or $ctx->{adzones}->{$currzone}) {
                    $didzones{$currzone}=1;
                    push @newnamed,"zone \"$currzone\" in {\n","\ttype master;\n","\tallow-update {\n","\t\tkey xcat_key;\n";
                    my @list;
                    if ($ctx->{adzones}->{$currzone}) {
                        @list = @{$ctx->{dnsupdaters}};
                    } else {
                        @list = @{$ctx->{adservers}};
                    }
                    foreach (@list) {
                        push @newnamed,"\t\t$_\n";
                    }
                    push @newnamed,"\t};\n","\tfile \"db.$currzone\";\n","};\n";
                    while ($line !~ /^\};/) { #skip the old file zone
                        $i++;
                        $line =  $currnamed[$i];
                    }
                    $i++;
                } else {
                    push @newnamed,$line;
                }
            } elsif ($line =~ /^key xcat_key/) {
                $gotkey=1;
                if ($ctx->{privkey}) {
                    push @newnamed,"key xcat_key {\n","\talgorithm hmac-md5;\n","\tsecret \"".$ctx->{privkey}."\";\n","};\n";
                } else {
                    while ($line !~ /^\};/) { #skip the old file zone
                        if ($line =~ /secret \"([^"]*)\"/) {
                            my $passtab = xCAT::Table->new("passwd",-create=>1);
                            $passtab->setAttribs({key=>"omapi",user=>"xcat_key"},{password=>$1});
                        }
                        $i++;
                        $line =  $currnamed[$i];
                    }
                }
            }
        }
    }
    unless ($gotoptions) {
        push @newnamed,"options {\n","\tdirectory \"/var/named/\";\n";
        if ($ctx->{forwarders}) {
            push @newnamed,"\tforwarders {\n";
            foreach (@{$ctx->{forwarders}}) {
                push @newnamed,"\t\t$_;\n";
            }
            push @newnamed,"\t};\n";
        }
        push @newnamed,"};\n";
        open($nameconf,"<",$namedlocation);
    }
    unless ($gotkey) {
        unless ($ctx->{privkey}) { #need to generate one
            $ctx->{privkey} = encode_base64(genpassword(32));
        }
        push @newnamed,"key xcat_key {\n","\talgorithm hmac-md5;\n","\tsecret \"".$ctx->{privkey}."\";\n","};\n";
    }
    my $zone;
    foreach $zone (keys %{$ctx->{zonestotouch}}) {
        if ($didzones{$zone}) { next; }
        push @newnamed,"zone \"$zone\" in {\n","\ttype master;\n","allow-update {\n","\t\tkey xcat_key;\n";
        foreach (@{$ctx->{dnsupdaters}}) {
            push @newnamed,"\t\t$_\n";
        }
        push @newnamed,"\t};","\tfile \"db.$zone\";\n","};\n";
    }
    foreach $zone (keys %{$ctx->{adzones}}) {
        if ($didzones{$zone}) { next; }
        push @newnamed,"zone \"$zone\" in {\n","\ttype master;\n","allow-update {\n","\t\tkey xcat_key;\n";
        foreach (@{$ctx->{adservers}}) {
            push @newnamed,"\t\t$_\n";
        }
        push @newnamed,"\t};","\tfile \"db.$zone\";\n","};\n";
    }
    use Data::Dumper;
    print Dumper(@newnamed);
}
my $resolver = Net::DNS::Resolver->new;

my $key_name = 'xcat_key';
my $key = 'UlpPekE5Zmg0VzBsbTA2alZSRkxWMGRWTDZRckhJaHM=';
my $update = Net::DNS::Update->new('xcat.e1350');
$update->push(update => rr_add('foo.xcat.e1350 A 172.16.0.22'));
$update->sign_tsig($key_name,$key);
my $reply = $resolver->send($update);

use Data::Dumper;
process_request({node=>['bmc1','n1','switch1']});