#!/usr/bin/perl
#
# multideb - compare package installation differences over
#            many machines remotely.
#
# example ~/.multideb.conf file:
#
#    servera port=2210 user=bob classes=web,db
#    serverb user=root classes=web
#    serverc user=root classes=web
#    serverd user=mysql classes=db
#    localhost classes=web
#
# Port 22 is the default.  User required unless servername is localhost.
#

use strict;
use Getopt::Long;
use Data::Dumper;

my $MD_DIR = ensure_dir("$ENV{'HOME'}/.multideb");

my %host;     # hostname -> {..., classes => { classname => 1 } }
my %classes;  # classname -> { hostname => 1 }
my %core;     # classname -> [ packagename, ... ]

my $opt_full = 0;
my $opt_core = 0;
help() unless GetOptions(
			 "full" => \$opt_full,
			 "core" => \$opt_core,
			 );

my $mode = shift @ARGV;

if ($mode eq "check")
{
    load_conf();
    my @pkgs =  @ARGV;
    my @hosts = sort keys %host;

    foreach my $host (@hosts) {
	my $h = $host{$host};
	parse_status($h);
    }

    foreach my $pkg (@pkgs) 
    {
	my %whowhat;
	foreach my $host (@hosts) {
	    my $h = $host{$host};
	    my $p = $h->{'pkg'}->{$pkg};
	    
	    my $status = status_of_package($p);
	    push @{$whowhat{$status}}, $host;
	}

	print "$pkg\n";
	foreach my $stat (sort keys %whowhat) {
	    print "  $stat: @{$whowhat{$stat}}\n";
	}
    }
    
    exit 0;
}

if ($mode eq "compare") 
{
    load_conf();
    my $class = shift @ARGV;
    my @hosts = sort keys %{$classes{$class}};

    unless (@hosts) {
	die "No matching '$class' hosts.\n";
    }

    my @comp_list;

    my %epkg;  # existing packages:  { name => 1 }
    foreach my $host (@hosts)
    {
	my $h = $host{$host};
	parse_status($h);
	foreach (keys %{$h->{'pkg'}}) {
	    $epkg{$_} = 1;
	}
    }
    
    if ($opt_core) {
	unless (defined $core{$class}) {
	    die "No core packages defined for class '$class'\n";
	}
	@comp_list = @{$core{$class}};
    } else {
	@comp_list = sort keys %epkg;
    }

    # iterate through all packages, showing differences:
    foreach my $pkg (@comp_list)
    {
	my %whowhat;
	my $installed = 0;
	foreach my $host (@hosts) {
	    my $h = $host{$host};
	    my $p = $h->{'pkg'}->{$pkg};

	    my $status = status_of_package($p);
	    push @{$whowhat{$status}}, $host;
	    
	    my ($sa, $sb, $sc) = split(/ /, $p->{'Status'});
	    if ($sc eq "installed") { $installed = 1; }
	}
	if ($installed && 
	    ($opt_full || scalar(keys %whowhat) > 1)) 
	{
	    print "$pkg\n";
	    foreach my $stat (sort keys %whowhat) {
		print "  $stat: @{$whowhat{$stat}}\n";
	    }
	}
    }

    exit 0;    
}

if ($mode eq "update") 
{
    load_conf();
    foreach my $host (sort keys %host)
    {
	my $h = $host{$host};
	my $user = $h->{'user'};
	my $port = $h->{'port'};

	print "$host...\n";
	if ($host eq "localhost") {
	    system("rsync", "/var/lib/dpkg/status",
		   "$MD_DIR/$host.status");
	} else {
	    system("rsync", "-e", "ssh -p $port", "-az", 
		   "$user\@$host:/var/lib/dpkg/status",
		   "$MD_DIR/$host.status");
	}
    }

    print "Done.\n";
    exit 0;
}

help();

sub status_of_package 
{
    my $p = shift;

    my $status = $p->{'Version'};
    if ($p->{'Status'} ne "install ok installed") {
	$status .= "/" if $status;
	$status .= "$p->{'Status'}";
    }
    $status ||= "(unknown)";

    return $status;
}

sub parse_status
{
    my $h = shift;
    my $fname = "$MD_DIR/$h->{'host'}.status";
    unless (-e $fname) {
	die "$fname doesn't exist.  Run update.\n";
    }
    open (F, $fname);
    while (<F>) {
	unless (/^Package: (.+)/) {
	    die "Corrupt $h->{'host'} status file?\n";
	}
	my $pkg = $1;
	my $p = $h->{'pkg'}->{$pkg} = {
	    'Package' => $pkg,
	};
	my $lastkey = 'Package';
	while (<F>) {
	    chomp;
	    unless ($_) { last; }
	    if (/^(\w+):\s*(.+)/i) {
		$p->{$1} = $2;
	    }
	}
    }
    close F;
}

sub help 
{
    die("Usage:\n".
	"    multideb update\n".
	"    multideb compare <classname>\n".
	"    multideb check <packagename> ...\n");
}

sub load_conf {
    open (C, "$ENV{'HOME'}/.multideb.conf");
    while (<C>)
    {
	s/^\s+//; s/\s+$//;
	next if (/^\#/);
	next unless $_;
	chomp;
	my ($p1, @opts) = split(/\s+/, $_);

	if ($p1 =~ /^core:(\w+)/) {
	    $core{$1} = [ @opts ];
	    next;
	}
	
	my $host = $p1;
	my $h = $host{$host} = { 
	    'host' => $host,
	    'port' => 22,
	};
	foreach (@opts) {
	    my ($k, $v) = split(/=/, $_);
	    if ($k eq "classes") {
		foreach (split(/,/, $v)) {
		    $h->{'classes'}->{$_} = 1;
		    $classes{$_}->{$host} = 1;
		}
	    } else {
		$h->{$k} = $v;
	    }
	}
    }
    close C;
}

sub ensure_dir {
    my $dir = shift;
    unless (-e $dir) {
	if (mkdir $dir) {
	    return $dir;
	} else {
	    die "Can't create $dir directory\n";
	}
    }
    unless (-w $dir) {
	die "Can't write to $dir directory\n";
    }
    return $dir;
}