#!/usr/bin/perl -wT

# Copyright (c) 2006 Anthony Towns <ajt@debian.org>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

use strict;
use Fcntl ':flock';
use File::Find;
use POSIX qw(strftime);

# configuration:

my $local_dir  = "/srv/ftp.debian.org/mirror";
my $rsync_host = undef; #"merkel.debian.org";
my $rsync_dir  = undef; #"debian";

my $dest       = "/srv/ftp.debian.org/rsync/typical";
my $max_del    = 1000;

$ENV{"PATH"} = "/bin:/usr/bin";

# program

my $hostname = `/bin/hostname -f`; 
die "bad hostname" unless $hostname =~ m/^([a-zA-Z0-9._-]+)/;
$hostname = $1;

my $lockfile = "./Archive-Update-in-Progress-$hostname";

unless (open LKFILE, "> $dest/$lockfile" and flock(LKFILE, LOCK_EX)) {
    print "$hostname is unable to start sync, lock file exists\n";
    exit(1);
}

if (defined $rsync_host && defined $rsync_dir) {
    system("rsync --links --hard-links --times --verbose --recursive"
           ." --delay-updates --files-from :indices/files/typical.files"
	   ." rsync://$rsync_host/$rsync_dir/ $dest/");
} else {
    open FILELIST, "< $local_dir/indices/files/typical.files"
        or die "typical.files index not found";
    while (<FILELIST>) {
        chomp;
        m/^(.*)$/; $_ = $1;
	my @l = lstat("$local_dir/$_");
	next unless (@l);

	if (-l _) {
	    my $lpath = readlink("$local_dir/$_");
	    $lpath =~ m/^(.*)$/; $lpath = $1;
	    if (-l "$dest/$_") {
		next if ($lpath eq readlink("$dest/$_"));
	    }

            unless (mk_dirname_as_dirs($dest, $_)) {
	        print "E: couldn't create path for $_\n";
	        next;
	    }

	    if (-d "$dest/$_") {
	        rename "$dest/$_", "$dest/$_.remove" or print "E: couldn't rename old dir $_ out of the way\n";
	    } elsif (-e "$dest/$_") {
	        unlink("$dest/$_") or print "E: couldn't unlink $_\n";
	    }
            symlink($lpath, "$dest/$_") or print "E: couldn't create $_ as symlink to $lpath\n";
	    next;
	}

        next if (-d _);

	unless (mk_dirname_as_dirs($dest, $_)) {
	    print "E: couldn't create path for $_\n";
	    next;
	}

	my @d = lstat("$dest/$_");
	if (@d) {
            if (-d _) {
                rename("$dest/$_", "$dest/$_.remove") or print "E: couldn't rename old dir $_ out of the way\n";
            } else {
	        next if (@l and @d and $l[0] == $d[0] and $l[1] == $d[1]);
	        #next if (@l and @d and $l[7] == $d[7]);
                print "I: updating $_\n";
                unlink("$dest/$_");
            }
	}

        link("$local_dir/$_", "$dest/$_") or print "E: couldn't link $_\n";
    }
    close(FILELIST);
}

print "Files synced, now deleting any unnecessary files\n";

my %expected_files = ();
open FILES, "< $dest/indices/files/typical.files" 
    or die "typical.files index not found";
while (<FILES>) {
    chomp;
    $expected_files{$_} = 1;
}
close(FILES);

chdir($dest);

my $del_count = 0;
my $last = '';
finddepth({wanted => \&wanted, no_chdir => 1}, ".");

open TRACE, "> $dest/project/trace/$hostname" or die "couldn't open trace";
print TRACE strftime("%a %b %e %H:%M:%S UTC %Y", gmtime) . "\n";
close TRACE;

close LKFILE;
unlink("$dest/$lockfile");
exit(0);

sub wanted  {
    my ($dev,$ino,$mode,$nlink,$uid,$gid) = lstat($_);
    if (-d _) {
        if (substr($last, 0, length($_) + 1) ne "$_/") {
	    print "Deleting empty directory: $_\n";
	    $_ = m/^(.*)$/;
	    my $f = $1;
            rmdir($f);
	} else {
	    $last = $_;
	}
    } elsif ($_ =~ m|^\./project/trace/| or $_ eq $lockfile) {
	$last = $_;
    } elsif (defined $expected_files{$_}) {
        $last = $_;
    } elsif ($del_count < $max_del) {
        $del_count++;
        print "Deleting file: $_\n";
	$_ = m/^(.*)$/;
	my $f = $1;
	unlink($f);
    }
}

sub mk_dirname_as_dirs {
    my ($base, $file) = @_;
    while ($file =~ m,^/*([^/]+)/+([^/].*)$,) {
        $file = $2;
	$base = "$base/$1";
        my @blah = lstat($base);
	if (!@blah) {
	    mkdir($base, 0777);
	} elsif (-l _ or ! -d _) {
	    print "SHOULD BE A DIRECTORY: $base\n";
	    unlink($base);
	    mkdir($base, 0777);
	}
    }
    1;
}