#!/usr/bin/perl -w
use strict;

use Getopt::Long;
use Cwd qw(abs_path cwd);
use Digest::MD4;
use Digest::MD5;
use File::ExtAttr ':all';

&Getopt::Long::Configure('bundling');
&usage if !&GetOptions(
    'recurse|r' => \( my $recurse_opt ),
    'list|l' => \( my $list_opt ),
    'check|c' => \( my $check_opt ),
    'verbose|v+' => \( my $verbosity = 0 ),
    'help|h' => \( my $help_opt ),
);
&usage if $help_opt;

my $start_dir = cwd();

my @dirs = @ARGV;
@dirs = '.' unless @dirs;
foreach (@dirs) {
    $_ = abs_path($_);
}

$| = 1;

my $exit_code = 0;

my $md4 = Digest::MD4->new;
my $md5 = Digest::MD5->new;

while (@dirs) {
    my $dir = shift @dirs;

    if (!chdir($dir)) {
	warn "Unable to chdir to $dir: $!\n";
	next;
    }
    if (!opendir(DP, '.')) {
	warn "Unable to opendir $dir: $!\n";
	next;
    }

    my $reldir = $dir;
    $reldir =~ s#^$start_dir(/|$)# $1 ? '' : '.' #eo;
    print "$reldir ... " if $verbosity;

    my @subdirs;
    my $d_cnt = 0;
    my $need_newline = $verbosity;
    while (defined(my $fn = readdir(DP))) {
	next if $fn =~ /^\.\.?$/ || -l $fn;
	if (-d _) {
	    push(@subdirs, "$dir/$fn");
	    next;
	}
	next unless -f _;
	$d_cnt++;

	my($size,$mtime,$ctime) = (stat(_))[7,9,10];

	my $xsum4 = getfattr($fn, 'rsync.%md4');
	my $xsum5 = getfattr($fn, 'rsync.%md5');

	my $sum_count = 0;
	foreach ($xsum4, $xsum5) {
	    if (defined $_) {
		if (length($_) == 24) {
		    my($sz,$mt,$sum) = unpack('V2a16', $_);
		    if ($sz != ($size & 0xFFFFFFFF)
		     || $mt != ($mtime & 0xFFFFFFFF)) {
			$_ = undef;
		    } else {
			$_ = $sum;
			$sum_count++;
		    }
		} else {
		    $_ = undef;
		}
	    }
	}

	if ($list_opt) {
	    if ($need_newline) {
		print "\n";
		$need_newline = 0;
	    }
	    if (defined $xsum4) {
		print ' ', unpack('H32', $xsum4);
	    } else {
		print ' ' x (1 + 32);
	    }
	    if (defined $xsum5) {
		print ' ', unpack('H32', $xsum5);
	    } else {
		print ' ' x (1 + 32);
	    }
	    print $verbosity ? ' ' : " $reldir/";
	    print $fn, "\n";
	    next;
	}

	if ($check_opt) {
	    if (!$sum_count) {
		if ($need_newline) {
		    print "\n";
		    $need_newline = 0;
		}
		print ' ' x (1 + 32 + 1 + 32) if $verbosity > 2;
		print $verbosity ? ' ' : "$reldir/";
		print $fn, " MISSING\n";
		next;
	    }
	} else {
	    next if $sum_count == 2;
	    print 'UPDATING' if $need_newline && $verbosity == 1;
	}

	if ($need_newline && (!$check_opt || $verbosity > 1)) {
	    print "\n";
	    $need_newline = 0;
	}

	if (!open(IN, $fn)) {
	    print STDERR "Unable to read $fn: $!\n";
	    next;
	}

	my($sum4, $sum5);
	while (1) {
	    while (sysread(IN, $_, 64*1024)) {
		$md4->add($_);
		$md5->add($_);
	    }
	    $sum4 = $md4->digest;
	    $sum5 = $md5->digest;
	    print ' ', unpack('H32', $sum4), ' ', unpack('H32', $sum5) if $verbosity > 2;
	    print " $fn" if $verbosity > 1;
	    my($size2,$mtime2,$ctime2) = (stat(IN))[7,9,10];
	    last if $size == $size2 && $mtime == $mtime2 && $ctime == $ctime2;
	    $size = $size2;
	    $mtime = $mtime2;
	    $ctime = $ctime2;
	    sysseek(IN, 0, 0);
	    print " REREADING\n" if $verbosity > 1;
	}

	close IN;

	if ($check_opt) {
	    if ((!defined $xsum4 || $xsum4 eq $sum4) && (!defined $xsum5 || $xsum5 eq $sum5)) {
		print " OK\n" if $verbosity > 1;
		next;
	    }
	    if ($need_newline) {
		print "\n";
		$need_newline = 0;
	    }
	    if ($verbosity < 2) {
		print $verbosity ? ' ' : "$reldir/";
		print $fn;
	    }
	    print " FAILED\n";
	    $exit_code = 1;
	} else {
	    print "\n" if $verbosity > 1;
	    my $szmt = pack('V2', $size, $mtime); # 32-bits, may truncate
	    setfattr($fn, 'rsync.%md4', $szmt.$sum4);
	    setfattr($fn, 'rsync.%md5', $szmt.$sum5);
	    #utime $mtime, $mtime, $fn; # Set mtime if it changes.
	}
    }

    if ($need_newline) {
	if ($d_cnt) {
	    print "ok\n";
	} else {
	    print "empty\n";
	}
    }

    closedir DP;

    unshift(@dirs, sort @subdirs) if $recurse_opt;
}

exit $exit_code;

sub usage
{
    die <<EOT;
Usage: rsyncsums [OPTIONS] [DIRS]

Options:
 -r, --recurse     Update checksums in subdirectories too.
 -l, --list        List the checksums for each file (doesn't update).
 -c, --check       Check if the checksums are right (doesn't update).
 -v, --verbose     Mention what we're doing.  Repeat for more info.
 -h, --help        Display this help message.
EOT
}