#! /usr/bin/perl

#   Copyright (c) 2016  Joey Schulze <joey@infodrom.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.
#
#   You should have received a copy of the GNU General Public License
#   along with this program; if not, write to the Free Software
#   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA

use strict;
use warnings;

use File::Copy;
use File::Path;
use File::DirCompare;
use Getopt::Long;

my $opt_dry_run;
my $opt_verbose;
my $opt_source;
my $opt_destination;

my @mirrordirs;

sub help
{
    print <<EOT;
mirrordir options sourcdir destdir

Options
--help|-h         This help
--verbose|-v      Verbose output
--dry-run         Don\'t actually mirror

EOT
    exit;
}

sub assert_directory
{
    my $dir = shift;
    return 1 if -d $dir;

    mkpath $dir;
}

sub copy_file
{
    my $src = shift;
    my $dst = shift;

    return unless -f $src;

    my $pos = rindex $dst, '/';
    assert_directory substr $dst, 0, $pos if $pos > 1;

    if (!copy $src, $dst) {
	printf STDERR "copy %s %s failed\n", $src, $dst;
	return;
    }

    my @stat_src = stat $src;
    my @stat_dst = stat $dst;

    if ($stat_src[7] != $stat_dst[7]) {
	printf STDERR "copy %s %s failed (size mismatch)\n", $src, $dst;
	return;
    }

    utime $stat_src[9], $stat_src[9], $dst;
}

sub compare_process_item
{
    my $a = shift;
    my $b = shift;

    if (! $b) {
	my $dst = $opt_destination . substr($a, length $opt_source);

	if (-d $a) {
	    printf "mirror %s %s\n", $a, $dst if $opt_verbose;
	    push @mirrordirs, [$a, $dst] unless $opt_dry_run;
	} else {
	    printf "copy %s %s\n", $a, $dst if $opt_verbose;
	    copy_file $a, $dst unless $opt_dry_run;
	}
    } elsif (! $a) {
	if (-d $b) {
	    printf "rmdir %s\n", $b if $opt_verbose;
	    rmtree $b unless $opt_dry_run;
	} else {
	    printf "delete %s\n", $b if $opt_verbose;
	    unlink $b unless $opt_dry_run;
	}
    } else {
	if (-f $a && -f $b) {
	    printf "copy %s %s\n", $a, $b if $opt_verbose;
	    copy_file $a, $b unless $opt_dry_run;
	} elsif (-d $b) {
	    printf "rmdir %s\n", $b if $opt_verbose;
	    rmtree $b unless $opt_dry_run;

	    printf "copy %s %s\n", $a, $b if $opt_verbose;
	    copy_file $a, $b unless $opt_dry_run;
	} elsif (-d $a) {
	    printf "delete %s\n", $b if $opt_verbose;
	    unlink $b unless $opt_dry_run;

	    my $pos = rindex $b, '/';
	    my $relpath = substr($b, $pos);
	    printf "mirror %s %s\n", $opt_source.$relpath, $opt_destination.$relpath if $opt_verbose;
	    push @mirrordirs, [$opt_source.$relpath, $opt_destination.$relpath] unless $opt_dry_run;
	}
    }
}

sub mirror_directory
{
    assert_directory $opt_destination;
    File::DirCompare->compare($opt_source, $opt_destination, \&compare_process_item);
}

sub mirror_directories
{
    mirror_directory;

    while (my $item = shift @mirrordirs) {
	$opt_source = $item->[0];
	$opt_destination = $item->[1];
	mirror_directory;
    }
}

GetOptions (
    'help|h' => \&help,
    'verbose|v' => \$opt_verbose,
    'dry-run|dryrun' => \$opt_dry_run,
);

die "Not enough parameters\n" unless scalar @ARGV == 2;

$| = 1;

$opt_source = $ARGV[0];
$opt_destination = $ARGV[1];

mirror_directories;