#!/usr/bin/env perl
## Copyright © 2010 by Daniel Friesel <derf@finalrewind.org>
## License: WTFPL <http://sam.zoy.org/wtfpl>
##   0. You just DO WHAT THE FUCK YOU WANT TO.
use strict;
use warnings;
use 5.010;

no if $] >= 5.018, warnings => "experimental::smartmatch";

use autodie;

use Derf::Visual 'GD_bar';
use Filesys::Df;
use GD;
use Getopt::Std;
use Term::ANSIColor;

my @mounts;
my %opts;
my $alpha;

sub format_size {
	my ($bytes) = @_;
	my @postfix = (' ', 'k', 'M', 'G', 'T');

	while ($bytes > 1000) {
		$bytes /= 1000;
		shift @postfix;
	}

	return sprintf('%3.1f%s', $bytes, $postfix[0]);
}

sub bar_console {
	my ($percent, $width) = @_;
	my $vlen = sprintf("%d", $width * $percent / 100);

	return sprintf(
		'[%s%s]',
		'=' x ($vlen),
		' ' x ($width - $vlen),
	);
}


sub show_df_console {
	my $mp_width = 10;

	foreach my $mount (@mounts) {
		my $this_width = length($mount->[1]);
		if ($this_width > $mp_width) {
			$mp_width = $this_width;
		}
	}

	my $h_format = "%-${mp_width}s %6s %6s %6s %4s%% %20s %s\n";
	my $l_format = "%-${mp_width}s %6s %6s %6s %04.1f%% %20s %s\n";

	print color('yellow');
	printf(
		$h_format,
		qw{Mountpoint Size Used Avail Use},
		q{},
		q{Filesystem},
	);
	print color('reset');

	foreach my $mount (@mounts) {

		# $mount->[4]->{'per'} (provided by Filesys::Df) is inaccurate
		my $percent = $mount->[4]->{'used'} * 100 / $mount->[4]->{'blocks'};

		printf(
			$l_format,
			$mount->[1],
			format_size($mount->[4]->{'blocks'}),
			format_size($mount->[4]->{'used'}),
			format_size($mount->[4]->{'bavail'}),
			$percent,
			bar_console($percent, 18),
			$mount->[0],
		);
	}

	return;
}

sub show_df_png {
	my $spacing = 32;
	my $h = @mounts * $spacing;
	my $w = 200;
	my $offset_left = 5;
	my $offset_top = 3;
	my $offset_right = 5;
	my $offset_free = $w - $offset_right - (6 * 6);
	my $bar_width = $w - $offset_left - $offset_right;
	my $bar_height = 10;
	my $bar_top = $offset_top + 13;
	my $im = GD::Image->new($w, $h);

	my $black = $im->colorAllocateAlpha(  0,   0,   0, $alpha);
	my $gray  = $im->colorAllocateAlpha(127, 127, 127, $alpha);
	my $lgray = $im->colorAllocateAlpha(191, 191, 191, $alpha);
	my $white = $im->colorAllocateAlpha(255, 255, 255, $alpha);

	$im->rectangle(0, 0, $w - 1, $h - 1, $gray);
	$im->filledRectangle(1, 1, $w - 2, $h - 2, $white);

	for my $i (0 .. $#mounts) {

		my $mount = $mounts[$i];
		my $percent = $mount->[4]->{'used'} * 100 / $mount->[4]->{'blocks'};

		$im->string(gdSmallFont, $offset_left, $spacing * $i + $offset_top,
			$mount->[1], $black);

		$im->string(gdSmallFont, $offset_free, $spacing * $i + $offset_top,
			sprintf("%6s", format_size($mount->[4]->{'bavail'})), $black);

		$im->copy(GD_bar(
				width => $bar_width,
				height => $bar_height,
				alpha => $alpha,
				percent_filled => $percent,
				lined => 6,
			),
			$offset_left, $spacing * $i + $bar_top, 0, 0, $bar_width,
			$bar_height);
	}

	open(my $out_fh, '>', '/tmp/vdf.png');
	binmode $out_fh;
	print $out_fh $im->png();
	close($out_fh);

	return;
}

getopts('Aa:cfgi:', \%opts);
$alpha = $opts{'a'} // 0;

open(my $mounts_fh, '<', '/proc/mounts');
while (my $line = <$mounts_fh>) {
	my ($device, $mountpoint, $type, $flags) = split(qr{ }, $line);
	my $df_ref = df($mountpoint, 1);

	if (not defined $df_ref) {
		next;
	}

	push(@mounts, [
		$device,
		$mountpoint,
		$type,
		$flags,
		$df_ref
	]);
}
close($mounts_fh);

if (not $opts{'A'}) {
	@mounts = grep { $_->[0] !~ qr{ ^ ( (root|tmp)fs | none ) $ }x } @mounts;
}
if ($opts{'i'}) {
	my @ignored = split(qr{,}, $opts{'i'});
	@mounts = grep { not ($_->[1] ~~ [@ignored]) } @mounts;
}

if ($opts{'c'}) {
	show_df_console();
}
elsif ($opts{'g'}) {
	show_df_png();
}

if ($opts{'f'}) {
	exec('feh', '/tmp/vdf.png');
}

__END__

=head1 NAME

=head1 SYNOPSIS

=head1 DESCRIPTION

=head1 OPTIONS

=head1 EXIT STATUS

=head1 CONFIGURATION

=head1 DEPENDENCIES

=head1 BUGS AND LIMITATIONS

=head1 AUTHOR

Copyright (C) 2010 by Daniel Friesel E<lt>derf@finalrewind.orgE<gt>

=head1 LICENSE

  0. You just DO WHAT THE FUCK YOU WANT TO.