#!/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;

use autodie;

use Filesys::Df;
use GD;
use Getopt::Std;
use Term::ANSIColor;

my @mounts;
my %opts;

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 bar_png {
	my ($percent, $w, $h) = @_;
	my $bar = GD::Image->new($w, $h);

	my $black = $bar->colorAllocate(  0,   0,   0);
	my $gray  = $bar->colorAllocate(127, 127, 127);
	my $lgray = $bar->colorAllocate(191, 191, 191);
	my $white = $bar->colorAllocate(255, 255, 255);

	my $vwidth = sprintf("%d", ($w- 2) * $percent / 100);

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

	return $bar;
}


sub show_df_console {
	my $mp_width = 0;

	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 %2.1f%% %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 = 40;
	my $h = @mounts * $spacing;
	my $w = 220;
	my $im = GD::Image->new($w, $h);

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

	$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, 10, $spacing * $i + 7, $mount->[1],
			$black);
		$im->string(gdSmallFont, $w - 46, $spacing * $i + 7,
			sprintf("%6s", format_size($mount->[4]->{'bavail'})), $black);
		$im->copy(bar_png($percent, $w - 20, 10), 10, $spacing * $i + 20, 0,
				0, $w - 20, 10);
	}

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

	return;
}

getopts('acg', \%opts);

open(my $mounts_fh, '<', '/proc/mounts');
while (my $line = <$mounts_fh>) {
	push(@mounts, [split(qr{ }, $line)]);
}
close($mounts_fh);

foreach my $mount (@mounts) {
	my ($device, $mountpoint, $type, $flags) = @{$mount};

	my $df_ref = df($mountpoint, 1);

	if (not defined $df_ref) {
		next;
	}

	$mount->[4] = $df_ref;
}

if (not $opts{'a'}) {
	@mounts = grep { $_->[0] !~ qr{ ^ ( (root|tmp)fs | none ) $ }x } @mounts;
}

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