#!/usr/bin/perl -w
##
# Make some pie graphics for the %ages of usage.
# We create a bunch of images for %ages 0-100, named
# "<dir>/<prefix><percent>.gif".
#
# The pie graphs are generated with a colour indicating the state.
# There are 3 colours - green, yellow, red - for good, ok, and bad.
# The thresholds are configurable, as is the ordering.
#
# Requires GD::Graph to provide the actual pies.
#
# History:
#
# 1.00 (12 May 2012) Initial version for rack state
# 1.01 (06 Jun 2012) Updated for ipv6 statistics
# 1.02 (11 Feb 2013) Genericised the pie generation
# 1.03 (12 Feb 2013) Added resampling and simple font labels,
#                    fixed thresholds and colours.
#
# @author Justin Fletcher
#

use Getopt::Long;
use Data::Dumper;
use GD::Graph::pie;
use GD::Text;
use GD;

my $dir = "imgs";
my $prefix = 'pie';
my $size = 24;
my $use3d = 0;
my $border = 'lgray';
my $fill = 'lgray';
my $label = 0;
my $resample = 0;
my $usefonts = 0;
my @colours = ( 'lgreen', 'lyellow', 'lred' );
my @thresholds = ( 80, 95, 101 );

GetOptions('dir=s'    => \$dir,
           'prefix=s' => \$prefix,
           'size=s'   => \$size,
           '3d'       => \$use3d,
           'border=s' => \$border,
           'fill=s'   => \$fill,
           'label'    => \$label,
           'thresholds=s' => sub {
                                # comma separated list
                                my ($arg, $val) = @_;
                                @thresholds = ( (split /,/, $val), 101 );
                             },
           'colours=s'  => sub {
                                # comma separated list
                                my ($arg, $val) = @_;
                                @colours = split /,/, $val;
                           },
           'reverse'  => sub { @colours = reverse @colours },
           'resample' => sub { $resample = 2; },
           'fonts'    => \$usefonts,
           'help'     => sub {
                            $" = ', '; # Magic: interpolate lists separated by commas
                            die <<EOM;
$0: Create some generic pie graphs for percentages.
Syntax: $0 <options>
Options:
    -dir <dir>          Directory to write to (default: $dir)
    -prefix <prefix>    Leafname prefix for files (default: $prefix)
    -thresholds <list>  Comma-separated list of colour threshold points
                        (default: @thresholds)
    -colours <list>     Comma-separated list of colours for pies below
                        thresholds (default: @colours)
    -reverse            Reverse the colour list
    -size <pixels>      Size of the pie (default: $size)
    -3d                 Whether the chart is 3D
                        (appears to break GD::Graph at some percentage)
    -border <colour>    Border colour (default: $border)
    -fill <colour>      Empty colour (default: $fill)
    -label              Enable labeling (increases the vertical size)
    -resample           Resample the image, making the edges smoother.
                        (this breaks the non-font rendered labels)
    -fonts              Use fonts in place of bitmap characters.
                        (may be unreliable)
EOM
}
          ) || exit 1;

my $font;
my $fontsize = 0;
if ($label)
{
    if ($size < 32)
    {
        $font = GD::Font->Tiny if (!defined $font);
        $fontsize = 8;
    }
    elsif ($size < 48)
    {
        $font = GD::Font->Small if (!defined $font);
        $fontsize = 12;
    }
    else
    {
        $font = GD::Font->Large if (!defined $font);
        $fontsize = 16;
    }
}

if ($resample)
{
    $size = $size * $resample;
    $fontsize = $fontsize * $resample;
}
my $fontpoint = $fontsize;

# Add the font paths (this might need modifying for your system)
if ($usefonts)
{
    my $fontroot = '/usr/share/fonts/truetype/';
    opendir(my $dh, $fontroot);
    my @fontpaths;
    for my $path (grep { !/^\./ } readdir($dh))
    {
        push @fontpaths, "$fontroot/$path";
    }
    closedir($dh);
    GD::Text->font_path( join ":", @fontpaths);
    $font = [ 'Arial', 'DejaVuSans', 'Vera' ];
    
    # Using a raw point height won't work; we need to make the size
    # of the font scale to the size we wanted.
    my $gd_text = GD::Text->new();
    $gd_text->set_font($font, $fontpoint);
    my $fontheight = $gd_text->get('height');
    if ($fontheight != $fontsize)
    {
        $fontpoint = $fontpoint / ($fontheight / $fontsize);
    }
}

for my $percent (0..100)
{
    my @data = ( [undef,undef],
                 [ $percent, 100-$percent ]
               );
    my $width = $size;
    my $height = $size + $fontsize;
    
    my $pie = new GD::Graph::pie( $width, $height );

    # Find the correct colour from our thresholds
    my $colour = 'white'; # Should never happen
    for my $index (0..$#colours)
    {
        if (defined $thresholds[$index] && 
            $percent < $thresholds[$index])
        {
            $colour = $colours[$index];
            last;
        }
    }

    $pie->set(  'dclrs'        => [ $colour,
                                    $fill
                                  ],
                'accentclr'    => $border,
                'transparent'  => 1,

                'l_margin'     => 0,
                'r_margin'     => 0,
                'start_angle'  => 180,
                '3d'           => $use3d,
                'pie_height'   => $use3d ? $height * 0.2 : 0,
                'text_space'   => 0,
                'label'        => $label ? $percent.'%' : undef,
             );
    if ($label)
    {
        $pie->set_label_font($font, $fontpoint);
    }
    
    $pie->plot( \@data );
    
    my $gd = $pie->gd;
    
    if ($resample)
    {
        # Create a new image to write into
        $dest = new GD::Image( $width / $resample, $height / $resample, 1 );
        # Make a background colour to fill with
        my $bg = $dest->colorAllocate(254,254,254);
        $dest->transparent($bg);
        $dest->filledRectangle(0,0, $width, $height, $bg);
        # Copy the image into it
        $dest->copyResampled($gd,
                             0, 0, # Dest x,y
                             0, 0, # Source x,y
                             $width / $resample, $height / $resample, # Dest width,height
                             $width, $height  # Source width, height
                            );
        # reduce to paletted, without dithering
        $dest->trueColorToPalette(0);
        # Our result is the one we write out.
        $gd = $dest;
    }
    
    # Save the images out
    open(my $fh, ">", "$dir/$prefix$percent.gif")
        || die "Cannot create pie: $!\n";

    binmode $fh;
    print $fh $gd->gif();
    close($fh);
}