#!/usr/bin/perl -w
#######################################
# gdf - graphically display disk fullness
#######################################

use strict;
use diagnostics;
use Tk;

my $debug_on = 0;

use vars qw( $dfproc @disks @fs @capac @avail @fullness $bogus $percent @percents );

########################
# attempt to find Berkely-style df (with percentages) - this is where the displayed info
# comes from
########################
if ( -f "/usr/bin/bdf" ) 
    { $dfproc = "/usr/bin/bdf"; }
else  
    { $dfproc = "/bin/df"; }

if ($debug_on)
    { print "Using $dfproc\n"; }

my $pid = open( DFPIPE, "$dfproc |" );

my $idx = -1;

while (<DFPIPE>)
{
     if ( ! $_=~/%/ )
     {  die "Couldn't find Berkely-style `df' (with percentages)"; }
     chop;
     if ($idx >= 0)
     {
         ($disks[$idx],$capac[$idx],$bogus,$avail[$idx],$percent,$fs[$idx]) = split;
         $percents[$idx] = $percent;

         # convert percentage full to sweep of arc for pie chart
         chop $percent;
         $fullness[$idx] = $percent * 3.6;

         if ($debug_on)
         { print "$disks[$idx], $capac[$idx], $avail[$idx], $percent, $fullness[$idx], $fs[$idx]\n"; }
     }
     $idx++;
}

#######################################
# Create main window, frame, and canvas
#######################################
my $main = MainWindow->new;

$main->title('Graphical Disk Fullness');

my $w_frame = $main->Frame();

$w_frame->pack(-side => 'top', 
               -fill => 'y', 
               -expand => 'yes');

my $fullheight = ($idx * 3) + 3.2 . 'c';

my $canvas = 
     $w_frame->Canvas( -scrollregion => ['0c', '0c', '12.1c', $fullheight ],
                       -width => '12.1c', -height => '6c',
                       -relief => 'sunken',
                       -bd => 2 );

$canvas->pack(-expand => 'yes', 
              -side => 'left',
              -fill => 'y');


my $w_frame_vscroll = $w_frame->Scrollbar(-command => [$canvas => 'yview']);

$canvas->configure( -yscrollcommand => [$w_frame_vscroll => 'set']);

$w_frame_vscroll->pack(-side => 'right', -fill => 'y');

#######################################
# Begin populating the canvas with interesting stuff.
#######################################

use vars qw( $fullpart $emptypart $startpoint $x1 $y1 $x2 $y2 );
my $num_disks = $idx - 1;
my $yoffset = 3;

$x1 = 0.5;
$x2 = 4;

# iterate through all disks 
foreach $idx (0..$num_disks)
{
    # compute arc empty/full proportions
    $fullpart = $fullness[$idx];
    $startpoint = $fullpart;
    $emptypart = 360 - $fullness[$idx];

    if ($debug_on)
    { print "Full: $fullpart  Empty: $emptypart\n"; }

    #compute Y positioning for framing rect.
    $y1 = ($idx * $yoffset) + 0.2;
    $y2 = ($idx * $yoffset) + 2.2 + 1;
   
    # draw framing rectangle
     $canvas->create(("rect", "0.1c", $y1 . 'c', "12c", $y2 . 'c'), -width => 1); 

    #compute Y positioning for pie chart
    $y1 = ($idx * $yoffset) + 0.6 + 0.6;
    $y2 = ($idx * $yoffset) + 2.15 + 0.6;
   
    # shadow oval beneath chart     # 0.5c 0.6c 4c 2.15c
    $canvas->create(("arc", $x1 . 'c', $y1 . 'c', $x2 . 'c', $y2 . 'c'), 
             -fill => "#000000", 
             qw(-outline black -start 0 -extent 359 -style pieslice -tags item));
    
    #compute Y positioning for pie chart
    $y1 = ($idx * $yoffset) + 0.5 + 0.6;
    $y2 = ($idx * $yoffset) + 2 + 0.6;
    
    # arc representing full part    # 0.5c 0.5c 4c 2c
    $canvas->create(("arc", $x1 . 'c', $y1 . 'c', $x2 . 'c', $y2 . 'c'), 
             -fill => "red", qw(-outline black -start 0 ), 
             -extent => $fullpart-1, -style => "pieslice", -tags => "item");
    
    # arc representing empty part   # 0.5c 0.5c 4c 2c
    $canvas->create(("arc", $x1 . 'c', $y1 . 'c', $x2 . 'c', $y2 . 'c'), 
             -fill => "green", qw(-outline black),
             -start => $startpoint, -extent => $emptypart, -style => "pieslice", -tags => "item");

    $debug_on and print "$disks[$idx], $capac[$idx], $avail[$idx], $percent, $fullness[$idx], $fs[$idx]\n";

    ################################
    # print accompanying information
    ################################
    $y1 = ($idx * $yoffset) + 0.6;
    $canvas->create(( "text", "1c", $y1 . 'c'), 
             -text => "DISK: $disks[$idx]", 
             -anchor => "w");
    $canvas->create(( "text", "6c", $y1 . 'c'), 
             -text => "Filesystem: $fs[$idx]", 
             -anchor => "w");
    $y1 = ($idx * $yoffset) + 1.1;
    $canvas->create(( "text", "6c", $y1 . 'c'), 
             -text => "Capacity:   $capac[$idx] KB", 
             -anchor => "w");
    $y1 = ($idx * $yoffset) + 1.6;
    $canvas->create(( "text", "6c", $y1 . 'c'), 
             -text => "Available:  $avail[$idx] KB", 
             -anchor => "w");
    $y1 = ($idx * $yoffset) + 2.1;
    $canvas->create(( "text", "6c", $y1 . 'c'), 
             -text => "Usage is $percents[$idx]", 
             -anchor => "w");
}

# put the "Dismiss" button at the bottom
my $btn_frame = $main->Frame();

$btn_frame->pack(-side => 'bottom', -fill => 'x', -expand => 'no');
#                This is VERY important           ^^^^^^^^^^^^^^^

my $w_dismiss = $btn_frame->Button( -text => 'Dismiss',
      -command => [$main => 'destroy']);

$w_dismiss->pack(-side => 'bottom', -fill => 'x', -expand => 1);

$main->resizable( 0,1 );

MainLoop;