#!/usr/bin/env perl
use warnings;
use strict;  

use version ; our $VERSION = 'v1.2.0';

# Disk usage for Unix system
# Author: R. W. Rodolico
# Date:   2016-04-08
#
# gets information on disks and partitions. Returns them as a hash
# uses standard df -kT and parses the output
# skips anything that does not have a device with /dev in it
# assumes the structure of the output is:
# device fstype size usedSpace availableSpace percentSpace mountPoint
# however, the output can sometimes wrap to multi lines, especially if the 
# device is long. So, we will replace all newlines with spaces, then 
# remove space duplications, then split on spaces and process each item in
# turn.
# NOTE: this will totally break if you have spaces in your mount point
#
# Revision History
#

# find our location and use it for searching for libraries. library.pm must be in the same directory as the calling script
# or, if run interactively, in the parent of the modules
BEGIN {
   use FindBin;
   use File::Spec;
   # prepend the bin directory and its parent
   use lib File::Spec->catdir($FindBin::Bin), File::Spec->catdir("$FindBin::Bin/..");
   eval( 'use library;' );
   die sprintf( "Could not find library.pm in %s, INC is %s\n", __FILE__, join( "\n", @INC ) ) if $@;
}

#####
##### Change these to match your needs
#####

# Make this a list of all the modules we are going to use. You can replace undef with the version you need, if you like
my $modulesList = {
        'Data::Dumper'     => undef,
   };

# hash of commands that are needed for the system. key is the name of the command and, in some cases, the value will become
# the full path (from which or where)
my $commandsList = {
        'df' => undef,
   };

# list of operating systems this module can be used on.
my $osList = {
#         'mswin32' => undef,
         'freebsd' => undef,
         'linux'   => undef,
   };

# the category the return data should go into. See sysinfo for a list
my $CATEGORY = 'diskinfo';

#####
##### End of required
#####

# some variables needed for our system
my $errorPrepend = 'error: in ' . __FILE__; # this is prepended to any error messages
my @out; # temporary location for each line of output

# Try to load the modules we need. If we can not, then make a list of missing modules for error message.
for my $module ( keys %$modulesList ) {
   eval ( "use $module;" );
   push @out, "$errorPrepend Could not load $module" if $@;
}

if ( ! @out && ! checkOS ( $osList ) ) { # check if we are on an acceptible operating system
    push @out, "$errorPrepend Invalid Operating System";
}
if ( !@out && ! validCommandOnSystem ( $commandsList ) ) {
   push @out, "$errorPrepend Can not find some commands needed";
}
if ( !@out ) { # we made it, we have everything, so do the processing
   #####
   ##### Your code starts here. Remember to push all output onto @out
   #####
   
   # process physical partitions
   my $temp = qx/df -kT/; # execute the system command df, returned values in kilobytes, showing file system types
   my @temp = split("\n", $temp ); # get array of lines
   shift @temp; # get rid of the first line . . . it is nothing but header info
   $temp = join( ' ', @temp ); # rejoin everything back with spaces
   $temp =~ s/ +/ /gi; # remove all duplicate spaces
   @temp = split( ' ', $temp ); # turn it back into an array of space separated values
   while (@temp) {
      my $device = shift @temp; # get the device name
      my $output = '';
      $output .=  "$CATEGORY\t$device\tfstype\t" . (shift @temp) . "\n"; # next is fs type
      $output .=  "$CATEGORY\t$device\tsize\t" . (shift @temp) . "\n"; # total partition size, in k
      $output .=  "$CATEGORY\t$device\tused\t" . (shift @temp) . "\n"; # disk usage, in k
      shift @temp; # $available, not recorded
      shift @temp; # $percent, not recorded
      $output .=  "$CATEGORY\t$device\tmount\t" . (shift @temp) . "\n"; # mount point
      # now, if it is a /dev device, we add it to the diskInfo hash
      push @out, $output if $device =~ m/\/dev/;
   }
   
   #####
   ##### Your code ends here.
   #####
}

# If we are testing from the command line (caller is undef), print the results for debugging
print join( "\n", @out ) . "\n" unless caller;
# called by do, which has a value of the last assignment made, so make the assignment. The equivilent of a return
my $return = join( "\n", @out );