source: client/bin/gbrm

#!/usr/bin/perl

# This script was largely written by Jessica Hamrick (jhamrick), with
# help from Kyle Brogle (broglek)

use strict;
use warnings;

use Net::CUPS;
use Net::CUPS::Destination;
use Getopt::Long;

# usage
my $usage = <<USAGE;
Usage: gbq [options] [-q QUEUE] ID

        -q, --queue             Specify a queue other than the default
        -h, --help              Print this message
USAGE

# initialize the variables for the options
my $q = "";
my $help = 0;

# parse the options
GetOptions ('q|queue=s' => \$q,
            'h|help', => \$help);

# if the -h flag was passed, then print the usage and exit
if ($help) {
    print $usage;
    exit 0;
}

my @ids = @ARGV[0 .. $#ARGV];

# if the -q option is not specified, then assume we're using the
# default queue
if (!$q) {
    $q = "DEFAULT";
}

# if there are no ids specified to remove, then print the usage
if (!@ids) {
    print $usage;
    exit 1
}

# set configuration path, and complain if it doesn't exist
my $configpath = "$ENV{'HOME'}/.gutenbach/$q";
if (! -e $configpath) {
    print "Queue '$q' does not exist!  Did you forget to add it with 'gutenbach-client-config'?\n";
    exit 1;
}

# initialize the host and queue variables: host holds the address for
# the machine on which the remote queue runs, and queue holds the name
# of the printer
my ($host, $queue);

# load the configuration file (this will set $host and $queue)
if (-r $configpath) {
    local $/;
    my $fh;
    open $fh, $configpath;
    eval <$fh>;
}

# initialize a new CUPS session
my $cups = Net::CUPS->new();
# set the server to the one specified in the config file
$cups->setServer("$host");
# set the printer name to the one specified in the config file
my $printer = $cups->getDestination("$queue");

# if $printer is not defined, then throw an error
unless( $printer){
    print "Cannot access queue $q...do you have network connectivity and permission to view the queue?\n";
    exit 1;
}

# get the list of jobs from the printer
my @jobs = $printer->getJobs(0, 0);

# for each id that we want to remove
foreach my $id(@ids){

    # if the id is 'all', then we remove all jobs
    if ($id eq "all") {
        foreach $id(@jobs) {
            cancel_job($id, $printer);
        }
    }

    # if the id is 'current', then we remove just the currently
    # playing job
    elsif ($id eq "current") {
        $id = $jobs[0];
        cancel_job($id, $printer);
    }

    # if the id is 'last', then we remove just the last job
    elsif ($id eq "last") {
        $id = $jobs[-1];
        cancel_job($id, $printer);
    }

    # otherwise, remove the job based on its actual (numeric) id
    else {
        foreach my $item(@jobs) {
            if($item =~ /$id/){
                cancel_job($item, $printer);
            }
        }
    }
}

# helper function to remove a job
sub cancel_job {
    # get the id and printer from the arguments
    my ($id, $printer) = @_;
    # get the reference to the job
    my $job_ref = $printer->getJob($id);
    # find the job title (so we can print it out for the user)
    my $title = $job_ref->{'title'};
    # cancel the job
    $printer->cancelJob($id);

    # print out that we canceled the job
    print "Canceled job '$title' (id $id)\n";
}