Simple Pomodoro Timer

#!/usr/bin/env perl

# This script shows a countdown timer of 3 different values.
# It starts with a 25 minute countdown ($work countdown)
# At the end of 25 minutes notify-send is called to
# alert you that it's break time. A new countdown timer
# is started based on whether it's a long break or a
# short break.
# The type of break is determined by how many breaks
# have been taken. Every 4th break is 15min, otherwise
# it's 5min.
# https://en.wikipedia.org/wiki/Pomodoro_Technique

use Modern::Perl;
use IPC::System::Simple qw( systemx );

my $work_countdown  = 25*60; # in seconds
my $short_countdown = 5*60;
my $long_countdown  = 15*60;
my $break_tracker = 1;
$| = 1; # This ensures the countdown gets updated every second.

while (1) {
    countdown($work_countdown);

    if ($break_tracker % 4) {
        systemx('notify-send', 'long-break');
        countdown($long_countdown);
    }
    else {
        systemx('notify-send', 'short-break');
        countdown($short_countdown);
    }

    systemx('notify-send', 'back_to_work');
    $break_tracker++;
}

# This sub was adapted from code found at
# https://stackoverflow.com/questions/25835958/perl-countdown
sub countdown {
    my ($sec) = @_;
    my $beginTime = time;
    my $endTime = $beginTime + $sec;

    for (;;) {
        my $time = time;
        last if ($time >= $endTime);
        printf("\r%02d:%02d:%02d",
           0,
           ($endTime - $time) / 60 % ($sec),
           ($endTime - $time) % 60,
        );

        sleep(1);
    }
}


exit(0);