#!/usr/bin/env perl
#    I'm just assuming the above line works...?

# This program presents a list of hard-coded hostnames to the user and lets them ssh to one by choosing it's number
# ^^ give love to da maintenance programmer

use strict; # Good!!
use warnings; # Better!!

# It's good practice to identify your globals by making them upper-case
our $USER = 'brannont';
our @HOSTS = qw(
          secdevfdsapp01
          dopey
          bonnie
         ) ;

# Use full path of program for exec to avoid security issues
our $SSH_PROGRAM = '/usr/bin/ssh';

# Moved the main program execution up here so the maintenance programmer doesn't have to read the whole program to see what it does...

our $SSH_ARGS = &get_ssh_args();
print $SSH_ARGS, "\n" ;

exec $SSH_PROGRAM, $SSH_ARGS;

# Gets the selected hostname from the user and returns
# the arguments we'll need to pass to the 'ssh' command
sub get_ssh_args {
  my $chosen_hostname = &choose_host();
  return &ssh_string($chosen_hostname) ;
}

# For a given host, return the ssh arguments to allow us to
# login as a hard-coded user on that host
sub ssh_string {
  my $host = shift;
  # Suggest also appending your domain here:
  return &username() . "@" . $host . &domain();
  # 'Programming Perl' suggests avoiding use of printf()
  # sprintf "%s@%s", $user, $host
}

# Prints the list of hosts with numbers in front to allow
# user to make a selection
sub printchoices {
  print "\n\n",
        "ssh hosts\n",
        "---------\n";
  for (my $i=0; $i < &num_hosts(); ++$i) {
    print "[$i] ", &hostname_by_num($i), "\n" ;
  }
}

# prints a prompt for user input
sub prompt {
  return "\n\nssh to: " ;
}

# Gets the user's chosen host
sub getchoice {
  print &prompt();
  my $choice = <STDIN> ;
  chomp $choice;
  return $choice;
}

# Get the user's chosen host (by number) or die trying
# renamed from 'mainloop'
sub choose_host {
  my $chosen_host;
  while ( !$chosen_host ) {
    &printchoices();
    my $user_choice = &getchoice();
    if( ($user_choice =~ /^\d+$/) && 
        ($user_choice >= 0) && 
        ($user_choice < &num_hosts()) ) {
      $chosen_host = $user_choice;
    }
  }
  # May as well dereference the name here...
  return &hostname_by_num($chosen_host);
}

# These three functions are simple lookups to the globals 
# now, but in the future they can be expanded
sub num_hosts { return scalar(@HOSTS); }
sub hostname_by_num { return $HOSTS[ $_[0] ]; }
sub username { return $USER; }

# In the future, this could return our domain
# eg. ".example.com", possibly from a global
sub domain { return ""; }