#! /usr/bin/perl -w

use strict;
use warnings;

my %people = (
    jim    => ['betty',  'claire'],
    betty  => ['frank',  'jim'   ],
    frank  => ['claire', 'john'  ],
    claire => ['john',   'betty' ],
    john   => ['jim',    'frank' ],
    nancy  => ['',       ''      ],             # new girl
);

my @allPeople = sort keys %people;
my %recipients;
@recipients{@allPeople}=undef;

srand; # randomize!
foreach (@allPeople)
{	
	my @remainingPeople = keys %recipients;
	my $randPerson;
	my $iterations;
	do
	{
		$randPerson = $remainingPeople[int (rand ($#remainingPeople))];
		$iterations++;
		die ("ERROR: Failed to generate list\n") unless ($iterations <$#allPeople);
	} until (testRecipient($_, $randPerson));
	
	print "$_ can give to $randPerson\n";
	delete $recipients {$randPerson};
}

sub testRecipient
{
	my ($santa, $recipient) = @_;
	my $arrayref = $people{$santa};

	# test for self giving
	return 0 if ($santa eq $recipient);
	
	#test for giving to the given
	foreach (@$arrayref){
		return 0 if ($_ eq $recipient);
	}
	return 1;
}