package Isanchez;
use strict;
use Carp;
our $VERSION = '0.01';

sub new {
    my ($class, $file) = @_;
    my $self = bless {}, $class;
    $self->_build($file);
    return $self;
}

sub _build {
    my ($self, $file) = @_;
    croak "Unable to retrieve data" unless open(INPUT,$file);
    while (<INPUT>) {
        my @field = split;
        unless (@field == 3 && $field[0] =~ /^\d+$/ && $field[0] =~ /^\d+/) {
            carp "Unable to parse\n$_";
            next;
        }
        $self->{$field[2]}{decendent} = $field[0];
        push @{$self->{decendents}[$field[1]]}, $field[2];
    }
}

sub get_decendents {
    my ($self, $origin) = @_;
    croak "You must enter an origin in the tree" unless $origin;
    croak "$origin can not be found" unless exists $self->{$origin};
    my $index = $self->{$origin}{decendent};
    my @list = @{$self->{decendents}[$index]} if exists $self->{decendents}[$index];
    return $origin unless @list;
    my @decendents = ($origin);
    while (@list) {
        push @decendents, @list;
        my @temp;
        for my $decendent (@list) {
            my $index = $self->{$decendent}{decendent};
            push @temp, @{$self->{decendents}[$index]} if exists $self->{decendents}[$index];
        }
        @list = @temp;
    }
    return join ', ' , @decendents;
}


#### Example Usage: ####

#!/usr/bin/perl -w
use strict;
use Isanchez;

my $family_tree = Isanchez->new('file.dat');
print $family_tree->get_decendents('dog'), "\n";

# Where file.dat looks like
__END__
1 0 domestic_animal
2 1 dog
3 2 terrier
4 2 collie
5 3 fox_terrier