#!/usr/bin/perl
use warnings;
use strict;
use feature 'say';

open my $IN, '<', '1.csv' or die $!;

my %groups;
while (<$IN>) {
    chomp;
    s/"//g;
    my ($group_id, $member, $group_descr) = split /;/;
    if (exists $groups{$group_id}) {
        die 'Invalid group description: '
                . "$group_descr != $groups{$group_id}{descr}\n"
            if $group_descr ne $groups{$group_id}{descr};
        die "Duplicate member $member in $group_id\n"
            if exists $groups{$group_id}{$member};
    } else {
        $groups{$group_id}{descr} = $group_descr;
    }

    undef $groups{$group_id}{member}{$member};
}

for my $group_id (keys %groups) {
    my $group = $groups{$group_id};
    say 'define hostgroup {';

    say "  hostgroup_name $group_id";

    $group->{descr} .= 's' if keys %{ $group->{member} } > 1;
    say "  alias          $group->{descr}";

    say '  members        ', join ',', keys %{ $group->{member} };

    say '}';
}