#!/usr/bin/perl

use strict;

use FindBin;
use JSON qw/encode_json/;

my $hostinfo = require $FindBin::Bin . '/hosts.dat';

my $groups;
foreach my $host (keys %{$hostinfo})    {
    foreach my $role (@{$hostinfo->{$host}{roles}}) {
        $groups->{$role}++;
    }
}

my $inventory;

foreach my $role (keys %{$groups})  {
    $inventory->{$role}{hosts} = [];
    foreach my $host (keys %{$hostinfo})    {
        push(@{$inventory->{$role}{hosts}}, $host) if grep { $_ eq $role } @{$hostinfo->{$host}{roles}};
    }
}

foreach my $host (keys %{$hostinfo})    {
    $inventory->{_meta}{hostvars}{$host} = $hostinfo->{$host}{vars};
}

print encode_json($inventory);