#!/usr/bin/env perl

use strict;
use warnings;
use autodie;

use constant {
    VALUE => 0,
    DEFER => 1,
};

use JSON;

my $json_file = 'pm_11145036_parm_defaults.json';

my $par = decode_json(
    do { local $/; open my $fh, '<', $json_file; <$fh>; }
);

sub _get {
    my ($key) = @_;

    if (! defined $par->{$key}[VALUE]) {
        _get($par->{$key}[DEFER])
    }
    else {
        return $par->{$key}[VALUE];
    }
}

sub _set {
    my ($key, $value) = @_;

    if (! defined $par->{$key}[DEFER]) {
        warn "Can't change factory default: '$key'.\n";
    }
    else {
        $par->{$key}[VALUE] = $value;
    }

    return;
}

# Some examples of usage:

print 'margin-left = ', _get('margin-left'), "\n";
_set('margin-horizontal', 20);
print 'margin-left = ', _get('margin-left'), "\n";
_set('margin-left', 30);
print 'margin-left = ', _get('margin-left'), "\n";

print 'margin = ', _get('margin'), "\n";
_set('margin', 50);
print 'margin = ', _get('margin'), "\n";