package Employee {
    use Moo; # loads strict and warnings and provides new()

    has name => (is => 'ro');
    has [qw/wage hours/] => (is => 'rw');
};

package Employees {
    use Employee;
    use Moo;
    use namespace::clean;

    has _db => ( # code can be swapped later when there is a real DB
        is      => 'rwp',
        default => sub { +{} },
    );

    sub add {
        my $self = shift;
        my $args = shift; # argument validation needed here

        $self->_db->{ $args->{name} } = $args;
    }

    sub find {
        my $self = shift;
        my $name = shift; # argument validation needed here

        my $record = $self->_db->{ $name } or die "$name not found";

        return Employee->new(
            name  => $name,
            wage  => $record->{wage},
            hours => $record->{hours},
        );
    }

    sub avg_hourly_wage {
        my $self = shift;

        my ($total_hours, $total_wages);

        for my $name (keys %{ $self->_db }) {
            $total_hours += $self->_db->{ $name }{hours};
            $total_wages += $self->_db->{ $name }{wage} * $self->_db->{ $name }{hours};
        }

        return sprintf('%d.2', $total_wages / $total_hours);
    }

    sub pay_change_for {
        my $self     = shift;
        my $employee = shift;
        my $new_wage = shift;

        $employee->wage($new_wage);

        $self->_db->{ $employee->name }->{wage} = $new_wage;
    }
};

#------------------------------------#
use strict;
use warnings;
use feature 'say';

use Employee;
use Employees;

my $employees = Employees->new;

for my $line (<DATA>) {
    chomp $line;
    my ($name, $wage, $hours) = split /,/, $line;

    $employees->add({
        name  => $name,
        wage  => $wage,
        hours => $hours,
    });
}

say 'Query for an employee: ';

chomp( my $name = <STDIN> );

my $employee = $employees->find($name);

say sprintf('%s earns %s for %s hours', map { $employee->$_ } qw/name wage hours/);

say 'The average hourly wage overall is ' . $employees->avg_hourly_wage;

say "Give $name a raise? Enter new wage or 'No'";

chomp( my $answer = <STDIN> );

if ($answer =~ /^\d+$/) {
    $employees->pay_change_for($employee, $answer);
} else {
    say 'No change';
}

say 'The average hourly wage overall is now ' . $employees->avg_hourly_wage;

__DATA__
Fred Flinstone,10,40
Barney Rubble,8,40
Dino Flintstone,15,40
Bam-Bam Rubble,5,12
Mr. Slate,65,32