#!/usr/bin/perl

use strict;
use warnings;

use Test::More tests => 24;
use Test::Exception;

BEGIN {
    use_ok('Moose');           
}

{
    package BankAccount;
    use Moose;
    
    has 'balance' => (isa => 'Num', is => 'rw', default => 0);

    sub deposit {
        my ($self, $amount) = @_;
        $self->balance($self->balance + $amount);
    }
    
    sub withdraw {
        my ($self, $amount) = @_;
        my $current_balance = $self->balance();
        ($current_balance >= $amount)
            || confess "Account overdrawn";
        $self->balance($current_balance - $amount);
    }

	package CheckingAccount;	
	use Moose;

 	extends 'BankAccount';
	
    has 'overdraft_account' => (isa => 'BankAccount', is => 'rw');	

	before 'withdraw' => sub {
		my ($self, $amount) = @_;
		my $overdraft_amount = $amount - $self->balance();
		if ($self->overdraft_account && $overdraft_amount > 0) {
			$self->overdraft_account->withdraw($overdraft_amount);
			$self->deposit($overdraft_amount);
		}
	};
}

my $savings_account = BankAccount->new(balance => 250);
isa_ok($savings_account, 'BankAccount');

is($savings_account->balance, 250, '... got the right savings balance');
lives_ok {
	$savings_account->withdraw(50);
} '... withdrew from savings successfully';
is($savings_account->balance, 200, '... got the right savings balance after withdrawl');

$savings_account->deposit(150);
is($savings_account->balance, 350, '... got the right savings balance after deposit');

{
    my $checking_account = CheckingAccount->new(
    							balance => 100,
    							overdraft_account => $savings_account
    						);
    isa_ok($checking_account, 'CheckingAccount');
    isa_ok($checking_account, 'BankAccount');

    is($checking_account->overdraft_account, $savings_account, '... got the right overdraft account');

    is($checking_account->balance, 100, '... got the right checkings balance');

    lives_ok {
    	$checking_account->withdraw(50);
    } '... withdrew from checking successfully';
    is($checking_account->balance, 50, '... got the right checkings balance after withdrawl');
    is($savings_account->balance, 350, '... got the right savings balance after checking withdrawl (no overdraft)');

    lives_ok {
    	$checking_account->withdraw(200);
    } '... withdrew from checking successfully';
    is($checking_account->balance, 0, '... got the right checkings balance after withdrawl');
    is($savings_account->balance, 200, '... got the right savings balance after overdraft withdrawl');
}

{
    my $checking_account = CheckingAccount->new(
    							balance => 100
    							# no overdraft account
    						);
    isa_ok($checking_account, 'CheckingAccount');
    isa_ok($checking_account, 'BankAccount');

    is($checking_account->overdraft_account, undef, '... no overdraft account');

    is($checking_account->balance, 100, '... got the right checkings balance');

    lives_ok {
    	$checking_account->withdraw(50);
    } '... withdrew from checking successfully';
    is($checking_account->balance, 50, '... got the right checkings balance after withdrawl');

    dies_ok {
    	$checking_account->withdraw(200);
    } '... withdrawl failed due to attempted overdraft';
    is($checking_account->balance, 50, '... got the right checkings balance after withdrawl failure');
}