package IMPL::Config::ServiceDescriptor;
use strict;

use IMPL::lang qw(:base);
use IMPL::Exception();
use IMPL::declare {
	require => {
		Bag                 => 'IMPL::Config::Bag',
		ActivationException => 'IMPL::Config::ActivationException'
	},
	base => [
		'IMPL::Object'             => undef,
		'IMPL::Config::Descriptor' => undef
	],
	props => [
		type       => 'ro',
		activation => 'ro',
		args       => 'ro',
		services   => 'ro',
		_name      => 'rw',
		_loaded    => 'rw'
	]
};

sub CTOR {
	my ( $this, %opts ) = @_;

	$this->type( $opts{type} )
	  or die IMPL::InvalidArgumentException->new('type');

	$this->activation(
		IMPL::Config::Descriptor::ParseActivation( $opts{activation} ) );
	$this->args( $opts{args} )         if exists $opts{args};
	$this->services( $opts{services} ) if exists $opts{services};

	$this->_name( 'new {'
		  . IMPL::Config::Descriptor::ActivationToString( $this->activation )
		  . '} '
		  . $this->type );
}

sub Activate {
	my ( $this, $context ) = @_;

	my $instance;
	$context->GuardScope(
		$this->_name,
		$this->services,
		sub {

			my $activation = $this->activation;
			my $cache;

			if ( $activation == IMPL::Config::Descriptor::ACTIVATE_SINGLETON ) {
				$cache = $context->container->root->instances;
			}
			elsif (
				$activation == IMPL::Config::Descriptor::ACTIVATE_CONTAINER )
			{
				$cache = $context->container->instances;
			}
			elsif ( $activation == IMPL::Config::Descriptor::ACTIVATE_CONTEXT )
			{
				$cache = $context->instances;
			}

			$instance = $cache->{ ref($this) } if $cache;
			unless ($instance) {
				$instance = $this->CreateInstance($context);
			}

			$cache->{ ref($this) } = $instance if $cache;
		}
	);

	return $instance;
}

sub CreateInstance {
	my ( $this, $context ) = @_;

	my $class = $context > container->Require( $this->type );

	my $args = $this->args ? $this->args->Activate($context) : undef;

	if ( defined $args ) {
		if ( isarray($args) ) {
			return $class->new(@$args);
		}
		elsif ( ishash($args) ) {
			return $class->new(%$args);
		}
		else {
			return $class->new($args);
		}
	}
	else {
		return $class->new();
	}
}

1;