Element_Type_Manager

class Element_Type_Manager extends Service {
	use Container_Service_Trait, Hook_Service_Trait;

	/**
	 * Registered element types.
	 *
	 * @since 1.0.0
	 * @var array
	 */
	protected $element_types = array();

	/**
	 * Default element types definition.
	 *
	 * @since 1.0.0
	 * @var array
	 */
	protected $default_element_types = array();

	/**
	 * The element manager service definition.
	 *
	 * @since 1.0.0
	 * @static
	 * @var string
	 */
	protected static $service_elements = Element_Manager::class;

	/**
	 * The Assets API service definition.
	 *
	 * @since 1.0.0
	 * @static
	 * @var string
	 */
	protected static $service_assets = Assets::class;

	/**
	 * Constructor.
	 *
	 * @since 1.0.0
	 *
	 * @param string $prefix   The instance prefix.
	 * @param array  $services {
	 *     Array of service instances.
	 *
	 *     @type Element_Manager $elements      The element manager instance.
	 *     @type Assets          $assets        The assets instance.
	 *     @type Error_Handler   $error_handler The error handler instance.
	 * }
	 */
	public function __construct( $prefix, $services ) {
		$this->set_prefix( $prefix );
		$this->set_services( $services );
		$this->setup_hooks();

		Field_Manager::register_field_type( 'torrochoices', Choices_Field::class );

		$this->default_element_types = array(
			'textfield'      => Base\Textfield::class,
			'textarea'       => Base\Textarea::class,
			'content'        => Base\Content::class,
			'dropdown'       => Base\Dropdown::class,
			'onechoice'      => Base\Onechoice::class,
			'multiplechoice' => Base\Multiplechoice::class,
			'media'          => Base\Media::class,
			'checkbox'       => Base\Checkbox::class,
		);
	}

	/**
	 * Checks whether a specific element type is registered.
	 *
	 * @since 1.0.0
	 *
	 * @param string $slug Element type slug.
	 * @return bool True if the element type is registered, false otherwise.
	 */
	public function has( $slug ) {
		return isset( $this->element_types[ $slug ] );
	}

	/**
	 * Returns a specific registered element type.
	 *
	 * @since 1.0.0
	 *
	 * @param string $slug Element type slug.
	 * @return Element_Type|Error Element type instance, or error object if element type is not registered.
	 */
	public function get( $slug ) {
		if ( ! $this->has( $slug ) ) {
			/* translators: %s: element type slug */
			return new Error( $this->get_prefix() . 'element_type_not_exist', sprintf( __( 'An element type with the slug %s does not exist.', 'torro-forms' ), $slug ), __METHOD__, '1.0.0' );
		}

		return $this->element_types[ $slug ];
	}

	/**
	 * Returns all registered element types.
	 *
	 * @since 1.0.0
	 *
	 * @return array Associative array of `$slug => $element_type_instance` pairs.
	 */
	public function get_all() {
		return $this->element_types;
	}

	/**
	 * Registers a new element type.
	 *
	 * @since 1.0.0
	 *
	 * @param string $slug                    Element type slug.
	 * @param string $element_type_class_name Element type class name.
	 * @return bool|Error True on success, error object on failure.
	 */
	public function register( $slug, $element_type_class_name ) {
		if ( ! did_action( 'init' ) ) {
			/* translators: 1: element type slug, 2: init hookname */
			return new Error( $this->get_prefix() . 'element_type_too_early', sprintf( __( 'The element type %1$s cannot be registered before the %2$s hook.', 'torro-forms' ), $slug, '<code>init</code>' ), __METHOD__, '1.0.0' );
		}

		if ( $this->has( $slug ) ) {
			/* translators: %s: element type slug */
			return new Error( $this->get_prefix() . 'element_type_already_exist', sprintf( __( 'An element type with the slug %s already exists.', 'torro-forms' ), $slug ), __METHOD__, '1.0.0' );
		}

		if ( ! class_exists( $element_type_class_name ) ) {
			/* translators: %s: element type class name */
			return new Error( $this->get_prefix() . 'element_type_class_not_exist', sprintf( __( 'The class %s does not exist.', 'torro-forms' ), $element_type_class_name ), __METHOD__, '1.0.0' );
		}

		if ( ! is_subclass_of( $element_type_class_name, Element_Type::class ) ) {
			/* translators: %s: element type class name */
			return new Error( $this->get_prefix() . 'element_type_class_not_allowed', sprintf( __( 'The class %s is not allowed for a element type.', 'torro-forms' ), $element_type_class_name ), __METHOD__, '1.0.0' );
		}

		$this->element_types[ $slug ] = new $element_type_class_name( $this );

		return true;
	}

	/**
	 * Unregisters a new element type.
	 *
	 * @since 1.0.0
	 *
	 * @param string $slug Element type slug.
	 * @return bool|Error True on success, error object on failure.
	 */
	public function unregister( $slug ) {
		if ( ! $this->has( $slug ) ) {
			/* translators: %s: element type slug */
			return new Error( $this->get_prefix() . 'element_type_not_exist', sprintf( __( 'An element type with the slug %s does not exist.', 'torro-forms' ), $slug ), __METHOD__, '1.0.0' );
		}

		if ( isset( $this->default_element_types[ $slug ] ) ) {
			/* translators: %s: element type slug */
			return new Error( $this->get_prefix() . 'element_type_is_default', sprintf( __( 'The default element type %s cannot be unregistered.', 'torro-forms' ), $slug ), __METHOD__, '1.0.0' );
		}

		unset( $this->element_types[ $slug ] );

		return true;
	}

	/**
	 * Registers the default element types.
	 *
	 * The function also executes a hook that should be used by other developers to register their own element types.
	 *
	 * @since 1.0.0
	 */
	protected function register_defaults() {
		foreach ( $this->default_element_types as $slug => $element_type_class_name ) {
			$this->register( $slug, $element_type_class_name );
		}

		/**
		 * Fires when the default element types have been registered.
		 *
		 * This action should be used to register custom element types.
		 *
		 * @since 1.0.0
		 *
		 * @param Element_Type_Manager $element_types Element type manager instance.
		 */
		do_action( "{$this->get_prefix()}register_element_types", $this );
	}

	/**
	 * Enqueues form builder scripts for the available element types.
	 *
	 * @since 1.0.0
	 */
	protected function enqueue_admin_scripts() {
		$services = array(
			'ajax'          => $this->elements()->ajax(),
			'assets'        => $this->elements()->assets(),
			'error_handler' => $this->elements()->error_handler(),
		);

		$dummy_manager = new Field_Manager( $this->get_prefix() . 'dummy_', $services, array(
			'get_value_callback'     => '__return_empty_array',
			'update_value_callback'  => '__return_empty_array',
			'name_prefix'            => $this->get_prefix() . 'dummy',
			'skip_js_initialization' => true,
		) );

		$added = array();
		foreach ( $this->element_types as $slug => $element_type ) {
			$fields = $element_type->get_settings_fields();
			foreach ( $fields as $field ) {
				if ( in_array( $field['type'], $added, true ) ) {
					continue;
				}

				$dummy_manager->add( 'dummy_' . $field['type'], $field['type'], array(
					'section' => 'main',
					'label'   => sprintf( 'Dummy %s', $field['type'] ),
				) );
				$added[] = $field['type'];
			}
		}

		$dummy_manager->enqueue();
	}

	/**
	 * Sets up all action and filter hooks for the service.
	 *
	 * This method must be implemented and then be called from the constructor.
	 *
	 * @since 1.0.0
	 */
	protected function setup_hooks() {
		$this->actions = array(
			array(
				'name'     => 'init',
				'callback' => array( $this, 'register_defaults' ),
				'priority' => 1,
				'num_args' => 0,
			),
			array(
				'name'     => "{$this->get_prefix()}enqueue_form_builder_scripts",
				'callback' => array( $this, 'enqueue_admin_scripts' ),
				'priority' => 1,
				'num_args' => 0,
			),
		);
	}
}