class WP_Block_Type {
	/**
	 * Block type key.
	 *
	 * @since 5.0.0
	 * @var string
	 */
	public $name;

	/**
	 * Block type render callback.
	 *
	 * @since 5.0.0
	 * @var callable
	 */
	public $render_callback;

	/**
	 * Block type attributes property schemas.
	 *
	 * @since 5.0.0
	 * @var array
	 */
	public $attributes;

	/**
	 * Block type editor script handle.
	 *
	 * @since 5.0.0
	 * @var string
	 */
	public $editor_script;

	/**
	 * Block type front end script handle.
	 *
	 * @since 5.0.0
	 * @var string
	 */
	public $script;

	/**
	 * Block type editor style handle.
	 *
	 * @since 5.0.0
	 * @var string
	 */
	public $editor_style;

	/**
	 * Block type front end style handle.
	 *
	 * @since 5.0.0
	 * @var string
	 */
	public $style;

	/**
	 * Constructor.
	 *
	 * Will populate object properties from the provided arguments.
	 *
	 * @since 5.0.0
	 *
	 * @see register_block_type()
	 *
	 * @param string       $block_type Block type name including namespace.
	 * @param array|string $args       Optional. Array or string of arguments for registering a block type.
	 *                                 Default empty array.
	 */
	public function __construct( $block_type, $args = array() ) {
		$this->name = $block_type;

		$this->set_props( $args );
	}

	/**
	 * Renders the block type output for given attributes.
	 *
	 * @since 5.0.0
	 *
	 * @param array  $attributes Optional. Block attributes. Default empty array.
	 * @param string $content    Optional. Block content. Default empty string.
	 * @return string Rendered block type output.
	 */
	public function render( $attributes = array(), $content = '' ) {
		if ( ! $this->is_dynamic() ) {
			return '';
		}

		$attributes = $this->prepare_attributes_for_render( $attributes );

		return (string) call_user_func( $this->render_callback, $attributes, $content );
	}

	/**
	 * Returns true if the block type is dynamic, or false otherwise. A dynamic
	 * block is one which defers its rendering to occur on-demand at runtime.
	 *
	 * @since 5.0.0
	 *
	 * @return boolean Whether block type is dynamic.
	 */
	public function is_dynamic() {
		return is_callable( $this->render_callback );
	}

	/**
	 * Validates attributes against the current block schema, populating
	 * defaulted and missing values.
	 *
	 * @since 5.0.0
	 *
	 * @param  array $attributes Original block attributes.
	 * @return array             Prepared block attributes.
	 */
	public function prepare_attributes_for_render( $attributes ) {
		// If there are no attribute definitions for the block type, skip
		// processing and return vebatim.
		if ( ! isset( $this->attributes ) ) {
			return $attributes;
		}

		foreach ( $attributes as $attribute_name => $value ) {
			// If the attribute is not defined by the block type, it cannot be
			// validated.
			if ( ! isset( $this->attributes[ $attribute_name ] ) ) {
				continue;
			}

			$schema = $this->attributes[ $attribute_name ];

			// Validate value by JSON schema. An invalid value should revert to
			// its default, if one exists. This occurs by virtue of the missing
			// attributes loop immediately following. If there is not a default
			// assigned, the attribute value should remain unset.
			$is_valid = rest_validate_value_from_schema( $value, $schema );
			if ( is_wp_error( $is_valid ) ) {
				unset( $attributes[ $attribute_name ] );
			}
		}

		// Populate values of any missing attributes for which the block type
		// defines a default.
		$missing_schema_attributes = array_diff_key( $this->attributes, $attributes );
		foreach ( $missing_schema_attributes as $attribute_name => $schema ) {
			if ( isset( $schema['default'] ) ) {
				$attributes[ $attribute_name ] = $schema['default'];
			}
		}

		return $attributes;
	}

	/**
	 * Sets block type properties.
	 *
	 * @since 5.0.0
	 *
	 * @param array|string $args Array or string of arguments for registering a block type.
	 */
	public function set_props( $args ) {
		$args = wp_parse_args(
			$args,
			array(
				'render_callback' => null,
			)
		);

		$args['name'] = $this->name;

		foreach ( $args as $property_name => $property_value ) {
			$this->$property_name = $property_value;
		}
	}

	/**
	 * Get all available block attributes including possible layout attribute from Columns block.
	 *
	 * @since 5.0.0
	 *
	 * @return array Array of attributes.
	 */
	public function get_attributes() {
		return is_array( $this->attributes ) ?
			array_merge(
				$this->attributes,
				array(
					'layout' => array(
						'type' => 'string',
					),
				)
			) :
			array(
				'layout' => array(
					'type' => 'string',
				),
			);
	}
}