<?php

/**

 * Background block support flag.

 *

 * @package WordPress

 * @since 6.4.0

 */

/**

 * Registers the style block attribute for block types that support it.

 *

 * @since 6.4.0

 * @access private

 *

 * @param WP_Block_Type $block_type Block Type.

 */

function wp_register_background_support( $block_type ) {

	// Setup attributes and styles within that if needed.

	if ( ! $block_type->attributes ) {

		$block_type->attributes = array();

	}

	// Check for existing style attribute definition e.g. from block.json.

	if ( array_key_exists( 'style', $block_type->attributes ) ) {

		return;

	}

	$has_background_support = block_has_support( $block_type, array( 'background' ), false );

	if ( $has_background_support ) {

		$block_type->attributes['style'] = array(

			'type' => 'object',

		);

	}

}

/**

 * Renders the background styles to the block wrapper.

 * This block support uses the `render_block` hook to ensure that

 * it is also applied to non-server-rendered blocks.

 *

 * @since 6.4.0

 * @since 6.5.0 Added support for `backgroundPosition` and `backgroundRepeat` output.

 * @since 6.6.0 Removed requirement for `backgroundImage.source`. A file/url is the default.

 * @since 6.7.0 Added support for `backgroundAttachment` output.

 *

 * @access private

 *

 * @param  string $block_content Rendered block content.

 * @param  array  $block         Block object.

 * @return string Filtered block content.

 */

function wp_render_background_support( $block_content, $block ) {

	$block_type                   = WP_Block_Type_Registry::get_instance()->get_registered( $block['blockName'] );

	$block_attributes             = ( isset( $block['attrs'] ) && is_array( $block['attrs'] ) ) ? $block['attrs'] : array();

	$has_background_image_support = block_has_support( $block_type, array( 'background', 'backgroundImage' ), false );

	if (

		! $has_background_image_support ||

		wp_should_skip_block_supports_serialization( $block_type, 'background', 'backgroundImage' ) ||

		! isset( $block_attributes['style']['background'] )

	) {

		return $block_content;

	}

	$background_styles                         = array();

	$background_styles['backgroundImage']      = $block_attributes['style']['background']['backgroundImage'] ?? null;

	$background_styles['backgroundSize']       = $block_attributes['style']['background']['backgroundSize'] ?? null;

	$background_styles['backgroundPosition']   = $block_attributes['style']['background']['backgroundPosition'] ?? null;

	$background_styles['backgroundRepeat']     = $block_attributes['style']['background']['backgroundRepeat'] ?? null;

	$background_styles['backgroundAttachment'] = $block_attributes['style']['background']['backgroundAttachment'] ?? null;

	if ( ! empty( $background_styles['backgroundImage'] ) ) {

		$background_styles['backgroundSize'] = $background_styles['backgroundSize'] ?? 'cover';

		// If the background size is set to `contain` and no position is set, set the position to `center`.

		if ( 'contain' === $background_styles['backgroundSize'] && ! $background_styles['backgroundPosition'] ) {

			$background_styles['backgroundPosition'] = '50% 50%';

		}

	}

	$styles = wp_style_engine_get_styles( array( 'background' => $background_styles ) );

	if ( ! empty( $styles['css'] ) ) {

		// Inject background styles to the first element, presuming it's the wrapper, if it exists.

		$tags = new WP_HTML_Tag_Processor( $block_content );

		if ( $tags->next_tag() ) {

			$existing_style = $tags->get_attribute( 'style' );

			$updated_style  = '';

			if ( ! empty( $existing_style ) ) {

				$updated_style = $existing_style;

				if ( ! str_ends_with( $existing_style, ';' ) ) {

					$updated_style .= ';';

				}

			}

			$updated_style .= $styles['css'];

			$tags->set_attribute( 'style', $updated_style );

			$tags->add_class( 'has-background' );

		}

		return $tags->get_updated_html();

	}

	return $block_content;

}

// Register the block support.

WP_Block_Supports::get_instance()->register(

	'background',

	array(

		'register_attribute' => 'wp_register_background_support',

	)

);

add_filter( 'render_block', 'wp_render_background_support', 10, 2 );