<?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 );