<?php
/**
 * Server-side rendering of the `core/video` block.
 *
 * @package WordPress
 */

/**
 * Renders the `core/video` block on the server to supply the width and height attributes from the attachment metadata.
 *
 * @since 6.9.0
 *
 * @phpstan-param  array{ "id"?: positive-int } $attributes
 *
 * @param array   $attributes The block attributes.
 * @param string  $content    The block content.
 * @return string The block content with the dimensions added.
 */
function render_block_core_video( array $attributes, string $content ): string {
    // if the content lacks any video tag, abort.
    if ( ! str_contains( $content, '<video' ) ) {
        return $content;
    }

    // If the 'id' attribute is not populated for a video attachment, abort.
    if (
        ! isset( $attributes['id'] ) ||
        ! is_int( $attributes['id'] ) ||
        $attributes['id'] <= 0
    ) {
        return $content;
    }

    // If the 'id' attribute wasn't for an attachment, abort.
    if ( get_post_type( $attributes['id'] ) !== 'attachment' ) {
        return $content;
    }

    // Get the width and height metadata for the video, and abort if absent or invalid.
    $metadata = wp_get_attachment_metadata( $attributes['id'] );
    if (
        ! isset( $metadata['width'], $metadata['height'] ) ||
        ! ( is_int( $metadata['width'] ) && is_int( $metadata['height'] ) ) ||
        ! ( $metadata['width'] > 0 && $metadata['height'] > 0 )
    ) {
        return $content;
    }

    // Locate the VIDEO tag to add the dimensions.
    $p = new WP_HTML_Tag_Processor( $content );
    if ( ! $p->next_tag( array( 'tag_name' => 'VIDEO' ) ) ) {
        return $content;
    }

    $p->set_attribute( 'width', (string) $metadata['width'] );
    $p->set_attribute( 'height', (string) $metadata['height'] );

    /*
     * The aspect-ratio style is needed due to an issue with the CSS spec: <https://github.com/w3c/csswg-drafts/issues/7524>.
     * Note that a style rule using attr() like the following cannot currently be used:
     *
     *     .wp-block-video video[width][height] {
     *         aspect-ratio: attr(width type(<number>)) / attr(height type(<number>));
     *     }
     *
     * This is because this attr() is yet only implemented in Chromium: <https://caniuse.com/css3-attr>.
     */
    $style = $p->get_attribute( 'style' );
    if ( ! is_string( $style ) ) {
        $style = '';
    }
    $aspect_ratio_style = sprintf( 'aspect-ratio: %d / %d;', $metadata['width'], $metadata['height'] );
    $p->set_attribute( 'style', $aspect_ratio_style . $style );

    return $p->get_updated_html();
}

/**
 * Registers the `core/video` block on server.
 *
 * @since 6.9.0
 */
function register_block_core_video(): void {
    register_block_type_from_metadata(
        __DIR__ . '/video',
        array(
            'render_callback' => 'render_block_core_video',
        )
    );
}
add_action( 'init', 'register_block_core_video' );