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

/**
 * Renders the `core/post-terms` block on the server.
 *
 * @since 5.8.0
 *
 * @param array    $attributes Block attributes.
 * @param string   $content    Block default content.
 * @param WP_Block $block      Block instance.
 * @return string Returns the filtered post terms for the current post wrapped inside "a" tags.
 */
function render_block_core_post_terms( $attributes, $content, $block ) {
    if ( ! isset( $block->context['postId'] ) || ! isset( $attributes['term'] ) ) {
        return '';
    }

    if ( ! is_taxonomy_viewable( $attributes['term'] ) ) {
        return '';
    }

    $classes = array( 'taxonomy-' . $attributes['term'] );
    if ( isset( $attributes['textAlign'] ) ) {
        $classes[] = 'has-text-align-' . $attributes['textAlign'];
    }
    if ( isset( $attributes['style']['elements']['link']['color']['text'] ) ) {
        $classes[] = 'has-link-color';
    }

    $separator = empty( $attributes['separator'] ) ? ' ' : $attributes['separator'];

    $wrapper_attributes = get_block_wrapper_attributes( array( 'class' => implode( ' ', $classes ) ) );

    $prefix = "<div $wrapper_attributes>";
    if ( isset( $attributes['prefix'] ) && $attributes['prefix'] ) {
        $prefix .= '<span class="wp-block-post-terms__prefix">' . $attributes['prefix'] . '</span>';
    }

    $suffix = '</div>';
    if ( isset( $attributes['suffix'] ) && $attributes['suffix'] ) {
        $suffix = '<span class="wp-block-post-terms__suffix">' . $attributes['suffix'] . '</span>' . $suffix;
    }

    $post_terms = get_the_term_list(
        $block->context['postId'],
        $attributes['term'],
        wp_kses_post( $prefix ),
        '<span class="wp-block-post-terms__separator">' . esc_html( $separator ) . '</span>',
        wp_kses_post( $suffix )
    );

    if ( is_wp_error( $post_terms ) || empty( $post_terms ) ) {
        return '';
    }

    return $post_terms;
}

/**
 * Returns the available variations for the `core/post-terms` block.
 *
 * @since 6.5.0
 *
 * @return array The available variations for the block.
 */
function block_core_post_terms_build_variations() {
    $taxonomies = get_taxonomies(
        array(
            'publicly_queryable' => true,
            'show_in_rest'       => true,
        ),
        'objects'
    );

    // Split the available taxonomies to `built_in` and custom ones,
    // in order to prioritize the `built_in` taxonomies at the
    // search results.
    $built_ins         = array();
    $custom_variations = array();

    // Create and register the eligible taxonomies variations.
    foreach ( $taxonomies as $taxonomy ) {
        $variation = array(
            'name'        => $taxonomy->name,
            'title'       => $taxonomy->label,
            'description' => sprintf(
                /* translators: %s: taxonomy's label */
                __( 'Display a list of assigned terms from the taxonomy: %s' ),
                $taxonomy->label
            ),
            'attributes'  => array(
                'term' => $taxonomy->name,
            ),
            'isActive'    => array( 'term' ),
            'scope'       => array( 'inserter', 'transform' ),
        );
        // Set the category variation as the default one.
        if ( 'category' === $taxonomy->name ) {
            $variation['isDefault'] = true;
        }
        if ( $taxonomy->_builtin ) {
            $built_ins[] = $variation;
        } else {
            $custom_variations[] = $variation;
        }
    }

    return array_merge( $built_ins, $custom_variations );
}

/**
 * Registers the `core/post-terms` block on the server.
 *
 * @since 5.8.0
 */
function register_block_core_post_terms() {
    register_block_type_from_metadata(
        __DIR__ . '/post-terms',
        array(
            'render_callback'    => 'render_block_core_post_terms',
            'variation_callback' => 'block_core_post_terms_build_variations',
        )
    );
}
add_action( 'init', 'register_block_core_post_terms' );