<?php
if (!defined('ABSPATH')) {
    exit;
}

/**
 * Featured-image caption rendering.
 *
 * The publishing pipeline stores a caption on the featured attachment
 * (post_excerpt) via the WP media REST endpoint. The block-theme
 * `core/post-featured-image` block renders only the <img> and ignores that
 * caption, so it would never show. This filter appends a <figcaption> built
 * from the attachment caption whenever a single post's featured image is
 * rendered, giving it the same visible treatment as the inline secondary
 * image's caption.
 *
 * The tsai-plugin is installed on every tsai + scike site, so this is the
 * single place that controls featured-caption output for all sites.
 */
class TSAI_Featured_Caption {

    public function __construct() {
        add_filter('render_block', array($this, 'append_caption'), 10, 2);
        add_action('wp_enqueue_scripts', array($this, 'enqueue_assets'));
    }

    /**
     * Append the featured image's caption as a <figcaption> inside the block.
     *
     * @param string $block_content Rendered block HTML.
     * @param array  $block         Parsed block (name + attrs).
     * @return string
     */
    public function append_caption($block_content, $block) {
        if (empty($block['blockName']) || $block['blockName'] !== 'core/post-featured-image') {
            return $block_content;
        }
        if (!is_singular('post') || empty($block_content)) {
            return $block_content;
        }

        $caption = get_the_post_thumbnail_caption(get_queried_object_id());
        if (!$caption) {
            return $block_content;
        }

        $figcaption = '<figcaption class="wp-element-caption tsai-featured-caption">'
            . esc_html($caption) . '</figcaption>';

        // Append the caption AFTER the block's <figure>, not inside it. Block
        // themes size the featured-image figure with `aspect-ratio` and an
        // `img { height: 100% }`, so a caption placed inside overflows that
        // fixed-ratio box and gets painted over by the following content —
        // present in the DOM but invisible. As a sibling in normal flow it
        // occupies its own space directly under the image.
        return $block_content . $figcaption;
    }

    public function enqueue_assets() {
        if (!is_singular('post')) {
            return;
        }
        wp_enqueue_style(
            'tsai-featured-caption',
            TSAI_PLUGIN_URL . 'assets/css/tsai-featured-caption.css',
            array(),
            '1.0.0'
        );
    }
}

new TSAI_Featured_Caption();