<?php
/**
 * Settings category recommend runtime helper.
 *
 * @package AKSRT
 */

defined('ABSPATH') || exit;

class AKSRT_Settings_Category_Runtime {

    /**
     * 获取分类推荐配置（含默认值）
     * @return array
     */
    public static function get_category_recommend_settings(): array {
        $defaults = [
            'enable_category_recommend'             => false,
            'category_recommend_title'              => __('分类推荐', 'aksrt'),
            'category_recommend_category_ids'       => [],
            'category_recommend_posts_per_category' => 5,
            'category_recommend_columns'            => 2,
            'category_recommend_show_description'   => true,
            'category_recommend_show_dates'         => true,
            'category_recommend_show_more_link'     => true,
        ];
        $saved = get_option('aksrt_category_recommend', []);
        return array_merge($defaults, $saved);
    }

    /**
     * 获取分类封面图 URL（带优先级回退）
     *
     * 优先级：
     * 1. aksrt_category_cover_id term meta
     * 2. 该分类最新一篇有缩略图文章的缩略图
     * 3. 默认占位图
     *
     * @param int $term_id
     * @return string
     */
    public static function get_category_cover_url(int $term_id): string {
        $cover_id = (int) get_term_meta($term_id, 'aksrt_category_cover_id', true);
        if ($cover_id > 0) {
            $url = wp_get_attachment_url($cover_id);
            if ($url) {
                return $url;
            }
        }

        $posts = get_posts([
            'category__in'   => [$term_id],
            'posts_per_page' => 1,
            'post_status'    => 'publish',
            'orderby'        => 'date',
            'order'          => 'DESC',
            'meta_query'     => [
                [
                    'key'     => '_thumbnail_id',
                    'compare' => 'EXISTS',
                ],
            ],
            'fields'         => 'ids',
        ]);

        if (!empty($posts)) {
            $thumb_url = get_the_post_thumbnail_url($posts[0], 'medium_large');
            if ($thumb_url) {
                return $thumb_url;
            }
        }

        return get_template_directory_uri() . '/assets/img/placeholder.svg';
    }

    /**
     * 获取分类推荐描述（带优先级回退）
     *
     * 优先级：
     * 1. aksrt_category_recommend_desc term meta
     * 2. 原生 category description
     * 3. 空字符串
     *
     * @param int $term_id
     * @return string
     */
    public static function get_category_recommend_desc(int $term_id): string {
        $description = (string) get_term_meta($term_id, 'aksrt_category_recommend_desc', true);
        if ($description !== '') {
            return $description;
        }

        $term = get_term($term_id, 'category');
        if ($term && !is_wp_error($term) && $term->description) {
            return $term->description;
        }

        return '';
    }

    /**
     * 清理分类推荐缓存
     */
    public static function flush_category_recommend_cache(): void {
        $keys = get_option('aksrt_category_recommend_cache_keys', []);
        if (is_array($keys)) {
            foreach ($keys as $key) {
                delete_transient($key);
            }
        }
        delete_option('aksrt_category_recommend_cache_keys');
    }

    /**
     * 获取分类推荐渲染数据（带缓存）
     *
     * @param array $settings 分类推荐配置
     * @return array 每项包含 term_id, name, description, count, link, cover, posts
     */
    public static function get_category_recommend_items(array $settings): array {
        $category_ids = array_map('absint', (array) ($settings['category_recommend_category_ids'] ?? []));
        $category_ids = array_filter($category_ids, fn($id) => $id > 0);
        if (empty($category_ids)) {
            return [];
        }

        $per_page = max(1, min(10, (int) ($settings['category_recommend_posts_per_category'] ?? 5)));
        $show_desc = !empty($settings['category_recommend_show_description']);
        $show_dates = !empty($settings['category_recommend_show_dates']);
        $show_more = !empty($settings['category_recommend_show_more_link']);

        $cache_key = 'aksrt_cr_' . md5(implode(',', $category_ids) . '|' . $per_page . '|' . (int) $show_desc . '|' . (int) $show_dates . '|' . (int) $show_more);
        $cached = get_transient($cache_key);
        if ($cached !== false) {
            return $cached;
        }

        $items = [];
        foreach ($category_ids as $term_id) {
            $term = get_term($term_id, 'category');
            if (!$term || is_wp_error($term)) {
                continue;
            }

            $description = $show_desc ? self::get_category_recommend_desc($term_id) : '';

            $recent_posts = get_posts([
                'category__in'   => [$term_id],
                'posts_per_page' => $per_page,
                'post_status'    => 'publish',
                'orderby'        => 'date',
                'order'          => 'DESC',
            ]);

            $posts = [];
            foreach ($recent_posts as $post) {
                $posts[] = [
                    'title' => get_the_title($post->ID),
                    'link'  => get_permalink($post->ID),
                    'date'  => get_the_date('Y-m-d', $post->ID),
                ];
            }

            $items[] = [
                'term_id'     => (int) $term_id,
                'name'        => $term->name,
                'description' => $description,
                'count'       => (int) $term->count,
                'link'        => get_category_link($term_id),
                'cover'       => self::get_category_cover_url($term_id),
                'posts'       => $posts,
            ];
        }

        set_transient($cache_key, $items, 12 * HOUR_IN_SECONDS);

        $keys = get_option('aksrt_category_recommend_cache_keys', []);
        if (!is_array($keys)) {
            $keys = [];
        }
        $keys[] = $cache_key;
        update_option('aksrt_category_recommend_cache_keys', array_unique($keys));

        return $items;
    }
}