<?php
/**
 * AKSRT Category Rewrite — Remove /category/ from URLs
 *
 * Rewrites category URLs from /category/slug/ to /slug/.
 * Adds 301 redirect for old /category/ URLs.
 *
 * WARNING: May conflict with other "no-category" plugins.
 * Enable via Settings → SEO → Remove category base.
 *
 * @package AKSRT
 */

defined('ABSPATH') || exit;

class AKSRT_Category_Rewrite {

    private static $instance = null;

	    private function __construct() {}

	    private function rewrite_version(): string {
	        return AKSRT_VERSION . ':category-rewrite-v1';
	    }

    public static function get_instance(): self {
        if (null === self::$instance) {
            self::$instance = new self();
        }
        return self::$instance;
    }

    public function init(): void {
        if (!$this->is_enabled()) {
            // If disabled, ensure old rules are cleaned up
            add_action('init', [$this, 'maybe_restore']);
            return;
        }

        add_filter('category_link', [$this, 'remove_category_base'], 10, 2);
        add_filter('term_link', [$this, 'remove_category_base_term'], 10, 3);
        add_action('init', [$this, 'add_rewrite_rules']);
        add_action('template_redirect', [$this, 'redirect_old_urls']);
        add_action('admin_init', [$this, 'maybe_flush']);
    }

    /**
     * Check if feature is enabled
     */
    private function is_enabled(): bool {
        if (!class_exists('AKSRT_Settings')) return false;
        // schema key = seo_no_category; runtime alias = seo_remove_category
        return (bool) (
            AKSRT_Settings::get_value('seo_remove_category', false)
            ?: AKSRT_Settings::get_value('seo_no_category', false)
        );
    }

    /**
     * Remove /category/ from category link
     */
    public function remove_category_base(string $link, $term): string {
        $base = get_option('category_base');
        if ($base && $base !== 'category') return $link;

        // Only process category taxonomy
        if ($term instanceof WP_Term && $term->taxonomy !== 'category') {
            return $link;
        }

	        $category_base_url = preg_quote(trailingslashit(home_url('/category')), '#');
	        return preg_replace('#' . $category_base_url . '#', trailingslashit(home_url('/')), $link, 1);
    }

    /**
     * Remove base from term_link for categories
     */
    public function remove_category_base_term(string $link, $term, $taxonomy): string {
        if ($taxonomy !== 'category') return $link;
        return $this->remove_category_base($link, $term);
    }

    /**
     * Add rewrite rules for category URLs without /category/
     */
    public function add_rewrite_rules(): void {
        // Get all category slugs
        $categories = get_categories(['hide_empty' => false]);
        foreach ($categories as $cat) {
            if (empty($cat->slug)) continue;
            $slug = $cat->slug;

            // /slug/ → index.php?category_name=$slug
            add_rewrite_rule(
                '^' . preg_quote($slug, '/') . '/?$',
                'index.php?category_name=' . $slug,
                'top'
            );

            // /slug/page/N/ → index.php?category_name=$slug&paged=$N
            add_rewrite_rule(
                '^' . preg_quote($slug, '/') . '/page/([0-9]+)/?$',
                'index.php?category_name=$slug&paged=$matches[1]',
                'top'
            );

            // /slug/feed/ → index.php?category_name=$slug&feed=$feed
            add_rewrite_rule(
                '^' . preg_quote($slug, '/') . '/feed/?$',
                'index.php?category_name=$slug&feed=rss2',
                'top'
            );
        }
    }

    /**
     * 301 redirect old /category/ URLs to new ones
     */
    public function redirect_old_urls(): void {
        $request = $_SERVER['REQUEST_URI'] ?? '';
        $home_path = wp_parse_url(home_url('/'), PHP_URL_PATH);

        // Remove home path prefix
        if ($home_path && strpos($request, $home_path) === 0) {
            $request = substr($request, strlen($home_path));
        }

        // Check if request starts with /category/
        if (preg_match('#^category/(.+?)/?$#', $request, $matches)) {
            $new_url = home_url('/' . $matches[1] . '/');
            wp_redirect($new_url, 301);
            exit;
        }
    }

    /**
     * Flush rewrite rules when setting changes
     */
	    public function maybe_flush(): void {
	        $rewrite_version = $this->rewrite_version();
	        $stored = (string) get_option('aksrt_category_rewrite_flushed', '');
	        if ($stored !== $rewrite_version) {
	            flush_rewrite_rules();
	            update_option('aksrt_category_rewrite_flushed', $rewrite_version);
	        }
	    }

    /**
     * Restore default rewrite rules when feature is disabled
     */
    public function maybe_restore(): void {
	        $stored = (string) get_option('aksrt_category_rewrite_flushed', '');
	        if ($stored !== '') {
	            flush_rewrite_rules();
	            delete_option('aksrt_category_rewrite_flushed');
	        }
    }

    /**
     * Force flush (call after enabling/disabling)
     */
	    public static function force_flush(): void {
	        flush_rewrite_rules();
	        update_option('aksrt_category_rewrite_flushed', AKSRT_VERSION . ':category-rewrite-v1');
	    }
}