<?php

declare(strict_types=1);

namespace Kommentti\WordPress;

use WP_Error;
use WP_REST_Request;
use WP_REST_Response;

final class Webhook
{
    public function __construct(private Settings $settings) {}

    public function register(): void
    {
        register_rest_route('kommentti/v1', '/webhook', [
            'methods' => 'POST', 'permission_callback' => [$this, 'authorize'], 'callback' => [$this, 'receive'],
        ]);
    }

    public function authorize(WP_REST_Request $request): bool|WP_Error
    {
        $body = $request->get_body();
        if (strlen($body) > 65536) {
            return new WP_Error('kommentti_body_size', __('The notification is too large.', 'kommentti'), ['status' => 413]);
        }
        $secret = $this->settings->credential('webhook_secret');
        if (!$this->settings->connected() || strlen($secret) < 40 || !preg_match('/^t=([0-9]{10}),v1=([a-f0-9]{64})$/D', (string) $request->get_header('x-kommentti-signature'), $parts)
            || abs(time() - (int) $parts[1]) > 300 || !hash_equals(hash_hmac('sha256', $parts[1].'.'.$body, $secret), $parts[2])) {
            return new WP_Error('kommentti_signature', __('A valid notification signature is required.', 'kommentti'), ['status' => 401]);
        }
        $event = json_decode($body, true, 16);
        if (!is_array($event) || ($event['site'] ?? null) !== $this->settings->all()['site_id'] || !Settings::uuid($event['id'] ?? null)
            || !in_array($event['type'] ?? null, ['thread.updated', 'endpoint.test'], true)
            || (isset($event['thread']) && (!is_string($event['thread']) || strlen($event['thread']) > 800))) {
            return new WP_Error('kommentti_event', __('The notification does not match this site.', 'kommentti'), ['status' => 401]);
        }
        return true;
    }

    public function receive(WP_REST_Request $request): WP_REST_Response
    {
        $event = json_decode($request->get_body(), true);
        $seenKey = 'kommentti_event_'.hash('sha256', $event['id']);
        if (!get_transient($seenKey) && $event['type'] === 'thread.updated') {
            if (!isset($event['thread'])) {
                update_option('kommentti_cache_generation', wp_generate_uuid4(), false);
                do_action('kommentti_purge_site');
                // A site-wide setting affects all cached articles, not only the plugin object cache.
                if (function_exists('rocket_clean_domain')) {
                    rocket_clean_domain();
                }
                if (function_exists('wp_cache_clear_cache')) {
                    wp_cache_clear_cache(get_current_blog_id());
                }
                if (function_exists('w3tc_flush_all')) {
                    w3tc_flush_all();
                }
                // phpcs:ignore WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedHooknameFound -- LiteSpeed’s documented public API.
                do_action('litespeed_purge_all');
            } else {
                foreach ($this->posts_for_thread($event['thread']) as $postId) {
                    $this->invalidate_post($postId);
                }
            }
            delete_transient('kommentti_api_backoff');
        }
        set_transient($seenKey, true, 600);
        update_option('kommentti_webhook_status', ['code' => 204, 'type' => $event['type'], 'delivered_at' => time()], false);
        $response = new WP_REST_Response(null, 204);
        $response->header('Cache-Control', 'no-store');
        return $response;
    }

    private function posts_for_thread(string $thread): array
    {
        $posts = get_posts(['post_type' => $this->settings->all()['post_types'], 'post_status' => 'publish', 'fields' => 'ids',
            'posts_per_page' => 100, 'meta_key' => '_kommentti_thread_id', 'meta_value' => $thread, 'no_found_rows' => true]);
        if (ctype_digit($thread) && strlen($thread) < 18) {
            $post = get_post((int) $thread);
            if ($post && (string) $post->ID === $thread && !get_post_meta($post->ID, '_kommentti_thread_id', true)) {
                $posts[] = $post->ID;
            }
        }
        return array_values(array_unique(array_map('intval', $posts)));
    }

    private function invalidate_post(int $postId): void
    {
        update_post_meta($postId, '_kommentti_cache_generation', wp_generate_uuid4());
        clean_post_cache($postId);
        if (function_exists('rocket_clean_post')) {
            rocket_clean_post($postId);
        }
        if (function_exists('wp_cache_post_change')) {
            wp_cache_post_change($postId);
        }
        if (function_exists('w3tc_flush_post')) {
            w3tc_flush_post($postId);
        }
        // phpcs:ignore WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedHooknameFound -- LiteSpeed’s documented public API.
        do_action('litespeed_purge_post', $postId);
        do_action('kommentti_purge_post', $postId);
    }
}