<?php
/**
 * VIP layered membership expiry and recovery service.
 *
 * @package AKSRT
 */

namespace AKSRT\Content;

defined('ABSPATH') || exit;

final class VipMembershipExpiry {

    public const CRON_HOOK = 'aksrt_vip_membership_expiry';
    private const BATCH_SIZE = 100;

    public static function init(): void {
        add_action(self::CRON_HOOK, [self::class, 'run_batch']);
        add_action('init', [self::class, 'maybe_schedule'], 20);
    }

    public static function maybe_schedule(): void {
        if (!wp_next_scheduled(self::CRON_HOOK)) {
            wp_schedule_event(time() + 300, 'hourly', self::CRON_HOOK);
        }
    }

    public static function run_batch(): void {
        global $wpdb;
        $now = time();
        $rows = $wpdb->get_col($wpdb->prepare(
            "SELECT DISTINCT um.user_id FROM {$wpdb->usermeta} um
             WHERE um.meta_key = 'aksrt_vip_level'
               AND CAST(um.meta_value AS UNSIGNED) > 0
               AND EXISTS (
                   SELECT 1 FROM {$wpdb->usermeta} expiry
                   WHERE expiry.user_id = um.user_id
                     AND expiry.meta_key = 'aksrt_vip_expires'
                     AND CAST(expiry.meta_value AS UNSIGNED) > 0
                     AND CAST(expiry.meta_value AS UNSIGNED) <= %d
               )
             ORDER BY user_id ASC LIMIT %d",
            $now,
            self::BATCH_SIZE
        ));
        foreach ((array) $rows as $user_id) {
            self::process_user((int) $user_id, 'cron');
        }
    }

    /**
     * Resolve an expired current layer exactly once.
     *
     * @return array{changed:bool,before:array,after:array}|\WP_Error
     */
    public static function process_user(int $user_id, string $source = 'resolver', string $reason = ''): array|\WP_Error {
        if ($user_id <= 0 || !get_userdata($user_id)) {
            return new \WP_Error('aksrt_vip_user_missing', __('用户不存在。', 'aksrt'));
        }
        $before = self::snapshot($user_id);
        if ($before['level'] <= 0 || $before['expires'] <= 0 || $before['expires'] > time()) {
            return ['changed' => false, 'before' => $before, 'after' => $before];
        }

        $repository = new VipMembershipEventRepository();
        $event_uuid = $repository->begin([
            'user_id' => $user_id,
            'actor_user_id' => 0,
            'operation' => 'expire_recover',
            'source' => $source,
            'reason' => $reason !== '' ? $reason : __('会员当前层到期处理', 'aksrt'),
            'request' => ['now' => time()],
            'before' => $before,
        ]);
        if (is_wp_error($event_uuid)) {
            return $event_uuid;
        }

        $fallback_valid = $before['base_level'] > 0
            && ($before['base_expires'] === 0 || $before['base_expires'] > time());
        if ($fallback_valid) {
            update_user_meta($user_id, 'aksrt_vip_level', $before['base_level']);
            update_user_meta($user_id, 'aksrt_vip_expires', $before['base_expires']);
        } else {
            update_user_meta($user_id, 'aksrt_vip_level_expired', max($before['expired_level'], $before['level']));
            update_user_meta($user_id, 'aksrt_vip_level', 0);
            update_user_meta($user_id, 'aksrt_vip_expires', 0);
        }
        delete_user_meta($user_id, 'aksrt_vip_base_level');
        delete_user_meta($user_id, 'aksrt_vip_base_expires');

        $after = self::snapshot($user_id);
        $expected_level = $fallback_valid ? $before['base_level'] : 0;
        $expected_expires = $fallback_valid ? $before['base_expires'] : 0;
        if ($after['level'] !== $expected_level || $after['expires'] !== $expected_expires || $after['base_level'] !== 0 || $after['base_expires'] !== 0) {
            self::restore($user_id, $before);
            $after = self::snapshot($user_id);
            $error = new \WP_Error('aksrt_vip_expiry_write_failed', __('会员到期状态保存失败。', 'aksrt'));
            $repository->complete($event_uuid, 'failed', $after, $error->get_error_code(), $error->get_error_message());
            return $error;
        }

        $repository->complete($event_uuid, 'succeeded', $after);
        do_action('aksrt_vip_membership_expired', $user_id, $before, $after, $source, $event_uuid);
        return ['changed' => true, 'before' => $before, 'after' => $after];
    }

    /** @return array{level:int,expires:int,base_level:int,base_expires:int,expired_level:int} */
    public static function snapshot(int $user_id): array {
        return [
            'level' => max(0, min(2, (int) get_user_meta($user_id, 'aksrt_vip_level', true))),
            'expires' => max(0, (int) get_user_meta($user_id, 'aksrt_vip_expires', true)),
            'base_level' => max(0, min(2, (int) get_user_meta($user_id, 'aksrt_vip_base_level', true))),
            'base_expires' => max(0, (int) get_user_meta($user_id, 'aksrt_vip_base_expires', true)),
            'expired_level' => max(0, min(2, (int) get_user_meta($user_id, 'aksrt_vip_level_expired', true))),
        ];
    }

    /** @param array<string,int> $snapshot */
    private static function restore(int $user_id, array $snapshot): void {
        foreach (['level' => 'aksrt_vip_level', 'expires' => 'aksrt_vip_expires', 'base_level' => 'aksrt_vip_base_level', 'base_expires' => 'aksrt_vip_base_expires', 'expired_level' => 'aksrt_vip_level_expired'] as $key => $meta_key) {
            $value = (int) ($snapshot[$key] ?? 0);
            if ($value > 0 || in_array($key, ['level', 'expires'], true)) {
                update_user_meta($user_id, $meta_key, $value);
            } else {
                delete_user_meta($user_id, $meta_key);
            }
        }
    }
}