<?php
/**
 * @package AKSRT
 */

namespace AKSRT\Payment;

defined('ABSPATH') || exit;

class WeChatNotify {

    private static $instance = null;

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

    public function init(): void {
        add_action('aksrt_notification_sent', [$this, 'maybe_send_wechat'], 10, 3);
        add_action('wp_ajax_aksrt_wechat_status', [$this, 'ajax_status']);
    }

    /**
     * 获取微信通知配置
     */
    public function get_config(): array {
        if (class_exists('\AKSRT\Settings\Settings')) {
            return \AKSRT\Settings\Settings::get_wechat_settings();
        }
        return ['enabled' => false];
    }

    /**
     * 发送微信模板消息
     *
     * @param int    $user_id  用户 ID
     * @param string $template 模板标识
     * @param array  $data     模板数据
     * @return bool
     */
    public function send(int $user_id, string $template, array $data = []): bool {
        $config = $this->get_config();

        if (empty($config['enabled'])) {
            return false;
        }

        // 获取用户的微信 openid
        $openid = get_user_meta($user_id, 'aksrt_wechat_openid', true);
        if (empty($openid)) {
            return false;
        }

        // 获取 access token
        $access_token = $this->get_access_token($config);
        if (empty($access_token)) {
            if (defined('WP_DEBUG') && WP_DEBUG) {
                error_log('[AKSRT WeChat] Failed to get access token');
            }
            return false;
        }

        // 构建模板消息
        $template_id = $config['template_id'] ?? '';
        if (empty($template_id)) {
            if (defined('WP_DEBUG') && WP_DEBUG) {
                error_log('[AKSRT WeChat] No template ID configured');
            }
            return false;
        }

        $message = $this->build_template_message($template, $data, $openid, $template_id);

        // 调用微信模板消息 API
        $response = wp_remote_post('https://api.weixin.qq.com/cgi-bin/message/template/send?access_token=' . $access_token, [
            'headers' => ['Content-Type' => 'application/json'],
            'body'    => wp_json_encode($message),
            'timeout' => 10,
        ]);

        if (is_wp_error($response)) {
            if (defined('WP_DEBUG') && WP_DEBUG) {
                error_log('[AKSRT WeChat] API error: ' . $response->get_error_message());
            }
            return false;
        }

        $body = json_decode(wp_remote_retrieve_body($response), true);
        $errcode = (int) ($body['errcode'] ?? 0);

        if (defined('WP_DEBUG') && WP_DEBUG) {
            error_log(sprintf('[AKSRT WeChat] User: %d, Template: %s, Result: %s', $user_id, $template, wp_json_encode($body)));
        }

        return $errcode === 0;
    }

    /**
     * 获取微信 access token（带缓存）
     */
    private function get_access_token(array $config): string {
        $cache_key = 'aksrt_wechat_token';
        $cached = get_transient($cache_key);
        if (!empty($cached)) return (string) $cached;

        $app_id = $config['app_id'] ?? '';
        $app_secret = $config['app_secret'] ?? '';
        if (empty($app_id) || empty($app_secret)) return '';

        $response = wp_remote_get(sprintf(
            'https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=%s&secret=%s',
            urlencode($app_id),
            urlencode($app_secret)
        ));

        if (is_wp_error($response)) return '';

        $body = json_decode(wp_remote_retrieve_body($response), true);
        $token = $body['access_token'] ?? '';
        $expires = max(600, (int) ($body['expires_in'] ?? 7200) - 300);

        if (!empty($token)) {
            set_transient($cache_key, $token, $expires);
        }

        return (string) $token;
    }

    /**
     * 构建模板消息体
     */
    private function build_template_message(string $template, array $data, string $openid, string $template_id): array {
        $url = $data['url'] ?? home_url('/');
        $values = $data['values'] ?? [];

        $template_data = [];
        foreach ($values as $key => $value) {
            $template_data[$key] = [
                'value' => (string) $value,
                'color' => '#333333',
            ];
        }

        return [
            'touser'      => $openid,
            'template_id' => $template_id,
            'url'         => esc_url($url),
            'data'        => $template_data,
        ];
    }

    /**
     * 绑定用户微信 openid
     */
    public function bind_user(int $user_id, string $openid): bool {
        if ($user_id <= 0 || empty($openid)) return false;
        return (bool) update_user_meta($user_id, 'aksrt_wechat_openid', sanitize_text_field($openid));
    }

    /**
     * 解绑用户微信
     */
    public function unbind_user(int $user_id): bool {
        return (bool) delete_user_meta($user_id, 'aksrt_wechat_openid');
    }

    /**
     * 监听站内通知，联动微信通知
     */
    public function maybe_send_wechat(int $user_id, string $type, array $data): void {
        $config = $this->get_config();
        if (empty($config['enabled'])) return;

        // 仅特定类型通知发送微信
        $allowed_types = ['comment_reply', 'system_notice', 'order_paid', 'credits_change'];
        if (!in_array($type, $allowed_types, true)) return;

        $this->send($user_id, $type, $data);
    }

    /**
     * AJAX: Get WeChat notification status (admin only).
     */
    public function ajax_status(): void {
        if (!current_user_can('manage_options')) {
            wp_send_json_error(['message' => __('权限不足', 'aksrt')]);
        }

        wp_send_json_success($this->get_status());
    }

    /**
     * Get WeChat service status (used by REST and AJAX).
     */
    public function get_status(): array {
        $config = $this->get_config();
        $has_token = false;

        if (!empty($config['app_id']) && !empty($config['app_secret'])) {
            $cached = get_transient('aksrt_wechat_token');
            $has_token = !empty($cached);
        }

        // Count bound users
        global $wpdb;
        $bound_count = 0;
        if ($wpdb) {
            $bound_count = (int) $wpdb->get_var(
                "SELECT COUNT(*) FROM {$wpdb->usermeta} WHERE meta_key = 'aksrt_wechat_openid' AND meta_value != ''"
            );
        }

        return [
            'enabled'      => !empty($config['enabled']),
            'appid'        => $config['app_id'] ?? '',
            'configured'   => !empty($config['app_id']) && !empty($config['app_secret']),
            'has_token'    => $has_token,
            'has_template' => !empty($config['template_id']),
            'bound_users'  => $bound_count,
            'app_secret'    => !empty($config['app_secret']) ? '***' : '',
            'allowed_types' => ['comment_reply', 'system_notice', 'order_paid', 'credits_change'],
        ];
    }

    /**
     * Get notification subscriptions for a user.
     */
    public function get_user_subscriptions(int $user_id): array {
        $subs = get_user_meta($user_id, 'aksrt_wechat_subscriptions', true);
        if (!is_array($subs)) {
            $subs = [
                'comment_reply'    => true,
                'system_notice'    => true,
                'order_paid'       => true,
                'credits_change'   => false,
            ];
        }
        return $subs;
    }

    /**
     * Update notification subscriptions for a user.
     */
    public function update_user_subscriptions(int $user_id, array $subscriptions): bool {
        $allowed = ['comment_reply', 'system_notice', 'order_paid', 'credits_change'];
        $clean = [];
        foreach ($allowed as $key) {
            $clean[$key] = !empty($subscriptions[$key]);
        }
        return (bool) update_user_meta($user_id, 'aksrt_wechat_subscriptions', $clean);
    }

    /**
     * Check if a user should receive a specific notification type via WeChat.
     */
    public function should_notify(int $user_id, string $type): bool {
        $config = $this->get_config();
        if (empty($config['enabled'])) return false;

        $openid = get_user_meta($user_id, 'aksrt_wechat_openid', true);
        if (empty($openid)) return false;

        $subs = $this->get_user_subscriptions($user_id);
        return !empty($subs[$type]);
    }
}