// Native fetch available in Node 20+
import { getSystemConfig } from '../admin/system-config.service';

type NotifyLevel = 'info' | 'warn' | 'error';

interface NotifyChannel {
  send(title: string, content: string, level: NotifyLevel): Promise<void>;
}

// ---- Feishu Webhook Channel ----
class FeishuChannel implements NotifyChannel {
  private webhookUrl: string;

  constructor(webhookUrl: string) {
    this.webhookUrl = webhookUrl;
  }

  async send(title: string, content: string, _level: NotifyLevel): Promise<void> {
    try {
      const body = JSON.stringify({
        msg_type: 'interactive',
        card: {
          header: {
            title: { tag: 'plain_text', content: title },
            template: _level === 'error' ? 'red' : _level === 'warn' ? 'orange' : 'blue',
          },
          elements: [
            { tag: 'div', text: { tag: 'lark_md', content } },
            {
              tag: 'note',
              elements: [
                { tag: 'plain_text', content: `CloudSearch · ${new Date().toLocaleString('zh-CN', { timeZone: 'Asia/Shanghai' })}` },
              ],
            },
          ],
        },
      });

      const resp = await fetch(this.webhookUrl, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body,
      });

      if (!resp.ok) {
        console.error(`[Notify] Feishu send failed: ${resp.status}`);
      }
    } catch (err: any) {
      console.error('[Notify] Feishu send error:', err.message);
    }
  }
}

// ---- Notification Manager ----
let _channel: NotifyChannel | null = null;

function getChannel(): NotifyChannel | null {
  const feishuUrl = process.env.FEISHU_WEBHOOK || getSystemConfig('feishu_webhook_url');
  if (!feishuUrl) return null;

  if (!_channel) {
    _channel = new FeishuChannel(feishuUrl);
    console.log('[Notify] Feishu webhook configured');
  }
  return _channel;
}

/**
 * Send a notification through configured channels.
 * Returns immediately — failures are logged silently.
 */
export function notify(title: string, content: string, level: NotifyLevel = 'info'): void {
  const ch = getChannel();
  if (!ch) return;
  // Fire-and-forget — don't block the caller
  ch.send(title, content, level).catch(() => {});
}

/**
 * Notify on critical events:
 * - Cookie expired / login failed
 * - Save/transfer failed repeatedly
 * - Storage below threshold
 */
export function notifyError(title: string, detail: string): void {
  notify(`⚠️ ${title}`, detail, 'error');
}

export function notifyWarn(title: string, detail: string): void {
  notify(`🔔 ${title}`, detail, 'warn');
}

export function notifyInfo(title: string, detail: string): void {
  notify(`ℹ️ ${title}`, detail, 'info');
}