import {
  registerFcmToken,
  deleteFcmToken,
} from '../lib/shared';
import { PushNotifications } from '@capacitor/push-notifications';
import { Capacitor } from '@capacitor/core';

/** AndroidManifest default_notification_channel_id 와 동일 */
export const FCM_CHANNEL_ID = 'goldenchart_trade_signals';

export interface FcmPayload {
  type?: string;
  market?: string;
  signalId?: string;
  signalType?: string;
  price?: string;
}

type FcmHandlers = {
  onForeground?: (title: string, body: string, data?: FcmPayload) => void;
  onTap?: (data: FcmPayload) => void;
};

let initialized = false;
let listenersAttached = false;

async function ensureAndroidNotificationChannel(): Promise<void> {
  if (Capacitor.getPlatform() !== 'android') return;
  try {
    await PushNotifications.createChannel({
      id: FCM_CHANNEL_ID,
      name: '매매 시그널 알림',
      description: '전략 조건 일치 시 매수·매도 푸시',
      importance: 5,
      visibility: 1,
      vibration: true,
    });
  } catch (e) {
    console.warn('[FCM] createChannel failed', e);
  }
}

function attachListeners(handlers: FcmHandlers): void {
  if (listenersAttached) return;
  listenersAttached = true;

  void PushNotifications.addListener('registration', async token => {
    try {
      await registerFcmToken(token.value);
      console.info('[FCM] token registered with server');
    } catch (e) {
      console.warn('[FCM] token register failed', e);
    }
  });

  void PushNotifications.addListener('registrationError', err => {
    console.warn('[FCM] registration error', err);
  });

  void PushNotifications.addListener('pushNotificationReceived', notification => {
    const title = notification.title ?? 'GoldenChart';
    const body = notification.body ?? '';
    handlers.onForeground?.(title, body, notification.data as FcmPayload);
  });

  void PushNotifications.addListener('pushNotificationActionPerformed', action => {
    handlers.onTap?.(action.notification.data as FcmPayload);
  });
}

/**
 * FCM 토큰 등록 (로그인 후 호출 — 서버 fcm_push_enabled 와 별개로 토큰만 등록)
 */
export async function initFcmPush(handlers: FcmHandlers = {}): Promise<boolean> {
  if (!Capacitor.isNativePlatform()) {
    console.info('[FCM] Web dev — native push skipped');
    return false;
  }

  await ensureAndroidNotificationChannel();
  attachListeners(handlers);

  const perm = await PushNotifications.checkPermissions();
  if (perm.receive !== 'granted') {
    const req = await PushNotifications.requestPermissions();
    if (req.receive !== 'granted') {
      console.warn('[FCM] notification permission denied');
      return false;
    }
  }

  if (!initialized) {
    await PushNotifications.register();
    initialized = true;
  }
  return true;
}

export async function unregisterFcmPush(): Promise<void> {
  if (!Capacitor.isNativePlatform()) return;
  try {
    await deleteFcmToken();
  } catch { /* ignore */ }
  initialized = false;
}

export async function checkPushPermission(): Promise<'granted' | 'denied' | 'prompt'> {
  if (!Capacitor.isNativePlatform()) return 'prompt';
  const perm = await PushNotifications.checkPermissions();
  if (perm.receive === 'granted') return 'granted';
  if (perm.receive === 'denied') return 'denied';
  return 'prompt';
}