import {
  registerFcmToken,
  deleteFcmToken,
  storageGet,
  storageSet,
  storageRemove,
} from '../lib/shared';
import { Capacitor, registerPlugin } from '@capacitor/core';

export const FCM_CHANNEL_ID = 'goldenchart_trade_signals';
export const FCM_USER_OPT_IN_KEY = 'gc_fcm_user_opt_in';
export const FCM_REGISTERED_KEY = 'gc_fcm_registered';

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;
};

interface GoldenFcmPlugin {
  checkPermissions(): Promise<{ receive: string }>;
  requestPermissions(): Promise<{ receive: string }>;
  register(): Promise<{ value: string }>;
  unregister(): Promise<void>;
  addListener(
    event: 'registration',
    listener: (data: { value: string }) => void,
  ): Promise<{ remove: () => void }>;
  addListener(
    event: 'registrationError',
    listener: (data: { error?: string }) => void,
  ): Promise<{ remove: () => void }>;
  addListener(
    event: 'pushNotificationReceived',
    listener: (data: { title?: string; body?: string; data?: FcmPayload }) => void,
  ): Promise<{ remove: () => void }>;
  addListener(
    event: 'pushNotificationActionPerformed',
    listener: (data: { notification?: { data?: FcmPayload } }) => void,
  ): Promise<{ remove: () => void }>;
}

const GoldenFcm = registerPlugin<GoldenFcmPlugin>('GoldenFcm');

let tokenRegistered = false;
let listenersAttached = false;

async function userOptedIn(): Promise<boolean> {
  return (await storageGet(FCM_USER_OPT_IN_KEY)) === '1';
}

export async function markFcmUserOptIn(): Promise<void> {
  await storageSet(FCM_USER_OPT_IN_KEY, '1');
}

async function attachListeners(handlers: {
  onForeground?: (title: string, body: string, data?: FcmPayload) => void;
  onTap?: (data: FcmPayload) => void;
}): Promise<void> {
  if (listenersAttached || Capacitor.getPlatform() !== 'android') return;
  listenersAttached = true;

  await GoldenFcm.addListener('registration', async data => {
    try {
      await registerFcmToken(data.value);
      await storageSet(FCM_REGISTERED_KEY, '1');
    } catch (e) {
      console.warn('[FCM] token register failed', e);
    }
  });

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

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

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

/** ① 알림 권한만 (FCM 미호출 — 허용 직후 크래시 방지) */
export async function requestNotificationPermissionOnly(): Promise<boolean> {
  if (Capacitor.getPlatform() !== 'android') return false;
  await markFcmUserOptIn();
  const perm = await GoldenFcm.checkPermissions();
  if (perm.receive === 'granted') return true;
  const req = await GoldenFcm.requestPermissions();
  return req.receive === 'granted';
}

/** ② 권한 허용 후 FCM 토큰 등록 */
export async function registerFcmTokenOnly(): Promise<boolean> {
  if (Capacitor.getPlatform() !== 'android') return false;
  if (!(await userOptedIn())) return false;

  const perm = await GoldenFcm.checkPermissions();
  if (perm.receive !== 'granted') return false;

  try {
    await attachListeners({});
    if (tokenRegistered) return true;

    await new Promise(r => setTimeout(r, 800));
    const result = await GoldenFcm.register();
    tokenRegistered = true;
    if (result?.value) {
      await registerFcmToken(result.value);
      await storageSet(FCM_REGISTERED_KEY, '1');
    }
    return !!result?.value;
  } catch (e) {
    console.warn('[FCM] register failed', e);
    return false;
  }
}

export async function isFcmRegisteredOnDevice(): Promise<boolean> {
  return (await storageGet(FCM_REGISTERED_KEY)) === '1';
}

/** @deprecated — requestNotificationPermissionOnly + registerFcmTokenOnly 사용 */
export async function initFcmPush(): Promise<boolean> {
  const ok = await requestNotificationPermissionOnly();
  if (!ok) return false;
  await new Promise(r => setTimeout(r, 1000));
  return registerFcmTokenOnly();
}

export async function unregisterFcmPush(): Promise<void> {
  if (!Capacitor.isNativePlatform()) return;
  try {
    await deleteFcmToken();
    if (Capacitor.getPlatform() === 'android' && (await userOptedIn())) {
      await GoldenFcm.unregister();
    }
  } catch { /* ignore */ }
  tokenRegistered = false;
  listenersAttached = false;
  await storageRemove(FCM_REGISTERED_KEY);
  await storageRemove(FCM_USER_OPT_IN_KEY);
}

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