import { NextResponse } from 'next/server';
import { getPublicOrigin } from '@/lib/auth/public-origin';
import {
  AUTH_COOKIE,
  OAUTH_STATE_COOKIE,
  authCookieOptions,
  createAuthSession,
  parseOAuthStateCookie,
  serializeAuthSession,
} from '@/lib/auth/session';
import {
  exchangeAuthorizationCode,
  fetchAuthedUser,
  revokeToken,
} from '@/lib/chzzk/oauth';
import {
  cancelScheduledDisconnectRoomChat,
  ensureRoomChat,
} from '@/lib/chzzk/chat-session';
import {
  clearDiceQueue,
  createRoom,
  findRoomByChannelId,
  getRoom,
  notifyRoom,
} from '@/lib/rooms/store';

export const runtime = 'nodejs';

function homeRedirect(origin: string, error?: string) {
  const url = new URL('/', origin);
  if (error) url.searchParams.set('authError', error);
  else url.searchParams.set('auth', 'ok');
  return url;
}

/**
 * 치지직 OAuth 콜백.
 * 채널 ID 확인 → 우리 세션 쿠키만 저장 → 치지직 토큰 폐기 → 룸 입장
 */
export async function GET(request: Request) {
  const url = new URL(request.url);
  const origin = getPublicOrigin(request);
  const code = url.searchParams.get('code') || '';
  const state = url.searchParams.get('state') || '';
  const stateCookie = request.headers
    .get('cookie')
    ?.match(/(?:^|;\s*)drinkmarble_oauth_state=([^;]+)/)?.[1];

  const decodedState = stateCookie
    ? parseOAuthStateCookie(decodeURIComponent(stateCookie))
    : null;

  if (!code || !state || !decodedState || decodedState.state !== state) {
    const res = NextResponse.redirect(
      homeRedirect(origin, '로그인 검증에 실패했습니다. 다시 시도해 주세요.'),
    );
    res.cookies.delete(OAUTH_STATE_COOKIE);
    return res;
  }

  let accessToken: string | null = null;
  let refreshToken: string | null = null;

  try {
    const tokens = await exchangeAuthorizationCode(code, state);
    accessToken = tokens.accessToken;
    refreshToken = tokens.refreshToken;

    const user = await fetchAuthedUser(accessToken);
    const session = createAuthSession(user.channelId, user.channelName);

    // 치지직 토큰은 저장하지 않고 즉시 폐기
    await revokeToken(accessToken, 'access_token');
    if (refreshToken) await revokeToken(refreshToken, 'refresh_token');
    accessToken = null;
    refreshToken = null;

    let room = findRoomByChannelId(user.channelId);
    if (!room) {
      room = createRoom({
        chzzkEnabled: true,
        liveUrl: `https://chzzk.naver.com/live/${user.channelId}`,
        channelId: user.channelId,
        cheesePerDice: decodedState.cheesePerDice,
        multiplyByCheese: decodedState.multiplyByCheese,
        maxMultiplier: decodedState.maxMultiplier,
      });
    }

    cancelScheduledDisconnectRoomChat(room.id);

    if (decodedState.resetDiceQueue) {
      clearDiceQueue(room.id);
      notifyRoom(room.id);
    }

    try {
      await ensureRoomChat(room.id);
    } catch {
      // 방송 중이 아니어도 세션·룸은 유지하고 게임으로 보냄
    }

    // room.id = 서버 룸 UUID (게임 URL용)
    // user.channelId = 치지직 채널 (세션·room.settings.channelId에 보관)
    const roomId = getRoom(room.id)?.id ?? room.id;
    const res = NextResponse.redirect(new URL(`/game?roomId=${roomId}`, origin));
    res.cookies.set(AUTH_COOKIE, serializeAuthSession(session), authCookieOptions());
    res.cookies.delete(OAUTH_STATE_COOKIE);
    return res;
  } catch {
    if (accessToken) await revokeToken(accessToken, 'access_token');
    if (refreshToken) await revokeToken(refreshToken, 'refresh_token');
    // 외부 오류 원문에는 계정 식별자 등이 포함될 수 있어 고정 문구만 전달한다.
    const res = NextResponse.redirect(
      homeRedirect(origin, '치지직 로그인에 실패했습니다. 다시 시도해 주세요.'),
    );
    res.cookies.delete(OAUTH_STATE_COOKIE);
    return res;
  }
}