import {
  ACCESS_TOKEN,
  AUTH_USER_ID,
  CLAIM_NAME,
  REFRESH_TOKEN,
  SERVER_API_URL,
  SITE_ID,
  DEVICE_ID,
} from "@/shared/config";
import { cookies } from "next/headers";
import { NextResponse } from "next/server";

async function handler(
  request: Request,
  params: { url: string[] },
  method: "GET" | "POST" | "PUT" | "DELETE",
) {
  const cookieStore = await cookies();
  const headers: Record<string, string> = {
    "Content-Type": "application/json",
    "X-Site-Id": SITE_ID,
  };
  let body = {};

  const isRefreshHandler = params.url.includes("refresh");
  const isLoginHandler = params.url.includes("login");

  // ── Silent Refresh ──────────────────────────────────────────────────────────
  // HttpOnly 쿠키에서 refresh-token 꺼내 Authorization 헤더에 주입.
  // 쿠키에 저장된 device-id도 X-Device-Id 헤더로 함께 전달한다.
  // 백엔드: TokenProvider.refreshToken(token, request, response)
  //   → userService.findByRefreshToken(refreshToken, deviceId)   (Redis Hash 검증)
  //   → userService.updateRefreshToken(userUnqId, newToken, deviceId) (RTR 갱신)
  if (isRefreshHandler) {
    const refreshToken = cookieStore.get(REFRESH_TOKEN);
    headers[CLAIM_NAME] = refreshToken?.value ?? "";

    if (!headers[CLAIM_NAME]) {
      return NextResponse.json({ message: "Can't refresh" }, { status: 401 });
    }

    // device-id 쿠키 → X-Device-Id 헤더 (Redis 다중 세션 식별)
    const deviceId = cookieStore.get(DEVICE_ID);
    if (deviceId?.value) {
      headers["X-Device-Id"] = deviceId.value;
    }
  }

  // ── Login ────────────────────────────────────────────────────────────────────
  // 클라이언트(login-service.ts)가 fetch 헤더에 X-Device-Id 를 포함해서 전송한다.
  // BFF는 해당 헤더를 그대로 백엔드로 포워딩한다.
  // 백엔드: AuthenticationFilter.successfulAuthentication
  //   → TokenProvider.createTokenAndAddHeader(request, ...)
  //   → request.getHeader("X-Device-Id") 로 deviceId 추출
  //   → userService.updateRefreshToken(userUnqId, refreshToken, deviceId)
  //   → Redis Hash[user:sessions:{userUnqId}][deviceId] = refreshToken (TTL 1일)
  if (isLoginHandler) {
    const deviceId = request.headers.get("X-Device-Id");
    if (deviceId) {
      headers["X-Device-Id"] = deviceId;
    }
  }

  try {
    if (!isRefreshHandler) {
      body = await request.json();
    }

    const result = await fetch(`${SERVER_API_URL}/${params.url.join("/")}`, {
      method,
      headers,
      body: JSON.stringify(body),
    });

    if (!result.ok) {
      return NextResponse.json(
        { message: "Invalid Credentials" },
        { status: 401 },
      );
    }

    const accessToken = result.headers.get(ACCESS_TOKEN);
    const refreshToken = result.headers.get(REFRESH_TOKEN);
    const userId = result.headers.get(AUTH_USER_ID);

    if (accessToken && userId) {
      const response = NextResponse.json({
        [ACCESS_TOKEN]: accessToken,
        [AUTH_USER_ID]: userId,
      });

      const forwardedHost = request.headers.get("x-forwarded-host");
      const host = request.headers.get("host");
      const rawHost =
        forwardedHost || host || new URL(request.url).hostname.toString();

      // 포트 번호 제거 (예: "localhost:3000" → "localhost")
      const hostname = rawHost.split(":")[0];

      // 쿠키 domain 결정
      // - localhost / 127.0.0.1: domain 미지정 (undefined) → 브라우저 기본 동작
      // - 운영(hasuon.or.kr): 서브도메인 공유를 위해 최상위 도메인 앞에 점(.) 붙임
      // - 그 외(IP, 기타 도메인): 현재 hostname 그대로 사용
      const isLocal = hostname === "localhost" || hostname === "127.0.0.1";
      const domain = isLocal
        ? undefined
        : hostname.includes("hasuon.or.kr")
          ? ".hasuon.or.kr"
          : hostname;

      if (refreshToken) {
        cookieStore.set(REFRESH_TOKEN, refreshToken, {
          httpOnly: true,
          sameSite: "strict",
          ...(domain !== undefined && { domain }),
          path: "/",
        });
      }

      return response;
    }

    return NextResponse.json(
      { message: "Invalid Credentials" },
      { status: 401 },
    );
  } catch (error) {
    return NextResponse.json(
      { message: "Server Error", error },
      { status: 500 },
    );
  }
}

export async function POST(
  request: Request,
  props: { params: Promise<{ url: string[] }> },
) {
  const params = await props.params;
  return handler(request, params, "POST");
}

export async function PUT(
  request: Request,
  props: { params: Promise<{ url: string[] }> },
) {
  const params = await props.params;
  return handler(request, params, "PUT");
}