import { NextRequest, NextResponse } from "next/server";
import { getApiUrlFromRequest, getPaymentConfig } from "@/config/services.config";
import {
  checkPaymentsByUserId,
  checkSiteVipByUserId,
  findLinkedMemberFromOrder,
  findVipEmailLinkByAnonymousUserId,
  getAdminToken,
  isAnonymousUserId,
  upsertVipEmailLink,
} from "@/app/api/vip/_helpers";

type PayjsVipResult = {
  vip: boolean;
  email?: string;
};

function resolvePayApiUrl(request: NextRequest): string {
  const payConfig = getPaymentConfig();
  const hostHeader = request.headers.get("host") || request.headers.get("x-forwarded-host");
  return (
    (hostHeader ? getApiUrlFromRequest(hostHeader) : null) ||
    process.env.PAYMENT_API_URL ||
    process.env.NEXT_PUBLIC_API_URL ||
    payConfig.apiUrl
  ).replace(/\/$/, "");
}

async function checkVipFromPayjsapi(
  request: NextRequest,
  userId: string
): Promise<PayjsVipResult | null> {
  try {
    const apiUrl = resolvePayApiUrl(request);
    const url = `${apiUrl}/nomadvip/check_vip?user_id=${encodeURIComponent(
      userId
    )}`;
    console.log("[check-by-user] payjsapi request user_id=%s url=%s", userId, url);
    const res = await fetch(
      url,
      { cache: "no-store", signal: AbortSignal.timeout(5000) }
    );
    if (!res.ok) {
      console.log(
        "[check-by-user] payjsapi non-ok user_id=%s status=%s",
        userId,
        res.status
      );
      return null;
    }

    const data = await res.json().catch(() => ({}));
    const result = {
      vip: !!data?.vip,
      email:
        typeof data?.email === "string" && data.email.trim()
          ? data.email.trim().toLowerCase()
          : undefined,
    };
    console.log(
      "[check-by-user] payjsapi response user_id=%s vip=%s email=%s",
      userId,
      result.vip,
      result.email ?? "(none)"
    );
    return result;
  } catch (error) {
    console.log(
      "[check-by-user] payjsapi request failed user_id=%s error=%s",
      userId,
      error instanceof Error ? error.message : String(error)
    );
    return null;
  }
}

export async function POST(request: NextRequest) {
  const body = await request.json().catch(() => ({}));
  const userId = String(body?.user_id ?? body?.userId ?? "").trim();

  console.log("[check-by-user] request user_id=%s", userId || "(empty)");

  if (!userId) {
    return NextResponse.json(
      { ok: false, vip: false, error: "缺少 user_id" },
      { status: 400 }
    );
  }

  const payjsResult = await checkVipFromPayjsapi(request, userId);
  let vip = !!payjsResult?.vip;
  let email = payjsResult?.email ?? null;
  let linkedUserId: string | undefined;
  let vipFromSite = false;
  let vipFromPayments = false;
  let vipSource = vip ? "payjsapi" : "none";

  try {
    if (vip) {
      console.log(
        "[check-by-user] hit payjsapi user_id=%s alreadyLinked=%s",
        userId,
        !!email
      );
      return NextResponse.json({
        ok: true,
        vip: true,
        alreadyLinked: !!email,
        email: email ?? undefined,
      });
    }

    const adminToken = await getAdminToken();
    if (!adminToken) {
      console.error("[check-by-user] missing PocketBase admin token");
      return NextResponse.json({ ok: false, vip: false }, { status: 500 });
    }

    if (!vip) {
      vipFromSite = await checkSiteVipByUserId(adminToken, userId);
      vip = vipFromSite;
      if (!vip) {
        vipFromPayments = await checkPaymentsByUserId(adminToken, userId);
        vip = vipFromPayments;
      }
      if (vipFromSite) {
        vipSource = "pocketbase:site_vip";
      } else if (vipFromPayments) {
        vipSource = "pocketbase:payments";
      }
      console.log(
        "[check-by-user] pb fallback user_id=%s site_vip=%s payments=%s",
        userId,
        vipFromSite,
        vipFromPayments
      );
    }

    if (vip && !email && isAnonymousUserId(userId)) {
      const linkRecord = await findVipEmailLinkByAnonymousUserId(
        adminToken,
        userId
      );
      const linkEmail =
        typeof linkRecord?.email === "string"
          ? linkRecord.email.trim().toLowerCase()
          : "";
      const linkUserId =
        typeof linkRecord?.user_id === "string" ? linkRecord.user_id.trim() : "";

      if (linkEmail) {
        email = linkEmail;
        if (linkUserId && !isAnonymousUserId(linkUserId)) {
          linkedUserId = linkUserId;
        }
        vipSource = "vip_email_link";
        console.log(
          "[check-by-user] linked by vip_email_link user_id=%s linkedUserId=%s email=%s",
          userId,
          linkedUserId || "(none)",
          email
        );
      } else {
        const linkedMember = await findLinkedMemberFromOrder(adminToken, userId);
        if (linkedMember) {
          email = linkedMember.email;
          linkedUserId = linkedMember.userId;
          await upsertVipEmailLink(
            adminToken,
            linkedMember.email,
            linkedMember.userId,
            userId
          );
          vipSource = "linked_from_order";
          console.log(
            "[check-by-user] linked by order user_id=%s linkedUserId=%s email=%s",
            userId,
            linkedUserId,
            email
          );
        }
      }
    }

    console.log(
      "[check-by-user] result user_id=%s vip=%s source=%s alreadyLinked=%s linkedUserId=%s",
      userId,
      vip,
      vipSource,
      !!email,
      linkedUserId || "(none)"
    );

    return NextResponse.json({
      ok: true,
      vip,
      alreadyLinked: !!email,
      email: email ?? undefined,
      linkedUserId,
    });
  } catch (error) {
    console.error("[check-by-user] failed:", error);
    return NextResponse.json({ ok: false, vip: false }, { status: 500 });
  }
}