import { NextRequest, NextResponse } from "next/server";
import { COOKIE_NAME } from "@/app/lib/auth-cookie";
import {
  findVipEmailLinkByUserId,
  getActiveSiteVipRecord,
  getAdminToken,
  hasVipByUserId,
  isAnonymousUserId,
} from "@/app/api/vip/_helpers";

type SessionPayload = {
  userId?: string;
  anonymousUserId?: string;
};

function readSessionPayload(request: NextRequest): SessionPayload | null {
  const raw = request.cookies.get(COOKIE_NAME)?.value;
  if (!raw) {
    return null;
  }

  try {
    return JSON.parse(Buffer.from(raw, "base64url").toString("utf-8"));
  } catch {
    return null;
  }
}

export async function GET(request: NextRequest) {
  const payload = readSessionPayload(request);
  const userId =
    typeof payload?.userId === "string" ? payload.userId.trim() : "";
  const anonymousUserId =
    typeof payload?.anonymousUserId === "string"
      ? payload.anonymousUserId.trim()
      : "";

  if (!userId) {
    return NextResponse.json({ ok: true, vip: false });
  }

  try {
    const adminToken = await getAdminToken();
    if (!adminToken) {
      return NextResponse.json({ ok: true, vip: false });
    }

    const userRecord = await getActiveSiteVipRecord(adminToken, userId);
    if (userRecord) {
      return NextResponse.json({
        ok: true,
        vip: true,
        expires_at:
          typeof userRecord.expires_at === "string" ? userRecord.expires_at : null,
      });
    }

    if (await hasVipByUserId(adminToken, userId)) {
      return NextResponse.json({ ok: true, vip: true, expires_at: null });
    }

    const candidates = isAnonymousUserId(anonymousUserId)
      ? [anonymousUserId]
      : [];
    if (!isAnonymousUserId(userId)) {
      const linkRecord = await findVipEmailLinkByUserId(adminToken, userId);
      const linkedAnonymousUserId =
        typeof linkRecord?.anonymous_user_id === "string"
          ? linkRecord.anonymous_user_id.trim()
          : "";
      if (isAnonymousUserId(linkedAnonymousUserId)) {
        candidates.push(linkedAnonymousUserId);
      }
    }

    for (const candidate of candidates) {
      if (await hasVipByUserId(adminToken, candidate)) {
        return NextResponse.json({ ok: true, vip: true, expires_at: null });
      }
    }

    return NextResponse.json({ ok: true, vip: false });
  } catch {
    return NextResponse.json({ ok: true, vip: false });
  }
}