import { NextRequest, NextResponse } from "next/server";
import { cookies } from "next/headers";

export async function GET(req: NextRequest) {
  const cookieStore = await cookies();
  const authCookieName =
    process.env.AUTH_COOKIE_NAME || "mintel_gatekeeper_session";
  const password = process.env.GATEKEEPER_PASSWORD || "mintel";

  const session = cookieStore.get(authCookieName);

  // 1. URL Parameter Bypass (for automated tests/staging)
  const originalUrl = req.headers.get("x-forwarded-uri") || "/";
  const host =
    req.headers.get("x-forwarded-host") || req.headers.get("host") || "";
  const proto = req.headers.get("x-forwarded-proto") || "https";

  try {
    const url = new URL(originalUrl, `${proto}://${host}`);
    if (url.searchParams.get("gk_bypass") === password) {
      // Remove the bypass parameter from the redirect URL
      url.searchParams.delete("gk_bypass");
      const cleanUrl = url.pathname + url.search;
      const absoluteCleanUrl = `${proto}://${host}${cleanUrl}`;

      const response = NextResponse.redirect(absoluteCleanUrl);

      // Set the session cookie so the bypass is persistent
      const isDev = process.env.NODE_ENV === "development";
      const cookieDomain = process.env.COOKIE_DOMAIN;
      const sessionValue = JSON.stringify({
        identity: "Bypass",
        timestamp: Date.now(),
      });

      response.cookies.set(authCookieName, sessionValue, {
        httpOnly: true,
        secure: !isDev,
        path: "/",
        maxAge: 30 * 24 * 60 * 60, // 30 days
        sameSite: "lax",
        ...(cookieDomain ? { domain: cookieDomain } : {}),
      });

      return response;
    }
  } catch (_e) {
    // URL parsing failed, proceed with normal logic
  }

  let isAuthenticated = false;
  let identity = "Guest";

  if (session?.value) {
    if (session.value === password) {
      isAuthenticated = true;
    } else {
      try {
        const payload = JSON.parse(session.value);
        if (payload.identity) {
          isAuthenticated = true;
          identity = payload.identity;
        }
      } catch (_e) {
        // Fallback or old format
      }
    }
  }

  if (isAuthenticated) {
    return new NextResponse("OK", {
      status: 200,
      headers: {
        "X-Auth-User": identity,
      },
    });
  }

  // Traefik ForwardAuth headers
  const gatekeeperUrl =
    process.env.NEXT_PUBLIC_BASE_URL || `${proto}://gatekeeper.${host}`;
  const absoluteOriginalUrl = `${proto}://${host}${originalUrl}`;

  const loginUrl = `${gatekeeperUrl}/login?redirect=${encodeURIComponent(absoluteOriginalUrl)}`;

  return NextResponse.redirect(loginUrl);
}