import { NextResponse } from "next/server";
import { isConvexEnabled } from "@/lib/convex/enabled";
import { HttpError, requireAuthContext } from "@/lib/auth/authContext";

export const dynamic = "force-dynamic";

const base64UrlEncodeUtf8 = (input: string) => {
  return Buffer.from(input, "utf8")
    .toString("base64")
    .replace(/\+/g, "-")
    .replace(/\//g, "_")
    .replace(/=+$/g, "");
};

const getRequestOrigin = (request: Request) => {
  const xfProto = request.headers.get("x-forwarded-proto")?.split(",")[0]?.trim();
  const xfHost = request.headers.get("x-forwarded-host")?.split(",")[0]?.trim();
  const host = xfHost || request.headers.get("host") || new URL(request.url).host;
  const protocol = (xfProto || new URL(request.url).protocol.replace(/:$/, "")) + ":";
  return `${protocol}//${host}`;
};

const isLocalHostname = (hostname: string) =>
  hostname === "127.0.0.1" || hostname === "localhost" || hostname === "host.docker.internal";

const maybeProxyForBrowser = (request: Request, rawUrl: string) => {
  const input = String(rawUrl || "").trim();
  if (!input) return input;
  if (input.startsWith("/api/onlyoffice/proxy")) return input;
  try {
    const u = new URL(input);
    if (!isLocalHostname(u.hostname)) return input;
    const origin = getRequestOrigin(request);
    const proxy = new URL("/api/onlyoffice/proxy", origin);
    proxy.searchParams.set("u", base64UrlEncodeUtf8(input));
    return proxy.toString();
  } catch {
    return input;
  }
};

export async function GET(request: Request) {
  if (isConvexEnabled()) {
    try {
      await requireAuthContext();
    } catch (err) {
      if (err instanceof HttpError) {
        return NextResponse.json({ error: "未登录" }, { status: err.status });
      }
      return NextResponse.json({ error: "未登录" }, { status: 401 });
    }

    const { searchParams } = new URL(request.url);
    const fileUrl = searchParams.get("fileUrl");
    if (!fileUrl) {
      return NextResponse.json({ error: "缺少 fileUrl" }, { status: 400 });
    }

    // 说明：Convex + MinIO 模式下，这个接口目前主要用于“外链文件”走 ONLYOFFICE 的场景。
    // 由于外链本身已经是可访问的 URL，这里只做最小透传。
    return NextResponse.json({ signedUrl: maybeProxyForBrowser(request, fileUrl) });
  }

  return NextResponse.json({ error: "当前仅支持 Convex 模式" }, { status: 501 });
}