import { NextRequest, NextResponse } from "next/server";
import { checkRateLimit, clientKeyFromHeaders, tryAcquireInspection } from "@/lib/inspect/admission";
import { inspectHost } from "@/lib/inspect/inspect";
import { InspectionInputError, InspectionPolicyError, InspectionResolutionError } from "@/lib/inspect/policy";

export const runtime = "nodejs";
export const dynamic = "force-dynamic";

function jsonError(error: string, status: number, headers: Record<string, string> = {}) {
  return NextResponse.json({ error }, { status, headers: { "Cache-Control": "no-store", ...headers } });
}

export function classifyInspectionError(error: unknown) {
  if (error instanceof InspectionInputError || error instanceof InspectionPolicyError) return { status: 400, message: error.message };
  if (error instanceof InspectionResolutionError) return { status: 422, message: error.message };
  return { status: 500, message: "Inspection service is temporarily unavailable. Try again shortly." };
}

export async function GET(request: NextRequest) {
  const host = request.nextUrl.searchParams.get("host") ?? "";
  const rate = checkRateLimit(clientKeyFromHeaders(request.headers));
  if (!rate.allowed) return jsonError("Request rate limit reached. Try again shortly.", 429, { "Retry-After": String(rate.retryAfterSeconds) });
  const release = tryAcquireInspection();
  if (!release) {
    return jsonError("Inspection capacity is temporarily full. Try again shortly.", 429, { "Retry-After": "1" });
  }

  try {
    return NextResponse.json(await inspectHost(host), { headers: { "Cache-Control": "no-store" } });
  } catch (error) {
    const classified = classifyInspectionError(error);
    if (classified.status === 500) console.error("inspection_unexpected_error", {
      name: error instanceof Error ? error.name : "UnknownError",
      code: typeof error === "object" && error !== null && "code" in error ? String((error as { code?: unknown }).code ?? "") : "",
    });
    return jsonError(classified.message, classified.status);
  } finally {
    release();
  }
}