import { apiError, apiJson } from "@/lib/api-handler";
import { resolveApiAuth } from "@/lib/api-auth";
import { getAssistantPreferences } from "@/lib/assistant-preference";
import { isValidAssistantModelRoute, listLlmModels, resolveAssistantModel } from "@/lib/llm/models";

export const dynamic = "force-dynamic";

function noStore(response: Response): Response {
  response.headers.set("Cache-Control", "no-store");
  return response;
}

export async function GET(request: Request) {
  const auth = await resolveApiAuth(request);
  if (!auth?.userId) {
    return noStore(apiError("Unauthorized", 401));
  }

  const assistant = await getAssistantPreferences(auth.userId);
  if (!assistant.enabled) {
    return noStore(apiError("Assistant not enabled", 403));
  }

  const requestedRoute = new URL(request.url).searchParams.get("route");
  if (requestedRoute !== null && !isValidAssistantModelRoute(requestedRoute)) {
    return noStore(apiError("Invalid assistant model route", 400));
  }

  const modelRoute = requestedRoute ?? assistant.modelRoute;
  const modelList = await listLlmModels({ route: modelRoute });
  const resolved = resolveAssistantModel({
    requestedModel: null,
    savedModel: requestedRoute === null ? assistant.model : null,
    fallbackModel: modelList.fallbackModel,
    models: modelList.models,
  });

  return noStore(
    apiJson({
      models: modelList.models,
      selectedModel: resolved.model,
      fallbackModel: modelList.fallbackModel,
      route: modelList.route,
      degraded: modelList.degraded,
    }),
  );
}