import type { AppContext } from "@/worker/types";
import { hashNullable } from "@/worker/util/request-context";
import { jsonError } from "@/worker/util/response";

export type RateLimitBinding = "RL_AUTH" | "RL_DAV_AUTH" | "RL_REPORT";

export async function rateLimitKey(parts: (string | null | undefined)[]): Promise<string> {
  return (await hashNullable(parts.filter((part): part is string => !!part).join(":"))) ?? "unknown";
}

export async function enforceRateLimit(
  c: AppContext,
  binding: RateLimitBinding,
  keyParts: (string | null | undefined)[],
): Promise<Response | null> {
  if (import.meta.env.DEV) return null;
  const key = await rateLimitKey(keyParts);
  const { success } = await c.env[binding].limit({ key });
  return success ? null : jsonError("rate_limited", "Too many requests.", 429);
}