import type { Upstream } from '../upstream.ts';
import type { CacheContext } from './cache.ts';

/** Everything a gateway route reads from: the network through `Upstream`, the cache, and the two
 * microcosm services it passes through to. */
export interface Gateway extends CacheContext {
  fetch: Upstream;
  /** This worker's origin. Cache keys live under it. */
  origin: string;
  slingshot: string;
  constellation: string;
}

/** A cache key: a URL under this worker's origin, with the params in a fixed order so equivalent
 * requests share one entry. */
export function cacheKey(g: Gateway, path: string, params: Record<string, string | undefined>): string {
  const url = new URL(path, g.origin);
  for (const [name, value] of Object.entries(params).sort(([a], [b]) => a.localeCompare(b))) {
    if (value !== undefined) url.searchParams.set(name, value);
  }
  return url.toString();
}