galaxy-game/ui/frontend/src/lib/env.ts

// Build-time configuration for the Galaxy gateway. Both values arrive
// through Vite `import.meta.env` and resolve to module-level constants
// at the first import.
//
// `VITE_GATEWAY_BASE_URL` is the base URL of the gateway public REST
// surface. An empty value means "same origin": the single-origin
// deployment serves the UI, the REST surface (`/api/...`), and the
// authenticated Connect-Web edge (`/rpc/...`) behind one host, so the
// browser issues same-origin requests and needs no absolute base. A
// non-empty value (the Vite dev proxy, `tools/local-ci`, the
// integration suite) points REST at that absolute host instead. The
// Connect base is derived from this value by `gatewayRpcBaseUrl`,
// which appends the `/rpc` routing prefix.
//
// `VITE_GATEWAY_RESPONSE_PUBLIC_KEY` is the gateway's response-signing
// Ed25519 public key, encoded as standard (non-URL-safe) base64 of
// the raw 32-byte key. Decoded once on module load and exported as
// `Uint8Array`. The value is only consumed by [GalaxyClient] when a
// signed unary call is dispatched; the unauthenticated routes do not
// need it. An empty or malformed value therefore does not block app
// boot — it surfaces only when the lobby route opens its first
// authenticated call.

const RAW_BASE_URL: string =
	(import.meta.env.VITE_GATEWAY_BASE_URL as string | undefined) ??
	"http://localhost:8080";

const RAW_RESPONSE_PUBLIC_KEY: string =
	(import.meta.env.VITE_GATEWAY_RESPONSE_PUBLIC_KEY as string | undefined) ??
	"";

export const GATEWAY_BASE_URL: string = stripTrailingSlash(RAW_BASE_URL);

/**
 * gatewayRpcBaseUrl is the base URL for the authenticated Connect-Web
 * surface. The edge Caddy and the Vite dev proxy route the `/rpc`
 * prefix to the gateway's Connect listener, stripping it before the
 * request reaches the proto-derived `edge.v1.Gateway` service path.
 * When `GATEWAY_BASE_URL` is empty the gateway shares the document
 * origin, so the origin is resolved at call time from `window`.
 */
export function gatewayRpcBaseUrl(): string {
	const origin =
		GATEWAY_BASE_URL ||
		(typeof window !== "undefined" ? window.location.origin : "");
	return `${origin}/rpc`;
}

export const GATEWAY_RESPONSE_PUBLIC_KEY: Uint8Array = decodeBase64(
	RAW_RESPONSE_PUBLIC_KEY,
);

function stripTrailingSlash(url: string): string {
	return url.endsWith("/") ? url.slice(0, -1) : url;
}

function decodeBase64(value: string): Uint8Array {
	if (value.length === 0) {
		return new Uint8Array();
	}
	const binary = atob(value);
	const bytes = new Uint8Array(binary.length);
	for (let i = 0; i < binary.length; i++) {
		bytes[i] = binary.charCodeAt(i);
	}
	return bytes;
}