/**
 * Discord Embedded App SDK
 * https://github.com/colyseus/colyseus/issues/707
 *
 * All URLs must go through the local proxy from
 * https://<app_id>.discordsays.com/.proxy/<mapped_url>/...
 *
 * URL Mapping Examples:
 *
 * 1. Using Colyseus Cloud:
 *   - /colyseus/{subdomain} -> {subdomain}.colyseus.cloud
 *
 *   Example:
 *     const client = new Client("https://xxxx.colyseus.cloud");
 *
 * -------------------------------------------------------------
 *
 * 2. Using `cloudflared` tunnel:
 *   - /colyseus/ -> <your-cloudflared-url>.trycloudflare.com
 *
 *   Example:
 *     const client = new Client("https://<your-cloudflared-url>.trycloudflare.com");
 *
 * -------------------------------------------------------------
 *
 * 3. Providing a manual /.proxy/your-mapping:
 *   - /your-mapping/ -> your-endpoint.com
 *
 *   Example:
 *     const client = new Client("/.proxy/your-mapping");
 *
 */
export function discordURLBuilder (url: URL): string {
    const localHostname = window?.location?.hostname || "localhost";

    const remoteHostnameSplitted = url.hostname.split('.');
    const subdomain = (
        !url.hostname.includes("trycloudflare.com") && // ignore cloudflared subdomains
        !url.hostname.includes("discordsays.com") &&  // ignore discordsays.com subdomains
        remoteHostnameSplitted.length > 2
    )
        ? `/${remoteHostnameSplitted[0]}`
        : '';

    return (url.pathname.startsWith("/.proxy"))
        ? `${url.protocol}//${localHostname}${subdomain}${url.pathname}${url.search}`
        : `${url.protocol}//${localHostname}/.proxy/colyseus${subdomain}${url.pathname}${url.search}`;
}