import type { Request } from "express";

/**
 * Public HTTPS origin this request arrived on (e.g. https://broadwaydental.mydentalofficemanagement.com).
 * Derived from the Host header rather than an env var so it's automatically correct
 * per-office — each office's nginx forwards its own public hostname in Host,
 * and Cloudflare/Let's Encrypt terminate TLS in front of it either way.
 *
 * Only valid for requests that actually arrived via the public tunnel (i.e. inside
 * a Twilio webhook handler). For anything triggered from the staff browser — which
 * reaches the backend over the LAN-only local-* hostname — use getTwilioPublicBaseUrl()
 * instead, since Twilio can never reach that LAN hostname to fetch a callback URL.
 */
export function getPublicBaseUrl(req: Request): string {
  return `https://${req.get("host")}`;
}

/**
 * Fixed public origin Twilio must use to call back into this office's server
 * (e.g. for outbound-call TwiML webhooks). Comes from CLOUDFLARE_HOST, the
 * per-office env var already reserved for this — not derived from the
 * triggering request, since that request may have arrived over the LAN-only
 * hostname, which Twilio cannot reach.
 */
export function getTwilioPublicBaseUrl(): string {
  const host = process.env.CLOUDFLARE_HOST?.trim();
  if (!host) {
    throw new Error(
      "CLOUDFLARE_HOST is not set — required to build a Twilio-reachable callback URL. Set it in .env to this office's public tunnel hostname."
    );
  }
  return `https://${host}`;
}