import { isVisible } from "./detect";
import { extractDomain } from "../shared/domain";

function getRegistrableDomain(hostname: string): string {
  return extractDomain(hostname) ?? hostname;
}

function checkFormAction(form: HTMLFormElement | null, expectedDomain: string): boolean {
  if (!form?.action) return true;
  try {
    const actionUrl = new URL(form.action);
    const actionDomain = getRegistrableDomain(actionUrl.hostname);
    if (actionDomain !== expectedDomain) {
      return false;
    }
  } catch {}
  return true;
}

export function fillFields(
  usernameEl: HTMLInputElement | null,
  passwordEl: HTMLInputElement | null,
  username: string,
  password: string,
  form?: HTMLFormElement | null,
  expectedDomain?: string
): void {
  if (expectedDomain && form && !checkFormAction(form, expectedDomain)) {
    return;
  }
  // Fill username regardless of visibility — on SPA step-by-step login flows
  // the username input may be visually hidden but still tracked by the form.
  if (usernameEl && username) {
    setNativeValue(usernameEl, username);
  }
  if (passwordEl && isVisible(passwordEl)) {
    setNativeValue(passwordEl, password);
  }
}

function setNativeValue(el: HTMLInputElement, value: string): void {
  const nativeInputValueSetter = Object.getOwnPropertyDescriptor(
    window.HTMLInputElement.prototype,
    "value"
  )?.set;
  nativeInputValueSetter?.call(el, value);
  el.dispatchEvent(new Event("input", { bubbles: true }));
  el.dispatchEvent(new Event("change", { bubbles: true }));
}