import type { ApplicationList } from "../../core/applications/application-list";
import type { PayloadOf, NavigationTarget } from "../../runtime/topics";

type ResolvedNavigation =
  | { status: "navigable"; href: string }
  | { status: "pending" }
  | { status: "refused" };

const APPLICATION_ROUTE =
  /^\/(?:(?:media|canvas)(?=\/|$)|(?:studio|application|local)\/([^/]+))/;

function applicationRoute(pathname: string) {
  const [base, id] = APPLICATION_ROUTE.exec(pathname) ?? [];
  return base === undefined ? null : { base, id };
}

export function targetOf(
  applications: ApplicationList,
  href: string,
): NavigationTarget {
  const url = new URL(href, window.location.origin);
  const route = applicationRoute(url.pathname);
  const application = route && applications.findByPath(url.pathname);
  if (!route || !application) return { appId: null, path: hrefOf(url) };
  return {
    appId: application.id,
    path: hrefOf(url).slice(route.base.length).replace(/^\/+/, ""),
  };
}

export function resolveNavigation(
  applications: ApplicationList | null,
  { url }: PayloadOf<"navigation.location.update">,
): ResolvedNavigation {
  const target = sameOriginUrl(url);
  if (!target) return { status: "refused" };
  if (!applications && applicationRoute(target.pathname)) {
    return { status: "pending" };
  }

  return { status: "navigable", href: hrefOf(target) };
}

export function normalizeHref(href: string): string {
  return hrefOf(new URL(href, window.location.origin));
}

function sameOriginUrl(href: string): URL | null {
  try {
    const url = new URL(href, window.location.origin);
    return url.origin === window.location.origin ? url : null;
  } catch {
    return null;
  }
}

function hrefOf({ pathname, search, hash }: URL): string {
  return pathname + search + hash;
}