/**
 * The whole site: sign in with an ATProto account, design a camo, read what
 * this is.
 *
 * The entry point only. It fills in the navigation a screen cannot import,
 * finds the masthead the layout rendered, catches anything that escapes, and
 * hands over to the router.
 */

import { ApiError } from "./api";
import { collectNavLinks } from "./chrome";
import { render } from "./dom";
import { nav } from "./nav";
import { markEntered, onHashChange, start } from "./router";
import { challengeScreen } from "./screens/challenge";
import { errorScreen } from "./screens/error";
import { matchesScreen } from "./screens/matches";

// The screens a screen can send the player to that it cannot import. See nav.ts.
nav.start = start;
nav.matches = matchesScreen;
nav.markShown = markEntered;
// Re-entering without a fresh Mode choice (waiting.ts's Back button) gets
// the least restrictive pool, Scenario, rather than silently narrowing to
// Duel's.
nav.challenge = (session) => challengeScreen(session, "scenario");

/**
 * Until start() renders, the page is the CSS "Loading…" on #app[aria-busy]. An
 * exception on the way there would leave that on screen for good, so both
 * channels an escaping error can take get turned into a screen with a way out.
 *
 * One shot: if the error screen's own render is what threw, a second pass would
 * only loop.
 */
let trapped = false;

function trap(channel: string, reason: unknown): void {
  if (trapped) return;
  trapped = true;
  // Names the channel, and says the trap - not the app - put that screen up.
  // The browser's own logging of the error is untouched.
  console.error(`trap: an error escaped the app (${channel})`, reason);
  render(
    ...errorScreen(
      // ApiError messages are written to be read; anything else is a stack
      // trace's worth of noise the player cannot act on.
      reason instanceof ApiError
        ? reason.message
        : "An unexpected error interrupted the page.",
      () => {
        window.location.reload();
      },
    ),
  );
}

window.addEventListener("error", (event) => {
  // Failed subresource loads fire here too, with the element as the target. A
  // missing image is no reason to throw away the whole page.
  if (event.target !== window) return;
  trap("error", event.error);
});

window.addEventListener("unhandledrejection", (event) => {
  trap("unhandledrejection", event.reason);
});

window.addEventListener("hashchange", onHashChange);

collectNavLinks();
void start();