/**
 * Renders the whole app, its providers around its routes. `main.tsx` mounts
 * it. Its paths follow one rule (`shared/paths.ts`): `@name` is a user, any
 * other word under the root a category or an app page, a view of a page one
 * more segment, and a default view the bare path, with no redirect.
 *
 * - `/` is the feed of every dump on the viewer's default tab, and `/hot`,
 *   `/new`, `/journal` and `/follow` its tabs (`Index`). `/?share_url=` opens
 *   the create form on a shared link.
 * - `/search` and `/search/:searchTab` are the search results (`Search`).
 * - `/register` and `/login` sign up and sign in (`UserRegister`,
 *   `UserLogin`), signed out only, `/login?next=` coming back to a page.
 * - `/authorize` lets another gerbeur instance sign the user in with their
 *   account here (`Authorize`), and `/federation/callback` finishes a sign-in
 *   here with an account on another (`FederationCallback`).
 * - `/reset-password` sets a new password from an emailed link
 *   (`ResetPassword`), and `/unsubscribe` turns off a digest from its emailed
 *   link (`Unsubscribe`).
 * - `/notifications` (`Notifications`) and `/settings` (`Settings`), signed in
 *   only, and `/manage`, the site's tools, for `category:manage` or
 *   `federation:manage` (`Manage`).
 * - `/community` and `/community/monthly`, the site's week and month
 *   (`Community`), signed in only.
 * - `/@:username/*` is a user's (`UserRoutes`): their profile and its tabs,
 *   their dumps at `dumps/:slug` (`Dump`) and `dumps/:slug/edit` (`DumpEdit`,
 *   signed in only), and their playlists at `playlists/:slug`
 *   (`PlaylistDetail`).
 * - `/:categorySlug` and `/:categorySlug/:feedTab` are a category's feed
 *   (`Index`).
 * - Any other path is `NotFound`.
 *
 * The pages not marked are open to anyone. Every page is loaded with its
 * route. Since category slugs share the root with the app's pages and the
 * feed tabs, the server reserves those words as slugs; no slug has an `@`.
 *
 * @module
 */

import { lazy, Suspense } from "react";
import {
  BrowserRouter,
  Route,
  Routes,
  useLocation,
  useParams,
} from "react-router";

import { RestrictedGuest } from "./pages/RestrictedGuest.tsx";
import { RestrictedLoggedIn } from "./pages/RestrictedLoggedIn.tsx";
import { FEED_TABS, type FeedTab } from "../shared/paths.ts";

import { AuthProvider } from "./contexts/auth/AuthProvider.tsx";
import { PlayerProvider } from "./contexts/player/PlayerProvider.tsx";
import { WSProvider } from "./contexts/ws/WSProvider.tsx";
import { FollowProvider } from "./contexts/social/FollowProvider.tsx";
import { CategoriesProvider } from "./contexts/category/CategoriesProvider.tsx";
import { ThemeProvider } from "./contexts/theme/ThemeProvider.tsx";
import { ChatProvider } from "./contexts/chat/ChatProvider.tsx";
import { GlobalPlayer } from "./components/player/GlobalPlayer.tsx";
import { DumpFab } from "./components/layout/DumpFab.tsx";
import { ChatFab } from "./components/layout/ChatFab.tsx";

import "./App.css";

const Index = lazy(() =>
  import("./pages/Index.tsx").then((m) => ({ default: m.Index }))
);
const Dump = lazy(() =>
  import("./pages/Dump.tsx").then((m) => ({ default: m.Dump }))
);
const DumpEdit = lazy(() =>
  import("./pages/DumpEdit.tsx").then((m) => ({ default: m.DumpEdit }))
);
const UserLogin = lazy(() =>
  import("./pages/UserLogin.tsx").then((m) => ({ default: m.UserLogin }))
);
const UserPublicProfile = lazy(() =>
  import("./pages/UserPublicProfile.tsx").then((m) => ({
    default: m.UserPublicProfile,
  }))
);
const UserRegister = lazy(() =>
  import("./pages/UserRegister.tsx").then((m) => ({ default: m.UserRegister }))
);
const PlaylistDetail = lazy(() =>
  import("./pages/PlaylistDetail.tsx").then((m) => ({
    default: m.PlaylistDetail,
  }))
);
const Community = lazy(() =>
  import("./pages/Community.tsx").then((m) => ({ default: m.Community }))
);
const Notifications = lazy(() =>
  import("./pages/Notifications.tsx").then((m) => ({
    default: m.Notifications,
  }))
);
const Settings = lazy(() =>
  import("./pages/Settings.tsx").then((m) => ({ default: m.Settings }))
);
const Manage = lazy(() =>
  import("./pages/Manage.tsx").then((m) => ({ default: m.Manage }))
);
const Search = lazy(() =>
  import("./pages/Search.tsx").then((m) => ({ default: m.Search }))
);
const ResetPassword = lazy(() =>
  import("./pages/ResetPassword.tsx").then((m) => ({
    default: m.ResetPassword,
  }))
);
const Unsubscribe = lazy(() =>
  import("./pages/Unsubscribe.tsx").then((m) => ({ default: m.Unsubscribe }))
);
const Authorize = lazy(() =>
  import("./pages/Authorize.tsx").then((m) => ({ default: m.Authorize }))
);
const FederationCallback = lazy(() =>
  import("./pages/FederationCallback.tsx").then((m) => ({
    default: m.FederationCallback,
  }))
);
const NotFound = lazy(() =>
  import("./pages/NotFound.tsx").then((m) => ({ default: m.NotFound }))
);

/**
 * Renders a feed, of every dump or of `categorySlug`'s, on the tab the path's
 * segment after the scope names, or the viewer's default one on the bare
 * path. Every feed path renders it at the same place in the tree, and the key
 * keeps `Index` mounted on a change of tab, which sorts on the client, and
 * remounts it on a change of category, so that it refetches.
 */
function Feed({ categorySlug }: { categorySlug?: string }) {
  const { pathname } = useLocation();
  const segments = pathname.split("/").filter(Boolean);
  const rest = segments.slice(categorySlug ? 1 : 0);
  const feedTab = rest[0];
  if (
    rest.length > 1 ||
    (feedTab && !(FEED_TABS as readonly string[]).includes(feedTab))
  ) {
    return <NotFound />;
  }
  return (
    <Index
      key={categorySlug ?? ""}
      categorySlug={categorySlug}
      feedTab={feedTab as FeedTab | undefined}
    />
  );
}

/**
 * Renders the pages under user `@:handle`, which the page fetches by name: a
 * former name or another case reaches them too, and the page then puts the
 * current one in its URL. A tab or view the profile doesn't have is
 * `NotFound`, which the profile answers itself.
 */
function UserRoutes() {
  return (
    <Routes>
      <Route path="dumps/:slug" element={<Dump />} />
      <Route
        path="dumps/:slug/edit"
        element={
          <RestrictedLoggedIn>
            <DumpEdit />
          </RestrictedLoggedIn>
        }
      />
      <Route path="playlists/:slug" element={<PlaylistDetail />} />
      <Route path="*" element={<UserPublicProfile />} />
    </Routes>
  );
}

/**
 * Dispatches a path's first segment: `@name` is a user's, any other word a
 * category's feed, the app's own pages having matched before.
 */
function HandleRoutes() {
  const { handle = "" } = useParams();
  return handle.startsWith("@")
    ? <UserRoutes />
    : <Feed categorySlug={handle} />;
}

/** Renders the route table, and the floating buttons over every page. */
function AppRoutes() {
  return (
    <>
      <Suspense>
        <Routes>
          <Route path="/" element={<Feed />} />
          {FEED_TABS.map((tab) => (
            <Route key={tab} path={`/${tab}`} element={<Feed />} />
          ))}
          <Route path="/search" element={<Search />} />
          <Route path="/search/:searchTab" element={<Search />} />
          <Route
            path="/register"
            element={
              <RestrictedGuest>
                <UserRegister />
              </RestrictedGuest>
            }
          />
          <Route
            path="/login"
            element={
              <RestrictedGuest>
                <UserLogin />
              </RestrictedGuest>
            }
          />
          <Route path="/authorize" element={<Authorize />} />
          <Route
            path="/federation/callback"
            element={<FederationCallback />}
          />
          <Route path="/reset-password" element={<ResetPassword />} />
          <Route path="/unsubscribe" element={<Unsubscribe />} />
          <Route
            path="/notifications"
            element={
              <RestrictedLoggedIn>
                <Notifications />
              </RestrictedLoggedIn>
            }
          />
          {["/community", "/community/:view"].map((path) => (
            <Route
              key={path}
              path={path}
              element={
                <RestrictedLoggedIn>
                  <Community />
                </RestrictedLoggedIn>
              }
            />
          ))}
          <Route
            path="/settings"
            element={
              <RestrictedLoggedIn>
                <Settings />
              </RestrictedLoggedIn>
            }
          />
          <Route
            path="/manage"
            element={
              <RestrictedLoggedIn>
                <Manage />
              </RestrictedLoggedIn>
            }
          />
          <Route path="/:handle/*" element={<HandleRoutes />} />
          <Route path="*" element={<NotFound />} />
        </Routes>
      </Suspense>
      <DumpFab />
      <ChatFab />
    </>
  );
}

/**
 * Renders the app. The theme, player, socket, follow and chat providers read
 * the session, and `ChatProvider` reads the URL, so it sits inside the router.
 * `GlobalPlayer` sits outside the routes, so playback survives navigation.
 */
export function App(): React.JSX.Element {
  return (
    <AuthProvider>
      <ThemeProvider>
        <PlayerProvider>
          <WSProvider>
            <FollowProvider>
              <CategoriesProvider>
                <BrowserRouter>
                  <ChatProvider>
                    <AppRoutes />
                    <GlobalPlayer />
                  </ChatProvider>
                </BrowserRouter>
              </CategoriesProvider>
            </FollowProvider>
          </WSProvider>
        </PlayerProvider>
      </ThemeProvider>
    </AuthProvider>
  );
}