import {
  lazy,
  Suspense,
  useCallback,
  useEffect,
  useRef,
  useState,
} from 'react';

import { useAuthUi } from './components/auth/AuthUiContext';
import { PlatformEntryFlowShell } from './components/platform-entry/PlatformEntryFlowShell';
import { getInitialPlatformDesktopLayout } from './components/platform-entry/platformEntryResponsive';
import type {
  CustomWorldRuntimeLaunchOptions,
  SelectionStage,
} from './components/platform-entry/platformEntryTypes';
import { useHostNavigationCanGoBack } from './hooks/useHostNavigationCanGoBack';
import type { HydratedSavedGameSnapshot } from './persistence/runtimeSnapshotTypes';
import {
  APP_RUNTIME_ROUTES,
  isAppHistoryState,
  normalizeAppPath,
  pushAppHistoryPath,
  readPublicWorkCodeFromLocationSearch,
  replaceAppHistoryPath,
  resolveInitialSelectionStageFromPath,
  resolvePathForSelectionStage,
  shouldRedirectEditorCanvasWithoutProject,
} from './routing/appPageRoutes';
import type { RpgRuntimeAppIntent } from './RpgRuntimeApp';
import {
  resolveAppTitleForSelectionStage,
  syncAppTitle,
} from './services/appTitle';
import {
  refreshNativeAppHostRuntime,
  subscribeHostRuntimeChange,
} from './services/host-bridge/hostBridge';
import type { CustomWorldProfile } from './types';

const RpgRuntimeApp = lazy(async () => {
  const module = await import('./RpgRuntimeApp');
  return {
    default: module.RpgRuntimeApp,
  };
});

function RuntimeLoadingFallback() {
  return (
    <div className="platform-ui-shell platform-viewport-shell platform-theme platform-theme--dark flex h-screen items-center justify-center bg-[image:var(--platform-body-fill)] p-4 font-sans text-[var(--platform-text-strong)]">
      <div className="platform-subpanel rounded-2xl px-5 py-4 text-sm text-zinc-300">
        正在启动
      </div>
    </div>
  );
}

function isRpgRuntimeRoute(pathname: string) {
  const normalizedPath = normalizeAppPath(pathname);
  return (
    normalizedPath === APP_RUNTIME_ROUTES['rpg-character-select'] ||
    normalizedPath === APP_RUNTIME_ROUTES['rpg-adventure']
  );
}

function resolveInitialAppSelectionStage() {
  if (
    shouldRedirectEditorCanvasWithoutProject(
      window.location.pathname,
      window.location.search,
    )
  ) {
    replaceAppHistoryPath('/creation');
    return 'creation-home';
  }

  return resolveInitialSelectionStageFromPath(
    window.location.pathname,
    getInitialPlatformDesktopLayout(),
  );
}

export default function App() {
  const authUi = useAuthUi();
  const runtimeIntentTokenRef = useRef(0);
  const hasHostNavigationAnchorRef = useRef(
    isAppHistoryState(window.history.state),
  );
  const hostNavigation = useHostNavigationCanGoBack();
  const [runtimeIntent, setRuntimeIntent] =
    useState<RpgRuntimeAppIntent | null>(null);
  const [, setHostRuntimeRevision] = useState(0);
  const [isRuntimeActive, setIsRuntimeActive] = useState(() =>
    isRpgRuntimeRoute(window.location.pathname),
  );
  const [selectionStage, setRawSelectionStage] = useState<SelectionStage>(
    resolveInitialAppSelectionStage,
  );
  const [runtimeReturnStage, setRuntimeReturnStage] =
    useState<SelectionStage>('platform');
  const [initialPublicWorkCode] = useState(() =>
    readPublicWorkCodeFromLocationSearch(window.location.search),
  );

  const setSelectionStage = useCallback(
    (stage: SelectionStage, options?: { path?: string }) => {
      setRawSelectionStage(stage);
      pushAppHistoryPath(options?.path ?? resolvePathForSelectionStage(stage));
    },
    [],
  );

  useEffect(() => {
    const unsubscribe = subscribeHostRuntimeChange(() => {
      setHostRuntimeRevision((revision) => revision + 1);
    });

    void refreshNativeAppHostRuntime();

    return unsubscribe;
  }, []);

  useEffect(() => {
    const syncStageFromHistory = () => {
      hasHostNavigationAnchorRef.current = isAppHistoryState(
        window.history.state,
      );

      if (
        shouldRedirectEditorCanvasWithoutProject(
          window.location.pathname,
          window.location.search,
        )
      ) {
        replaceAppHistoryPath('/creation');
        setIsRuntimeActive(false);
        setRawSelectionStage('creation-home');
        return;
      }

      if (isRpgRuntimeRoute(window.location.pathname)) {
        setIsRuntimeActive(true);
        return;
      }

      setIsRuntimeActive(false);
      setRawSelectionStage(
        resolveInitialSelectionStageFromPath(
          window.location.pathname,
          getInitialPlatformDesktopLayout(),
        ),
      );
    };

    window.addEventListener('popstate', syncStageFromHistory);
    return () => window.removeEventListener('popstate', syncStageFromHistory);
  }, []);

  useEffect(() => {
    if (
      !hostNavigation.isSupported ||
      hostNavigation.canGoBack ||
      isRuntimeActive ||
      selectionStage === 'platform' ||
      isAppHistoryState(window.history.state) ||
      hasHostNavigationAnchorRef.current
    ) {
      return;
    }

    const currentPath = normalizeAppPath(window.location.pathname);
    const currentSearch = window.location.search;

    hasHostNavigationAnchorRef.current = true;
    replaceAppHistoryPath('/');
    pushAppHistoryPath(`${currentPath}${currentSearch}`);
  }, [
    hostNavigation.canGoBack,
    hostNavigation.isSupported,
    isRuntimeActive,
    selectionStage,
  ]);

  const createRuntimeIntent = useCallback(
    (intent: Omit<RpgRuntimeAppIntent, 'token'>) => {
      runtimeIntentTokenRef.current += 1;
      setRuntimeIntent({
        ...intent,
        token: runtimeIntentTokenRef.current,
      });
      setIsRuntimeActive(true);
    },
    [],
  );

  const handleContinueGame = useCallback(
    (snapshot?: HydratedSavedGameSnapshot | null) => {
      createRuntimeIntent({
        kind: 'snapshot',
        snapshot: snapshot ?? null,
      });
    },
    [createRuntimeIntent],
  );

  const handleCustomWorldSelect = useCallback(
    (
      customWorldProfile: CustomWorldProfile,
      options?: CustomWorldRuntimeLaunchOptions,
    ) => {
      // 中文注释：作品测试需要在结束测试后精确返回启动它的结果页；
      // 正式进入世界仍保持既有平台首页返回语义。
      setRuntimeReturnStage(options?.returnStage ?? 'platform');
      createRuntimeIntent({
        kind: 'custom-world',
        profile: customWorldProfile,
        mode: options?.mode ?? 'play',
        disablePersistence: options?.disablePersistence,
        exitToResult: options?.returnStage === 'custom-world-result',
      });
    },
    [createRuntimeIntent],
  );
  const platformThemeClass =
    authUi?.platformTheme === 'dark'
      ? 'platform-theme--dark'
      : 'platform-theme--light';
  const isImageEditorStage = selectionStage === 'image-editor';
  const platformShellSurfaceClass = isImageEditorStage
    ? 'bg-white p-0'
    : 'bg-[image:var(--platform-body-fill)] p-2 sm:p-4';

  useEffect(() => {
    syncAppTitle(
      isRuntimeActive
        ? 'RPG 运行中 - 陶泥儿'
        : resolveAppTitleForSelectionStage(selectionStage),
    );
  }, [isRuntimeActive, selectionStage]);

  if (isRuntimeActive) {
    return (
      <Suspense fallback={<RuntimeLoadingFallback />}>
        <RpgRuntimeApp
          initialIntent={runtimeIntent}
          onExitRuntime={() => {
            setIsRuntimeActive(false);
            setSelectionStage(runtimeReturnStage);
          }}
        />
      </Suspense>
    );
  }

  return (
    <div
      className={`platform-ui-shell platform-viewport-shell platform-theme ${platformThemeClass} flex flex-col overflow-hidden ${platformShellSurfaceClass} font-sans text-[var(--platform-text-strong)]`}
    >
      <PlatformEntryFlowShell
        selectionStage={selectionStage}
        setSelectionStage={setSelectionStage}
        initialPublicWorkCode={initialPublicWorkCode}
        hasSavedGame={false}
        savedSnapshot={null}
        handleContinueGame={handleContinueGame}
        handleStartNewGame={() => {}}
        handleCustomWorldSelect={handleCustomWorldSelect}
      />
    </div>
  );
}