// Copyright 2026 The Lynx Authors. All rights reserved.
// Licensed under the Apache License Version 2.0 that can be found in the
// LICENSE file in the root directory of this source tree.

import type { ComponentChild, ContainerNode } from 'preact';
import { render } from 'preact';

import { canReEvalBackgroundEntry, reEvalBackgroundEntry } from '../../core/entry-reload.js';
import { applyUpdatePageData } from '../../core/lynx-page-data.js';
import { increaseReloadVersion } from '../../core/reload-version.js';
import { resetElementTemplateCommitState } from '../background/commit-hook.js';
import { destroyElementTemplateBackgroundRuntime } from '../background/destroy.js';
import { setupBackgroundElementTemplateDocument } from '../background/document.js';
import { installElementTemplateHydrationListener } from '../background/hydration-listener.js';
import { BackgroundPageRootInstance } from '../background/instance.js';
import { profileEnd, profileStart } from '../debug/profile.js';
import { resetEventStateForRuntime } from '../prop-adapters/event.js';
import { __root, setRoot } from '../runtime/page/root-instance.js';

export function reloadBackground(updateData: unknown, options?: Record<string, unknown>): void {
  if (canReEvalBackgroundEntry()) {
    reEvalBackgroundEntry(updateData as Record<string, unknown>, options, () => {
      // The unmount of the old tree must not reach the new entry.
      resetElementTemplateCommitState();
      // A queued `updateGlobalProps` callback must not render it again.
      __root.__jsx = undefined;
    });
    return;
  }

  if (typeof __PROFILE__ !== 'undefined' && __PROFILE__) {
    profileStart('ReactLynx::reloadBackground');
  }

  try {
    const jsx = __root.__jsx;
    destroyElementTemplateBackgroundRuntime();
    increaseReloadVersion();
    // Reload creates a new object so InitData Provider / Consumer observers do
    // not retain the pre-reload object identity.
    lynx.__initData = Object.assign({}, lynx.__initData);
    applyUpdatePageData(updateData);

    setRoot(new BackgroundPageRootInstance());
    __root.__jsx = jsx;
    setupBackgroundElementTemplateDocument();
    installElementTemplateHydrationListener();
    resetEventStateForRuntime();
    render(jsx as ComponentChild, __root as unknown as ContainerNode);
  } finally {
    if (typeof __PROFILE__ !== 'undefined' && __PROFILE__) {
      profileEnd();
    }
  }
}