/*
 * Copyright (C)  2021-2022 Kristóf Marussy <kristof@marussy.com>
 *
 * This file is part of Sophie.
 *
 * Sophie is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, version 3.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 * SPDX-License-Identifier: AGPL-3.0-only
 */

import { ipcRenderer, webFrame } from 'electron';
import { ServiceToMainIpcMessage, webSource } from '@sophie/service-shared';

if (webFrame.parent === null) {
  // Inject CSS to simulate `browserView.setBackgroundColor`.
  // This is injected before the page loads, so the styles from the website will overwrite it.
  webFrame.insertCSS('html { background-color: #fff; }');
}

/**
 * Fetches and executes the service inject script in the isolated world.
 *
 * The service inject script relies on exposed APIs, so this function can only
 * be called after APIs have been exposed via `contextBridge` to the main world.
 *
 * We have to call `executeJavaScriptInIsolatedWorld` from the service preload script,
 * beause there is no way currently (electron 16) to execute a script on a
 * `WebFrameMain` in the main process by specifying a `WebSource`.
 * Calling `executeJavaScriptInInsolatedWorld` on a `WebContents` in the main process
 * will always inject the script into the _top-level_ frame, but here we
 * are injecting into the _current_ frame instead.
 * As a tradeoff, the promise returned by `executeJavaScriptInIsolatedWorld`
 * will resolve to `unknown` (instead of rejecting) even if the injected script fails,
 * because chromium doesn't dispatch main world errors to isolated worlds.
 *
 * @return A promise that only rejects if we fail to fetch the inject script.
 * @see https://www.electronjs.org/docs/latest/api/web-frame#webframeexecutejavascriptinisolatedworldworldid-scripts-usergesture-callback
 * @see https://www.electronjs.org/docs/latest/api/web-frame-main#frameexecutejavascriptcode-usergesture
 * @see https://www.electronjs.org/docs/latest/api/web-contents#contentsexecutejavascriptinisolatedworldworldid-scripts-usergesture
 */
async function fetchAndExecuteInjectScript(): Promise<void> {
  const apiExposedResponse = await ipcRenderer.invoke(
    ServiceToMainIpcMessage.ApiExposedInMainWorld,
  );
  const injectSource = webSource.parse(apiExposedResponse);
  // Isolated world 0 is the main world.
  return webFrame.executeJavaScriptInIsolatedWorld(0, [injectSource]);
}

fetchAndExecuteInjectScript().catch((err) => {
  console.log('Failed to fetch inject source:', err);
});