Register custom themes after the monaco theme init

arduino-ide-extension/src/browser/arduino-ide-frontend-module.ts

@@ -82,7 +82,10 @@ import { BoardsAutoInstaller } from './boards/boards-auto-installer';
 import { ShellLayoutRestorer } from './theia/core/shell-layout-restorer';
 import { ListItemRenderer } from './widgets/component-list/list-item-renderer';
 import { ColorContribution } from '@theia/core/lib/browser/color-application-contribution';
-import { MonacoThemingService } from '@theia/monaco/lib/browser/monaco-theming-service';
+import {
+  MonacoThemeJson,
+  MonacoThemingService,
+} from '@theia/monaco/lib/browser/monaco-theming-service';
 import {
   ArduinoDaemonPath,
   ArduinoDaemon,
@@ -310,20 +313,34 @@ import { SelectedBoard } from './contributions/selected-board';
 import { CheckForUpdates } from './contributions/check-for-updates';
 import { OpenBoardsConfig } from './contributions/open-boards-config';
 import { SketchFilesTracker } from './contributions/sketch-files-tracker';
-
-MonacoThemingService.register({
-  id: 'arduino-theme',
-  label: 'Light (Arduino)',
-  uiTheme: 'vs',
-  json: require('../../src/browser/data/default.color-theme.json'),
-});
-
-MonacoThemingService.register({
-  id: 'arduino-theme-dark',
-  label: 'Dark (Arduino)',
-  uiTheme: 'vs-dark',
-  json: require('../../src/browser/data/dark.color-theme.json'),
-});
+import { MonacoThemeServiceIsReady } from './utils/window';
+import { Deferred } from '@theia/core/lib/common/promise-util';
+
+const registerArduinoThemes = () => {
+  const themes: MonacoThemeJson[] = [
+    {
+      id: 'arduino-theme',
+      label: 'Light (Arduino)',
+      uiTheme: 'vs',
+      json: require('../../src/browser/data/default.color-theme.json'),
+    },
+    {
+      id: 'arduino-theme-dark',
+      label: 'Dark (Arduino)',
+      uiTheme: 'vs-dark',
+      json: require('../../src/browser/data/dark.color-theme.json'),
+    },
+  ];
+  themes.forEach((theme) => MonacoThemingService.register(theme));
+};
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+const global = window as any;
+const ready = global[MonacoThemeServiceIsReady] as Deferred;
+if (ready) {
+  ready.promise.then(registerArduinoThemes);
+} else {
+  registerArduinoThemes();
+}
 
 export default new ContainerModule((bind, unbind, isBound, rebind) => {
   // Commands and toolbar items

arduino-ide-extension/src/browser/utils/window.ts

@@ -5,3 +5,11 @@
 export function setURL(url: URL, data: any = {}): void {
   history.pushState(data, '', url);
 }
+
+/**
+ * If available from the `window` object, then it means, the IDE2 has successfully patched the `MonacoThemingService#init` static method,
+ * and can wait the custom theme registration.
+ */
+export const MonacoThemeServiceIsReady = Symbol(
+  '@arduino-ide#monaco-theme-service-is-ready'
+);

electron-app/patch/frontend/index.js

@@ -0,0 +1,100 @@
+// Patch for the startup theme. Customizes the `ThemeService.get().defaultTheme();` to dispatch the default IDE2 theme based on the OS' theme.
+// For all subsequent starts of the IDE the theme applied will be the last one set by the user.
+
+// With the current version of Theia adopted (1.25) it is not possible to extend the `ThemeService`, it will be possible starting from Theia 1.27.
+// Once the version of Theia is updated, this patch will be removed and this functionality will be implemented via dependency injection.
+// Ideally, we should open a PR in Theia and add support for `light` and `dark` default themes in the app config.
+
+const {
+  ThemeService,
+  ThemeServiceSymbol,
+  BuiltinThemeProvider,
+} = require('@theia/core/lib/browser/theming');
+const {
+  ApplicationProps,
+} = require('@theia/application-package/lib/application-props');
+const {
+  FrontendApplicationConfigProvider,
+} = require('@theia/core/lib/browser/frontend-application-config-provider');
+
+// It is a mighty hack to support theme updates in the bundled IDE2.
+// If the custom theme registration happens before the restoration of the existing monaco themes, then any custom theme changes will be ignored.
+// This patch introduces a static deferred promise in the monaco-theming service that will be resolved when the restoration is ready.
+// IDE2 cannot require the monaco theme service on the outer module level, as it requires the application config provider to be initialized,
+// but the initialization happens only in the generated `index.js`.
+// This patch customizes the monaco theme service behavior before loading the DI containers via the preload.
+// The preload is called only once before the app loads. The Theia extensions are not loaded at that point, but the app config provider is ready.
+const preloader = require('@theia/core/lib/browser/preloader');
+const originalPreload = preloader.preload;
+preloader.preload = async function () {
+  const { MonacoThemingService } = require('@theia/monaco/lib/browser/monaco-theming-service');
+  const { MonacoThemeServiceIsReady } = require('arduino-ide-extension/lib/browser/utils/window');
+  const { Deferred } = require('@theia/core/lib/common/promise-util');
+  const ready = new Deferred();
+  if (!window[MonacoThemeServiceIsReady]) {
+    window[MonacoThemeServiceIsReady] = ready;
+    console.log('Registered a custom monaco-theme service initialization signal on the window object.');
+  }
+  // Here, it is safe to patch the theme service, app config provider is ready.
+  MonacoThemingService.init = async function () {
+    this.updateBodyUiTheme();
+    ThemeService.get().onDidColorThemeChange(() => this.updateBodyUiTheme());
+    await this.restore();
+    ready.resolve();
+  }.bind(MonacoThemingService);
+  return originalPreload();
+}.bind(preloader);
+
+const lightTheme = 'arduino-theme';
+const darkTheme = 'arduino-theme-dark';
+const defaultTheme =
+  window.matchMedia && window.matchMedia('(prefers-color-scheme: dark)').matches
+    ? darkTheme
+    : lightTheme;
+
+const originalGet = FrontendApplicationConfigProvider.get;
+FrontendApplicationConfigProvider.get = function () {
+  const originalProps = originalGet.bind(FrontendApplicationConfigProvider)();
+  return { ...originalProps, defaultTheme };
+}.bind(FrontendApplicationConfigProvider);
+
+const arduinoDarkTheme = {
+  id: 'arduino-theme-dark',
+  type: 'dark',
+  label: 'Dark (Arduino)',
+  editorTheme: 'arduino-theme-dark',
+  activate() {},
+  deactivate() {},
+};
+
+const arduinoLightTheme = {
+  id: 'arduino-theme',
+  type: 'light',
+  label: 'Light (Arduino)',
+  editorTheme: 'arduino-theme',
+  activate() {},
+  deactivate() {},
+};
+
+if (!window[ThemeServiceSymbol]) {
+  const themeService = new ThemeService();
+  Object.defineProperty(themeService, 'defaultTheme', {
+    get: function () {
+      return (
+        this.themes[defaultTheme] ||
+        this.themes[ApplicationProps.DEFAULT.frontend.config.defaultTheme]
+      );
+    },
+  });
+  themeService.register(
+    ...BuiltinThemeProvider.themes,
+    arduinoDarkTheme,
+    arduinoLightTheme
+  );
+  themeService.startupTheme();
+  themeService.setCurrentTheme(defaultTheme);
+  window[ThemeServiceSymbol] = themeService;
+}
+
+// Require the original, generated `index.js` for `webpack` as the next entry for the `bundle.js`.
+require('../../src-gen/frontend/index');

electron-app/webpack.config.js

@@ -17,4 +17,10 @@ config.module.rules.push({
     loader: require.resolve('@theia/application-manager/lib/expose-loader')
 }); */
 
+
+// Load the patched `index.js` that sets the desired theme in IDE2 based on the OS' theme.
+// The `patch/frontend/index.js` will require the original, generated `index.js`.
+// See: https://github.com/arduino/arduino-ide/pull/1160.
+config.entry.bundle = require('path').resolve(__dirname, 'patch/frontend/index.js');
+
 module.exports = config;

electron/build/patch/frontend/index.js

@@ -17,6 +17,34 @@ const {
   FrontendApplicationConfigProvider,
 } = require('@theia/core/lib/browser/frontend-application-config-provider');
 
+// It is a mighty hack to support theme updates in the bundled IDE2.
+// If the custom theme registration happens before the restoration of the existing monaco themes, then any custom theme changes will be ignored.
+// This patch introduces a static deferred promise in the monaco-theming service that will be resolved when the restoration is ready.
+// IDE2 cannot require the monaco theme service on the outer module level, as it requires the application config provider to be initialized,
+// but the initialization happens only in the generated `index.js`.
+// This patch customizes the monaco theme service behavior before loading the DI containers via the preload.
+// The preload is called only once before the app loads. The Theia extensions are not loaded at that point, but the app config provider is ready.
+const preloader = require('@theia/core/lib/browser/preloader');
+const originalPreload = preloader.preload;
+preloader.preload = async function () {
+  const { MonacoThemingService } = require('@theia/monaco/lib/browser/monaco-theming-service');
+  const { MonacoThemeServiceIsReady } = require('arduino-ide-extension/lib/browser/utils/window');
+  const { Deferred } = require('@theia/core/lib/common/promise-util');
+  const ready = new Deferred();
+  if (!window[MonacoThemeServiceIsReady]) {
+    window[MonacoThemeServiceIsReady] = ready;
+    console.log('Registered a custom monaco-theme service initialization signal on the window object.');
+  }
+  // Here, it is safe to patch the theme service, app config provider is ready.
+  MonacoThemingService.init = async function () {
+    this.updateBodyUiTheme();
+    ThemeService.get().onDidColorThemeChange(() => this.updateBodyUiTheme());
+    await this.restore();
+    ready.resolve();
+  }.bind(MonacoThemingService);
+  return originalPreload();
+}.bind(preloader);
+
 const lightTheme = 'arduino-theme';
 const darkTheme = 'arduino-theme-dark';
 const defaultTheme =