Add WindowState active in plugin API (#13718)

fixes #13692

contributed on behalf of STMicroelectronics

Signed-off-by: Remi Schnekenburger <rschnekenburger@eclipsesource.com>

CHANGELOG.md

@@ -12,6 +12,8 @@
 
 ## 1.50.0
 
+- [plugin] Support WindowState active API [#13718](https://github.com/eclipse-theia/theia/pull/13718) - contributed on behalf of STMicroelectronics
+
 <a name="breaking_changes_1.50.0">[Breaking Changes:](#breaking_changes_1.50.0)</a>
 
 - [core] Classes implementing the `Saveable` interface no longer need to implement the `autoSave` field. However, a new `onContentChanged` event has been added instead.

packages/plugin-ext/src/common/plugin-api-rpc.ts

@@ -893,7 +893,8 @@ export interface WindowMain {
 }
 
 export interface WindowStateExt {
-    $onWindowStateChanged(focus: boolean): void;
+    $onDidChangeWindowFocus(focused: boolean): void;
+    $onDidChangeWindowActive(active: boolean): void;
 }
 
 export interface NotificationExt {

packages/plugin-ext/src/main/browser/window-activity-tracker.ts

@@ -0,0 +1,96 @@
+// *****************************************************************************
+// Copyright (C) 2024 STMicroelectronics and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { Disposable, Emitter, Event } from '@theia/core';
+
+const CHECK_INACTIVITY_LIMIT = 30;
+const CHECK_INACTIVITY_INTERVAL = 1000;
+
+const eventListenerOptions: AddEventListenerOptions = {
+    passive: true,
+    capture: true
+};
+export class WindowActivityTracker implements Disposable {
+
+    private inactivityCounter = 0; // number of times inactivity was checked since last reset
+    private readonly inactivityLimit = CHECK_INACTIVITY_LIMIT; // number of inactivity checks done before sending inactive signal
+    private readonly checkInactivityInterval = CHECK_INACTIVITY_INTERVAL; // check interval in milliseconds
+    private interval: NodeJS.Timeout | undefined;
+
+    protected readonly onDidChangeActiveStateEmitter = new Emitter<boolean>();
+    private _activeState: boolean = true;
+
+    constructor(readonly win: Window) {
+        this.initializeListeners(this.win);
+    }
+
+    get onDidChangeActiveState(): Event<boolean> {
+        return this.onDidChangeActiveStateEmitter.event;
+    }
+
+    private set activeState(newState: boolean) {
+        if (this._activeState !== newState) {
+            this._activeState = newState;
+            this.onDidChangeActiveStateEmitter.fire(this._activeState);
+        }
+    }
+
+    private initializeListeners(win: Window): void {
+        // currently assumes activity based on key/mouse/touch pressed, not on mouse move or scrolling.
+        win.addEventListener('mousedown', this.resetInactivity, eventListenerOptions);
+        win.addEventListener('keydown', this.resetInactivity, eventListenerOptions);
+        win.addEventListener('touchstart', this.resetInactivity, eventListenerOptions);
+    }
+
+    dispose(): void {
+        this.stopTracking();
+        this.win.removeEventListener('mousedown', this.resetInactivity);
+        this.win.removeEventListener('keydown', this.resetInactivity);
+        this.win.removeEventListener('touchstart', this.resetInactivity);
+
+    }
+
+    // Reset inactivity time
+    private resetInactivity = (): void => {
+        this.inactivityCounter = 0;
+        if (!this.interval) {
+            // it was not active. Set as active and restart tracking inactivity
+            this.activeState = true;
+            this.startTracking();
+        }
+    };
+
+    // Check inactivity status
+    private checkInactivity = (): void => {
+        this.inactivityCounter++;
+        if (this.inactivityCounter >= this.inactivityLimit) {
+            this.activeState = false;
+            this.stopTracking();
+        }
+    };
+
+    public startTracking(): void {
+        this.stopTracking();
+        this.interval = setInterval(this.checkInactivity, this.checkInactivityInterval);
+    }
+
+    public stopTracking(): void {
+        if (this.interval) {
+            clearInterval(this.interval);
+            this.interval = undefined;
+        }
+    }
+}

packages/plugin-ext/src/main/browser/window-state-main.ts

@@ -23,6 +23,7 @@ import { UriComponents } from '../../common/uri-components';
 import { Disposable, DisposableCollection } from '@theia/core/lib/common/disposable';
 import { open, OpenerService } from '@theia/core/lib/browser/opener-service';
 import { ExternalUriService } from '@theia/core/lib/browser/external-uri-service';
+import { WindowActivityTracker } from './window-activity-tracker';
 
 export class WindowStateMain implements WindowMain, Disposable {
 
@@ -46,14 +47,22 @@ export class WindowStateMain implements WindowMain, Disposable {
         const fireDidBlur = () => this.onFocusChanged(false);
         window.addEventListener('blur', fireDidBlur);
         this.toDispose.push(Disposable.create(() => window.removeEventListener('blur', fireDidBlur)));
+
+       const tracker = new WindowActivityTracker(window);
+       this.toDispose.push(tracker.onDidChangeActiveState(isActive => this.onActiveStateChanged(isActive)));
+       this.toDispose.push(tracker);
     }
 
     dispose(): void {
         this.toDispose.dispose();
     }
 
     private onFocusChanged(focused: boolean): void {
-        this.proxy.$onWindowStateChanged(focused);
+        this.proxy.$onDidChangeWindowFocus(focused);
+    }
+
+    private onActiveStateChanged(isActive: boolean): void {
+        this.proxy.$onDidChangeWindowActive(isActive);
     }
 
     async $openUri(uriComponent: UriComponents): Promise<boolean> {

packages/plugin-ext/src/plugin/window-state.ts

@@ -31,21 +31,28 @@ export class WindowStateExtImpl implements WindowStateExt {
 
     constructor(rpc: RPCProtocol) {
         this.proxy = rpc.getProxy(PLUGIN_RPC_CONTEXT.WINDOW_MAIN);
-        this.windowStateCached = { focused: true }; // supposed tab is active on start
+        this.windowStateCached = { focused: true, active: true }; // supposed tab is active on start
     }
 
     getWindowState(): WindowState {
         return this.windowStateCached;
     }
 
-    $onWindowStateChanged(focused: boolean): void {
-        const state = { focused: focused };
-        if (state === this.windowStateCached) {
+    $onDidChangeWindowFocus(focused: boolean): void {
+        this.onDidChangeWindowProperty('focused', focused);
+    }
+
+    $onDidChangeWindowActive(active: boolean): void {
+        this.onDidChangeWindowProperty('active', active);
+    }
+
+    onDidChangeWindowProperty(property: keyof WindowState, value: boolean): void {
+        if (value === this.windowStateCached[property]) {
             return;
         }
 
-        this.windowStateCached = state;
-        this.windowStateChangedEmitter.fire(state);
+        this.windowStateCached = { ...this.windowStateCached, [property]: value };
+        this.windowStateChangedEmitter.fire(this.windowStateCached);
     }
 
     openUri(uri: URI): Promise<boolean> {

packages/plugin/src/theia.d.ts

@@ -2741,6 +2741,12 @@ export module '@theia/plugin' {
          * Whether the current window is focused.
          */
         readonly focused: boolean;
+
+        /**
+         * Whether the window has been interacted with recently. This will change
+         * immediately on activity, or after a short time of user inactivity.
+         */
+        readonly active: boolean;
     }
 
     /**