path: root/src/vs/workbench/contrib/notebook/browser/contrib/editorStatusBar/editorStatusBar.ts

/*---------------------------------------------------------------------------------------------
 *  Copyright (c) Microsoft Corporation. All rights reserved.
 *  Licensed under the MIT License. See License.txt in the project root for license information.
 *--------------------------------------------------------------------------------------------*/

import { groupBy } from 'vs/base/common/arrays';
import { createCancelablePromise } from 'vs/base/common/async';
import { CancellationToken } from 'vs/base/common/cancellation';
import { Codicon } from 'vs/base/common/codicons';
import { Event } from 'vs/base/common/event';
import { Disposable, DisposableStore, IDisposable, MutableDisposable } from 'vs/base/common/lifecycle';
import { Schemas } from 'vs/base/common/network';
import { compareIgnoreCase, uppercaseFirstLetter } from 'vs/base/common/strings';
import { ILanguageFeaturesService } from 'vs/editor/common/services/languageFeatures';
import * as nls from 'vs/nls';
import { Action2, MenuId, registerAction2 } from 'vs/platform/actions/common/actions';
import { ContextKeyExpr, IContextKeyService } from 'vs/platform/contextkey/common/contextkey';
import { ExtensionIdentifier } from 'vs/platform/extensions/common/extensions';
import { IInstantiationService, ServicesAccessor } from 'vs/platform/instantiation/common/instantiation';
import { ILabelService } from 'vs/platform/label/common/label';
import { ILogService } from 'vs/platform/log/common/log';
import { IProductService } from 'vs/platform/product/common/productService';
import { ProgressLocation } from 'vs/platform/progress/common/progress';
import { IQuickInputService, IQuickPick, IQuickPickItem, QuickPickInput } from 'vs/platform/quickinput/common/quickInput';
import { Registry } from 'vs/platform/registry/common/platform';
import { Extensions as WorkbenchExtensions, IWorkbenchContribution, IWorkbenchContributionsRegistry } from 'vs/workbench/common/contributions';
import { ViewContainerLocation } from 'vs/workbench/common/views';
import { IExtensionsViewPaneContainer, IExtensionsWorkbenchService, VIEWLET_ID as EXTENSION_VIEWLET_ID } from 'vs/workbench/contrib/extensions/common/extensions';
import { CENTER_ACTIVE_CELL } from 'vs/workbench/contrib/notebook/browser/contrib/navigation/arrow';
import { NOTEBOOK_ACTIONS_CATEGORY, SELECT_KERNEL_ID } from 'vs/workbench/contrib/notebook/browser/controller/coreActions';
import { getNotebookEditorFromEditorPane, INotebookEditor, INotebookExtensionRecommendation, KERNEL_RECOMMENDATIONS } from 'vs/workbench/contrib/notebook/browser/notebookBrowser';
import { NotebookEditorWidget } from 'vs/workbench/contrib/notebook/browser/notebookEditorWidget';
import { selectKernelIcon } from 'vs/workbench/contrib/notebook/browser/notebookIcons';
import { NotebookTextModel } from 'vs/workbench/contrib/notebook/common/model/notebookTextModel';
import { NotebookCellsChangeType } from 'vs/workbench/contrib/notebook/common/notebookCommon';
import { NOTEBOOK_IS_ACTIVE_EDITOR, NOTEBOOK_KERNEL_COUNT } from 'vs/workbench/contrib/notebook/common/notebookContextKeys';
import { INotebookKernel, INotebookKernelMatchResult, INotebookKernelService, ISourceAction } from 'vs/workbench/contrib/notebook/common/notebookKernelService';
import { IEditorService } from 'vs/workbench/services/editor/common/editorService';
import { IExtensionService } from 'vs/workbench/services/extensions/common/extensions';
import { LifecyclePhase } from 'vs/workbench/services/lifecycle/common/lifecycle';
import { IPaneCompositePartService } from 'vs/workbench/services/panecomposite/browser/panecomposite';
import { IStatusbarEntry, IStatusbarEntryAccessor, IStatusbarService, StatusbarAlignment } from 'vs/workbench/services/statusbar/browser/statusbar';

type KernelPick = IQuickPickItem & { kernel: INotebookKernel };
function isKernelPick(item: QuickPickInput<IQuickPickItem>): item is KernelPick {
	return 'kernel' in item;
}
type SourcePick = IQuickPickItem & { action: ISourceAction };
function isSourcePick(item: QuickPickInput<IQuickPickItem>): item is SourcePick {
	return 'action' in item;
}
type InstallExtensionPick = IQuickPickItem & { extensionId: string };
function isInstallExtensionPick(item: QuickPickInput<IQuickPickItem>): item is InstallExtensionPick {
	return item.id === 'installSuggested' && 'extensionId' in item;
}
type KernelQuickPickItem = IQuickPickItem | InstallExtensionPick | KernelPick | SourcePick;
const KERNEL_PICKER_UPDATE_DEBOUNCE = 200;

registerAction2(class extends Action2 {
	constructor() {
		super({
			id: SELECT_KERNEL_ID,
			category: NOTEBOOK_ACTIONS_CATEGORY,
			title: { value: nls.localize('notebookActions.selectKernel', "Select Notebook Kernel"), original: 'Select Notebook Kernel' },
			// precondition: NOTEBOOK_IS_ACTIVE_EDITOR,
			icon: selectKernelIcon,
			f1: true,
			menu: [{
				id: MenuId.EditorTitle,
				when: ContextKeyExpr.and(
					NOTEBOOK_IS_ACTIVE_EDITOR,
					ContextKeyExpr.notEquals('config.notebook.globalToolbar', true)
				),
				group: 'navigation',
				order: -10
			}, {
				id: MenuId.NotebookToolbar,
				when: ContextKeyExpr.equals('config.notebook.globalToolbar', true),
				group: 'status',
				order: -10
			}, {
				id: MenuId.InteractiveToolbar,
				when: NOTEBOOK_KERNEL_COUNT.notEqualsTo(0),
				group: 'status',
				order: -10
			}],
			description: {
				description: nls.localize('notebookActions.selectKernel.args', "Notebook Kernel Args"),
				args: [
					{
						name: 'kernelInfo',
						description: 'The kernel info',
						schema: {
							'type': 'object',
							'required': ['id', 'extension'],
							'properties': {
								'id': {
									'type': 'string'
								},
								'extension': {
									'type': 'string'
								},
								'notebookEditorId': {
									'type': 'string'
								}
							}
						}
					}
				]
			},
		});
	}

	async run(accessor: ServicesAccessor, context?:
		{ id: string; extension: string } |
		{ notebookEditorId: string } |
		{ id: string; extension: string; notebookEditorId: string } |
		{ ui?: boolean; notebookEditor?: NotebookEditorWidget } |
		undefined
	): Promise<boolean> {
		const notebookKernelService = accessor.get(INotebookKernelService);
		const editorService = accessor.get(IEditorService);
		const productService = accessor.get(IProductService);
		const quickInputService = accessor.get(IQuickInputService);
		const labelService = accessor.get(ILabelService);
		const logService = accessor.get(ILogService);
		const paneCompositeService = accessor.get(IPaneCompositePartService);
		const extensionWorkbenchService = accessor.get(IExtensionsWorkbenchService);
		const extensionHostService = accessor.get(IExtensionService);

		let editor: INotebookEditor | undefined;
		if (context !== undefined && 'notebookEditorId' in context) {
			const editorId = context.notebookEditorId;
			const matchingEditor = editorService.visibleEditorPanes.find((editorPane) => {
				const notebookEditor = getNotebookEditorFromEditorPane(editorPane);
				return notebookEditor?.getId() === editorId;
			});
			editor = getNotebookEditorFromEditorPane(matchingEditor);
		} else if (context !== undefined && 'notebookEditor' in context) {
			editor = context?.notebookEditor;
		} else {
			editor = getNotebookEditorFromEditorPane(editorService.activeEditorPane);
		}

		if (!editor || !editor.hasModel()) {
			return false;
		}
		let controllerId = context && 'id' in context ? context.id : undefined;
		let extensionId = context && 'extension' in context ? context.extension : undefined;

		if (controllerId && (typeof controllerId !== 'string' || typeof extensionId !== 'string')) {
			// validate context: id & extension MUST be strings
			controllerId = undefined;
			extensionId = undefined;
		}

		const notebook = editor.textModel;
		const scopedContextKeyService = editor.scopedContextKeyService;
		const matchResult = notebookKernelService.getMatchingKernel(notebook);
		const { selected, all } = matchResult;

		if (selected && controllerId && selected.id === controllerId && ExtensionIdentifier.equals(selected.extension, extensionId)) {
			// current kernel is wanted kernel -> done
			return true;
		}

		let newKernel: INotebookKernel | undefined;
		if (controllerId) {
			const wantedId = `${extensionId}/${controllerId}`;
			for (const candidate of all) {
				if (candidate.id === wantedId) {
					newKernel = candidate;
					break;
				}
			}
			if (!newKernel) {
				logService.warn(`wanted kernel DOES NOT EXIST, wanted: ${wantedId}, all: ${all.map(k => k.id)}`);
				return false;
			}
		}

		if (newKernel) {
			notebookKernelService.selectKernelForNotebook(newKernel, notebook);
			return true;
		}

		const quickPick = quickInputService.createQuickPick<KernelQuickPickItem>();
		const quickPickItems = this._getKernelPickerQuickPickItems(notebook, matchResult, notebookKernelService, scopedContextKeyService);
		quickPick.items = quickPickItems;
		quickPick.canSelectMany = false;
		quickPick.placeholder = selected
			? nls.localize('prompt.placeholder.change', "Change kernel for '{0}'", labelService.getUriLabel(notebook.uri, { relative: true }))
			: nls.localize('prompt.placeholder.select', "Select kernel for '{0}'", labelService.getUriLabel(notebook.uri, { relative: true }));

		// run extension recommendataion task if quickPickItems is empty
		const extensionRecommendataionPromise = quickPickItems.length === 0
			? createCancelablePromise(token => this._showInstallKernelExtensionRecommendation(notebook, quickPick, extensionWorkbenchService, token))
			: undefined;

		const kernelChangeEventListener = Event.debounce<void, void>(
			Event.any(
				notebookKernelService.onDidChangeSourceActions,
				notebookKernelService.onDidAddKernel,
				notebookKernelService.onDidRemoveKernel,
				notebookKernelService.onDidChangeNotebookAffinity
			),
			(last, _current) => last,
			KERNEL_PICKER_UPDATE_DEBOUNCE
		)(async () => {
			// reset quick pick progress
			quickPick.busy = false;
			extensionRecommendataionPromise?.cancel();

			const currentActiveItems = quickPick.activeItems;
			const matchResult = notebookKernelService.getMatchingKernel(notebook);
			const quickPickItems = this._getKernelPickerQuickPickItems(notebook, matchResult, notebookKernelService, scopedContextKeyService);
			quickPick.keepScrollPosition = true;

			// recalcuate active items
			const activeItems: KernelQuickPickItem[] = [];
			for (const item of currentActiveItems) {
				if (isKernelPick(item)) {
					const kernelId = item.kernel.id;
					const sameItem = quickPickItems.find(pi => isKernelPick(pi) && pi.kernel.id === kernelId) as KernelPick | undefined;
					if (sameItem) {
						activeItems.push(sameItem);
					}
				} else if (isSourcePick(item)) {
					const sameItem = quickPickItems.find(pi => isSourcePick(pi) && pi.action.action.id === item.action.action.id) as SourcePick | undefined;
					if (sameItem) {
						activeItems.push(sameItem);
					}
				}
			}

			quickPick.items = quickPickItems;
			quickPick.activeItems = activeItems;
		}, this);

		const pick = await new Promise<KernelQuickPickItem>((resolve, reject) => {
			quickPick.onDidAccept(() => {
				const item = quickPick.selectedItems[0];
				if (item) {
					resolve(item);
				} else {
					reject();
				}

				quickPick.hide();
			});

			quickPick.onDidHide(() => () => {
				kernelChangeEventListener.dispose();
				quickPick.dispose();
				reject();
			});
			quickPick.show();
		});

		if (pick) {
			if (isKernelPick(pick)) {
				newKernel = pick.kernel;
				notebookKernelService.selectKernelForNotebook(newKernel, notebook);
				return true;
			}

			// actions
			if (pick.id === 'install') {
				await this._showKernelExtension(
					paneCompositeService,
					extensionWorkbenchService,
					extensionHostService,
					notebook.viewType
				);
				// suggestedExtension must be defined for this option to be shown, but still check to make TS happy
			} else if (isInstallExtensionPick(pick)) {
				await this._showKernelExtension(
					paneCompositeService,
					extensionWorkbenchService,
					extensionHostService,
					notebook.viewType,
					pick.extensionId,
					productService.quality !== 'stable'
				);
			} else if (isSourcePick(pick)) {
				// selected explicilty, it should trigger the execution?
				pick.action.runAction();
			}
		}

		return false;
	}

	private _getKernelPickerQuickPickItems(
		notebookTextModel: NotebookTextModel,
		matchResult: INotebookKernelMatchResult,
		notebookKernelService: INotebookKernelService,
		scopedContextKeyService: IContextKeyService
	): QuickPickInput<KernelQuickPickItem>[] {
		const { selected, all, suggestions, hidden } = matchResult;

		function toQuickPick(kernel: INotebookKernel) {
			const res = <KernelPick>{
				kernel,
				picked: kernel.id === selected?.id,
				label: kernel.label,
				description: kernel.description,
				detail: kernel.detail
			};
			if (kernel.id === selected?.id) {
				if (!res.description) {
					res.description = nls.localize('current1', "Currently Selected");
				} else {
					res.description = nls.localize('current2', "{0} - Currently Selected", res.description);
				}
			}
			return res;
		}
		const quickPickItems: QuickPickInput<KernelQuickPickItem>[] = [];
		if (all.length) {
			// Always display suggested kernels on the top.
			if (suggestions.length) {
				quickPickItems.push({
					type: 'separator',
					label: nls.localize('suggestedKernels', "Suggested")
				});
				quickPickItems.push(...suggestions.map(toQuickPick));
			}

			// Next display all of the kernels not marked as hidden grouped by categories or extensions.
			// If we don't have a kind, always display those at the bottom.
			const picks = all.filter(item => (!suggestions.includes(item) && !hidden.includes(item))).map(toQuickPick);
			const kernelsPerCategory = groupBy(picks, (a, b) => compareIgnoreCase(a.kernel.kind || 'z', b.kernel.kind || 'z'));
			kernelsPerCategory.forEach(items => {
				quickPickItems.push({
					type: 'separator',
					label: items[0].kernel.kind || nls.localize('otherKernelKinds', "Other")
				});
				quickPickItems.push(...items);
			});
		}

		const sourceActions = notebookKernelService.getSourceActions(notebookTextModel, scopedContextKeyService);
		if (sourceActions.length) {
			quickPickItems.push({
				type: 'separator',
				// label: nls.localize('sourceActions', "")
			});

			sourceActions.forEach(sourceAction => {
				const res = <SourcePick>{
					action: sourceAction,
					picked: false,
					label: sourceAction.action.label,
				};

				quickPickItems.push(res);
			});
		}

		return quickPickItems;
	}

	private async _showInstallKernelExtensionRecommendation(
		notebookTextModel: NotebookTextModel,
		quickPick: IQuickPick<KernelQuickPickItem>,
		extensionWorkbenchService: IExtensionsWorkbenchService,
		token: CancellationToken
	) {
		quickPick.busy = true;

		const newQuickPickItems = await this._getKernelRecommendationsQuickPickItems(notebookTextModel, extensionWorkbenchService);
		quickPick.busy = false;

		if (token.isCancellationRequested) {
			return;
		}

		if (newQuickPickItems && quickPick.items.length === 0) {
			quickPick.items = newQuickPickItems;
		}
	}


	private async _getKernelRecommendationsQuickPickItems(
		notebookTextModel: NotebookTextModel,
		extensionWorkbenchService: IExtensionsWorkbenchService,
	): Promise<QuickPickInput<KernelQuickPickItem>[] | undefined> {
		const quickPickItems: QuickPickInput<KernelQuickPickItem>[] = [];

		const language = this.getSuggestedLanguage(notebookTextModel);
		const suggestedExtension: INotebookExtensionRecommendation | undefined = language ? this.getSuggestedKernelFromLanguage(notebookTextModel.viewType, language) : undefined;
		if (suggestedExtension) {
			await extensionWorkbenchService.queryLocal();
			const extension = extensionWorkbenchService.installed.find(e => e.identifier.id === suggestedExtension.extensionId);

			if (extension) {
				// it's installed but might be detecting kernels
				return undefined;
			}

			// We have a suggested kernel, show an option to install it
			quickPickItems.push({
				id: 'installSuggested',
				description: suggestedExtension.displayName ?? suggestedExtension.extensionId,
				label: `$(${Codicon.lightbulb.id}) ` + nls.localize('installSuggestedKernel', 'Install suggested extensions'),
				extensionId: suggestedExtension.extensionId
			});
		}
		// there is no kernel, show the install from marketplace
		quickPickItems.push({
			id: 'install',
			label: nls.localize('searchForKernels', "Browse marketplace for kernel extensions"),
		});

		return quickPickItems;
	}

	/**
	 * Examine the most common language in the notebook
	 * @param notebookTextModel The notebook text model
	 * @returns What the suggested language is for the notebook. Used for kernal installing
	 */
	private getSuggestedLanguage(notebookTextModel: NotebookTextModel): string | undefined {
		const metaData = notebookTextModel.metadata;
		let suggestedKernelLanguage: string | undefined = (metaData.custom as any)?.metadata?.language_info?.name;
		// TODO how do we suggest multi language notebooks?
		if (!suggestedKernelLanguage) {
			const cellLanguages = notebookTextModel.cells.map(cell => cell.language).filter(language => language !== 'markdown');
			// Check if cell languages is all the same
			if (cellLanguages.length > 1) {
				const firstLanguage = cellLanguages[0];
				if (cellLanguages.every(language => language === firstLanguage)) {
					suggestedKernelLanguage = firstLanguage;
				}
			}
		}
		return suggestedKernelLanguage;
	}

	/**
	 * Given a language and notebook view type suggest a kernel for installation
	 * @param language The language to find a suggested kernel extension for
	 * @returns A recommednation object for the recommended extension, else undefined
	 */
	private getSuggestedKernelFromLanguage(viewType: string, language: string): INotebookExtensionRecommendation | undefined {
		const recommendation = KERNEL_RECOMMENDATIONS.get(viewType)?.get(language);
		return recommendation;
	}

	private async _showKernelExtension(
		paneCompositePartService: IPaneCompositePartService,
		extensionWorkbenchService: IExtensionsWorkbenchService,
		extensionService: IExtensionService,
		viewType: string,
		extId?: string,
		isInsiders?: boolean
	) {
		// If extension id is provided attempt to install the extension as the user has requested the suggested ones be installed
		if (extId) {
			const extension = (await extensionWorkbenchService.getExtensions([{ id: extId }], CancellationToken.None))[0];
			const canInstall = await extensionWorkbenchService.canInstall(extension);
			// If we can install then install it, otherwise we will fall out into searching the viewlet
			if (canInstall) {
				await extensionWorkbenchService.install(
					extension,
					{
						installPreReleaseVersion: isInsiders ?? false,
						context: { skipWalkthrough: true }
					},
					ProgressLocation.Notification
				);
				await extensionService.activateByEvent(`onNotebook:${viewType}`);
				return;
			}
		}

		const viewlet = await paneCompositePartService.openPaneComposite(EXTENSION_VIEWLET_ID, ViewContainerLocation.Sidebar, true);
		const view = viewlet?.getViewPaneContainer() as IExtensionsViewPaneContainer | undefined;
		const pascalCased = viewType.split(/[^a-z0-9]/ig).map(uppercaseFirstLetter).join('');
		view?.search(`@tag:notebookKernel${pascalCased}`);
	}
});


class ImplictKernelSelector implements IDisposable {

	readonly dispose: () => void;

	constructor(
		notebook: NotebookTextModel,
		suggested: INotebookKernel,
		@INotebookKernelService notebookKernelService: INotebookKernelService,
		@ILanguageFeaturesService languageFeaturesService: ILanguageFeaturesService,
		@ILogService logService: ILogService
	) {
		const disposables = new DisposableStore();
		this.dispose = disposables.dispose.bind(disposables);

		const selectKernel = () => {
			disposables.clear();
			notebookKernelService.selectKernelForNotebook(suggested, notebook);
		};

		// IMPLICITLY select a suggested kernel when the notebook has been changed
		// e.g change cell source, move cells, etc
		disposables.add(notebook.onDidChangeContent(e => {
			for (const event of e.rawEvents) {
				switch (event.kind) {
					case NotebookCellsChangeType.ChangeCellContent:
					case NotebookCellsChangeType.ModelChange:
					case NotebookCellsChangeType.Move:
					case NotebookCellsChangeType.ChangeCellLanguage:
						logService.trace('IMPLICIT kernel selection because of change event', event.kind);
						selectKernel();
						break;
				}
			}
		}));


		// IMPLICITLY select a suggested kernel when users start to hover. This should
		// be a strong enough hint that the user wants to interact with the notebook. Maybe
		// add more triggers like goto-providers or completion-providers
		disposables.add(languageFeaturesService.hoverProvider.register({ scheme: Schemas.vscodeNotebookCell, pattern: notebook.uri.path }, {
			provideHover() {
				logService.trace('IMPLICIT kernel selection because of hover');
				selectKernel();
				return undefined;
			}
		}));
	}
}

export class KernelStatus extends Disposable implements IWorkbenchContribution {

	private readonly _editorDisposables = this._register(new DisposableStore());
	private readonly _kernelInfoElement = this._register(new DisposableStore());

	constructor(
		@IEditorService private readonly _editorService: IEditorService,
		@IStatusbarService private readonly _statusbarService: IStatusbarService,
		@INotebookKernelService private readonly _notebookKernelService: INotebookKernelService,
		@IInstantiationService private readonly _instantiationService: IInstantiationService,
	) {
		super();
		this._register(this._editorService.onDidActiveEditorChange(() => this._updateStatusbar()));
	}

	private _updateStatusbar() {
		this._editorDisposables.clear();

		const activeEditor = getNotebookEditorFromEditorPane(this._editorService.activeEditorPane);
		if (!activeEditor) {
			// not a notebook -> clean-up, done
			this._kernelInfoElement.clear();
			return;
		}

		const updateStatus = () => {
			if (activeEditor.notebookOptions.getLayoutConfiguration().globalToolbar) {
				// kernel info rendered in the notebook toolbar already
				this._kernelInfoElement.clear();
				return;
			}

			const notebook = activeEditor.textModel;
			if (notebook) {
				this._showKernelStatus(notebook);
			} else {
				this._kernelInfoElement.clear();
			}
		};

		this._editorDisposables.add(this._notebookKernelService.onDidAddKernel(updateStatus));
		this._editorDisposables.add(this._notebookKernelService.onDidChangeSelectedNotebooks(updateStatus));
		this._editorDisposables.add(this._notebookKernelService.onDidChangeNotebookAffinity(updateStatus));
		this._editorDisposables.add(activeEditor.onDidChangeModel(updateStatus));
		this._editorDisposables.add(activeEditor.notebookOptions.onDidChangeOptions(updateStatus));
		updateStatus();
	}

	private _showKernelStatus(notebook: NotebookTextModel) {

		this._kernelInfoElement.clear();

		const { selected, suggestions, all } = this._notebookKernelService.getMatchingKernel(notebook);
		const suggested = (suggestions.length === 1 ? suggestions[0] : undefined)
			?? (all.length === 1) ? all[0] : undefined;
		let isSuggested = false;

		if (all.length === 0) {
			// no kernel -> no status
			return;

		} else if (selected || suggested) {
			// selected or single kernel
			let kernel = selected;

			if (!kernel) {
				// proceed with suggested kernel - show UI and install handler that selects the kernel
				// when non trivial interactions with the notebook happen.
				kernel = suggested!;
				isSuggested = true;
				this._kernelInfoElement.add(this._instantiationService.createInstance(ImplictKernelSelector, notebook, kernel));
			}
			const tooltip = kernel.description ?? kernel.detail ?? kernel.label;
			this._kernelInfoElement.add(this._statusbarService.addEntry(
				{
					name: nls.localize('notebook.info', "Notebook Kernel Info"),
					text: `$(notebook-kernel-select) ${kernel.label}`,
					ariaLabel: kernel.label,
					tooltip: isSuggested ? nls.localize('tooltop', "{0} (suggestion)", tooltip) : tooltip,
					command: SELECT_KERNEL_ID,
				},
				SELECT_KERNEL_ID,
				StatusbarAlignment.RIGHT,
				10
			));

			this._kernelInfoElement.add(kernel.onDidChange(() => this._showKernelStatus(notebook)));


		} else {
			// multiple kernels -> show selection hint
			this._kernelInfoElement.add(this._statusbarService.addEntry(
				{
					name: nls.localize('notebook.select', "Notebook Kernel Selection"),
					text: nls.localize('kernel.select.label', "Select Kernel"),
					ariaLabel: nls.localize('kernel.select.label', "Select Kernel"),
					command: SELECT_KERNEL_ID,
					backgroundColor: { id: 'statusBarItem.prominentBackground' }
				},
				SELECT_KERNEL_ID,
				StatusbarAlignment.RIGHT,
				10
			));
		}
	}
}

Registry.as<IWorkbenchContributionsRegistry>(WorkbenchExtensions.Workbench).registerWorkbenchContribution(KernelStatus, LifecyclePhase.Restored);

export class ActiveCellStatus extends Disposable implements IWorkbenchContribution {

	private readonly _itemDisposables = this._register(new DisposableStore());
	private readonly _accessor = this._register(new MutableDisposable<IStatusbarEntryAccessor>());

	constructor(
		@IEditorService private readonly _editorService: IEditorService,
		@IStatusbarService private readonly _statusbarService: IStatusbarService,
	) {
		super();
		this._register(this._editorService.onDidActiveEditorChange(() => this._update()));
	}

	private _update() {
		this._itemDisposables.clear();
		const activeEditor = getNotebookEditorFromEditorPane(this._editorService.activeEditorPane);
		if (activeEditor) {
			this._itemDisposables.add(activeEditor.onDidChangeSelection(() => this._show(activeEditor)));
			this._itemDisposables.add(activeEditor.onDidChangeActiveCell(() => this._show(activeEditor)));
			this._show(activeEditor);
		} else {
			this._accessor.clear();
		}
	}

	private _show(editor: INotebookEditor) {
		if (!editor.hasModel()) {
			this._accessor.clear();
			return;
		}

		const newText = this._getSelectionsText(editor);
		if (!newText) {
			this._accessor.clear();
			return;
		}

		const entry: IStatusbarEntry = {
			name: nls.localize('notebook.activeCellStatusName', "Notebook Editor Selections"),
			text: newText,
			ariaLabel: newText,
			command: CENTER_ACTIVE_CELL
		};
		if (!this._accessor.value) {
			this._accessor.value = this._statusbarService.addEntry(
				entry,
				'notebook.activeCellStatus',
				StatusbarAlignment.RIGHT,
				100
			);
		} else {
			this._accessor.value.update(entry);
		}
	}

	private _getSelectionsText(editor: INotebookEditor): string | undefined {
		if (!editor.hasModel()) {
			return undefined;
		}

		const activeCell = editor.getActiveCell();
		if (!activeCell) {
			return undefined;
		}

		const idxFocused = editor.getCellIndex(activeCell) + 1;
		const numSelected = editor.getSelections().reduce((prev, range) => prev + (range.end - range.start), 0);
		const totalCells = editor.getLength();
		return numSelected > 1 ?
			nls.localize('notebook.multiActiveCellIndicator', "Cell {0} ({1} selected)", idxFocused, numSelected) :
			nls.localize('notebook.singleActiveCellIndicator', "Cell {0} of {1}", idxFocused, totalCells);
	}
}

Registry.as<IWorkbenchContributionsRegistry>(WorkbenchExtensions.Workbench).registerWorkbenchContribution(ActiveCellStatus, LifecyclePhase.Restored);