export function stop<T extends CancellableEvent>(event: _Event<T>): _Event<T> {
	return mapEvent(event, e => {
		e.preventDefault();
		e.stopPropagation();
		return e;
	});
}

	private static getOnDidClientConnect(): Event<ClientConnectionEvent> {
		const onHello = fromNodeEventEmitter<WebContents>(ipcMain, 'ipc:hello', ({ sender }) => sender);

		return mapEvent(onHello, webContents => {
			const onMessage = createScopedOnMessageEvent(webContents.getId());
			const protocol = new Protocol(webContents, onMessage);
			const onDidClientDisconnect = fromNodeEventEmitter<void>(webContents, 'destroyed');

			return { protocol, onDidClientDisconnect };
		});
	}

	private static getOnDidClientConnect(): Event<ClientConnectionEvent> {
		const onHello = fromNodeEventEmitter<Electron.WebContents>(ipcMain, 'ipc:hello', ({ sender }) => sender);

		return mapEvent(onHello, webContents => {
			const onMessage = createScopedOnMessageEvent(webContents.id, 'ipc:message');
			const onDidClientDisconnect = signalEvent(createScopedOnMessageEvent(webContents.id, 'ipc:disconnect'));
			const protocol = new Protocol(webContents, onMessage);

			return { protocol, onDidClientDisconnect };
		});
	}

	listen(context, event: string): Event<any> {
		const uriTransformer = this.getUriTransformer(context);
		switch (event) {
			case 'onInstallExtension': return this.onInstallExtension;
			case 'onDidInstallExtension': return mapEvent(this.onDidInstallExtension, i => ({ ...i, local: this._transformOutgoing(i.local, uriTransformer) }));
			case 'onUninstallExtension': return this.onUninstallExtension;
			case 'onDidUninstallExtension': return this.onDidUninstallExtension;
		}

		throw new Error('Invalid listen');
	}

	constructor() {
		const rawOnOpenUrl = fromEventEmitter(app, 'open-url', (event: Electron.Event, url: string) => ({ event, url }));

		const uriEvent = mapEvent(rawOnOpenUrl, ({ event, url }) => {
			event.preventDefault();

			try {
				return URI.parse(url);
			} catch(e) {
				return null;
			}
		});

		this.onOpenURL = filterEvent(uriEvent, uri => !!uri);

		app.setAsDefaultProtocolClient(product.urlProtocol);
	}

	get onSelectionChange(): Event<ISelectionChangeEvent<T>> {
		return mapEvent(this.list.onSelectionChange, ({ elements, indexes }) => ({ elements: elements.map(e => this._model.get(e)), indexes }));
	}

	get onDidInstallExtension(): Event<DidInstallExtensionEvent> { return mapEvent(this.channel.listen('onDidInstallExtension'), i => ({ ...i, local: this._transformIncoming(i.local) })); }

	get onFocusChange(): Event<IListEvent<T>> {
		return mapEvent(this.list.onFocusChange, ({ elements, indexes }) => ({ elements: elements.map(e => this._model.get(e)), indexes }));
	}

	get onOpen(): Event<IListOpenEvent<T>> {
		return mapEvent(this.list.onOpen, ({ elements, indexes, browserEvent }) => ({ elements: elements.map(e => this._model.get(e)), indexes, browserEvent }));
	}

	get onContextMenu(): Event<IListContextMenuEvent<T>> {
		return mapEvent(this.list.onContextMenu, ({ element, index, anchor, browserEvent }) => ({ element: this._model.get(element!), index, anchor, browserEvent }));
	}