/**
* Cross-tool lifecycle helpers for host readiness, teardown, and event subscriptions. It standardizes app lifecycle behavior across UI surfaces.
*/
import type { RpcClient } from './rpc-client.js';
interface UiHostLifecycleOptions {
appName: string;
appVersion?: string;
getRootElement?: () => Element | null;
}
export interface UiHostLifecycle {
notifyRender: () => void;
observeResize: () => void;
initialize: () => void;
}
export function createUiHostLifecycle(rpcClient: RpcClient, options: UiHostLifecycleOptions): UiHostLifecycle {
const { appName, appVersion = '1.0.0', getRootElement } = options;
const resolveRootElement = (): Element | null => getRootElement?.() ?? (document.getElementById('app')?.firstElementChild ?? document.getElementById('app'));
const notifySizeChanged = (): void => {
const node = resolveRootElement();
const height = Math.max(28, Math.ceil(node?.getBoundingClientRect().height ?? 0));
rpcClient.notify('ui/notifications/size-changed', { height });
};
return {
notifyRender: () => {
notifySizeChanged();
setTimeout(notifySizeChanged, 80);
},
observeResize: () => {
if (!window.ResizeObserver) {
return;
}
const observer = new ResizeObserver(() => notifySizeChanged());
observer.observe(document.documentElement);
},
initialize: () => {
void rpcClient.request('ui/initialize', {
appInfo: { name: appName, version: appVersion },
appCapabilities: {},
protocolVersion: '2026-01-26',
}).then(() => {
rpcClient.notify('ui/notifications/initialized', {});
}).catch(() => {
// Initialization handshake failure should not break rendering.
// Still send initialized in case host is lenient.
rpcClient.notify('ui/notifications/initialized', {});
});
},
};
}
