Squashed 'third_party/pi/' content from commit d981de122

git-subtree-dir: third_party/pi
git-subtree-split: d981de1229ef899957bbe968bc8dcda02a21f477

packages/coding-agent/test/experimental-service-binding.ts

@@ -0,0 +1,90 @@
+import type { Context, RemoteServices } from "@earendil-works/chord";
+import { BACKGROUND_CONTEXT } from "@earendil-works/chord/context";
+import type { Client } from "@earendil-works/pi-client";
+import {
+	createServerServiceSource,
+	createSessionServiceSource,
+	type ServerServiceSource,
+	type ServiceSourceOptions,
+	type SessionServiceSource,
+} from "../src/experimental/services/connection.ts";
+
+interface ServiceBindingOptions extends ServiceSourceOptions {
+	readonly services: readonly { readonly id: string }[];
+}
+
+/** Test helper for binding server services without a facet host. */
+export function createServerServiceBinding(
+	client: Client,
+	options: ServiceBindingOptions,
+): ServerServiceSource & RemoteServices {
+	const source = createServerServiceSource(client, options);
+	const services = source.open({
+		services: options.services,
+		assertAccess() {},
+		onError: options.onError ?? (() => {}),
+	});
+	const activation = services.ready(BACKGROUND_CONTEXT);
+	void activation.catch(options.onError ?? (() => {}));
+	const ready = async (context: Context): Promise<void> => {
+		await activation;
+		await services.ready(context);
+	};
+	return {
+		acceptsUnavailableServices: source.acceptsUnavailableServices,
+		connection: source.connection,
+		catalogue: (context) => source.catalogue(context),
+		open: (openOptions) => source.open(openOptions),
+		use: (service) => services.use(service),
+		observe: (service, handler) => services.observe(service, handler),
+		ready,
+		async dispose(context) {
+			const results = await Promise.allSettled([services.dispose(context), source.dispose(context)]);
+			throwFailures(results, "Failed to dispose server service binding");
+		},
+	};
+}
+
+/** Test helper for binding selected-Session services without a facet host. */
+export function createSessionServiceBinding(
+	client: Client,
+	options: ServiceBindingOptions,
+): SessionServiceSource & RemoteServices {
+	const source = createSessionServiceSource(client, options);
+	const services = source.open({
+		services: options.services,
+		assertAccess() {},
+		onError: options.onError ?? (() => {}),
+	});
+	const activation = services.ready(BACKGROUND_CONTEXT);
+	void activation.catch(options.onError ?? (() => {}));
+	const ready = async (context: Context): Promise<void> => {
+		await activation;
+		const attachment = source.attachment.value;
+		if (attachment?.status === "detached") await source.whenDetached(context);
+		else if (attachment !== undefined) await source.whenAttached(attachment.sessionId, context);
+	};
+	return {
+		get acceptsUnavailableServices() {
+			return source.acceptsUnavailableServices;
+		},
+		attachment: source.attachment,
+		catalogue: (context) => source.catalogue(context),
+		open: (openOptions) => source.open(openOptions),
+		use: (service) => services.use(service),
+		observe: (service, handler) => services.observe(service, handler),
+		ready,
+		whenAttached: (sessionId, context) => source.whenAttached(sessionId, context),
+		whenDetached: (context) => source.whenDetached(context),
+		async dispose(context) {
+			const results = await Promise.allSettled([services.dispose(context), source.dispose(context)]);
+			throwFailures(results, "Failed to dispose Session service binding");
+		},
+	};
+}
+
+function throwFailures(results: readonly PromiseSettledResult<unknown>[], message: string): void {
+	const errors = results.flatMap((result) => (result.status === "rejected" ? [result.reason] : []));
+	if (errors.length === 1) throw errors[0];
+	if (errors.length > 1) throw new AggregateError(errors, message);
+}