/**
 * @file The runtime of an OCapN vat: SES, an OCapN peer, and the vat's own
 * module (`vat.js`), which exports `buildRootObject(vatPowers, params)`.
 *
 * Bundled (see build.js) and loaded as the facet's main module beside the
 * vat's code. The vat's designator is its id; it reaches other peers, and
 * they reach it, through the vatAdmin's router (`env.router`).
 */
import "@endo/init";
import { DurableObject } from "cloudflare:workers";
import { E, Far } from "@endo/far";
import { makeClient } from "@endo/ocapn";
import { makeRpcNetLayer } from "./netlayer.js";
import * as vat from "./vat.js";

/**
 * The swissnum of a vat's bootstrap: the vatAdmin starts the vat through it.
 * Not exported: workerd takes every export of a main module for an entrypoint.
 */
const VAT_SWISSNUM = "vat";

export class App extends DurableObject {
	#gateway;

	constructor(ctx, env) {
		super(ctx, env);
		this.#gateway = this.#boot();
	}

	async #boot() {
		const { vatId, router } = this.env;
		let root;
		const vatPowers = Object.freeze({ E, Far, storage: this.ctx.storage.kv });
		const bootstrap = Far("vatBootstrap", {
			start: (params) => {
				root ??= vat.buildRootObject(vatPowers, params);
				return root;
			},
		});
		// workerd runs FinalizationRegistry callbacks outside any request, where
		// sending the resulting GC message is forbidden I/O. So imports are
		// never collected here; they go when their session does.
		const ocapn = makeClient({
			debugLabel: vatId.slice(0, 8),
			swissnumTable: new Map([[VAT_SWISSNUM, bootstrap]]),
			enableImportCollection: false,
		});
		const netlayer = await ocapn.registerNetlayer(
			makeRpcNetLayer({ designator: vatId, openGateway: (designator) => router.gateway(designator) }),
		);
		return netlayer.gateway;
	}

	/** This vat's OCapN gateway, for the router. */
	gateway() {
		return this.#gateway;
	}
}