novy-syndicate/src/examples/secure-chat-client.ts

import { $joinedUser, $says, $user, fromNickClaim, fromSays, NickClaim, Says, UserId } from "../gen/secureChatProtocol.js";
import { during, observe, P } from "../runtime/dataspace.js";
import { Assertion, Ref, Turn } from "../runtime/actor.js";
import { attachReadline } from './readline.js';
import { Embedded } from "@preserves/core";

export default function (t: Turn, ds_ptr: Embedded<Ref>) {
    const ds = ds_ptr.embeddedValue;
    observe(t, ds, P.rec($joinedUser, P.bind(), P.bind()),
            during(async (t, bindings) => {
                let [uid, handle] = bindings as [UserId, Ref];
                const facet = t.facet(t => runSession(t, uid, handle));
                return t => t.stop(facet);
            }));
}

function runSession(t: Turn, uid: UserId, session: Ref) {
    let username: string | undefined;
    let cleanShutdown = false;

    t.activeFacet.onStop(_t => {
        if (!cleanShutdown) {
            console.log('Moderator retracted room permission.');
        }
    });

    function updateUsername(t: Turn, name: string) {
        const q = t.assert(session, fromNickClaim(NickClaim({ uid, name, k: t.ref({
            message(t, reply0) {
                if (reply0 === true) {
                    username = name;
                    console.log(`Nick changed to ${username}`);
                } else {
                    console.log(`Nick conflict: name is still ${username ?? '<not set>'}`);
                }
                t.retract(q);
            }
        })})));
    }
    updateUsername(t, 'user' + process.pid);

    const users = new Map<UserId, string>();
    observe(t, session, P.rec($user, P.bind(), P.bind()),
            during(async (_t, bindings) => {
                let [uid, name] = bindings as [UserId, string];
                const oldName = users.get(uid);
                console.log(oldName === void 0
                    ? `${name} arrived`
                    : `${oldName} changed name to ${name}`);
                users.set(uid, name);
                return (_t) => {
                    if (users.get(uid) === name) {
                        console.log(`${name} departed`);
                        users.delete(uid);
                    }
                };
            }));

    observe(t, session, P.rec($says, P.bind(), P.bind()), {
        message(_t: Turn, bindings: Assertion): void {
            let [who, what] = bindings as [UserId, string];
            console.log(`${users.get(who) ?? `<unknown ${who}>`}: ${what}`);
        },
    });

    attachReadline(t, {
        retract(t) {
            cleanShutdown = true;
            t.stopActor();
        },
        message(t, line: string) {
            if (line.toLowerCase().startsWith('/nick ')) {
                updateUsername(t, line.slice(5).trimLeft());
            } else {
                t.message(session, fromSays(Says({ who: uid, what: line })));
            }
        },
    });
}