import { $Present, $Says, asPresent, asSays, fromPresent, fromSays, Present, Says } from "./gen/simple-chat-protocol.js";
import { during, observe } from "./dataspace.js";
import { Assertion, Handle, Ref, Turn } from "./actor.js";
import readline from 'readline';

export default function (t: Turn, ds: Ref) {
    let username = '';
    let usernameHandle: Handle | undefined;

    function updateUsername(t: Turn, u: string) {
        username = u;
        usernameHandle = t.replace(ds, usernameHandle, fromPresent(Present(username)));
    }
    updateUsername(t, 'user' + process.pid);

    observe(t, ds, $Present, during((_t, e0) => {
        const e = asPresent(e0);
        console.log(`${e.username} arrived`);
        return (_t) => console.log(`${e.username} departed`);
    }));

    observe(t, ds, $Says, {
        message(_t: Turn, u0: Assertion): void {
            const u = asSays(u0);
            console.log(`${u.who}: ${u.what}`);
        },
    });

    const rl = readline.createInterface({ input: process.stdin, output: process.stdout });
    t.activeFacet.actor.atExit(_t => rl.close());

    rl.on('line', (line: string) => t.freshen(t => {
        if (line.toLowerCase().startsWith('/nick ')) {
            updateUsername(t, line.slice(5).trimLeft());
        } else {
            t.message(ds, fromSays(Says({ who: username, what: line })));
        }
    }));

    rl.on('close', () => t.freshen(t => t.stopActor()));
}