import { $Present, $Says, asPresent, asSays, fromPresent, fromSays, Present, Says } from "./gen/chat-protocol.js";
import { fromObserve, Observe } from "./gen/dataspace.js";
import { Assertion, Handle, LocalAction, 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);

    const usermap = new Map<Handle, LocalAction>();
    t.assert(ds, fromObserve(Observe({
        label: $Present,
        observer: t.ref({
            assert(_t: Turn, e0: Assertion, h: Handle): void {
                const e = asPresent(e0);
                console.log(`${e.username} arrived`);
                usermap.set(h, (_t: Turn) => console.log(`${e.username} departed`));
            },
            retract(t: Turn, h: Handle): void {
                usermap.get(h)?.(t);
                usermap.delete(h);
            },
        }),
    })));

    t.assert(ds, fromObserve(Observe({
        label: $Says,
        observer: t.ref({
            message(_t: Turn, u0: Assertion): void {
                const u = asSays(u0);
                console.log(`${u.who}: ${u.what}`);
            },
        }),
    })));

    const rl = readline.createInterface({ input: process.stdin, output: process.stdout });

    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.quit()));
}