import { connect, StringCodec } from '../esm/nats.js'

// add an entry to the document
function addEntry(s) {
    const p = document.createElement("pre");
    p.appendChild(document.createTextNode(s));
    document.getElementById("messages").appendChild(p);
}

const sc = StringCodec();

const init = async function () {
    // create a connection
    const nc = await connect({ servers: 'ws://localhost:9222' })
    addEntry('connected to NATS!');

    // simple publisher
    nc.publish('hello', sc.encode('nats'))
    addEntry('published a message to `hello`');

    // simple subscriber, if the message has a reply subject
    // send a reply
    const sub = await nc.subscribe('help');
    (async () => {
        addEntry('listening for request on `help`');
        for await (const m of sub) {
            m.respond(sc.encode(`I can help ${sc.decode(m.data)}`));
        }
    })().then()

    // request data - requests only receive one message
    // to receive multiple messages, create a subscription
    addEntry('making a request to `help`');
    const msg = await nc.request('help', sc.encode('nats request'))

    addEntry(`got response '${sc.decode(msg.data)}'`);

    // close the connection
    nc.close();
    addEntry('closed the connection');
}
init();