pico.chat/pico.js

const State = Object.seal({
    username: null,
    websocket: null,
    online: [],
    messages: [],
    get isConnected() {
        return State.websocket && State.websocket.readyState === 1
    },
})

/*
*
* SIGNALING
*
*/
const wire = (message) => State.websocket.send(JSON.stringify(message))
const signal = (message) => dispatchEvent(new CustomEvent(message.kind, {detail: message}))
const signalPeerRequest = () => wire({kind: 'peerInfo', value: {type: 'request'}})
const signalPeerStop = (username) => signal({kind: 'peerInfo', value: {type: 'stop'}, source: username})
const listen = (kind, handler) => {
    addEventListener(kind, handler)
}
listen('login', ({detail}) => {
    State.username = detail.value
    State.messages = []
})
listen('logout', ({detail}) => {
    State.online = []
})
listen('state', ({detail}) => {
    delete detail.ts
    delete detail.kind
    Object.assign(State, detail)
})
listen('post', ({detail}) => {
    State.messages.push(detail)
    m.redraw()
})
const doNotLog = new Set(['login', 'state', 'post', 'peerInfo', 'join', 'leave'])

/*
*
* ALERTS
*
*/
State.unseen = 0
listen('post', () => {State.unseen += !document.hasFocus(); updateTitle()})
listen('focus', () => {State.unseen = 0; updateTitle()})
const updateTitle = () => {
    document.title = location.href.split('//')[1] + (State.unseen ? ` (${State.unseen})` : ``)
}
/*
*
* UTILS
*
*/
const autoFocus = (vnode) => {
    vnode.dom.focus()
}
/*
*
* BASE
*
*/
const Base = {
    sendLogin: (e) => {
        e.preventDefault()
        const username = e.target.username.value
        localStorage.username = username
        connect(username)
    },
    sendLogout: (e) => {
        e.preventDefault()
        wire({kind: 'logout'})
        signal({kind: 'logout'})
    },
    view() {
        const attrs = {
            oncreate: autoFocus,
            name: 'username',
            autocomplete: 'off',
            value: localStorage.username,
        }
        return m('main',
            m('.login-container',
                m('form.login' + (State.isConnected ? '.hidden' : ''),
                    {onsubmit: Base.sendLogin},
                    m('input', attrs),
                    m('button', 'Login'),
                ),
                m('form.logout' + (State.isConnected ? '' : '.hidden'),
                    {onsubmit: Base.sendLogout},
                    m('button', 'Logout'),
                ),
                m('.error', State.info),
            ),
            m(StreamContainer),
        )
    },
}
m.mount(document.body, Base)

/*
*
* WEBSOCKET
*
*/
const connect = (username) => {
    const wsUrl = location.href.replace('http', 'ws')

    State.websocket = new WebSocket(wsUrl)

    State.websocket.onopen = (e) => {
        wire({kind: 'login', value: username})
    }

    State.websocket.onmessage = (e) => {
        const message = JSON.parse(e.data)

        if(message.online) {
            const difference = (l1, l2) => l1.filter(u => !l2.includes(u))
            difference(message.online, State.online).forEach(username => {
                signal({kind: 'post', ts: message.ts, value: `${username} joined`})
                signal({kind: 'join', username: username})
            })
            difference(State.online, message.online).forEach(username => {
                signal({kind: 'post', ts: message.ts, value: `${username} left`})
                signal({kind: 'leave', username: username})
            })
        }

        if(!doNotLog.has(message.kind)) {
            console.log(message)
        }
        signal(message)

        m.redraw()
    }

    State.websocket.onclose = (e) => {
        State.online.forEach(signalPeerStop)
        if(!e.wasClean) {
            setTimeout(connect, 1000, username)
        }
        m.redraw()
    }
}
if(localStorage.username) {
    connect(localStorage.username)
}