(async () => {
    // check notification permission
    // This is useful to alert people that they should do something
    await Notification.requestPermission()
})()

/**
 * Display a new notification with the given title and the given body.
 * @param title The title of the notification
 * @param body The body of the notification
 * @param timeout The time (in milliseconds) after that the notification automatically closes. 0 to make indefinite. Default to 5000 ms.
 * @return Notification
 */
function showNotification(title, body, timeout = 5000) {
    let notif = new Notification(title, {'body': body, 'icon': "/static/tfjm.svg"})
    if (timeout)
        setTimeout(() => notif.close(), timeout)
    return notif
}

document.addEventListener('DOMContentLoaded', () => {
    /**
     * Process the received data from the server.
     * @param data The received message
     */
    function processMessage(data) {
        // TODO Implement chat protocol
        console.log(data)
    }

    function setupSocket(nextDelay = 1000) {
        // Open a global websocket
        socket = new WebSocket(
            (document.location.protocol === 'https:' ? 'wss' : 'ws') + '://' + window.location.host + '/ws/chat/'
        )

        // Listen on websockets and process messages from the server
        socket.addEventListener('message', e => {
            // Parse received data as JSON
            const data = JSON.parse(e.data)

            processMessage(data)
        })

        // Manage errors
        socket.addEventListener('close', e => {
            console.error('Chat socket closed unexpectedly, restarting…')
            setTimeout(() => setupSocket(2 * nextDelay), nextDelay)
        })

        socket.addEventListener('open', e => {
            socket.send(JSON.stringify({
                'type': 'fetch_channels',
            }))
        })
    }

    setupSocket()
})