websocket_panel = websocket_panel or NULL
if websocket_panel:IsValid() then websocket_panel:Remove() end

local i = 0
local sockets = {}

local function create_html_panel()
    local pnl = vgui.Create("DHTML")
    websocket_panel = pnl

    pnl:AddFunction("websocket", "Event", function(id, event, val)
        if id == 0 then
            if event == "error" then
                ErrorNoHalt(val .. "\n")
                return
            end
        end

        print(i, id, event, val)

        local socket = sockets[id] or NULL
        if socket:IsValid() and socket[event] then
            socket[event](socket, val)
        end
    end)
    pnl:SetSize(50, 50)
    pnl:SetPos(50, 50)

    pnl:QueueJavascript([[
    var sockets = []
    var i = 0

    function SocketEvent(id, event, val)
    {
        try
        {
            var socket = sockets[id]
            if (val)
            {
                if (event == "send")
                {
                    socket.send(val)
                }
                else if (event == "close")
                {
                    socket.close()
                }
            }
        }
        catch(err)
        {
            websocket.Event(0, "error", err.message)
        }
    }

    function CreateSocket(url)
    {
        try
        {
            i++

            var id = i

            var socket = new WebSocket(url)
            sockets[id] = socket

            socket.onmessage = function(event) { websocket.Event(id, "OnMessage", event.data) }
            socket.onopen = function(event) { websocket.Event(id, "OnOpen") }
            socket.onclose = function() { websocket.Event(id, "OnClose") }

            websocket.Event("OnCreated", id)
        }
        catch(err)
        {
            websocket.Event(0, "error", err.message)
        }
    }
    ]])
end

local META = {}
META.__index = META

function META:__tostring()
    return string.format("websocket[%i]", self.id)
end

function META:IsValid()
    return true
end

function META:Send(data)
    websocket_panel:QueueJavascript(("SocketEvent(%i, %q, %q)"):format(self.id, "send", data))
end

function META:Remove()
    sockets[self.id] = nil
    websocket_panel:QueueJavascript(("SocketEvent(%i, %q)"):format(self.id, "close"))
    setmetatable(self, getmetatable(NULL))

    if table.Count(sockets) == 0 then
        websocket_panel:Remove()
    end
end

function WebSocket(url)
    if not websocket_panel:IsValid() then
        create_html_panel()
    end

    i = i + 1

    websocket_panel:QueueJavascript(("CreateSocket(%q)"):format(url))

    local socket = setmetatable({id = i}, META)
    sockets[i] = socket

    return socket
end

function GetAllWebSockets()
    local out = {}
    for key, val in pairs(sockets) do
        table.insert(out, val)
    end
    return out
end

-- !lm test = WebSocket("ws://node.remysharp.com:8001") test.OnMessage = Say
-- !lm test:Send("hello world")