slots.lua

ulx.convar( "rslotsMode", "0", " - Sets the slots mode. See config for more information.", ULib.ACCESS_ADMIN )
ulx.convar( "rslots", "2", " - Sets the number of reserved slots, only applicable for modes 1 and 2.", ULib.ACCESS_ADMIN )
ulx.convar( "rslotsVisible", "1", " - Sets whether slots are visible. See config for more information.", ULib.ACCESS_ADMIN )

local access = "ulx reservedslots" -- Access string needed for reserved slots
local access_groups = {"owner","admin","superadmin","donator"}
ULib.ucl.registerAccess( access, access_groups, "Access to reserved slots", "Other" ) -- Give admins access to reserved slots by default

function calcSlots( disconnect )
    local mode = GetConVarNumber( "ulx_rslotsMode" )
    if mode == 3 then return 1 end -- Only one slot on this mode

    local slots = GetConVarNumber( "ulx_rslots" )
    if mode == 2 then return slots end

    if mode == 1 then
        local admins = 0 -- Keep track of how many people with access we have

        local players = player.GetAll()
        for _, player in ipairs( players ) do
            if player:IsConnected() and player:query( access ) then
                admins = admins + 1
            end
        end

        if disconnect then admins = admins - 1 end -- Otherwise we're counting the disconnecting admin
        if admins < 0 then admins = 0 end -- Just to be safe!

        local rslots = slots - admins
        if rslots < 0 then rslots = 0 end -- If we have more admins right now then slots for them, we don't want to return a negative number.
        return rslots
    end

    return 0 -- We're actually having an error if we get here, but let's handle it gracefully
end

local function updateSlots( ply, disconnect )
    local visible = util.tobool( GetConVarString( "ulx_rslotsVisible" ) )
    if not visible then -- Make sure our visible slots is up to date
        local slots = calcSlots( disconnect )
        local max = game.MaxPlayers()
        game.ConsoleCommand( "sv_visiblemaxplayers " .. max - slots .. "\n" )
    end
end
hook.Add( "PlayerDisconnected", "ulxSlotsDisconnect", function( ply ) updateSlots( ply, ply:query( access ) ) end )
hook.Add( ulx.HOOK_ULXDONELOADING, "ULXUpdateSlots", updateSlots )

local function playerAccess( ply )
    local mode = GetConVarNumber( "ulx_rslotsMode" )
    if mode == 0 then return end -- Off!

    local visible = util.tobool( GetConVarString( "ulx_rslotsVisible" ) )
    local slots = calcSlots()
    local cur = #player.GetAll()
    local max = game.MaxPlayers()

    if ply:query( access ) then -- If they have access, handle this differently
        if not visible then -- Make sure our visible slots is up to date
            updateSlots()
        end

        if mode == 3 and cur + slots > max then -- We've got some kicking to do!
            local shortestply
            local shortesttime = 0

            local players = player.GetAll()
            for _, player in ipairs( players ) do
                if not ULib.ucl.query( player, access ) then
                    if player:TimeConnected() > shortesttime then
                        shortesttime = player:TimeConnected()
                        shortestply = player
                    end
                end
            end

            if not shortestply then -- We've got a server filled to the brim with admins? Odd but okay
                return
            end

            ULib.kick( shortestply, "[ULX] Freeing slot. Sorry, you had the shortest connection time." )
        end

        return
    end

    if cur + slots > max then
        ULib.queueFunctionCall( ULib.kick, ply, "[ULX] Reserved slot, sorry!" ) -- Wait a frame so all access hooks can be called properly.
    end
end
hook.Add( ULib.HOOK_UCLAUTH, "ULXReservedSlots", playerAccess, 20 ) -- Run at the end of auth

// http://www.facepunch.com/showthread.php?t=1253982&p=39923262
// Made by Map in a Box and edited by others.
local function tosteamid(cid)
  local steam64=tonumber(cid:sub(2))
  local a = steam64 % 2 == 0 and 0 or 1
  local b = math.abs(6561197960265728 - steam64 - a) / 2
  local sid = "STEAM_0:" .. a .. ":" .. (a == 1 and b -1 or b)
  return sid
end

 hook.Add("CheckPassword", "CheckPassword_reserve", function( comID, ipPort, serverPassword, userPassword, name )
    local mode = GetConVarNumber( "ulx_rslotsMode" )
    local conply = tosteamid(comID)
    if not mode == 2 then
        return true
    end
    local slots = GetConVarNumber( "ulx_rslots" )
    local cur = #player.GetAll()
    local max = game.MaxPlayers()
    if cur + slots > max then
        if not conply:query( access ) then
            return false, "The server is full."
        end
    else
        return true
    end
    end)