Trade Station Controller

--Trade Station Controller
local protocol = "AUTOBUYER"
local gui = require("SmallGUI");
rednet.open("top");

file = fs.open("data.dat", "r");
data = textutils.unserialize(file.readAll());

local hostname = data["itemID"];
local side = "back";

rednet.host(hostname, protocol);

local uptime = 0;
local currentLog = {};

function log(input)
    local tempOut = "[" .. gui.parseTime(uptime) .. "] " .. input;
    table.insert(currentLog, tempOut);
end

function enableMachine()
    if redstone.getOutput(side) == false then
        redstone.setOutput(side, true);
        log("Enabling Trading Station");
    end
end

function disableMachine()
    if redstone.getOutput(side) == true then
        redstone.setOutput(side, false);
        log("Disabling Trading Station");
    end
end

disableMachine();
function waitForMessage()
    while true do
        address, message = rednet.receive(protocol);
        if message == "enable" then
            enableMachine();
        elseif message == "disable" then
            disableMachine();
        elseif message == "getData" then
            log("Sending Data...");
            rednet.send(address, textutils.serialize(data), protocol);
        end
    end
end


function setUptime()
    while true do uptime = uptime + 1; sleep(1) end
end

function tradeStationStatus()
    if redstone.getOutput(side) == false then return "Disabled" else return "Enabled" end
end

function updateScreen()
    term.clear()
    while true do
        gui.printf(string.rep("=", term.getSize()),1,1);
        gui.printf("Trade Station Controller [Ver 2.0]|Uptime: " .. gui.parseTime(uptime),1,2);
        gui.printf(string.rep("=", term.getSize()),1,3);
        gui.printf("Item: " .. data["displayName"],1,4);
        gui.printf("Trade Station Status: " .. tradeStationStatus() .. "            ",1,5);
        gui.printf(string.rep("=", term.getSize()),1,6);
        for i = 1, 12, 1 do
            tableLength = table.getn(currentLog);
            if currentLog[tableLength - i] ~= nil then
                gui.printf(currentLog[tableLength - i] .. string.rep(" ", term.getSize()), 1, 6+i);
            end
        end
        gui.printf(string.rep("=", term.getSize()),1,19);
        sleep(0);
    end
end

parallel.waitForAny(waitForMessage, setUptime, updateScreen);