Evil silly cat turtle

function string.starts(String, Start)
    return string.sub(String, 1, string.len(Start)) == Start
end

local protoSub = 'STOP_SPYING_ON_REDNET_'
local file = 'THECODE_'
local id = os.getComputerID()

rednet.open('left')

function floodTraffic()
	rednet.broadcast('STOP_SPYING', protoSub..math.random(0,200000))
end

local detector = peripheral.find('playerDetector')
if not detector then
    error('Couldn\'t find the stalker thingie')
end

local envDet = peripheral.find('environmentDetector')

local code

if not fs.exists(file) then
    print('ID?')
    code = read()

    local newFile = fs.open(file, 'w')
    newFile.write(code)

    newFile.close()
else
    local filePass = fs.open(file, 'r')
    code = filePass.readAll()
end

local prot = protoSub..code

term.clear()

if envDet == nil then
	print('Environment Detector could not be found.')
end

local dim = (envDet and envDet.getDimension() or "UNKNOWN")

local cmds = {
    ['RESTART'] = function(...)
        os.reboot()
    end,
    ['EVAL'] = function(...)
        local luaStr = ...
        xpcall(function()
            loadstring(luaStr)()
        end, function(...)
            print(...)
        end)
    end,
}

function commandSent(dataStr)
    if type(dataStr) ~= "string" then return end
    if not string.starts(tostring(dataStr), '{') then return end

    xpcall(function()
        local data = textutils.unserialize(dataStr)
        cmds[data.cmd](data.txt)
    end, function(...)
        print(...)
    end)
end

while true do
    local event,_,_, m, n, t = os.pullEvent()
    if event == "modem_message" then
        if n.sProtocol == prot and m == 1 then
            commandSent(n.message)
        end
    end

    local playerPositions = {}
    local players = detector.getOnlinePlayers()

    if players then
        for _, player in next, players do
            local position = detector.getPlayerPos(player)
            if position then
                playerPositions[player] = player..': X: '..position.x..' Y: '..position.y..' Z: '..position.z
            else
                playerPositions[player] = nil
            end
        end

        local serialized = textutils.serialize({
            ['dem'] = dim,
            ['positions'] = playerPositions
        })
        if #serialized > 2 then
            rednet.send(1, serialized, prot)
        else
            rednet.send(1, 'NONE', prot)
        end
    end
    floodTraffic()
end