MultiMobRoof

RADIO="top"
BUNDLE="back"

mobs = {}
mobs["creaper"]  = colors.green
mobs["skeleton"] = colors.white
mobs["pigmen"]   = colors.yellow

controller = nil

function colorOn(color)
    local c = redstone.getBundledOutput(BUNDLE)
    c = colors.combine(c, color)
    redstone.setBundledOutput(BUNDLE, c)
end

function colorOff(color)
    local c = redstone.getBundledOutput(BUNDLE)
    c = colors.subtract(c, color)
    redstone.setBundledOutput(BUNDLE, c)
end

function colorToggle(color)
    local c = redstone.getBundledOutput(BUNDLE)
    if colors.test(c, color) then
        c = colors.subtract(c, color)
    else
        c = colors.combine(c, color)
    end
    redstone.setBundledOutput(BUNDLE, c)
end

function colorAllOn()
    redstone.setBundledOutput(BUNDLE, 65535)
end

function processMessage(data)
    if data["action"] == "acknowledge" or (data["action"] == "announce" and data["device"] == "controller") then
        controller = data["computer_id"]
        if data["action"] == "announce" then
            rednet.send(data["computer_id"], textutils.serialize({action="acknowledge", type="multimob", device="roof"}))
        end
    elseif data["action"] == "mobon" then
        colorAllOn()
        if mobs[data["mob"]] ~= nil then
            colorOff(mobs[data["mob"]])
        end
    elseif data["action"] == "off" then
        colorAllOn()
    end
end

colorAllOn()

if peripheral.isPresent(RADIO) and peripheral.getType(RADIO) == "modem" then
    rednet.open(RADIO)
    rednet.broadcast(textutils.serialize({action="announce", type="multimob", device="roof"}))
else
    print("Modem not found")
    return
end

while true do
    ev,p1,p2,p3 = os.pullEvent()
    if ev == "rednet_message" then
        data = textutils.unserialize(p2)
        if data["type"] == "multimob" then
            data["computer_id"] = p1
            processMessage(data)
        end
    end
end