BioReactor controller

--Credit Flaghacker

--Settings
--how many slots the bioreactor has to contain in order to be "filled"
local minSlots = 4
-- the peripheral id for a bioreactor
local bioReactorId = "bioreactor"
--(optionally) the side of the bioreactor
local bioReactorSide

--vars
local p

local s = 10
local e = 18

--util
function printBoolean(boolean)
        if term.isColor() then
                if boolean then
                        term.setTextColor(colors.lime)
                else
                        term.setTextColor(colors.red)
                end
        end
        print(boolean)
        if term.isColor() then
                term.setTextColor(colors.white)
        end
end

--functions
local function wrapPeripheral()
    if bioReactorSide == nil then
        for i, v in ipairs(rs.getSides()) do
            if peripheral.getType(v) == bioReactorId then
                p = peripheral.wrap(v)
                bioReactorSide = v;
                return
            end
        end
    else
        if (peripheral.getType(bioReactorSide)) == bioReactorId then
            p = peripheral.wrap(bioReactorSide)
        else
            error(string.format("The peripheral on side '%s' is not of type '%s', but of type '%s'", tostring(bioReactorSide), tostring(bioReactorId), tostring(peripheral.getType(bioReactorSide))))
        end
    end

    error("No bioreactor could be found")
end

local function isSlotFilled(slot)
    return not (p.getStackInSlot(slot) == nil)
end

local function isReactorFilled()
    local t = 0;
    for i = s, e do
        if (isSlotFilled(i)) then
            t = t + 1
        end
    end

    return t >= minSlots
end

--main code
wrapPeripheral()

while true do
    local a = isReactorFilled()
    rs.setOutput(bioReactorSide, not a)
    rs.setOutput("top", not a)
    term.clear()
    write("Bio reactor enabled: ")
    printBoolean(a)
    sleep(.5)
end