[CC] Simple reactor controller

--
-- Nuclear reactor controller for Computercraft/Industrialcraft
-- Powers the reactor as long as
-- * Required by redstone input (lever)
-- * The reactor is safe (heat < threshold)
-- * The battery is not full
--

------- PARAMETERS ----------------------------------
REDSTONE_INPUT_SIDE = ''
BATTERY_SIDE = ''
REACTOR_SIDE = ''
REACTOR_REDSTONE_SIDE = ''
MONITOR_SIDE = '' -- Set to NIL to disable

HEAT_THRESHOLD = 65 -- %
BATTERY_LOW_THRESHOLD = 80 -- %

CHECK_PERIOD = 2 --sec
------- END PARAMS ----------------------------------

local nextTimer = nil
local prevState = false
local reactor = nil
local battery = nil
local monitor = nil
local prevBattCharge = 0

os.loadAPI('/lib/slot_sig')

function updateScreen(nState, status)
    monitor.clear()
    monitor.setCursorPos(1,1)

    if(nState==true) then
        monitor.setTextColor(colors.lime)
    else
        monitor.setTextColor(colors.red)
    end
    monitor.write(status)
    monitor.setTextColor(colors.white)
    monitor.setCursorPos(1,3)
    monitor.write('Heat: '..math.floor(reactor.getHeat())..'/'..math.floor(reactor.getMaxHeat()))
    monitor.setCursorPos(1,4)
    monitor.write('Batt: '..math.floor(battery.getEUStored()/battery.getEUCapacity()*100)..'%')
    monitor.setCursorPos(7,5)
    monitor.write(math.floor((battery.getEUStored()-prevBattCharge)/CHECK_PERIOD)..'EU/s')
end

function setReactorState(nState, status)
    prevState = nState

    redstone.setOutput(REACTOR_REDSTONE_SIDE, nState)
    updateScreen(nState, status)
end

function onTimer(data)
    if(nextTimer ~= data[1]) then
        return
    end

    -- Determine whether the reactor should be ON or OFF
    if(redstone.getInput(REDSTONE_INPUT_SIDE) == true) then
        heatPercent = reactor.getHeat() / reactor.getMaxHeat() * 100
        battPercent = battery.getEUStored() / battery.getEUCapacity() * 100
        if(heatPercent > HEAT_THRESHOLD) then
            setReactorState(false, 'Cooldown')
        elseif( (prevState == true and battPercent > 98)
             or (prevState == false and battPercent > BATTERY_LOW_THRESHOLD) ) then
            setReactorState(false, 'Batt. full')
        else
            setReactorState(true, 'Running')
        end
    else
        setReactorState(false, 'Inactive')
    end

    prevBattCharge = battery.getEUStored()
    nextTimer = os.startTimer(CHECK_PERIOD)
end

function main()
    reactor = peripheral.wrap(REACTOR_SIDE)
    battery = peripheral.wrap(BATTERY_SIDE)
    if(MONITOR_SIDE ~= nil) then
        monitor = peripheral.wrap(MONITOR_SIDE)
    end

    slot_sig.connectSlot('timer',onTimer)

    nextTimer = os.startTimer(0.5)
    slot_sig.run()
end
main()