simple

-- Basic little control program for a passively cooled reactor. This program would not be possible, even in the primitive state it is now, without the inspiration and coding support of lolmer and ScatmanJohn. Will passively detect a reactor and a monitor, either through direct proximity or a wired modem. Please ensure the computer and monitors are the advanced version (it's just gold, not exactly rare in Minecraft), and that the monitor is a 3x2.
local progVer = "1.06"
local progName = "IC_SimpleNuke"
local loopTime = 0.5 -- Time between program loops, in seconds. Increase this value if program somehow causes a lot of lag. Which should not happen on any computers made this century
local baseControlRodLevel = 95 -- Put this as close to what you guess the optimum control rod level will be for your reactor, plus a little more
local minStoredEnergyPercent = 20 -- Min energy % to store before activating, probably keep it at default (20)
local maxStoredEnergyPercent = 90 -- Max energy % to store before shutdown, probably keep it at default (70)
-- This program doesn't care about heat anymore, only tried to maintain the internal power buffer, following 2 lines only included for legacy
local minReactorTemp = 20 -- Minimum reactor temperature (^C) to maintain
local maxReactorTemp = 3000 -- Maximum reactor temperature (^C) to maintain

----------

-- Basic side determination for wrapping
function getDeviceSide(deviceType)
    deviceType = deviceType:lower()

    for i, side in pairs(rs.getSides()) do
        if (peripheral.isPresent(side)) then
            if (string.lower(peripheral.getType(side)) == deviceType) then
                return side;
            end
        end
    end

    return nil;
end

-- Peripheral wrapping function
function wrapThis(thing, f)
    local wrapped = nil
    while wrapped == nil and f <= 100 do
        wrapped = peripheral.wrap(thing.."_"..f)
        f = f + 1
    end

    if wrapped == nil then
        side = getDeviceSide(thing)
        if side ~= nil then
            return peripheral.wrap(side)
        else
            return nil
        end
    else
        return wrapped
    end
end


print("Initializing program...",1,1);

-- Initialize the monitor
-- If it can't find a monitor, will wait 5 seconds then reboot
-- This is needed for server restarts when the computer starts up before the modem does
local monitor = wrapThis("monitor", 0)
if monitor == nil then
    sleep(5)
    finished = true
    os.reboot()
end
local monitorx, monitory = monitor.getSize()
if monitorx ~= 29 or monitory ~= 12 then
    print("Monitor is the wrong size! Needs to be 3x2.")
    sleep(5)
    finished = true
    os.reboot()
end

-- Connect to the big reactor peripheral
-- If it can't find a reactor, will wait 5 seconds then reboot
-- This is needed for server restarts when the computer starts up before the modem does
local reactor = wrapThis("BigReactors-Reactor", 0)
if reactor == nil then
    sleep(5)
    finished = true
    os.reboot()
end

-- Easyprint, saves program space elsewhere
local function print(str, x, y)
    term.setCursorPos(x, y)
    term.write(str)
end

-- Move stuff to monitor
if  monitor then
    sleep(1)
    term.clear()
    term.setCursorPos(1,1)
    term.write("Display redirected to Monitor. Type r to reboot, or")
    term.setCursorPos(1,2)
    term.write("q to quit and return control to this terminal.")
    term.redirect(monitor)
end

-- Restore functions to computer terminal
function restoreNativeTerminal()
    repeat
        term.restore()
        local w, h = term.getSize()
    until w == 51 and h == 19
end

-- Draw some decorative lines
function drawLines()
    term.setBackgroundColor(colors.black)
    paintutils.drawLine(1, 2, 29, 2, colors.lightBlue)
    paintutils.drawLine(1, 7, 29, 7, colors.lightBlue)
    term.setBackgroundColor(colors.black)
end

-- Just to make sure they're relatively high before the control program starts
if  reactor then
    sleep(1)
    reactor.setAllControlRodLevels(baseControlRodLevel)
else
    sleep(5)
    finished = true
    os.reboot()
end

-- Draw stuff on the monitor
local function drawInfo()

    statusstring = "Reactor status: "
    tempstring = "Temperature: "
    tempstring2 = "deg. C"
    powerstring = "Power Output: "
    powerstring2 = "RF/t"
    rodstring = "Control Rods: "
    rodstring2 = "%"

    monitor.setTextColor(colors.green)
    print(progName,5,1)
    monitor.setTextColor(colors.red)
    print("v",19,1)
    monitor.setTextColor(colors.green)
    print(progVer,20,1)
    monitor.setTextColor(colors.white)

    print(statusstring,1,3)
    if reactor.getActive() then
        monitor.setTextColor(colors.green)
        print(" online",23,3)
    else
        monitor.setTextColor(colors.red)
        print("offline",23,3)
    end

    monitor.setTextColor(colors.white)
    --reactortemp = math.floor(reactor.getFuelTemperature())
    print(tempstring,1,4)
    print(reactortemp,16,4)
    print(tempstring2,24,4)

    power = math.floor(reactor.getEnergyProducedLastTick())
    print(powerstring,1,5)
    print(power,16,5)
    print(powerstring2,26,5)

    rods = reactor.getControlRodLevel(1)
    print(rodstring,1,6)
    print(rods,16,6)
    print(rodstring2,29,6)
end

-- Draw stuff on the bottom part of the monitor, power bar etc
function drawBottomPart()
    reactivity = math.floor(reactor.getFuelReactivity())
        paintutils.drawLine(2, 9, 28, 9, colors.gray)
        if reactivity > 400 then
                paintutils.drawLine(2, 9, math.floor(26*reactivity/500)+1, 9, colors.red)
        elseif reactivity > 320 then
                paintutils.drawLine(2, 9, math.floor(26*reactivity/500)+1, 9, colors.orange)
        elseif reactivity > 240 then
                paintutils.drawLine(2, 9, math.floor(26*reactivity/500)+1, 9, colors.yellow)
        elseif reactivity > 160 then
                paintutils.drawLine(2, 9, math.floor(26*reactivity/500)+1, 9, colors.green)
        elseif reactivity > 0 then
                paintutils.drawLine(2, 9, math.floor(26*reactivity/500)+1, 9, colors.blue)
        end
        term.setBackgroundColor(colors.black)
        print("Fuel Reactivity:",1,8)
        print(reactivity,24,8)
        print("%",29,8)
        term.setBackgroundColor(colors.black)

    energystorage = reactor.getEnergyStored()
    storagepercent = math.floor(energystorage/10000000*100)
    paintutils.drawLine(2, 12, 28, 12, colors.gray)
    if storagepercent > 4 then
        paintutils.drawLine(2, 12, math.floor(26*storagepercent/100)+2, 12, colors.yellow)
    elseif storagepercent > 0 then
        paintutils.drawPixel(2,12,colors.yellow)
    end
    term.setBackgroundColor(colors.black)
    print("Internal buffer: ",1,11)
    print(storagepercent,24,11)
    print("%",29,11)
    term.setBackgroundColor(colors.black)
end

-- Controls the reactor, keeping it between configured temps and power storage
function control()
    energystorage = reactor.getEnergyStored()
    reactortemp = math.floor(reactor.getFuelTemperature())
    ediff = (maxStoredEnergyPercent - minStoredEnergyPercent)*100000
    ediffper = ediff / 100
    if energystorage > maxStoredEnergyPercent*100000 then
        reactor.setActive(false)
    reactor.setAllControlRodLevels(95)
    elseif energystorage < minStoredEnergyPercent*100000 then
        reactor.setActive(true)
        reactor.setAllControlRodLevels(5)
    elseif energystorage > minStoredEnergyPercent*100000 then
        reactor.setActive(true)
        blarg = energystorage - minStoredEnergyPercent*100000
        blarg2 = math.floor(blarg/(ediffper+1))
        reactor.setAllControlRodLevels(blarg2)
    end
end

-- Main program
function main()
    while not finished do
        if reactor.getConnected() then
            drawLines()
            drawInfo()
            drawBottomPart()
            control()
            sleep(loopTime)
        end
    end
end

-- Event handler for exiting, editting and debugging
function eventHandler()
    while not finished do
        event, arg1, arg2, arg3 = os.pullEvent()
        if event == "char" and not inManualMode then
            local ch = string.lower(arg1)
            if ch == "q" then
                finished = true
            elseif ch == "r" then
                finished = true
                os.reboot()
            end
        end
    end
end

while not finished do
    parallel.waitForAny(eventHandler, main)
    sleep(loopTime)
end

-- Returns control to the terminal if the program has an error or whatever
term.clear()
term.setCursorPos(1,1)
restoreNativeTerminal()
term.clear()
term.setCursorPos(1,1)