controller.lua

local INTERPRETER = 18
local has_fuel = true
local busy = false
local ready = false
local current_time = 0
local current_task = nil

local screen = peripheral.wrap("front")

local function update_screen()
    screen.clear()
    screen.setTextScale(1.5)

    screen.setCursorPos(1,1)
    screen.write("State:")

    screen.setCursorPos(1,2)
    if not ready then
        screen.write("Initting")
    elseif not has_fuel then
        screen.write("NO FUEL")
    elseif busy then
        if current_task == "bake_bread" then
            screen.write("Baking bread")
        else
            screen.write("Planting crops")
        end
    else
        screen.write("Growing")
    end

    screen.setCursorPos(1,4)
    screen.write("Time until harvest:")
    screen.write(40 - current_time .. "m")

    screen.setCursorPos(1,5)
    screen.write("[")

    -- Can fit 27 |'s in a single line
    for c = 0, (current_time / 40) * 27 do
        screen.write("|")
    end

    screen.write("]")
end

local function handleMessage(msg)
    if msg == "has_fuel" then
        has_fuel = true
    elseif msg == "has_no_fuel" then
        has_fuel = false
    elseif msg == "performing_task" then
        busy = true
    elseif msg == "done_task" then
        busy = false
    elseif msg == "ready" then
        ready = true
    end
    update_screen()
end

local function check_state()
    local res = rednet.receive(1)
    if not res then
        return
    end
    local id, msg = res

    if id == INTERPRETER then
        handleMessage(msg)
    end
end

local function freeze_while_waiting()
    while has_fuel or busy or not ready do
        check_state()
    end
end

local function start_farm()
    redstone.setOutput("back", true)
    sleep(60)
    redstone.setOutput("back", false)
    sleep(30)
    redstone.setOutput("left", true)
    sleep(10)
    redstone.setOutput("left", false)

    rednet.send(INTERPRETER, "farm")
end

local function iterate()
    while true do
        freeze_while_waiting()

        -- 40 minutes, time to fully grow a crop
        for t = 0, 8 do
            -- 5 minutes
            for f = 0, 5 do
                -- 1 minute
                for s = 0, 60 do
                    check_state()
                end

                current_time = current_time + 1
                update_screen()
            end

            freeze_while_waiting()
            -- Make bread
            rednet.send(INTERPRETER, "bake_bread")
            current_task = "bake_bread"
            busy = true
            freeze_while_waiting()
        end

        current_time = 0
        update_screen()

        freeze_while_waiting()
        -- Trigger flood and then replant crops
        start_farm()
        current_task = "farm"
        busy = true
        freeze_while_waiting()
    end
end

local function init()
    rednet.open("right")
end

init()