-- Input Signals:
-- control
-- comparator
-- Output Signals:
-- reactor: control and (comparator < threshold)

local signal_comparator = "top"
local signal_control = "right"
local signal_reactor = "front"
local signal_reactor_local = "left"
local monitor = peripheral.wrap("back")

local threshold = 12

local current_reactor_signal = false
local last_read_comparator_level = 0

local function update()
    local comparator = redstone.getAnalogInput(signal_comparator)
    local control = redstone.getInput(signal_control)

    local reactor = control and (comparator < 12)

    redstone.setOutput(signal_reactor, reactor)
    redstone.setOutput(signal_reactor_local, reactor)

    current_reactor_signal = reactor
    last_read_comparator_level = comparator
end

local function drawBox(x, y, width, height, color)
    monitor.setBackgroundColor(color)
    for i = x, x + width do
        for j = y, y + height do
            monitor.setCursorPos(i, j)
            monitor.write(" ")
        end
    end
    monitor.setBackgroundColor(colors.black)
end

local function render()
    local width, height = monitor.getSize()

    monitor.clear()

    monitor.setTextScale(2)
    monitor.setCursorPos(1, 1)
    monitor.write("Reactor Buffer State:")
    monitor.setTextScale(1)

    local bar_x = 1
    local bar_y = 5
    local bar_width = width - 2
    local inner_width = bar_width - 2
    local bar_height = height - 6
    local inner_height = bar_height - 2


    drawBox(bar_x, bar_y, bar_width, bar_height, colors.yellow)
    local fill_percent = last_read_comparator_level / 15
    local fill_level = math.floor(inner_width * fill_percent)
    drawBox(bar_x + 1, bar_y + 1, fill_level, inner_height, colors.red)
end


local function run()
    update()
    render()
    while true do
        if redstone.getAnalogInput(signal_comparator) ~= last_read_comparator_level then
            update()
            render()
        end
        os.sleep(2)
    end
end

run()