local reactor = peripheral.wrap("BigReactors-Reactor_1")
local mon = peripheral.wrap("monitor_0")

-- clear the monitor at startup
mon.setBackgroundColor(colors.black)
mon.clear()

function repeats(s, n)
  return n > 0 and s .. repeats(s, n-1) or ""
end


function drawLine (m, row, color)
  local currentColor = m.getBackgroundColor()
  local oldX, oldY = m.getCursorPos()
  local sizeX, sizeY = m.getSize()

  m.setCursorPos(row, 0)
  m.setBackgroundColor(color)
  m.write(repeats(" ", sizeX))

  m.setCursorPos(oldX, oldY)
  m.setBackgroundColor(currentColor)
end

function drawDisplay ()
  drawLine(mon, 1, colors.red)
end

drawDisplay()