Chest Checker

chestSide = "bottom"
signalSide = "top"
updateDelay = 5 --in seconds
fill = 0.98 --in % --> 0-1
x,y = term.getSize()

function clear() --GUI stuff.
 term.clear()
 term.setCursorPos(1,1)
end

function drawLine() --GUI stuff.
 for i=1,x-1 do
  write("-")
 end
end

function valueExists(tbl,value) --Checks if a value exists in a table.
 for k,v in ipairs(tbl) do
  if value == v then
   return true
  end
 end
 return false
end

function setup()
 clear()
 drawLine()
 print("Monitoring on side: "..chestSide)
 print("Sending signal to side: "..signalSide.." every "..updateDelay.." seconds.")
 print("Outputting if above "..(fill*100).."%")
 drawLine()
 chest = peripheral.wrap(chestSide)
 if chest == nil then
  clear()
  drawLine()
  print("No chest found!")
  drawLine()
  error()
 end
 sleep(2)
end

function display()
 clear()
 drawLine()
 print("Status:")
 print("Chest: "..currentContent.."/"..maxContent*64)
 percentage = (currentContent *100) / (maxContent*64)
 print("Chest is "..math.floor(percentage).."% full.")
 print("Threshold is: "..(fill*100).."%")
 signal = currentContent > ((maxContent*64)*fill)
 if signal then
  print("Above Threshold!")
 else
  print("Below Threshold.")
 end
 print("")
 print("Update Interval: "..updateDelay.."s")
 drawLine()
end

function main()
 while true do
  maxContent = chest.getInventorySize()
  currentContent = 0
  for i = 1,maxContent do
   data = chest.getStackInSlot(i)
   if data == nil then
    data = 0
   else
    currentContent = currentContent + data.qty
   end
  end
  display()
  rs.setOutput(signalSide,signal)
  sleep(updateDelay)
 end
end

setup()
main()