Spiral Program For Mining Turtle

function digForward(x)
 for i = 1,x,1 do
  if spaceInInventory() == 0 then
   placeChest()
  end
  while(turtle.detect()) do
   turtle.dig()
   os.sleep(0.45)
  end
  turtle.forward()
  while(turtle.detectUp()) do
   turtle.digUp()
   os.sleep(0.45)
  end
 end
end

function spaceInInventory()
 for i = 1,16,1 do
  if turtle.getItemCount(i) == 0 then
   return 1
  end
 end
 return 0
end

function goBack(x, numberSpirals)
 turtle.turnRight()
 for i=0,x/2,1 do
  turtle.back()
 end
 turtle.turnLeft()
 digForward(3*(numberSpirals/4))
end

function placeChest()
 refuel()
 turtle.select(2)
 turtle.turnRight()
 turtle.dig()
 turtle.forward()
 turtle.digUp()
 turtle.back()
 turtle.select(1)
 turtle.place(1)
 for i = 2 , 16 do
  turtle.select(i)
  turtle.drop()
 end
 turtle.select(1)
 turtle.dig()
 turtle.turnLeft()
end

function refuel()
 if turtle.getFuelLevel() > 5000 then
  return
 end
 for i=2,16,1 do
  turtle.select(i)
  turtle.refuel(64)
 end
end

local arguments = {...}

x = 0
for i = 1,tonumber(arguments[1]),1 do
 if i % 2 == 0 then
  x = x+2
 else x = x+1 end
 digForward(x)
 turtle.turnLeft()
end
goBack(x, tonumber(arguments[1]))
placeChest()