local finished = false
local wall = 0
local x = 0
local z = 0
local x1 = 0
local z1 = 0

function line()
  turtle.select(2)
  if not turtle.detectDown() then
   turtle.placeDown()
   print("block placed")
  end
  if not turtle.detect() then
   turtle.forward()
   print("moving forward")
   if wall == 0 then
     x = x + 1
     else
       x = x - 1
   end
   else
     turtle.select(3)
     if turtle.compare() then
      finished = true
      print("i am finished")
      else
        print("I have reached a wall")
        if wall == 0 then
          turtle.turnRight()
          turtle.forward()
          z = z + 1
          turtle.turnLeft()
          while not turtle.detect() do
            turtle.forward()
            x = x + 1
          end
          print("I have reached the second wall")
          turtle.select(3)
          if turtle.compare() then
            finished = true
            print("i am finished")
          end
          turtle.select(2)
          wall = 1
          turtle.turnRight()
          turtle.turnRight()
          elseif wall == 1 then
            turtle.turnLeft()
            turtle.forward()
            z = z + 1
            turtle.turnRight()
            while not turtle.detect() do
              turtle.forward()
              x = x - 1
            end
            print("I have reached the third wall")
            turtle.select(3)
            if turtle.compare() then
              finished = true
              print("i am finished")
            end
            turtle.select(2)
            wall = 0
            turtle.turnLeft()
            turtle.turnLeft()
        end
     end
  end
end

function base()
  if wall == 0 then
       turtle.turnLeft()
       else
         turtle.turnRight()
   end
   print(z1)
   print(x1)
   while z1 <= 1 do
     turtle.forward()
     z1 = z1 - 1
   end
   turtle.turnLeft()
   while x1 <= 1 do
     turtle.forward()
     x1 = x1 - 1
   end
   turtle.down()
   turtle.suck(2)
   if turtle.getItemCount(2) == 1 then
     print("Welp, no more items, ending.")
     turtle.turnLeft()
     turtle.turnLeft()
     finished = true
   end
   print("returning to work location")
   turtle.up()
   turtle.turnLeft()
   turtle.turnLeft()
   while x1 ~= x do
     turtle.forward()
     x1 = x1 + 1
   end
   turtle.turnRight()
   while z1 ~= z do
     turtle.forward()
     z1 = z1 + 1
   end
   turtle.down()
   if wall == 0 then
     turtle.turnLeft()
     else
       turtle.turnRight()
   end
end

while finished == false do
  if turtle.getItemCount(2) == 1 then
    print("I have run out of blocks")
   -- os.pullevent("turtle_inventory")
   -- print("my inventory has changed, sure hope it was blocks")
--   print("returning to base")
--   turtle.up()
--   z1 = z
--   x1 = x
--   base()
    turtle.select(4)
    turtle.transferTo(2)
    turtle.select(5)
    turtle.transferTo(2)
    turtle.select(6)
    turtle.transferTo(2)
    turtle.select(7)
    turtle.transferTo(2)
    turtle.select(8)
    turtle.transferTo(2)
    turtle.select(9)
    turtle.transferTo(2)
    turtle.select(10)
    turtle.transferTo(2)
    turtle.select(11)
    turtle.transferTo(2)
    turtle.select(12)
    turtle.transferTo(2)
    turtle.select(13)
    turtle.transferTo(2)
    turtle.select(14)
    turtle.transferTo(2)
    turtle.select(15)
    turtle.transferTo(2)
    turtle.select(16)
    turtle.transferTo(2)
    turtle.select(2)
  end
  if turtle.getFuelLevel() < 1 then
    turtle.select(1)
    turtle.refuel(1)
    print("I have refueled")
  end
  line()
  print("restarting while loop")
end