--replaces block in direction
function replaceBlock(slot, dir)
  turtle.select(slot)
  if dir == "up" then
    turtle.digUp()
    turtle.placeUp()
  elseif dir == "front" then
    turtle.dig()
    turtle.place()
  elseif dir == "down" then
    turtle.digDown()
    turtle.placeDown()
  end
end

--places light in the middle
function placeLight(lslot)
  turtle.digDown()
  turtle.select(lslot)
  turtle.placeDown()
end

--places tracks
function placeTrack(count, railslot)
  if count == 13 then
    turtle.select(16)
    turtle.place()
    turtle.turnLeft()
    turtle.turnLeft()
    turtle.select(railslot)
    turtle.place()
    turtle.turnRight()
  elseif count == 14 then
    turtle.select(15)
    turtle.place()
    turtle.turnLeft()
    turtle.turnLeft()
    turtle.place()
    turtle.turnRight()
  elseif count == 15 then
    turtle.select(railslot)
    turtle.place()
    turtle.turnLeft()
    turtle.turnLeft()
    turtle.select(16)
    turtle.place()
    turtle.turnRight()
  else
    turtle.select(railslot)
    turtle.place()
    turtle.turnLeft()
    turtle.turnLeft()
    turtle.place()
    turtle.turnRight()
  end
end

--fuel check
function checkFuel()
  if turtle.getFuelLevel() < 12 then
    turtle.refuel(1)
  end
end

--creates 1 new slice of tunnel
function newSlice(count, lcount, slot, railslot)
  turtle.turnRight()
  turtle.forward()
  if turtle.compareDown(slot) == false then
      replaceBlock(slot, "down")
  end
  if turtle.compare(slot) == false then
    replaceBlock(slot, "front")
  end
  turtle.up()
  if turtle.compare(slot) == false then
    replaceBlock(slot, "front")
  end
  if turtle.compareUp(slot) == false then
    replaceBlock(slot, "up")
  end
  turtle.turnLeft()
  turtle.turnLeft()
  turtle.forward()
  if turtle.compareUp(slot) == false then
    replaceBlock(slot, "up")
  end
  turtle.forward()
  if turtle.compareUp(slot) == false then
    replaceBlock(slot, "up")
  end
  if turtle.compare(slot) == false then
    replaceBlock(slot, "front")
  end
  turtle.down()
  if turtle.compare(slot) == false then
    replaceBlock(slot, "front")
  end
  if turtle.compareDown(slot) == false then
    replaceBlock(slot, "down")
  end
  turtle.turnRight()
  turtle.turnRight()
  turtle.forward()

  if lcount == 8 then
    placeLight(14)
  else
    if turtle.compareDown(slot) == false then
      replaceBlock(slot, "down")
    end
  end
  placeTrack(count, railslot)
  turtle.forward()
end


loopCounter = 0
count = 0
lcount = 0
ccount = 0
slot = 2
railslot = 11
turtle.refuel(1)

while loopCounter <= 64 do
  print(count)
  if turtle.getItemCount(slot) < 10 then
    if slot < 10 then
      slot = slot + 1
    else
      os.exit()
    end
  end
  if turtle.getItemCount(railslot) < 2 then
    if railslot < 13 then
      railslot = railslot + 1
    else
      os.exit()
    end
  end
  if ccount == 4 then
    turtle.select(1)
    turtle.refuel(1)
  end
  newSlice(count, lcount, slot, railslot)

  lcount = lcount + 1
  count = count + 1
  ccount = ccount + 1
  if lcount > 8 then
    lcount = 0
  end
  if count > 15 then
    count = 0
  end
  if ccount > 4 then
    ccount = 0
  end
  loopCounter = loopCounter + 1
end
os.exit()