chunckminer

layer = 1
line = 1
torch = 1
room = 0

function fuel()
  if turtle.getFuelLevel() < 250 then
    turtle.digUp()
    turtle.select(13)
    turtle.placeUp()
    turtle.select(12)
    turtle.dropDown()
    turtle.suckUp()
    turtle.refuel()
    turtle.suckDown()
    turtle.select(13)
    turtle.digUp()
    turtle.select(1)
  end
end

function drop()
  turtle.digUp()
  turtle.select(14)
  turtle.placeUp()
  for i = 1,12 do
    turtle.select(i)
    turtle.dropUp()
  end
  turtle.select(14)
  turtle.digUp()
  turtle.select(1)
end

function inv()
  for i = 1,12 do
    if turtle.getItemCount(i) == 0 then
      room = room + 1
    end
  end

  if room == 0 then
    drop()
  else room = 0
  end

end

function forward()
  while not turtle.forward() do
    inv()
    if not turtle.dig() then
      turtle.attack()
    end
  end
end

function up()
  while not turtle.up() do
    inv()
    turtle.digUp()
  end
end

function down()
  while not turtle.down() do
    inv()
    turtle.digDown()
  end
end

function updown()
  inv()
  turtle.digUp()
  inv()
  turtle.digDown()
end

function left()
  turtle.turnLeft()
  forward()
  turtle.turnLeft()
  updown()
end

function right()
  turtle.turnRight()
  forward()
  turtle.turnRight()
  updown()
end

function deployAnchor()
  forward()
  inv()
  turtle.digDown()
  turtle.select(15)
  turtle.placeDown()
  turtle.select(1)
  right()
  forward()
  updown()
end

function grabAnchor()
  turtle.select(15)
  inv()
  turtle.digDown()
  turtle.select(1)
end

function placeTorch()
  down()
  if turtle.detectDown() then
      up()
      turtle.select(16)
      turtle.placeDown()
      turtle.select(1)
  else
    up()
  end
end

function goStart()
  for i = 1,2 do
    turtle.turnLeft()
    for i = 1,6 do
      forward()
    end
  end
  turtle.turnLeft()
  turtle.turnLeft()
  if layer == 1 then
    grabAnchor()
  end
end

function row()
  for i = 1,6 do
    forward()
    updown()
    torch = torch + 1
    if torch == 4 and line == 4 and layer == 1 then
      placeTorch()
    end
  end
  torch = 1

  if line == 1 and layer == 1 then
    deployAnchor()
    line = line + 1
  elseif line < 7 then
    if (line % 2) == 0 then
      left()
      line = line + 1
    else
      right()
      line = line + 1
    end
  else
    goStart()
    line = 1
  end
end

function chunck()
  for i = 1,7 do
    row()
  end
  layer = layer + 1
end

function layerUp()
  for i = 1,3 do
    up()
  end
  inv()
  turtle.digUp()
end

while true do
    fuel()
    while layer ~= 4 do
      chunck()
      if layer ~= 4 then
        layerUp()
      else
        inv()
        turtle.digUp()
        for i = 1,7 do
          forward()
        end
        for i = 1,6 do
          down()
        end
      end
    end
end