GauDigger v0.7

-- Digs a 5x5 tunnel straight forward until it runs out of fuel. Will attempt to refuel as it goes, using coal it finds
-- Place chests in slot 16 of the turtle inventory to make it place chests and fill them as it travels

local ChestSlot = 16


function refuel()
  local slot = 0
  while ( turtle.getFuelLevel() < 100 and slot < 15 ) do
    slot = slot + 1
    turtle.select(slot)
    turtle.refuel(10)
  end
  turtle.select(1)
end

function tryForward()
  refuel()
  if ( turtle.getFuelLevel() < 100 ) then
    print "Ran out of fuel!"
    os.exit()
  end
  while ( not turtle.forward() ) do
    turtle.dig()
    os.sleep(1)
  end
end

function tryUp()
  refuel()
  if ( turtle.getFuelLevel() < 100 ) then
    print "Ran out of fuel!"
    os.exit()
  end
  while ( not turtle.up() ) do
    turtle.digUp()
    os.sleep(1)
  end
end

function tryDown()
  refuel()
  if ( turtle.getFuelLevel() < 100 ) then
    print "Ran out of fuel!"
    os.exit()
  end
  while ( not turtle.down() ) do
    turtle.digDown()
    os.sleep(1)
  end
end



function checkSpace()
  if ( turtle.getItemCount(12) > 0 ) then
    if ( turtle.getItemCount(ChestSlot) <= 0 ) then
      print "Ran out of space"
      os.exit()
    end

    turtle.turnLeft()
    turtle.turnLeft()
    turtle.select(ChestSlot)
    turtle.place()
    for slot = 1,15 do
      turtle.select(slot)
      turtle.drop()
    end

    turtle.turnLeft()
    turtle.turnLeft()

  end
  turtle.select(1)
end


function digTunnel()
  turtle.turnLeft()
  tryForward()
  tryForward()
  turtle.turnRight()
  for x=1,5 do
    for y=1,5 do
      tryUp()
    end
    for y=1,5 do
      tryDown()
      turtle.dig()
    end
    if ( x < 5 ) then
        turtle.turnRight()
        tryForward()
        turtle.turnLeft()
    end

  end
  turtle.turnLeft()
  tryForward()
  tryForward()
  turtle.turnRight()
  tryForward()
end

while true do
  digTunnel()
  checkSpace()
end