GauSubway v0.5

-- A digging turtle program that will make a tunnel
-- The tunnel will attempt to contour to the ground, but if it reaches a slope higher than 1 block
--  it will start digging or placing filler blocks.

-- The turtle will likely error out of it runs out of fuel or any type of block

-- Cover blocks ( try glass! ) : Slots 1-4
-- Filler blocks ( try gravel!) : Slots 5-6
-- Floor blocks ( try stone bricks!) : Slots 7-9
--  Note: Filler blocks must be affected by gravity for it to work ( ie. gravel, sand, etc. )


-- Settings

-- You can change how many slots to use of the inventory and for which types of blocks by changing these numbers
local coverSpotEnd = 8
local fillerSpotEnd = 10
local floorSpotEnd = 12

-- Change the height of the tunnel
local height = 4

-- Change the length of the tunnel
local distance = 100






-- Used by program
local currentCover = 1
local currentFiller = coverSpotEnd + 1
local currentFloor = fillerSpotEnd + 1

local FORWARD = 1
local UP = 2

function refuel()
  local slot = 1
  while ( turtle.getFuelLevel() < 100 and slot < 16 ) do
    slot = slot + 1
    turtle.select(slot)
    turtle.refuel(10)
  end
  turtle.select(1)
end

function goForward()
  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 goUp()
  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 goDown()
  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 PlaceFiller()
    turtle.select(currentFiller)
    while ( turtle.getItemCount(currentFiller) < 1 ) do
        currentFiller = currentFiller + 1
        if ( currentFiller > 16 or currentFiller > fillerSpotEnd ) then
            print( "Ran out of filler blocks!" )
            os.exit()
        end
        turtle.select(currentFiller)
    end
    turtle.placeDown()
end

function MoveForward()
    -- Block in front of us, go up
    if ( turtle.detect() ) then
        goUp()
    end
    goForward()
    -- Nothing below us, go down
    if ( not turtle.detectDown() ) then
        goDown()
    end

    -- Still nothing below us, drop filler
    while ( not turtle.detectDown() ) do
        PlaceFiller()
    end



end

function PlaceCover(direction)
    turtle.select(currentCover)
    while ( turtle.getItemCount(currentCover) < 1 ) do
        currentCover = currentCover + 1
        if ( currentCover > 16 or currentCover > coverSpotEnd ) then
            print( "Ran out of cover blocks!" )
            os.exit()
        end
        turtle.select(currentCover)
    end
    if (direction == FORWARD) then
        turtle.place()
    elseif ( direction == UP ) then
        turtle.placeUp()
    end
end


function BuildCover()
    for h = 1,height do
        turtle.turnLeft()
        PlaceCover(FORWARD)
        turtle.turnRight()
        turtle.turnRight()
        PlaceCover(FORWARD)
        turtle.turnLeft()
        goUp()
    end
    goDown()
    PlaceCover(UP)
    for h = 2,height do
        goDown()
    end
end

function BuildFloor()
    turtle.select(currentFloor)
    while ( turtle.getItemCount(currentFloor) < 1 ) do
        currentFloor = currentFloor + 1
        if ( currentFloor > 16 or currentFloor > floorSpotEnd ) then
            print( "Ran out of floor blocks!" )
            os.exit()
        end
        turtle.select(currentFloor)
    end
    turtle.digDown()
    turtle.placeDown()
end

function BuildTunnel()
    BuildCover()
    BuildFloor()

end

for dist = 1,distance do
    BuildTunnel()
    MoveForward()
end