branchMine.lua

-- This work is licensed under a CC BY-NC-SA 3.0 license.
-- http://creativecommons.org/licenses/by-nc-sa/3.0/
-- 
-- by Spike Padley
--
-- Usage: branchMine <length>
-- Fuel goes in slot 1. Torches go in slot 2. Floor blocks (usually cobblestone) go in slot 3.
-- Mines a trunk <length> blocks long, with an 8 block long branch, on each side, every 3 blocks, starting 2 blocks in (n=3n-1)

local blocksMovedForward = 0
local blocksMovedSideways = 0
local kBoring = 2
	
-- If fuel level is less than needed to get home, refuel
function fuel()
	if turtle.getFuelLevel() < blocksMovedForward + blocksMovedSideways + 50 then
		print("Refuelling")
		turtle.select(1)
		if turtle.refuel(1) then
			return true
		end
		print("Refuelling failed.")
		return false
	end
	return true
end

-- Place floor block, if there is not already one.
function placeFloorBlock()
	if not turtle.detectDown() then
		print("Placing floor block")
		if turtle.getItemCount(3) <= 1 then
			print ("Out of floor blocks")
			return false
		end
		turtle.select(3)
		if turtle.placeDown() then
			return true
		end
		print("Placing floor block failed.")
		return false
	end
	return true
end

function mineMaybe()
	for i = 16 - kBoring + 1, 16 do
		turtle.select(i)
		if turtle.compare() then
			return false
		end
	end
	for i = 2, 3 do
		turtle.select(i)
		if turtle.compare() then
			return false
		end
	end
	return turtle.dig()
end

function mineDownMaybe()
	for i = 16 - kBoring + 1, 16 do
		turtle.select(i)
		if turtle.compareDown() then
			return false
		end
	end
	for i = 2, 3 do
		turtle.select(i)
		if turtle.compareDown() then
			return false
		end
	end
	return turtle.digDown()
end

function mineUpMaybe()
	for i = 16 - kBoring + 1, 16 do
		turtle.select(i)
		if turtle.compareUp() then
			return false
		end
	end
	for i = 2, 3 do
		turtle.select(i)
		if turtle.compareUp() then
			return false
		end
	end
	return turtle.digUp()
end

-- Digs and moves into a 1x2x1 (xyz) area.
function basicDigAndMove()
	while not turtle.forward() do
		if not turtle.dig() then
			turtle.attack()
		end
	end
	while turtle.detectUp() do
		turtle.digUp()
		sleep(0.5)
	end
	mineDownMaybe()
	turtle.turnLeft()
	mineMaybe()
	turnAround()
	mineMaybe()
	turtle.turnLeft()
	if not placeFloorBlock() then
		return false
	end
	return true
end

function basicMoveBack()
	while not turtle.forward() do
		if not turtle.dig() then
			turtle.attack()
		end
	end
	mineUpMaybe()
	turtle.turnLeft()
	mineMaybe()
	turnAround()
	mineMaybe()
	turtle.turnLeft()
end

-- Turn turtle 180 degrees
function turnAround()
	turtle.turnLeft()
	turtle.turnLeft()
end

-- Place torch on floor, in front of the turtle
function placeTorch()
	turtle.select(2)
	if turtle.place() then
		return true
	end
	print("Placing torch failed.")
	return false
end

-- This function mines a 1x2x8 (xyz) tunnel directly infront of the turtle, placing a torch near the end, and returning to start point (but in opposite orientation)
-- pre/post condition: blocksMovedSideways == 0
function branch()
	print("Doing a branch")
	while blocksMovedSideways < 8 do
		if not fuel() then
			break
		end
		if not basicDigAndMove() then break end
		blocksMovedSideways = blocksMovedSideways + 1

		if blocksMovedSideways == 8 then
			turnAround()
			placeTorch()
		end
	end
	
	print("Backing out of branch")
	-- Back to start point (goes up to avoid the torch on floor)
	while not turtle.up() do end
	while blocksMovedSideways > 0 do
		basicMoveBack()
		blocksMovedSideways = blocksMovedSideways - 1
	end
	while not turtle.down() do end
end

function inventoryFull()
	-- recover space by dumping cobblestone on the floor
	for i = 4, 16 - kBoring do
		if turtle.getItemCount(i) == 0 then
			return false
		end
	end
	madeSpace = false
	for i = 4, 16 - kBoring do
		turtle.select(i)
		if turtle.compareTo(3) == true then
			turtle.drop()
			madeSpace = true
		end
	end
	return not madeSpace
end

function outOfSupplies()
	for i = 1,3 do
		-- We need at least one cobblestone, to keep it in the right slot.
		-- The others we could wait for zero if we wanted.
		if turtle.getItemCount(i) <= 1 then
			return true
		end
	end
	return false
end

-- Arguments
local tArgs = {...}
if #tArgs ~= 1 or tonumber(tArgs[1]) == nil or math.floor(tonumber(tArgs[1])) ~= tonumber(tArgs[1]) or tonumber(tArgs[1]) < 1 then
	print("Usage: branchMine <length>")
	return
end

local length = tonumber(tArgs[1])

print("Starting branchMine...")
while blocksMovedForward < length do
	if not fuel() then
		break
	end
	if inventoryFull() then
		break
	end
	if outOfSupplies() then
		break
	end
	if not basicDigAndMove() then break end
	blocksMovedForward = blocksMovedForward + 1

	-- Add torch (on floor) every 8 blocks
	if (blocksMovedForward % 8) == 0 then
		turnAround()
		placeTorch()
		turnAround()
	end

	-- n=3n-1
	if ((blocksMovedForward + 1) % 3) == 0 then
		turtle.turnLeft()
		branch()
		branch()
		turtle.turnRight()
	end
end

print("Done mining, backing out...")
turnAround()
while not turtle.up() do end
while blocksMovedForward > 0 do
	basicMoveBack()
	blocksMovedForward = blocksMovedForward - 1
end
while not turtle.down() do end

for i = 4, 16 - kBoring do
	turtle.select(i)
	turtle.drop()
end
turtle.select(3)
turtle.drop(turtle.getItemCount(3) - 1)

turnAround()