LevelAreaExcavate

local tArgs = { ... }
if #tArgs ~= 2 then
	print( "Width and Length needed." )
	return
end

-- length of area
local xSize = tonumber( tArgs[1] )
-- Width of area
local zSize = tonumber( tArgs[2] )
if xSize < 1 then
	print( "Width can not be negative" )
	return
end

if zSize < 1 then
	print( "Length can not be negative" )
	return
end

local depth = 0
local unloaded = 0
local collected = 0

local xPos,zPos = 0,0
local xDir,zDir = 0,1

local goTo -- Filled in further down
local refuel -- Filled in further down

local function unload( _bKeepOneFuelStack )
	print( "Unloading items..." )
	for n=1,16 do
		local nCount = turtle.getItemCount(n)
		if nCount > 0 then
			turtle.select(n)
			local bDrop = true
			if _bKeepOneFuelStack and turtle.refuel(0) then
				bDrop = false
				_bKeepOneFuelStack = false
			end
			if bDrop then
				turtle.drop()
				unloaded = unloaded + nCount
			end
		end
	end
	collected = 0
	turtle.select(1)
end

local function returnSupplies()
	local x,y,z,xd,zd = xPos,depth,zPos,xDir,zDir
	print( "Returning to surface..." )
	goTo( 0,0,0,0,-1 )

	local fuelNeeded = 2*(x+y+z) + 1
	if not refuel( fuelNeeded ) then
		unload( true )
		print( "Waiting for fuel" )
		while not refuel( fuelNeeded ) do
			sleep(1)
		end
	else
		unload( true )
	end

	print( "Resuming mining..." )
	goTo( x,y,z,xd,zd )
end

local function collect()
	local bFull = true
	local nTotalItems = 0
	for n=1,16 do
		local nCount = turtle.getItemCount(n)
		if nCount == 0 then
			bFull = false
		end
		nTotalItems = nTotalItems + nCount
	end

	if nTotalItems > collected then
		collected = nTotalItems
		if math.fmod(collected + unloaded, 50) == 0 then
			print( "Mined "..(collected + unloaded).." items." )
		end
	end

	if bFull then
		print( "No empty slots left." )
		return false
	end
	return true
end

function refuel( ammount )
	local fuelLevel = turtle.getFuelLevel()
	if fuelLevel == "unlimited" then
		return true
	end

	local needed = ammount or (xPos + zPos + depth + 1)
	if turtle.getFuelLevel() < needed then
		local fueled = false
		for n=1,16 do
			if turtle.getItemCount(n) > 0 then
				turtle.select(n)
				if turtle.refuel(1) then
					while turtle.getItemCount(n) > 0 and turtle.getFuelLevel() < needed do
						turtle.refuel(1)
					end
					if turtle.getFuelLevel() >= needed then
						turtle.select(1)
						return true
					end
				end
			end
		end
		turtle.select(1)
		return false
	end

	return true
end

-- The aim of this function is that the turtle detects a block above it, and digs the block if there is one. if there is no block it should go upwards to detect if there was just a hole and there are blocks above the hole.
-- This should be done for two blocks over the last one that was dug. if there are no further blocks, the turtle should go to the position it was before it dug up the first time.
local function upwards()
	local x,y,z,xd,zd = xPos,depth,zPos,xDir,zDir
	local depth = 0
	if not refuel() then
		print( "Not enough Fuel" )
		returnSupplies()
	end
	while not turtle.up() do
		if turtle.detectUp() then
			if turtle.digUp() then
				depth = depth -1
				if not collect() then
				returnSupplies()
				end
			-- else
				-- return false
			end
		elseif turtle.attackUp() then
			if not collect() then
				returnSupplies()
			end
		else turtle.up()
			if turtle.detectUp() then
				if turtle.digUp() then
					depth = depth -1
					if not collect() then
					returnSupplies()
					end
				-- else
					-- return false
				end
			elseif turtle.attackUp() then
					if not collect() then
					returnSupplies()
					end
			else turtle.up()
					if turtle.detectUp() then
						if turtle.digUp() then
						depth = depth -1
							if not collect() then
							returnSupplies()
							end
						-- else
							-- return false
						end
					else goTo( x,0,z,xd,zd )
					end
			end
		end

	end
	goTo( x,0,z,xd,zd )
	return true
end

-- The aim of this function is that the turtle goes one forward, digs, then uses the upward() function, goes one block forward, digs, etc...

local function tryForwards()
	if not refuel() then
		print( "Not enough Fuel" )
		returnSupplies()
	end

	while not turtle.forward() do
		if turtle.detect() then
			if turtle.dig() then
				turtle.forward()
				upwards()
			end
		elseif turtle.attack() then
			upwards()
			if not collect() then
				returnSupplies()
			end
		else
			sleep( 0.5 )
		end
	end

	xPos = xPos + xDir
	zPos = zPos + zDir
	return true
end


local function turnLeft()
	turtle.turnLeft()
	xDir, zDir = -zDir, xDir
end

local function turnRight()
	turtle.turnRight()
	xDir, zDir = zDir, -xDir
end

function goTo( x, y, z, xd, zd )
	while depth > y do
		if turtle.up() then
			depth = depth - 1
		elseif turtle.digUp() or turtle.attackUp() then
			collect()
		else
			sleep( 0.5 )
		end
	end

	if xPos > x then
		while xDir ~= -1 do
			turnLeft()
		end
		while xPos > x do
			if turtle.forward() then
				xPos = xPos - 1
			elseif turtle.dig() or turtle.attack() then
				collect()
			else
				sleep( 0.5 )
			end
		end
	elseif xPos < x then
		while xDir ~= 1 do
			turnLeft()
		end
		while xPos < x do
			if turtle.forward() then
				xPos = xPos + 1
			elseif turtle.dig() or turtle.attack() then
				collect()
			else
				sleep( 0.5 )
			end
		end
	end

	if zPos > z then
		while zDir ~= -1 do
			turnLeft()
		end
		while zPos > z do
			if turtle.forward() then
				zPos = zPos - 1
			elseif turtle.dig() or turtle.attack() then
				collect()
			else
				sleep( 0.5 )
			end
		end
	elseif zPos < z then
		while zDir ~= 1 do
			turnLeft()
		end
		while zPos < z do
			if turtle.forward() then
				zPos = zPos + 1
			elseif turtle.dig() or turtle.attack() then
				collect()
			else
				sleep( 0.5 )
			end
		end
	end

	while depth < y do
		if turtle.down() then
			depth = depth + 1
		elseif turtle.digDown() or turtle.attackDown() then
			collect()
		else
			sleep( 0.5 )
		end
	end

	while zDir ~= zd or xDir ~= xd do
		turnLeft()
	end
end

if not refuel() then
	print( "Out of Fuel" )
	return
end

print( "Beggining to level the given area." )

-- local reseal = false
-- turtle.select(1)
-- if turtle.digDown() then
	-- reseal = true
-- end


-- this function is slightly (and wrongly) modified from the original excavate program. The turtle shuold dig go one block forward from the start, detect if there are blocks above (the described upwards() function) etc,
-- then come down, go one step further, etc. The are can be chosen in length and width, and when there are no blocks in front of the turtle anymore, it stays in this area.
--when there are blocks in front of the turtle it digs, goes one forward and one up. this repeats until there is no block in front of the turtle.
local alternate = 0
local done = false
while not done do
	for n=1,xSize do
		for m=1,zSize-1 do
			if not tryForwards() then
				done = true
				break
			end
		end
		if done then
			break
		end
		if n<xSize then
			if math.fmod(n + alternate,2) == 0 then
				turnLeft()
				if not tryForwards() then
					done = true
					break
				end
				turnLeft()
			else
				turnRight()
				if not tryForwards() then
					done = true
					break
				end
				turnRight()
			end
		end
	end
	if done then
		break
	end

	if xSize > 1 then
		if math.fmod(xSize,2) == 0 then
			turnRight()
		else
			if alternate == 0 then
				turnLeft()
			else
				turnRight()
			end
			alternate = 1 - alternate
		end
	end


end

print( "Returning to surface..." )

-- Return to where we started
goTo( 0,0,0,0,-1 )
unload( false )
goTo( 0,0,0,0,1 )

-- Seal the hole
-- if reseal then
	-- turtle.placeDown()
-- end

print( "Mined "..(collected + unloaded).." items total." )