clear room

local tArgs = { ... }
if #tArgs == 0 then
	print( "Usage: clearRoomLarge <radius> <(optional, if not go until bedrock)depth>" )
	return
end

-- Mine in a quarry pattern until we hit something we can't
local size = tonumber( tArgs[1] )
if size < 1 then
	print( "Excavate radius must be positive" )
	return
end

targetDepth = 256
if #tArgs > 1 then
	targetDepth = tonumber( tArgs[2] )
	if targetDepth < 1 then
		print( "Depth provided too shallow" )
		return
	end
	targetDepth = targetDepth - 1
end
collected = 0
depth = 0
tripDepth = 0
stopCause = 0

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

local function collect()
	collected = collected + 1
	if math.fmod(collected, 25) == 0 then
		print( "Mined "..collected.." blocks." )
	end

	for n=1,9 do
		if turtle.getItemCount(n) == 0 then
			return true
		end
	end

	print( "No empty slots left." )
	return false
end

local function tryForwards()
	while not turtle.forward() do
		if turtle.dig() then
			if not collect() then
				stopCause = 2
				return false
			end
	    else
			-- give sand a chance to fall
 			sleep(0.8)
	    	if turtle.dig() then
	    		if not collect() then
	    			stopCause = 2
					return false
				end
	    	else
	    		stopCause = 1
		    	return false
		    end
	    end
	end
	xPos = xPos + xDir
	zPos = zPos + zDir
	return true
end

local function tryDown()
	if depth == targetDepth then
		return false
	end
	if not turtle.down() then
		if turtle.digDown() then
			if not collect() then
				return false
			end
		end
		if not turtle.down() then
			return false
		end
	end
	depth = depth + 1
	if math.fmod( depth, 10 ) == 0 then
		print( "Descended "..depth.." metres." )
	end
	return true
end

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

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

local function main() -- ===================START MAIN LOOP FUNCTION

print( "Excavating..." )

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

local alternate = 0
local done = false
while not done do
	for n=1,size do
		for m=1,size-1 do
			if not tryForwards() then
				done = true
				break
			end
		end
		if done then
			break
		end
		if n<size 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 size > 1 then
		if math.fmod(size,2) == 0 then
			turnRight()
		else
			if alternate == 0 then
				turnLeft()
			else
				turnRight()
			end
			alternate = 1 - alternate
		end
	end

	if not tryDown() then
		done = true
		break
	end
end

tripDepth = depth

print( "Returning to surface..." )
-- Return to where we started
while depth > 0 do
	if turtle.up() then
		depth = depth - 1
	elseif turtle.digUp() then
		collect()
	else
		sleep( 0.5 )
	end
end

if xPos > 0 then
	while xDir ~= -1 do
		turnLeft()
	end
	while xPos > 0 do
		if turtle.forward() then
			xPos = xPos - 1
		elseif turtle.dig() then
			collect()
		else
			sleep( 0.5 )
		end
	end
end

if zPos > 0 then
	while zDir ~= -1 do
		turnLeft()
	end
	while zPos > 0 do
		if turtle.forward() then
			zPos = zPos - 1
		elseif turtle.dig() then
			collected = collected + 1
		else
			sleep( 0.5 )
		end
	end
end
while zDir ~= 1 do
	turnLeft()
end

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

turtle.turnLeft()
turtle.forward()
for n=1,9 do
	turtle.drop()
end
turtle.back()
turtle.turnRight()
end -- ===========================================END MAIN LOOP FUNCTION

local done = false
while not done do
	if (tripDepth == targetDepth) or (stopCause == 1) then
		done = true
	else
		stopCause = 0
		xPos,zPos = 0,0
		xDir,zDir = 0,1
		turtle.digDown()
		for n=1,tripDepth do
			if turtle.down() then
				depth = depth + 1
			end
		end
		main()
	end
end

print( "Mined "..collected.." blocks total." )