LWOG = {};

function LWOG.new() --[[LWOG for Location WithOut GPS]]--
	local self = {};

--[[
All the positions and the heading are relative to the initial position of the turtle when the LWOG is initialized and not necessary match with the minecraft coordinate / GPS system of computercraft
]]--

	local position_x = 0;
	local position_y = 0;
	local position_z = 0;

	local heading = 0; --[[Heading relative from the initial heading. 0: front; 1: right; 2: behind; 3: left]]--

	function self.updatePosition(order) --[[Keep in mind that the heading determine if we are "really" going forward or not in the relative environment]]--
		if (order == "forward") then
			if (heading == 0) then
				position_x = position_x + 1;
			elseif (heading == 1) then
				position_y = position_y + 1;
			elseif (heading == 2) then
				position_x = position_x - 1;
			elseif (heading == 3) then
				position_y = position_y - 1;
			else
				write("Wrong self.heading")
			end
		elseif (order == "back") then
			if (heading == 0) then
				position_x = position_x - 1;
			elseif (heading == 1) then
				position_y = position_y - 1;
			elseif (heading == 2) then
				position_x = position_x + 1;
			elseif (heading == 3) then
				position_y = position_y + 1;
			else
				write("Wrong self.heading")
			end
		elseif (order == "up") then
			position_z = position_z + 1;
		elseif (order == "down") then
			position_z = position_z - 1;
		elseif (order == "turnLeft") then
			if (heading == 0) then
				heading = 3;
			else
				heading = heading - 1;
			end
		elseif (order == "turnRight") then
			if (heading == 3) then
				heading = 0;
			else
				heading = heading + 1;
			end
		end
	end

--[[All moving functions give a parameter called "how_much" to allow you to call just one time forward to travel 100 blocks for example. just call LWOG.forward(100)]]--
	function self.forward(how_much)
		if (how_much <= 0) then
			print("Don't move.");
		end
		for i = 1, how_much do
			turtle.forward();
			self.updatePosition("forward");
		end
	end

	function self.back(how_much)
		if (how_much <= 0) then
			print("Don't move.");
		end
		for i = 1, how_much do
			turtle.back();
			self.updatePosition("back");
		end
	end

	function self.up(how_much)
		if (how_much <= 0) then
			print("Up: Don't move.");
		else
			print("Up for");
			print(how_much);
		end
		for i = 1, how_much do
			turtle.up();
			self.updatePosition("up");
		end
	end

	function self.down(how_much)
		local last_state = false;
		if (how_much <= 0) then
			print("Don't move.");
		end
		for i = 1, how_much do
			last_state = turtle.down();
			self.updatePosition("down");
		end
		return last_state;
	end

	function self.turnLeft(how_much)
		if (how_much <= 0) then
			print("Don't move.");
		end
		for i = 1, how_much do
			turtle.turnLeft();
			self.updatePosition("turnLeft");
		end
	end

	function self.turnRight(how_much)
		if (how_much <= 0) then
			print("Don't move.");
		end
		for i = 1, how_much do
			turtle.turnRight();
			self.updatePosition("turnRight");
		end
	end

	function self.printPosition()
		print("x:", position_x, " y:", position_y, " z:", position_z);
		print("orientation: ", heading);
	end

	function self.getPosition()
		return position_x, position_y, position_z;
	end

	function self.goToX(dest)
		local distance = dest - position_x;
		if (distance == 0) then
			print("[ ERROR  ] goToX: nil distance");
		elseif (distance > 0) then
			while (heading ~= 0) do
				self.turnRight(1);
			end
		elseif (distance < 0) then
			distance = distance * -1;
				while (heading ~= 2) do
					self.turnRight(1);
				end
		end
		print("goToX: ");
		print(distance);
		self.forward(distance);
	end

	function self.goToY(dest)
		local distance = dest - position_y;
		if (distance == 0) then
			print("[ ERROR  ] goToY: nil distance");
		elseif (distance > 0) then
			while (heading ~= 1) do
				self.fuelCheck();
				self.turnRight(1);
			end
		elseif (distance < 0) then
			distance = distance * -1;
				while (heading ~= 1) do
					self.fuelCheck();
					self.turnRight(1);
				end
		end
		print("goToY: ");
		print(distance);
		self.forward(distance);
	end

	function self.goToZ(dest)
		local distance = dest - position_z;
		if  (distance == 0) then
			print("[ ERROR  ] goToZ: nil distance");
		elseif (distance > 0) then
			print("goToZ: ");
			print(distance);
			turtle.up(distance);
		elseif (distance < 0) then
			distance = distance * -1;
			print("goToZ: ");
			print(distance);
			turtle.up(distance);
		end
	end

	function self.goTo(destX, destY)
		self.goToX(destX);
		self.goToY(destY);
	end

	function self.fuelCheck()
	  local fuelLevel = turtle.getFuelLevel()
	  if fuelLevel < 16 then
	    turtle.select(1)
	    turtle.refuel(1)
	    print("Refueled!")
	  end
end

	return self;
end

function inspect_column(t)
	turtle.digDown();
	while (t.down(1)) do
		t.fuelCheck();
		turtle.digDown();
		print("Digging down");
		for i = 0, 3 do -- No need to rotate 4 time, just 3
			local s, d = turtle.inspect();
			if (d.name ~= "minecraft:stone" and d.name ~= "minecraft:cobblestone" and d.name ~= "minecraft:dirt" and d.name ~= "minecraft:gravel") then
				turtle.dig();
			end
			t.turnRight(1);
		end
	end
	t.goToZ(0);
end


--[[---------------- Here start the code for optimized_mining ----------------]]--
local t = LWOG.new();

t.fuelCheck();
local x, y, z = t.getPosition();
for i = 0, 3 do
	x, y, z = t.getPosition();
	t.fuelCheck();
	inspect_column(t);
	t.goTo(x + 2, y + 1);
end
t.goTo(x - 1, y + 2);
inspect_column(t);
--[[
for i = 0, 5 do
	x, y, z = t.getPosition();
	t.fuelCheck();
	inspect_column();
	t.goTo(x - 2, y - 1);
end]]--