local history = {}
local keep = {
	"minecraft:iron_ore",
	"minecraft:coal_ore",
	"minecraft:diamond_ore",
	"minecraft:redstone_ore",
	"minecraft:gold_ore"
}
local miningMode = true
local stopMoving = false
turtle.select(1)
turtle.refuel()

function hasval(tbl, val)
	for i,v in ipairs(tbl) do
		if v == val then
			return true
		end
	end
	return false
end

function checkore()
	for i=1,16 do
		turtle.select(i)
		local idata = turtle.getItemDetail()
		if idata then
			if hasval(keep, idata.name) == false then
				turtle.drop()
			end
		end
	end
end

function postmove()
	checkore()
	if turtle.getFuelLevel() == table.getn(history) then
		gohome()
	end
end

function fwd()
	if stopMoving then
		return false
	end
	if miningMode then
		if turtle.detect() then
			turtle.dig()
		end
	end
	table.insert(history, "f")
	turtle.forward()
	postmove()
end

function left()
	if stopMoving then
		return false
	end
	turtle.turnLeft()
	if miningMode then
		if turtle.detect() then
			turtle.dig()
		end
	end
	table.insert(history, "l")
	turtle.forward()
	postmove()
end

function right()
	if stopMoving then
		return false
	end
	table.insert(history, "r")
	turtle.turnRight()
	if miningMode then
		if turtle.detect() then
			turtle.dig()
		end
	end
	turtle.forward()
	postmove()
end

function down()
	if stopMoving then
		return false
	end
	table.insert(history, "d")
	if miningMode then
		if turtle.detectDown() then
		turtle.digDown()
		end
	end
	turtle.down()
	postmove()
end

function up()
	if stopMoving then
		return false
	end
	turtle.insert(history, "u")
	if miningMode then
		if turtle.detectUp() then
		turtle.digUp()
		end
	end
	turtle.up()
	postmove()
end

function gohome()
	stopMoving = true
	for i=table.getn(history), 1,-1 do
		local event = history[i]
			print(event)
		if event == "f" then
			turtle.back()
		elseif event == "l" then
			turtle.back()
			turtle.turnRight()
		elseif event == "r" then
			turtle.back()
			turtle.turnLeft()
		elseif event == "u" then
			turtle.down()
		elseif event == "d" then
			turtle.up()
		end
	end
end

fwd()
for z=1,3 do
	down()
	for y=1,5 do
		fwd()
	end
	right()
	for x=1,4 do
		fwd()
	end
	right()
	right()
	for x=1,4 do
		fwd()
	end
	left()
	left()
	for x=1,4 do
		fwd()
	end
	right()
	right()
	for x=1,4 do
		fwd()
	end
	left()
	left()
	for x=1,4 do
		fwd()
	end
	right()
	right()
	for x=1,4 do
		fwd()
	end
	turtle.turnRight()
end
gohome()