minerL

m = 0															--mining counter
ds = 2															--drop slot selection
ic = 0															--item count
d = 0															--distance (length of tunnel)
cl = 0															--current loop
lt = 3															--loop target
fl = turtle.getFuelLevel()										--fuel level
lat = 1															--layer target
cla = 1 														--current layer
icf = 0															--item count fuel

--start the turtle on top of water stream it will go up by 1 more block

--hints
print("1: Put Cobblestone/Deep Slate in my first inventory slot")
print("2: Put fuel in my second inventory slot")
print("3: Place me right above the water stream")
print("Current fuel level is:", turtle.getFuelLevel())

--user inputs
print("Enter length of tunnels:")
local d = tonumber(io.read())
print("Enter amount of loops:")
local lt = tonumber(io.read())
print("Enter amount of layers (upwards):")
local lat = tonumber(io.read())

--checking starting parameters

if fl == 0 then
	print("ERROR: I need starter fuel")
	error()
end

turtle.select(1)
ic = turtle.getItemCount()

if ic < 1 then
	print("ERROR: Put Cobblestone/Deep Slate in my first inventory slot!")
    error()
end


--OPERATIONAL FUNCTIONS

--refuel function
local function fuelCheck()
	fl = turtle.getFuelLevel()
	while fl <= 1000 do
		turtle.select(2)
		icf = turtle.getItemCount()
		if icf > 1 then
   			turtle.refuel(1)
			print("I refuelled to", turtle.getFuelLevel())
		else
			print("I'm out of fuel!")
			error()
		end
		turtle.select(1)
		fl = turtle.getFuelLevel()
	end
end


--drop trash function
function dropCobble(slot)
	turtle.select(slot)
	turtle.dropDown(turtle.getItemCount() - 1)
end

--anti gravel function
local function digUntilEmpty()
	while turtle.detect() do
    	turtle.dig()
  	end
end

--dig straight line
local function digForward()
   	digUntilEmpty()
	turtle.forward()
	turtle.digDown()
	turtle.digUp()
end


--MINING OPERATION

--layer loop
while cla <= lat do

	--back and forth loop
	while cl < lt do
    	cl = cl + 1

        --move turtle up to mining level
		if cla > 1 then
			for i = 0, (cla-1)*3, 1 do
				turtle.digUp()
				turtle.up()
				turtle.digUp()
			end
		else
			turtle.digUp()
			turtle.up()
			turtle.digUp()
		end

		--first straight
		while m < d do
			digForward()
			m = m + 1
			if m == 10 or m == 20 or m == 30 or m == 40 or m == 50 then
				dropCobble(1)
			end
		end

		--turn around
		if m == d then
	    	turtle.turnLeft()
	    	digUntilEmpty()
	    	turtle.forward()
			turtle.digUp()
			turtle.digDown()
	    	turtle.turnLeft()
			fuelCheck()
			dropCobble(1)
			m = 0
		end

		--second straight
		while m < d do
			digForward()
    		m = m + 1
			if m == 10 or m == 20 or m == 30 or m == 40 or m == 50 then
				dropCobble(1)
			end
		end

		--user information
		print("I just finished loop:", cl, "out of", lt)
        print("on layer:", cla, "out of", lat)

		--item drop-off

      	if cla > 1 then
			for i = 0, (cla - 1) * 3, 1 do
				turtle.digDown()
				turtle.down()
			end
		else
			turtle.digDown()
			turtle.down()
		end

		while ds < 16 do										--dropping everything except slot 1 and 2
			ds = ds + 1
			turtle.select(ds)
			turtle.dropDown()
		end

		ds = 2													--reset for next loop
		m = 0
		turtle.select(1)

		--second turn around unless it's the last loop
		if cl < lt then
			turtle.turnRight()
			digUntilEmpty()
			turtle.forward()
			turtle.digDown()
			turtle.digUp()
    		turtle.turnRight()
		end
    end															--back and forth looping ends
	cl = 0														--reset current loop for next layer

	--bring turtle back to layer starting pos
	turtle.turnLeft()
	for i = 0, lt*2-2, 1 do
    	turtle.forward()
	end
    turtle.turnLeft()
	cla = cla + 1												--finished layer   increase current layer
end

--end info
print("Fuel level after job:", turtle.getFuelLevel())
print("Job's done!")