----------------------------------------------------------
--                 Stripmining turtle                   --
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--                   Version 1.3.2                      --
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-- Makes the turtle mine straight down to the bedrock.  --
-- Usege: dig <max Y> <length>                          --
-- <max Y> - maximum height for mining                  --
-- <length> - number of blocks to mine forward          --
-- (return) - go back to the starting point.            --
----------------------------------------------------------
-- Based on a script pastebin.com/JbFMHaNg by Eonsv     --
-- Tested with CC 1.5                                   --
-- Don't forget to use chunkloaders!                    --
----------------------------------------------------------

--Tests wether a file with the filename name exists.
--Returns true if it does and false if not
function fileExists(name)
   local f = io.open(name,'r')
   if (f ~= nil) then
		f:close()
		return true
	else
		return false
	end
end

local arg = {...}

--Saves current position to file
function save()
	local str = ''
	str = str..y..'\n'
	str = str..x..'\n'
	str = str..distance..'\n'
	local file = io.open('save', 'w')
	file:write(str)
	file:close()
end

--Consumes a stack of fuel from the 2nd enderchest
function refuel(fuel)
	if(9999 >= fuel) then
		return true
	end
	print('Refueling')
	turtle.select(2)
	while(not turtle.placeUp()) do
		turtle.digUp()
		turtle.attackUp()
	end
	turtle.select(16)
	while(not turtle.suckUp()) do
		sleep('No fuel found. Sleeping.', 10)
	end
	turtle.refuel(64)
	turtle.select(2)
	turtle.digUp()
	if(9999  <= fuel) then
		sleep('Refueling failed!', 10)
		dump()
		refuel(200)
	end
end

--Dumps all items into the 1st enderchest
function dump()
	turtle.select(1)
	while(not turtle.placeUp()) do
		turtle.digUp()
		turtle.attackUp()
	end
	for i = 3, 16 do
		if(turtle.getItemCount(i) > 0) then
			turtle.select(i)
			while(not turtle.dropUp()) do
				sleep('Dropoff chest is full. Sleeping.', 10)
			end
		end
	end
	turtle.select(1)
	turtle.digUp()
	print('Dropoff successful')
end

function dropoff()
	local empty = 0
	--Calculates number of empty slots
	for i = 2, 16 do
		if(turtle.getItemCount(i) == 0) then
			empty = empty + 1
		end
	end
	--Dumps items if the inventory is full
	if(empty == 0) then
		dump()
	end
end

--Clears the screen
function clear()
	term.clear()
	term.setCursorPos(1, 1)
end

--Sleeps for %time% seconds, while displaying %text% and counting down
function sleep(text, time)
	for i = 0, time - 1 do
		clear()
		print(text)
		print('Countdown: '..time - i..'s.')
		os.sleep(1)
	end
end

--Returns true if successful, and false if the block is bedrock
local function bedrockTest()
	local test
	test = turtle.down()
	return test
end

--Moves up until reaching initial height
function moveUp()
	for i = 1, y do
		refuel(200)
		while(not turtle.up()) do
			turtle.attackUp()
			turtle.digUp()
		end
	end
end

--Digging down until bedrock
function digDown()
	local fail = 0
	while(true) do
		dropoff()
		refuel(500)
		turtle.digDown()
		if(not bedrockTest()) then
				while(turtle.detectDown() == false) do
					turtle.attackDown()
					turtle.down()
				end
			os.sleep(0.2)
			fail = fail + 1
			if(fail == 6) then
				break
			end
		end
	end
end

--Mining loop
function loop()
	while(x > 0) do
		clear()
		print('Blocks left to mine: '..x)
		digDown()
		print('Hit bedrock, moving up '..y..' blocks')
		moveUp()
		while(not turtle.forward()) do
			turtle.attack()
			turtle.dig()
		end
		dump()
		x = x - 1
		save()
	end
end

--Init sequence
function init()
	clear()
	y = tonumber(arg[1])
	y = y - 1
	x = tonumber(arg[2])
	if(arg[3] ~= nil) then
		distance = x
		print('Return mode on, distance: '..distance..' blocks')
	else distance = 0
	end
	while(turtle.getItemCount(1) ~= 1) do
		sleep('Wrong number of items in slot 1. Place one dropoff ender chest.', 5)
	end
	save()
	-- Creating startup file to continue mining after server restarts
	if(not fileExists('startup')) then
		local file = io.open('startup', 'w')
		file:write("shell.run(\'dig\')")
		file:close()
	end
	loop()
end

--------
--MAIN--
--------
if true then
	for i = 1, 2 do
		if(arg[i] == nil) then
			clear()
			print('Usage: dig <max Y> <length> return')
			print()
			print('<max Y> - maximum height for mining (e.g. your Y coordinate).')
			print('<length> - number of blocks to mine forward.')
			print('return - optional command to make the turtle go back to the starting point.')
			do return end
		end
	end
	init()
else
	clear()
	--Reading save file
	local file = io.open('save', 'r')
	y = tonumber(file:read('*l'))
	x = tonumber(file:read('*l'))
	distance = tonumber(file:read('*l'))
	file:close()
	--If rebooted while dumping items
	if(turtle.getItemCount(1) == 0) then
		turtle.select(1)
		turtle.digUp()
		dump()
		while(turtle.getItemCount(1) == 0) do
			sleep('Missing chest in slot 1.', 10)
		end
	end
	--If rebooted while refueling
	if(turtle.getItemCount(2) == 0) then
		turtle.select(2)
		turtle.digUp()
		refuel(500)
		while(turtle.getItemCount(1) == 0) do
			sleep('Missing chest in slot 2.', 10)
		end
	end
	loop()
end

--Finishing
shell.run('delete', 'save')
shell.run('delete', 'startup')
print('Done!')

--Going to the starting point
if distance > 0 then
	turtle.turnRight()
	turtle.turnRight()
		while(distance > 0) do
		clear()
		print('Going back '..distance..' blocks')
		while(not turtle.forward()) do
			turtle.attack()
			turtle.dig()
		end
		distance = distance - 1
	end
print('Done!')
end