mine

print("Press x in 5 seconds to cancel startup")
do
	local timer = os.startTimer(5)
	local evt, p
	repeat
		evt, p = os.pullEvent()
	until (evt == "char" and p == "x") or (evt == "timer" and p == timer)
	if evt == "char" then return end
end

local startX, startZ -- world coords of centre of mine
local state
local miningX, miningZ -- centre-relative coords of next block to mine
local turtX, turtZ -- centre-relative turtle coords
local faceX, faceZ = 0, 0

print("Attempting self-update")
pcall(function()
	local c = http.get("http://immibis.com/ccfiles/rrts1/mine.lua")
	if not c then print("Update failed") return end
	local d = c.readAll()
	c.close()

	local f = fs.open("startup", "r")
	local d2 = f.readAll()
	f.close()

	if d ~= d2 then
		f = fs.open("startup", "w")
		f.write(d)
		f.close()
		print("Update successful")
		os.reboot()
		while true do coroutine.yield() end
	else
		print("No update required")
	end
end)

function onDumpFull()
	-- rednet.send(8, "wrs16 full") -- notify shuttle via long distance relay
end

function onFuelEmpty()
	-- rednet.send(8, "wrs16 fuel") -- notify shuttle via long distance relay
end

function onDumpFinished()
	-- rednet.send(8, "wrs16 call") -- notify shuttle via long distance relay
end

--rednet.open("right")

local function save()
	if fs.exists("/minestate") then
		if fs.exists("/msbak") then
			fs.delete("/msbak")
		end
		fs.move("/minestate", "/msbak")
	end
	local f = fs.open("/minestate", "w")
	f.writeLine(tostring(startX))
	f.writeLine(tostring(startZ))
	f.writeLine(state)
	f.writeLine(tostring(miningX))
	f.writeLine(tostring(miningZ))
	f.writeLine(tostring(turtX))
	f.writeLine(tostring(turtZ))
	f.writeLine(tostring(faceX))
	f.writeLine(tostring(faceZ))
	f.close()
end

local function checkGPS()
	write("GPS is ")
	local x = gps.locate(1)
	if x == nil then
		print("down")
		return false
	else
		print("up")
		return true
	end
end

local function gpslocate()
	local x, y, z
	repeat
		x, y, z = gps.locate(2)
		if not x then
			print("GPS failure!")
		end
	until x ~= nil
	return x, z
end

local function f()
	while not turtle.forward() do
		if peripheral.getType("front") ~= nil then
			-- Don't mine other turtles
			sleep(0.5)
		else
			if not turtle.dig() then
				turtle.attack()
			end
		end
	end
	turtX = turtX + faceX
	turtZ = turtZ + faceZ
end

local function forwardNoDig()
	if turtle.forward() then
		turtX = turtX + faceX
		turtZ = turtZ + faceZ
		save()
		return true
	else
		return false
	end
end

local function r()
	turtle.turnRight()
	faceX, faceZ = -faceZ, faceX
end

local function l()
	turtle.turnLeft()
	faceX, faceZ = faceZ, -faceX
end

local function gpsgetfacing()
	local x1, z1 = gpslocate()
	f()
	local x2, z2 = gpslocate()
	r()
	r()
	f()
	r()
	r()
	return x2 - x1, z2 - z1
end

function manualCoordReset()
	print("Enter current turtle coordinates.")
	write("X: ")
	turtX = tonumber(read()) or error("Invalid number", 0)
	write("Z: ")
	turtZ = tonumber(read()) or error("Invalid number", 0)

	turtX = turtX - startX
	turtZ = turtZ - startZ

	print("Enter current turtle direction (+X/-X/+Z/-Z)")
	local dir = read():lower()
		if dir == "-x" then faceX, faceZ = -1, 0
	elseif dir == "+x" then faceX, faceZ =  1, 0
	elseif dir == "-z" then faceX, faceZ = 0, -1
	elseif dir == "+z" then faceX, faceZ = 0,  1
	else error("Invalid direction", 0)
	end
end

if fs.exists("/minestate") or fs.exists("/msbak") then
	function readState(filename)
		local f = fs.open(filename,"r")
		startX = tonumber(f.readLine())
		startZ = tonumber(f.readLine())
		state = f.readLine()
		miningX = tonumber(f.readLine())
		miningZ = tonumber(f.readLine())
		turtX = tonumber(f.readLine())
		turtZ = tonumber(f.readLine())
		faceX = tonumber(f.readLine())
		faceZ = tonumber(f.readLine())
		f.close()
	end
	if not pcall(readState, "/minestate") then
		readState("/msbak")
	end

	if checkGPS() then
		turtX, turtZ = gpslocate()
		turtX = turtX - startX
		turtZ = turtZ - startZ
		faceX, faceZ = gpsgetfacing()
	else
		state = "resetpos"
	end
else
	if not checkGPS() then
		startX, startZ = 0, 0
		manualCoordReset()
		startX, startZ = turtX, turtZ
	else
		startX, startZ = gpslocate()
		turtX, turtZ = 0, 0
		faceX, faceZ = gpsgetfacing()
	end
	turtX, turtZ = 0, 0
	state = "mine"
	miningX, miningZ = -1, -1
end

local function face(dx, dz)
	if dx == faceX and dz == faceZ then
		-- do nothing
	elseif dx == faceZ and dz == -faceX then
		l()
	elseif dx == -faceZ and dz == faceX then
		r()
	elseif dx == -faceX and dz == -faceZ then
		l() l()
	else
		error("invalid orientation "..dx..","..dz, 2)
	end
end

function go(x, z)
	--print("goto ",x,",",z," from ",turtX,",",turtZ)
	if x > turtX then
		face(1, 0)
		while x > turtX do f() save() end
	elseif x < turtX then
		face(-1, 0)
		while x < turtX do f() save() end
	end
	if z > turtZ then
		face(0, 1)
		while z > turtZ do f() save() end
	elseif z < turtZ then
		face(0, -1)
		while z < turtZ do f() save() end
	end
	assert(x == turtX and z == turtZ, "something fucked up")
end

print("At ",turtX,",",turtZ," facing ",faceX,",",faceZ)
save()

turtle.select(1)

while true do
	if state == "mine" then
		go(miningX, miningZ)
		local radius = math.max(math.abs(miningX), math.abs(miningZ))

		--[[

		 --       -->       +-
		 <<
		  ^                 v

		 -+       <--       ++


		]]

		if miningZ == -radius and miningX ~= radius then
			face(1, 0)
		elseif miningX == radius and miningZ ~= radius then
			face(0, 1)
		elseif miningZ == radius and miningX ~= -radius then
			face(-1, 0)
		elseif miningX == -radius and miningZ ~= -radius then
			face(0, -1)
		else
			error("shouldn't get here, position "..miningX..","..miningZ.." (radius is "..radius..")")
		end

		-- leave a 5x5 platform
		if math.abs(turtX) > 2 or math.abs(turtZ) > 2 then
			turtle.digUp()
			turtle.digDown()
		end
		f()
		if turtX == -radius and turtZ == -radius + 1 then
			-- expand radius
			miningX = turtX - 1
			miningZ = turtZ - 2

			-- otherwise there's a diagonal line of unmined blocks
			if math.abs(turtX) > 2 or math.abs(turtZ) > 2 then
				turtle.digUp()
				turtle.digDown()
			end
		else
			miningX, miningZ = turtX, turtZ
		end

		if turtle.getFuelLevel() < 600 or turtle.getItemCount(16) > 0 then
			if math.abs(turtX) > math.abs(turtZ) then
				state = "dropoff_zfirst"
			else
				state = "dropoff_xfirst"
			end
		end

		save()

	elseif state == "dropoff_zfirst" then
		go(turtX, 0)
		state = "dropoff_last"
		save()
	elseif state == "dropoff_xfirst" then
		go(0, turtZ)
		state = "dropoff_last"
		save()
	elseif state == "dropoff_last" then
		go(0, 0)

		for k=1,16 do
			while turtle.getItemCount(k) > 0 do
				turtle.select(k)
				while not turtle.dropUp() do
					onDumpFull()
					print("Dump chest full")
					sleep(5)
				end
			end
		end
		onDumpFinished()

		while turtle.getFuelLevel() < 2000 do
			turtle.select(1)
			while not turtle.suckDown() do
				print("No fuel in chest!")
				onFuelEmpty()
				sleep(5)
			end
			if not turtle.refuel() then
				print("Found non-fuel item in fuel chest")
				while not turtle.dropUp() do
					print("Dump chest full")
					onDumpFull()
					sleep(5)
				end
			end
		end

		turtle.select(1)
		state = "resume"
		save()

	elseif state == "resume" then
		if math.abs(miningX) > math.abs(miningZ) then
			state = "resume_xfirst"
		else
			state = "resume_zfirst"
		end
		save()

	elseif state == "resume_xfirst" then
		go(miningX, turtZ)
		state = "mine"
		save()

	elseif state == "resume_zfirst" then
		go(turtX, miningZ)
		state = "mine"
		save()

	elseif state == "resetpos" then
		if math.abs(turtX) > math.abs(turtZ) then
			go(turtX, 0)
			go(0, 0)
		else
			go(0, turtZ)
			go(0, 0)
		end
		if checkGPS() then
			turtX, turtZ = gpslocate()
			turtX = turtX - startX
			turtZ = turtZ - startZ
			faceX, faceZ = 0, 0
			faceX, faceZ = gpsgetfacing()
			state = "resume"
			save()

			print("Recovered position from GPS, resuming mining")

		else
			print("No GPS signal to reset position")
			manualCoordReset()
			state = "resume"
			save()
		end

	else
		error("unknown state! "..state)
	end
end