SylMiner -- ComputerCraft Turtle Program

-- SylMiner

local tunnelPairCount
local tunnelLength
local fuelRequired
local totalItems = 0
local torchSpacing = 7

local function calculateFuelRequired()
	local mainFuel = 20 * tunnelPairCount + 4
	local fuelPerPair = 10 * tunnelLength + 8
	return mainFuel + (tunnelPairCount * fuelPerPair)
end

local function fuelBotForDig()
	if fuelRequired > turtle.getFuelLimit() then
		print("Job requires more fuel than the limit (20000)")
		return false
	end

	local currentFuel = turtle.getFuelLevel()
	if currentFuel > fuelRequired then
		return true
	end

	local startFuel = turtle.getFuelLevel()
	-- select the fuel slot
	turtle.select(1)
	local fuelInSlot = turtle.getItemCount()
	if fuelInSlot == 0 then
		-- There's nothing in the fuel slot
		print("Nothing in fuel slot")
		return false
	end

	if not turtle.refuel(1) then
		-- The slot didn't have a fuel item
		print("Non-fuel item in fuel slot")
		return false
	end

	local fuelDifference = currentFuel - startFuel
	local fuelItemsRequired = math.ceil(fuelRequired / fuelDifference)
	local fuelToUse = math.min(fuelItemsRequired, fuelInSlot - 1)

	turtle.refuel(fuelToUse)
	-- At this point, the fuel slot should be empty
	return true
end

local function unload()
-- assumes the turtle is over a chest
	for n=4,16 do
		local nCount = turtle.getItemCount(n)
		if nCount > 0 then
			turtle.select(n)
			turtle.dropDown()
		end
	end
	totalItems = 0
end

local function checkCollected()
	local newTotalItems = 0
	for n=1,16 do
		newTotalItems = newTotalItems + turtle.getItemCount(n)
	end
	if newTotalItems > totalItems then
		totalItems = newTotalItems
		return true
	end
	return false
end

local function digAndMoveForward()
	while not turtle.forward() do
		if turtle.detect() then
			if not turtle.dig() then
				return false
			end
		else
			turtle.attack()
			sleep(0.5)
		end
	end
	return true
end

local function digUp()
	if turtle.detectUp() then
		if not turtle.digUp() then
			return false
		end
	else
		turtle.attackUp()
	end
	return true
end

local function digDown()
	if turtle.detectDown() then
		if not turtle.digDown() then
			return false
		end
	else
		turtle.attackDown()
	end
	return true
end

local function placeTorchBelow()
	turtle.select(3)
	turtle.placeDown()
end

local function digSlice(sliceNumber)
	-- This function assumes that for an odd slice, we start left
	-- for an even slice, we start right
	if sliceNumber % 2 == 0 then
		digAndMoveForward()
		digUp()
		digDown()
		turtle.turnLeft()

		digAndMoveForward()
		digUp()
		digDown()

		digAndMoveForward()
		digUp()
		digDown()
		turtle.turnRight()
	else
		digAndMoveForward()
		digUp()
		digDown()
		turtle.turnRight()

		digAndMoveForward()
		digUp()
		digDown()

		digAndMoveForward()
		digUp()
		digDown()
		turtle.turnLeft()
	end

	-- the problem with checking after the whole slice is done
	-- is that we might miss some stuff
	if not checkCollected() then
		-- return to pair chest
		if sliceNumber % 2 == 0 then
			turtle.turnRight()
			turtle.forward()
			turtle.turnRight()
		else
			turtle.turnLeft()
			turtle.forward()
			turtle.turnLeft()
		end

		-- now facing pair chest
		for i=1,sliceNumber+1 do
			turtle.forward()
		end

		unload()

		turtle.turnRight()
		turtle.turnRight()

		for i=1,sliceNumber+1 do
			turtle.forward()
		end

		-- return to spot
		if sliceNumber % 2 == 0 then
			turtle.turnLeft()
			turtle.forward()
			turtle.turnRight()
		else
			turtle.turnRight()
			turtle.forward()
			turtle.turnLeft()
		end
	end

	if sliceNumber % 7 == 0 then
		placeTorchBelow()
	end
end

local function digTunnel(isLeft)
-- assumes you're positioned at left center of tunnel face
	placeTorchBelow()
	for slice = 1,tunnelLength do
		digSlice(slice)
	end

	-- center turtle in tunnel
	turtle.turnRight()
	if turtle.detect() then
		turtle.turnRight()
		turtle.turnRight()
		turtle.forward()
		turtle.turnLeft()
	else
		turtle.forward()
		turtle.turnRight()
	end

	--return to center
	for i=1,tunnelLength+1 do
		turtle.forward()
	end

 	if isLeft then
		turtle.turnLeft()
	else
		turtle.turnRight()
	end

	unload()
end

local function placePairChest()
	-- This function assumes you're in the exact center of the pair
	turtle.select(2)
	turtle.placeDown()
end

local function digPair()
-- assumes you're in pair center
	-- go to left start
	turtle.turnLeft()
	turtle.forward()
	turtle.turnLeft()
	turtle.forward()
	turtle.turnRight()
	digTunnel(true)
	-- go to right start
	turtle.turnRight()
	turtle.forward()
	turtle.turnLeft()
	turtle.forward()
	turtle.turnRight()
	digTunnel(false)
end

local function runDig()
	-- dig main tunnel
	local mainTunnelLength = 4 * tunnelPairCount
	for slice = 1,mainTunnelLength do
		digSlice(slice)
	end

	-- return to first pair center
	turtle.turnRight()
	if turtle.detect() then
		turtle.turnRight()
		turtle.turnRight()
		turtle.forward()
		turtle.turnLeft()
	else
		turtle.forward()
		turtle.turnRight()
	end

	for i=1,mainTunnelLength-3 do
		turtle.forward()
	end

	turtle.turnRight()
	turtle.turnRight()

	--place first chest
	placePairChest()

	--dig first pair
	digPair()

	--dig the remaining pairs
	for pair = 1,tunnelPairCount-1 do
		for i=1,4 do
			turtle.forward()
		end
		placePairChest()
		digPair()
	end

	--return to the tunnel start
	turtle.turnRight()
	turtle.turnRight()

	for i=1,mainTunnelLength-3 do
		turtle.forward()
	end
end

term.clear()
textutils.slowPrint("SylMiner v0.1")

print("Enter number of tunnel pairs to dig: ")
local input = read()
tunnelPairCount = tonumber(input)
print("Enter length of each tunnel: ")
input = read()
tunnelLength = tonumber(input)

fuelRequired = calculateFuelRequired()
torchesRequired = tunnelPairCount * 2 * (math.ceil(tunnelLength / torchSpacing) + 1)

print(string.format("This job requires %d units of fuel.", fuelRequired))
print(string.format("This job requires %d chests", tunnelPairCount))
print(string.format("This job requires %d torches", torchesRequired))
print("Slot 1: Fuel | Slot 2: Chests | Slot 3: Torches")
print("Press any key to start...")

read()

if fuelBotForDig() then
	runDig()
end