SylLumberjack -- ComputerCraft

-- SylLumberjack

local monitorWaitTime = 30
local nextTurn = "left"
local shouldStop = false
local shouldStopThreshold = 10

local function outOfSaplings()
	return turtle.getItemCount(3) == 0
end

local function tryUp()
	if turtle.getFuelLevel() == 0 then
		shouldStop = true
	else
		turtle.up()
	end
end

local function tryDown()
	if turtle.getFuelLevel() == 0 then
		shouldStop = true
	else
		turtle.down()
	end
end

local function tryForward()
	if turtle.getFuelLevel() == 0 then
		shouldStop = true
	else
		turtle.forward()
	end
end

local function chopTree()
	-- assumes we are facing the base of the tree
	local stepsUp = 0
	turtle.dig()
	tryForward()
	while turtle.detectUp() do
		turtle.digUp()
		tryUp()
		stepsUp = stepsUp + 1
	end

	for i=1,stepsUp do
		turtle.digDown()
		tryDown()
	end

	if turtle.getFuelLevel() < shouldStopThreshold then
		shouldStop = true
	end
end

local function plantTree()
	turtle.select(3)
	turtle.place()
end

local function checkTreeLeft()
	turtle.select(3)
	turtle.turnLeft()
	if turtle.detect() and not turtle.compare() then
		chopTree()
		turtle.turnRight()
		turtle.turnRight()
		tryForward()
		turtle.turnLeft()
		return true
	else
		turtle.turnRight()
		return false
	end
end

local function checkTreeRight()
	turtle.select(3)
	turtle.turnRight()
	if turtle.detect() and not turtle.compare() then
		chopTree()
		turtle.turnRight()
		turtle.turnRight()
		tryForward()
		turtle.turnRight()
		return true
	else
		turtle.turnLeft()
		return false
	end
end

local function checkTreeRow()
	while not turtle.detect() and not shouldStop do
		turtle.forward()
		if checkTreeLeft() then
			turtle.turnLeft()
			plantTree()
			turtle.turnRight()
		end
		if checkTreeRight() then
			turtle.turnRight()
			plantTree()
			turtle.turnLeft()
		end
	end
end

local function toggleNextTurn()
	if nextTurn == "left" then
		nextTurn = "right"
	else
		nextTurn = "left"
	end
end

local function goToNextRow()
	if nextTurn == "left" then
		turtle.turnLeft()
		for i=1,4 do
			tryForward()
		end
		turtle.turnLeft()
	else
		turtle.turnRight()
		for i=1,4 do
			tryForward()
		end
		turtle.turnRight()
	end
	toggleNextTurn()
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
end

local function runTreePath()
	local done = false

	while not done do
		checkTreeRow()

		if shouldStop then
			return
		end

		-- once we get here, something is in front of us
		turtle.select(1)
		if turtle.compare() then
			-- Stop marker hit
			done = true
		end

		turtle.select(2)
		if turtle.compare() then
			-- Turn marker hit
			goToNextRow()
		end
	end

	unload()
	turtle.turnRight()
	turtle.turnRight()
end

local function run()
	-- fuel for run
	turtle.select(4)
	turtle.refuel()

	while not shouldStop do
		-- assumes we start on the row
		-- that ends with a left turn
		runTreePath()
		sleep(monitorWaitTime)
	end
end

term.clear()
textutils.slowPrint("SylLumberjack v0.1")
print("Slots: 1 - Stop Marker | 2 - Turn Marker | 3 - Saplings | 4 - Fuel")

local input = "none"
while (input ~= "left") and (input ~= "right") do
	print("Enter first turn direction (left/right): ")
	input = read()
end
nextTurn = input

run()