local _VERSION = "1.0.0"

local args = table.pack(...)
local command = args[1]

local GOO_BLOCK_PREFIX = "justdirethings:gooblock_tier"
local MIN_START_FUEL = 50
local REFUEL_THRESHOLD = 1000
local WAIT_SECONDS = 2
local MIN_FEEDING_ITEMS = 4
local MAX_SUCK_ATTEMPTS = 16

local FUEL_ITEMS = {
	"justdirethings:coal_t4",
	"justdirethings:coal_t3",
	"justdirethings:coal_t2",
	"justdirethings:coal_t1",
	"minecraft:coal",
}

local PROCESS_ITEMS = {
	["minecraft:iron_block"] = { tier = 1 },
	["minecraft:coal_block"] = { tier = 1 },
	["mekanism:block_charcoal"] = { tier = 1 },
	["justdirethings:coalblock_t1"] = { tier = 1 },
	["justdirethings:coalblock_t2"] = { tier = 2 },
	["justdirethings:coalblock_t3"] = { tier = 3 },
	["justdirethings:coalblock_t4"] = { tier = 4 },
	["minecraft:gold_block"] = { tier = 2 },
	["minecraft:diamond_block"] = { tier = 3 },
	["minecraft:netherite_block"] = { tier = 4 },
}

local FEEDING_ITEMS_BY_TIER = {
	[1] = { "minecraft:sugar", "minecraft:rotten_flesh" },
	[2] = { "minecraft:nether_wart" },
	[3] = { "minecraft:chorus_fruit" },
	[4] = { "minecraft:sculk" },
}

local DIR_NORTH = 0
local DIR_EAST = 1
local DIR_SOUTH = 2
local DIR_WEST = 3

local DIRECTION_DELTAS = {
	[DIR_NORTH] = { x = 0, z = -1 },
	[DIR_EAST] = { x = 1, z = 0 },
	[DIR_SOUTH] = { x = 0, z = 1 },
	[DIR_WEST] = { x = -1, z = 0 },
}

local HOME = { x = -2, y = 0, z = 0, facing = DIR_EAST }
local GOO_CHECK = { x = -1, y = 0, z = 0, facing = DIR_EAST }

local GOO_CHECKS = {
	{ name = "west goo check", x = -1, y = 0, z = 0, facing = DIR_EAST, action = "forward" },
	{ name = "east goo check", x = 1, y = 0, z = 0, facing = DIR_WEST, action = "forward" },
	{ name = "north goo check", x = 0, y = 0, z = -1, facing = DIR_SOUTH, action = "forward" },
	{ name = "south goo check", x = 0, y = 0, z = 1, facing = DIR_NORTH, action = "forward" },
	{ name = "top goo check", x = 0, y = 1, z = 0, facing = DIR_EAST, action = "down" },
}

local TARGETS = {
	{ name = "west side", x = -2, y = 0, z = 0, facing = DIR_EAST, action = "forward" },
	{ name = "east side", x = 2, y = 0, z = 0, facing = DIR_WEST, action = "forward" },
	{ name = "north side", x = 0, y = 0, z = -2, facing = DIR_SOUTH, action = "forward" },
	{ name = "south side", x = 0, y = 0, z = 2, facing = DIR_NORTH, action = "forward" },
	{ name = "top", x = -1, y = 1, z = 0, facing = DIR_EAST, action = "forward" },
}

local position = { x = HOME.x, y = HOME.y, z = HOME.z }
local facing = HOME.facing
local loggedBlockedItems = {}
local placedTargets = {}
local lastGooTier = nil

local function isFlag(name)
	return function(arg)
		return arg == "-" .. name or arg == "--" .. name
	end
end

local isHelpFlag = isFlag("help")
local isVersionFlag = isFlag("version")

local function printUsage()
	print("goo usage:")
	print()
	print("\t\t\tgoo start")
	print("\t\t\tgoo version")
	print("\t\t\tgoo help")
end

if command == "version" or isVersionFlag(command) then
	print("goo v" .. _VERSION)
	return
end

if command == nil or command == "" or command == "help" or isHelpFlag(command) then
	printUsage()
	return
end

if command ~= "start" then
	printUsage()
	return
end

if not turtle then
	error("goo must be run on a turtle")
end

local function hasPickaxeEquipped()
	local left = turtle.getEquippedLeft()
	local right = turtle.getEquippedRight()

	return (left and string.match(left.name or "", "_pickaxe$") ~= nil)
		or (right and string.match(right.name or "", "_pickaxe$") ~= nil)
end

local function parseGooTier(blockName)
	local tier = string.match(blockName or "", "^" .. GOO_BLOCK_PREFIX .. "(%d+)$")

	return tonumber(tier)
end

local function isGooBlock(blockName)
	return parseGooTier(blockName) ~= nil
end

local function isProcessBlock(blockName)
	return PROCESS_ITEMS[blockName] ~= nil
end

local function isFuelItem(itemName)
	for i = 1, #FUEL_ITEMS do
		if FUEL_ITEMS[i] == itemName then
			return true
		end
	end

	return false
end

local function isFeedingItemForTier(itemName, gooTier)
	local feedingItems = FEEDING_ITEMS_BY_TIER[gooTier] or {}

	for i = 1, #feedingItems do
		if feedingItems[i] == itemName then
			return true
		end
	end

	return false
end

local function countItem(itemName)
	local count = 0

	for slot = 1, 16 do
		local item = turtle.getItemDetail(slot)

		if item and item.name == itemName then
			count = count + item.count
		end
	end

	return count
end

local function countFeedingItems(gooTier)
	local count = 0
	local feedingItems = FEEDING_ITEMS_BY_TIER[gooTier] or {}

	for i = 1, #feedingItems do
		count = count + countItem(feedingItems[i])
	end

	return count
end

local function findItemSlot(itemName)
	for slot = 1, 16 do
		local item = turtle.getItemDetail(slot)

		if item and item.name == itemName then
			return slot, item
		end
	end

	return nil
end

local function hasFreeSlot()
	for slot = 1, 16 do
		if turtle.getItemCount(slot) == 0 then
			return true
		end
	end

	return false
end

local function getFuelLevel()
	local fuelLevel = turtle.getFuelLevel()

	if fuelLevel == "unlimited" then
		return nil
	end

	return fuelLevel
end

local function getRefuelTarget()
	local fuelLimit = turtle.getFuelLimit()

	if fuelLimit == "unlimited" or fuelLimit >= REFUEL_THRESHOLD then
		return REFUEL_THRESHOLD
	end

	return fuelLimit
end

local function findFuelSlot()
	for i = 1, #FUEL_ITEMS do
		local slot, item = findItemSlot(FUEL_ITEMS[i])

		if slot then
			return slot, item
		end
	end

	return nil
end

local function turnRight()
	turtle.turnRight()
	facing = (facing + 1) % 4
end

local function turnLeft()
	turtle.turnLeft()
	facing = (facing + 3) % 4
end

local function turnTo(direction)
	while facing ~= direction do
		local rightTurns = (direction - facing) % 4

		if rightTurns == 3 then
			turnLeft()
		else
			turnRight()
		end
	end
end

local function moveForward()
	if not turtle.forward() then
		return false
	end

	local delta = DIRECTION_DELTAS[facing]
	position.x = position.x + delta.x
	position.z = position.z + delta.z

	return true
end

local function moveUp()
	if not turtle.up() then
		return false
	end

	position.y = position.y + 1

	return true
end

local function moveDown()
	if not turtle.down() then
		return false
	end

	position.y = position.y - 1

	return true
end

local function moveAxis(target, positiveDirection, negativeDirection, axis)
	while position[axis] ~= target do
		if position[axis] < target then
			turnTo(positiveDirection)
		else
			turnTo(negativeDirection)
		end

		if not moveForward() then
			return false
		end
	end

	return true
end

local function goTo(target)
	while position.y < target.y do
		if not moveUp() then
			return false
		end
	end

	while position.y > target.y do
		if not moveDown() then
			return false
		end
	end

	if not moveAxis(target.x, DIR_EAST, DIR_WEST, "x") then
		return false
	end

	if not moveAxis(target.z, DIR_SOUTH, DIR_NORTH, "z") then
		return false
	end

	if target.facing then
		turnTo(target.facing)
	end

	return true
end

local function mustGoTo(target, description)
	while not goTo(target) do
		print("Cannot reach " .. description .. ". Clear the path and waiting...")
		os.sleep(WAIT_SECONDS)
	end
end

local function goHome()
	mustGoTo(HOME, "home/provider")
end

local function goToGooCheck()
	mustGoTo(GOO_CHECK, "goo check position")
end

local function inspectDirection(action)
	if action == "forward" then
		return turtle.inspect()
	elseif action == "up" then
		return turtle.inspectUp()
	elseif action == "down" then
		return turtle.inspectDown()
	end

	error("unknown inspect action " .. tostring(action))
end

local function placeDirection(action)
	if action == "forward" then
		return turtle.place()
	elseif action == "up" then
		return turtle.placeUp()
	elseif action == "down" then
		return turtle.placeDown()
	end

	error("unknown place action " .. tostring(action))
end

local function refuelFromInventory()
	local fuelLevel = getFuelLevel()

	if not fuelLevel or fuelLevel >= getRefuelTarget() then
		return false
	end

	local previousSlot = turtle.getSelectedSlot()
	local consumedFuel = false

	while fuelLevel < getRefuelTarget() do
		local slot, item = findFuelSlot()

		if not slot then
			break
		end

		turtle.select(slot)

		if turtle.refuel(1) then
			consumedFuel = true
			print("Refueled with " .. item.name .. ". Fuel: " .. tostring(turtle.getFuelLevel()))
			fuelLevel = getFuelLevel()
		else
			print("Could not refuel with " .. item.name .. ".")
			break
		end
	end

	turtle.select(previousSlot)

	return consumedFuel
end

local function isProviderBelow()
	local ok = turtle.inspectDown()

	return ok
end

local function pullFromProvider()
	goHome()

	local pulled = false

	for _ = 1, MAX_SUCK_ATTEMPTS do
		if not hasFreeSlot() then
			break
		end

		if turtle.suckDown() then
			pulled = true
		else
			break
		end
	end

	return pulled
end

local function shouldKeepItem(item, gooTier)
	if isFuelItem(item.name) then
		return true
	end

	local processItem = PROCESS_ITEMS[item.name]

	if processItem and processItem.tier <= gooTier then
		return true
	end

	if isFeedingItemForTier(item.name, gooTier) then
		return countFeedingItems(gooTier) <= MIN_FEEDING_ITEMS
	end

	return false
end

local function depositOutputs(gooTier)
	goHome()

	local previousSlot = turtle.getSelectedSlot()

	for slot = 1, 16 do
		local item = turtle.getItemDetail(slot)

		if item and not shouldKeepItem(item, gooTier) then
			turtle.select(slot)

			if turtle.dropDown() then
				print("Deposited " .. item.name .. ".")
			else
				print("Could not deposit " .. item.name .. ". Provider may be full.")
				break
			end
		end
	end

	turtle.select(previousSlot)
end

local function waitForProvider(message)
	if message then
		print(message)
	end

	repeat
		os.sleep(WAIT_SECONDS)
	until pullFromProvider()
end

local function ensureStartFuel()
	while true do
		local fuelLevel = getFuelLevel()

		if not fuelLevel or fuelLevel >= MIN_START_FUEL then
			return
		end

		refuelFromInventory()
		fuelLevel = getFuelLevel()

		if not fuelLevel or fuelLevel >= MIN_START_FUEL then
			return
		end

		waitForProvider("Fuel is below " .. tostring(MIN_START_FUEL) .. ". Add fuel to the provider below home.")
	end
end

local function ensureRuntimeFuel()
	local fuelLevel = getFuelLevel()

	if not fuelLevel then
		return
	end

	if fuelLevel < getRefuelTarget() then
		refuelFromInventory()
	end

	fuelLevel = getFuelLevel()

	while fuelLevel and fuelLevel < MIN_START_FUEL do
		waitForProvider("Fuel is below " .. tostring(MIN_START_FUEL) .. ". Add fuel to the provider below home.")
		refuelFromInventory()
		fuelLevel = getFuelLevel()
	end
end

local function findFeedingSlot(gooTier)
	local feedingItems = FEEDING_ITEMS_BY_TIER[gooTier] or {}

	for i = 1, #feedingItems do
		local slot, item = findItemSlot(feedingItems[i])

		if slot then
			return slot, item
		end
	end

	return nil
end

local function findEligibleProcessSlot(gooTier)
	for slot = 1, 16 do
		local item = turtle.getItemDetail(slot)
		local processItem = item and PROCESS_ITEMS[item.name]

		if processItem then
			if processItem.tier <= gooTier then
				return slot, item, processItem
			end

			local logKey = item.name .. ":" .. tostring(gooTier)

			if not loggedBlockedItems[logKey] then
				print(
					item.name
						.. " requires goo tier "
						.. tostring(processItem.tier)
						.. ", current tier is "
						.. tostring(gooTier)
				)
				loggedBlockedItems[logKey] = true
			end
		end
	end

	return nil
end

local function inspectGoo()
	for i = 1, #GOO_CHECKS do
		local check = GOO_CHECKS[i]

		if goTo(check) then
			local ok, inspected = inspectDirection(check.action)

			if ok then
				local tier = parseGooTier(inspected.name)

				if tier then
					lastGooTier = tier

					return tier, inspected, check
				end
			end
		end
	end

	if lastGooTier then
		print("Cannot reach the goo to inspect it. Using last known tier " .. tostring(lastGooTier) .. ".")

		return lastGooTier, { state = { alive = true } }, nil
	end

	error("expected a reachable Just Dire Things goo block around the turtle")
end

local function ensureGooAlive()
	while true do
		local gooTier, inspected, check = inspectGoo()

		if not check or inspected.state and inspected.state.alive == true then
			return gooTier
		end

		local slot, item = findFeedingSlot(gooTier)

		if not slot then
			waitForProvider("Goo tier " .. tostring(gooTier) .. " is not alive. Add feeding items to the provider.")
		else
			turtle.select(slot)
			print("Goo tier " .. tostring(gooTier) .. " is not alive. Feeding with " .. item.name .. "...")

			if not placeDirection(check.action) then
				print("Could not feed the goo. Waiting before retry...")
				os.sleep(WAIT_SECONDS)
			else
				os.sleep(1)
			end
		end
	end
end

local function selectProcessItem(gooTier)
	local slot, item = findEligibleProcessSlot(gooTier)

	if not slot then
		return nil
	end

	turtle.select(slot)

	return item
end

local function inspectTarget(target)
	if target.action == "forward" then
		return turtle.inspect()
	elseif target.action == "up" then
		return turtle.inspectUp()
	elseif target.action == "down" then
		return turtle.inspectDown()
	end

	error("unknown target action " .. tostring(target.action))
end

local function digTarget(target)
	if target.action == "forward" then
		return turtle.dig()
	elseif target.action == "up" then
		return turtle.digUp()
	elseif target.action == "down" then
		return turtle.digDown()
	end

	error("unknown target action " .. tostring(target.action))
end

local function placeTarget(target)
	if target.action == "forward" then
		return turtle.place()
	elseif target.action == "up" then
		return turtle.placeUp()
	elseif target.action == "down" then
		return turtle.placeDown()
	end

	error("unknown target action " .. tostring(target.action))
end

local function ensureMiningSpace(gooTier)
	while not hasFreeSlot() do
		depositOutputs(gooTier)

		if not hasFreeSlot() then
			print("Inventory is full and provider may be full. Waiting...")
			os.sleep(WAIT_SECONDS)
		end
	end
end

local function isTargetQueued(target)
	for i = 1, #placedTargets do
		if placedTargets[i] == target then
			return true
		end
	end

	return false
end

local function removeQueuedTarget(index)
	table.remove(placedTargets, index)
end

local function goToTarget(target)
	mustGoTo(target, target.name)
end

local function mineQueuedTarget(gooTier)
	if #placedTargets == 0 then
		return false
	end

	local target = placedTargets[1]

	goToTarget(target)
	ensureGooAlive()
	goToTarget(target)

	local ok, inspected = inspectTarget(target)

	if not ok then
		print("Queued " .. target.name .. " is empty.")
		removeQueuedTarget(1)
		return true
	end

	if isProcessBlock(inspected.name) then
		return false
	end

	if isGooBlock(inspected.name) then
		removeQueuedTarget(1)
		return true
	end

	print("Mining processed " .. target.name .. " block: " .. tostring(inspected.name))
	ensureMiningSpace(gooTier)
	goToTarget(target)

	if digTarget(target) then
		removeQueuedTarget(1)
		return true
	end

	print("Could not mine " .. target.name .. ".")

	return false
end

local function placeAvailableTarget(gooTier)
	for i = 1, #TARGETS do
		local target = TARGETS[i]

		if not isTargetQueued(target) then
			goToTarget(target)
			ensureGooAlive()
			goToTarget(target)

			local ok, inspected = inspectTarget(target)

			if ok then
				if not isProcessBlock(inspected.name) and not isGooBlock(inspected.name) then
					print("Mining existing " .. target.name .. " block: " .. tostring(inspected.name))
					ensureMiningSpace(gooTier)
					goToTarget(target)

					if digTarget(target) then
						return true
					end
				end
			else
				local item = selectProcessItem(gooTier)

				if not item then
					return false
				end

				print("Placing " .. item.name .. " on goo " .. target.name)

				if placeTarget(target) then
					placedTargets[#placedTargets + 1] = target
					return true
				end

				print("Could not place " .. target.name .. ".")
			end
		end
	end

	return false
end

local function waitAtOldestTarget()
	if #placedTargets == 0 then
		goToGooCheck()
	else
		goToTarget(placedTargets[1])
	end

	print("Waiting for goo processing...")
	os.sleep(WAIT_SECONDS)
end

local function startup()
	print("goo started. Layout: provider below turtle, goo two blocks ahead, turtle facing goo.")

	if not hasPickaxeEquipped() then
		error("goo requires a turtle with a pickaxe equipped")
	end

	if not isProviderBelow() then
		error("goo requires a provider/deposit barrel below the turtle")
	end

	pullFromProvider()
	ensureStartFuel()
end

startup()

while true do
	ensureRuntimeFuel()

	local gooTier = ensureGooAlive()
	depositOutputs(gooTier)
	pullFromProvider()
	ensureRuntimeFuel()

	gooTier = ensureGooAlive()
	local changed = mineQueuedTarget(gooTier)

	if not changed then
		changed = placeAvailableTarget(gooTier)
	end

	if not changed then
		if findEligibleProcessSlot(gooTier) then
			waitAtOldestTarget()
		else
			waitForProvider("No eligible process block found. Add inputs to the provider below home.")
		end
	end
end