local function get_formspec(power, input, state, active, percent)
	local t = "image[3.5,1.75;1,1;elepower_uv_bulb.png]"

	if active then
		t = "image[3.5,1.75;1,1;elepower_uv_bulb_lit.png]"
	end

	return "size[8,8.5]"..
		default.gui_bg..
		default.gui_bg_img..
		default.gui_slots..
		ele.formspec.power_meter(power)..
		ele.formspec.state_switcher(7, 0, state)..
		ele.formspec.fluid_bar(1, 0, input)..
		"image[3.5,1;1,1;gui_furnace_arrow_bg.png^[lowpart:"..
			  (percent)..":gui_furnace_arrow_fg.png^[transformR270]"..
		t..
		"list[context;src;2.5,1;1,1;]"..
		"list[context;dst;4.5,1;1,1;]"..
		"list[current_player;main;0,4.25;8,1;]"..
		"list[current_player;main;0,5.5;8,3;8]"..
		"listring[current_player;main]"..
		"listring[context;src]"..
		"listring[current_player;main]"..
		"listring[context;dst]"..
		"listring[current_player;main]"..
		default.get_hotbar_bg(0, 4.25)
end

local function on_timer(pos, elapsed)
	local refresh = false
	local meta    = minetest.get_meta(pos)
	local inv     = meta:get_inventory()

	local input  = fluid_lib.get_buffer_data(pos, "acid")
	local src    = inv:get_stack("src", 1)
	local dst    = inv:get_stack("dst", 1)
	local state  = meta:get_int("state")
	local time   = meta:get_int("time")

	local is_enabled = ele.helpers.state_enabled(meta, pos, state)

	local capacity   = ele.helpers.get_node_property(meta, pos, "capacity")
	local usage      = ele.helpers.get_node_property(meta, pos, "usage")
	local storage    = ele.helpers.get_node_property(meta, pos, "storage")
	local pow_buffer = {capacity = capacity, storage = storage, usage = 0}

	local status = "Idle"

	while true do
		if not is_enabled then
			status = "Off"
			break
		end

		if pow_buffer.storage < usage then
			status = "Out of Power!"
			break
		end

		if src:is_empty() or src:get_name() ~= "elepower_dynamics:pcb_blank" then
			time = 0
			break
		end

		if input.fluid == "" or input.amount < 10 then
			status = "Out of Acid!"
			time = 0
			break
		end

		status = "Active"
		pow_buffer.usage = usage
		pow_buffer.storage = pow_buffer.storage - usage

		input.amount = input.amount - 10
		refresh = true

		if input.amount == 0 then
			input.fluid = ""
		end

		if time < 4 then
			time = time + 1
			break
		end

		if not inv:room_for_item("dst", ItemStack("elepower_dynamics:pcb")) then
			status = "Output full!"
			break
		end

		src:take_item(1)
		inv:add_item("dst", "elepower_dynamics:pcb")
		inv:set_list("src", {src})
		time = 0

		break
	end

	local active = status == "Active"
	if active then
		ele.helpers.swap_node(pos, "elepower_machines:pcb_plant_active")
	else
		ele.helpers.swap_node(pos, "elepower_machines:pcb_plant")
	end

	meta:set_int("acid_fluid_storage", input.amount)
	meta:set_string("acid_fluid", input.fluid)

	meta:set_int("storage", pow_buffer.storage)
	meta:set_int("time", time)

	meta:set_string("infotext", ("PCB Plant %s\n%s"):format(status, ele.capacity_text(pow_buffer.capacity, pow_buffer.storage)))
	meta:set_string("formspec", get_formspec(pow_buffer, input, state, active, math.floor((time / 4) * 100)))

	return refresh
end

local function allow_metadata_inventory_put(pos, listname, index, stack, player)
	if minetest.is_protected(pos, player:get_player_name()) then
		return 0
	end

	if listname == "dst" or (listname == "src" and stack:get_name() ~= "elepower_dynamics:pcb_blank") then
		return 0
	end

	return stack:get_count()
end

local function allow_metadata_inventory_move(pos, from_list, from_index, to_list, to_index, count, player)
	local meta = minetest.get_meta(pos)
	local inv = meta:get_inventory()
	local stack = inv:get_stack(from_list, from_index)
	return allow_metadata_inventory_put(pos, to_list, to_index, stack, player)
end

ele.register_machine("elepower_machines:pcb_plant", {
	description = "Printed Circuit Board Plant",
	groups = {oddly_breakable_by_hand = 1, cracky = 1, fluid_container = 1, ele_user = 1},
	fluid_buffers = {
		acid = {
			capacity = 8000,
			accepts  = {"elepower_dynamics:etching_acid_source"},
			drainable = false,
		},
	},
	on_timer = on_timer,
	on_construct = function (pos)
		local meta = minetest.get_meta(pos)
		local inv = meta:get_inventory()
		inv:set_size("src", 1)
		inv:set_size("dst", 1)
		meta:set_string("formspec", get_formspec())
	end,
	tiles = {
		"elepower_machine_top.png", "elepower_machine_base.png", "elepower_machine_side.png",
		"elepower_machine_side.png", "elepower_machine_side.png", "elepower_machine_side.png^elepower_pcb_plant.png",
	},
	ele_active_node = true,
	ele_active_nodedef = {
		tiles = {
			"elepower_machine_top.png", "elepower_machine_base.png", "elepower_machine_side.png",
			"elepower_machine_side.png", "elepower_machine_side.png", "elepower_machine_side.png^elepower_pcb_plant_active.png",
		},
	},
	ele_usage = 32,
	allow_metadata_inventory_put = allow_metadata_inventory_put,
	allow_metadata_inventory_move = allow_metadata_inventory_move,
})