
-- see elepower_papi >> external_nodes_items.lua for explanation
-- shorten table ref
local epr = ele.external.ref
local epg = ele.external.graphic

local function get_formspec(power, input, output, state)
	return "size[8,8.5]"..
		epr.gui_bg..
		epr.gui_bg_img..
		epr.gui_slots..
		ele.formspec.power_meter(power)..
		ele.formspec.state_switcher(3.5, 1, state)..
		ele.formspec.fluid_bar(1, 0, input)..
		ele.formspec.fluid_bar(7, 0, output)..
		"image[3.5,2;1,1;"..epg.gui_furnace_arrow_bg.."^[transformR270]"..
		"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]"..
		epr.get_hotbar_bg(0, 4.25)
end

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

	local input  = fluid_lib.get_buffer_data(pos, "input")
	local output = fluid_lib.get_buffer_data(pos, "output")
	local state  = meta:get_int("state")

	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 efficiency = 0.8
	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 input.fluid == "" or input.amount == 0 then
			break
		end

		local fdef = minetest.registered_nodes[input.fluid]
		if not fdef["gas_form"] then
			break
		end

		local inp = input.amount
		if inp > 100 then inp = 100 end
		local outp = math.floor(inp * efficiency)

		if (output.amount + outp > output.capacity) or (output.fluid ~= "" and output.fluid ~= fdef["gas_form"]) then
			break
		end

		status = "Active"
		pow_buffer.usage = usage
		pow_buffer.storage = pow_buffer.storage - usage
		output.amount = output.amount + outp
		output.fluid = fdef["gas_form"]
		input.amount = input.amount - inp
		refresh = true

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

		break
	end

	if refresh then
		ele.helpers.swap_node(pos, "elepower_machines:evaporator_active")
	else
		ele.helpers.swap_node(pos, "elepower_machines:evaporator")
	end

	meta:set_int("input_fluid_storage", input.amount)
	meta:set_string("input_fluid", input.fluid)

	meta:set_int("output_fluid_storage", output.amount)
	meta:set_string("output_fluid", output.fluid)

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

	meta:set_string("infotext", ("Evaporator %s\n%s"):format(status, ele.capacity_text(pow_buffer.capacity, pow_buffer.storage)))
	meta:set_string("formspec", get_formspec(pow_buffer, input, output, state))

	return refresh
end

local animated = {
	name = "elepower_machine_base.png^elepower_machine_vaporidenser_animated.png",
	animation = {
		type = "vertical_frames",
		aspect_w = 16,
		aspect_h = 16,
		length = 2.0,
	}
}

ele.register_machine("elepower_machines:evaporator", {
	description = "Evaporator",
	groups = {oddly_breakable_by_hand = 1, cracky = 1, fluid_container = 1, ele_user = 1},
	fluid_buffers = {
		input = {
			capacity = 8000,
			accepts  = {"group:liquid"},
			drainable = false,
		},
		output = {
			capacity  = 8000,
			accepts   = false,
			drainable = true,
		},
	},
	on_timer = on_timer,
	on_construct = function (pos)
		local meta = minetest.get_meta(pos)
		meta:set_string("formspec", get_formspec())
	end,
	tiles = {
		"elepower_machine_top.png^elepower_power_port.png", "elepower_machine_base.png^elepower_power_port.png",
		"elepower_machine_side.png^elepower_machine_vaporidenser.png",
	},
	ele_active_node = true,
	ele_no_automatic_ports = true,
	ele_active_nodedef = {
		tiles = {
			"elepower_machine_top.png^elepower_power_port.png", "elepower_machine_base.png^elepower_power_port.png", animated,
		},
	},
	ele_usage = 128,
})
