Bubberstation/code/modules/wiremod/components/admin/signal_handler/signal_handler.dm

#define COMP_SIGNAL_HANDLER_GLOBAL "Global"
#define COMP_SIGNAL_HANDLER_OBJECT "Object"

/**
 * # Signal Handler Component
 *
 * A component that registers signals on events and listens for them.
 */
/obj/item/circuit_component/signal_handler
	display_name = "Signal Handler"
	desc = "A component that listens for signals on an object. Registering a new object will automatically unregister the old."
	circuit_flags = CIRCUIT_FLAG_ADMIN|CIRCUIT_FLAG_INSTANT

	/// Whether it is a global or object signal
	var/datum/port/input/option/signal_handler_options

	/// The list of signal IDs that can be selected as an option.
	var/datum/port/input/option/signal_id

	var/list/signal_map

	/// Entity to register the signal on
	var/datum/port/input/target
	/// Registers the signal
	var/datum/port/input/register
	/// Unregisters the signal from the current registered entity.
	var/datum/port/input/unregister

	/// The custom signal ports from the current signal type. Used for saving and loading.
	var/list/signal_ports
	/// The custom input from the current signal type.
	var/list/datum/port/input/input_signal_ports = list()
	/// The custom output from the current signal type.
	var/list/datum/port/output/output_signal_ports = list()

	/// The entity received from the event.
	var/datum/port/output/entity
	/// The event has been triggered
	var/datum/port/output/event_triggered

	/// The current entity that has the signal registered on it
	var/datum/weakref/current_registered_entity
	/// The current registered signal
	var/registered_signal

	/// Whether it is a custom signal id or not.
	var/custom_signal = FALSE

/obj/item/circuit_component/signal_handler/populate_options()
	var/static/list/component_options = list(
		COMP_SIGNAL_HANDLER_OBJECT,
		COMP_SIGNAL_HANDLER_GLOBAL,
	)
	signal_handler_options = add_option_port("Signal Handler Options", component_options, trigger = null)

	signal_id = add_option_port("Signal ID", GLOB.integrated_circuit_signal_ids, trigger = null)
	signal_map = GLOB.integrated_circuit_signal_ids

/obj/item/circuit_component/signal_handler/populate_ports()
	register = add_input_port("Register", PORT_TYPE_SIGNAL, order = 2, trigger = .proc/register_signals)
	unregister = add_input_port("Unregister Current", PORT_TYPE_SIGNAL, order = 2, trigger = .proc/unregister_signals)

	add_source_entity()
	event_triggered = add_output_port("Triggered", PORT_TYPE_SIGNAL, order = 2)

/obj/item/circuit_component/signal_handler/proc/add_source_entity()
	if(target)
		remove_input_port(target)
	if(entity)
		remove_output_port(entity)

	target = add_input_port("Target", PORT_TYPE_DATUM, order = 1, trigger = null)
	entity = add_output_port("Source Entity", PORT_TYPE_DATUM, order = 0)

/obj/item/circuit_component/signal_handler/save_data_to_list(list/component_data)
	. = ..()
	component_data["signal_id"] = signal_id.value
	component_data["signal_port_data"] = signal_ports

/obj/item/circuit_component/signal_handler/load_data_from_list(list/component_data)
	signal_id.set_value(component_data["signal_id"], force = TRUE)
	registered_signal = signal_id.value
	load_new_ports(component_data["signal_port_data"])
	custom_signal = TRUE
	return ..()


/obj/item/circuit_component/signal_handler/pre_input_received(datum/port/input/port)
	if(signal_id == port)
		custom_signal = FALSE
		if(current_registered_entity)
			unregister_signals(port)

		var/last_registered_signal = registered_signal
		registered_signal = signal_id.value

		if(registered_signal != last_registered_signal)
			var/list/data = signal_map[registered_signal]
			if(data)
				load_new_ports(data)
		unregister_signals(port)

	if(signal_handler_options == port)
		set_signal_options(port)

/obj/item/circuit_component/signal_handler/proc/set_signal_options(datum/port/input/port)
	CIRCUIT_TRIGGER

	switch(signal_handler_options.value)
		if(COMP_SIGNAL_HANDLER_GLOBAL)
			signal_id.possible_options = GLOB.integrated_circuit_global_signal_ids
			signal_map = GLOB.integrated_circuit_global_signal_ids
			remove_output_port(entity)
			remove_input_port(target)
		if(COMP_SIGNAL_HANDLER_OBJECT)
			signal_id.possible_options = GLOB.integrated_circuit_signal_ids
			signal_map = GLOB.integrated_circuit_signal_ids
			add_source_entity()

	if(!custom_signal)
		signal_id.set_value(null, TRUE)
	unregister_signals()

/obj/item/circuit_component/signal_handler/proc/register_signals(datum/port/input/port)
	CIRCUIT_TRIGGER
	if(current_registered_entity)
		unregister_signals(port)

	var/datum/target_datum = target.value
	if(signal_handler_options.value == COMP_SIGNAL_HANDLER_GLOBAL)
		target_datum = SSdcs

	if(target_datum)
		RegisterSignal(target_datum, registered_signal, .proc/handle_signal_received)
		current_registered_entity = WEAKREF(target_datum)

/obj/item/circuit_component/signal_handler/proc/load_new_ports(list/ports_to_load)
	for(var/datum/port/input/input_port as anything in input_signal_ports)
		remove_input_port(input_port)
	for(var/datum/port/output/output_port as anything in output_signal_ports)
		remove_output_port(output_port)
	input_signal_ports = list()
	output_signal_ports = list()

	signal_ports = ports_to_load
	for(var/list/data in signal_ports)
		if(data["is_response"])
			var/datum/port/input/bitflag_input = add_input_port(data["name"], PORT_TYPE_SIGNAL, order = 1, trigger = .proc/handle_bitflag_received)
			input_signal_ports[bitflag_input] = data["bitflag"]
		else
			output_signal_ports += add_output_port(data["name"], data["type"], order = 1)


/obj/item/circuit_component/signal_handler/proc/unregister_signals(datum/port/input/port)
	CIRCUIT_TRIGGER

	var/datum/registered_datum = current_registered_entity?.resolve()
	if(!registered_datum)
		return

	UnregisterSignal(registered_datum, registered_signal)
	current_registered_entity = null

/obj/item/circuit_component/signal_handler/proc/handle_signal_received(...)
	SIGNAL_HANDLER
	var/list/arguments = args.Copy()

	// usr is not supposed to be defined whilst these execute, which it can be for some signal IDs.
	// Especially if you try to proccall something - it'll fail because of this reason.
	// No other way to solve this problem without refactoring proccall code, but it's admin tooling so it's whatever.
	var/temp_usr = usr
	usr = null

	SScircuit_component.queue_instant_run()
	var/first_arg = popleft(arguments)
	if(entity)
		entity.set_output(first_arg)

	for(var/datum/port/output/port as anything in output_signal_ports)
		port.set_output(popleft(arguments))
	event_triggered.set_output(COMPONENT_SIGNAL)
	var/list/output = SScircuit_component.execute_instant_run()

	usr = temp_usr

	if(!output)
		message_admins("[parent.get_creator_admin()] took too much CPU time trying to handle a signal. Reduce the amount of circuit components attached to your [name] circuit component.")
		return

	return output["bitflag"] || NONE

/obj/item/circuit_component/signal_handler/proc/handle_bitflag_received(datum/port/input/port, list/return_values)
	CIRCUIT_TRIGGER
	if(!return_values)
		return

	if(!return_values["bitflag"])
		return_values["bitflag"] = NONE

	return_values["bitflag"] |= input_signal_ports[port]

#undef COMP_SIGNAL_HANDLER_GLOBAL
#undef COMP_SIGNAL_HANDLER_OBJECT