#define AIRLOCK_CONTROL_RANGE 5

// This code allows for airlocks to be controlled externally by setting an id_tag and comm frequency (disables ID access)
/obj/machinery/door/airlock
	var/id_tag
	var/frequency
	var/datum/radio_frequency/radio_connection


/obj/machinery/door/airlock/receive_signal(datum/signal/signal)
	if(!signal || signal.encryption)
		return

	if(id_tag != signal.data["tag"] || !signal.data["command"])
		return

	switch(signal.data["command"])
		if("open")
			open(1)

		if("close")
			close(1)

		if("unlock")
			locked = FALSE
			update_icon()

		if("lock")
			locked = TRUE
			update_icon()

		if("secure_open")
			locked = FALSE
			update_icon()

			sleep(2)
			open(1)

			locked = TRUE
			update_icon()

		if("secure_close")
			locked = FALSE
			close(1)

			locked = TRUE
			sleep(2)
			update_icon()

	send_status()


/obj/machinery/door/airlock/proc/send_status()
	if(radio_connection)
		var/datum/signal/signal = new
		signal.transmission_method = 1 //radio signal
		signal.data["tag"] = id_tag
		signal.data["timestamp"] = world.time

		signal.data["door_status"] = density?("closed"):("open")
		signal.data["lock_status"] = locked?("locked"):("unlocked")

		radio_connection.post_signal(src, signal, range = AIRLOCK_CONTROL_RANGE, filter = GLOB.RADIO_AIRLOCK)


/obj/machinery/door/airlock/open(surpress_send)
	. = ..()
	if(!surpress_send)
		send_status()


/obj/machinery/door/airlock/close(surpress_send)
	. = ..()
	if(!surpress_send)
		send_status()


/obj/machinery/door/airlock/proc/set_frequency(new_frequency)
	SSradio.remove_object(src, frequency)
	if(new_frequency)
		frequency = new_frequency
		radio_connection = SSradio.add_object(src, frequency, GLOB.RADIO_AIRLOCK)

/obj/machinery/door/airlock/Destroy()
	if(frequency && SSradio)
		SSradio.remove_object(src,frequency)
	return ..()

/obj/machinery/airlock_sensor
	icon = 'icons/obj/airlock_machines.dmi'
	icon_state = "airlock_sensor_off"
	name = "airlock sensor"
	resistance_flags = INDESTRUCTIBLE | LAVA_PROOF | FIRE_PROOF | UNACIDABLE | ACID_PROOF

	anchored = TRUE
	power_channel = ENVIRON

	var/id_tag
	var/master_tag
	var/frequency = 1449

	var/datum/radio_frequency/radio_connection

	var/on = TRUE
	var/alert = FALSE


/obj/machinery/airlock_sensor/update_icon()
	if(on)
		if(alert)
			icon_state = "airlock_sensor_alert"
		else
			icon_state = "airlock_sensor_standby"
	else
		icon_state = "airlock_sensor_off"

/obj/machinery/airlock_sensor/attack_hand(mob/user)
	var/datum/signal/signal = new
	signal.transmission_method = 1 //radio signal
	signal.data["tag"] = master_tag
	signal.data["command"] = "cycle"

	radio_connection.post_signal(src, signal, range = AIRLOCK_CONTROL_RANGE, filter = GLOB.RADIO_AIRLOCK)
	flick("airlock_sensor_cycle", src)

/obj/machinery/airlock_sensor/process()
	if(on)
		var/datum/signal/signal = new
		signal.transmission_method = 1 //radio signal
		signal.data["tag"] = id_tag
		signal.data["timestamp"] = world.time

		var/datum/gas_mixture/air_sample = return_air()

		var/pressure = round(air_sample.return_pressure(),0.1)
		alert = (pressure < ONE_ATMOSPHERE*0.8)

		signal.data["pressure"] = num2text(pressure)

		radio_connection.post_signal(src, signal, range = AIRLOCK_CONTROL_RANGE, filter = GLOB.RADIO_AIRLOCK)

	update_icon()

/obj/machinery/airlock_sensor/proc/set_frequency(new_frequency)
	SSradio.remove_object(src, frequency)
	frequency = new_frequency
	radio_connection = SSradio.add_object(src, frequency, GLOB.RADIO_AIRLOCK)

/obj/machinery/airlock_sensor/Initialize()
	. = ..()
	set_frequency(frequency)

/obj/machinery/airlock_sensor/Destroy()
	SSradio.remove_object(src,frequency)
	return ..()