PROCESSING_SUBSYSTEM_DEF(nanoui)
	// Subsystem stuff.
	name = "NanoUI"
	flags = SS_NO_INIT
	priority = SS_PRIORITY_NANOUI
	stat_tag = "A"

	// NanoUI stuff.
	var/list/open_uis = list()

/datum/controller/subsystem/processing/nanoui/New()
	NEW_SS_GLOBAL(SSnanoui)

/**
 * Get an open /nanoui ui for the current user, src_object and ui_key and try to update it with data
 *
 * * user - /mob The mob who opened/owns the ui
 * * src_object - /obj|/mob The obj or mob which the ui belongs to
 * * ui_key - A string key used for the ui
 * * data - List, the data to be passed to the ui, if it exists
 * * force_open - Boolean, the ui is being forced to (re)open, so close ui if it exists (instead of updating)
 *
 * Returns the `/nanoui` found ui, for null if none exists
 */
/datum/controller/subsystem/processing/nanoui/proc/try_update_ui(mob/user, src_object, ui_key, datum/nanoui/ui, data, force_open = FALSE)
	if (!ui) // no ui has been passed, so we'll search for one
		ui = get_open_ui(user, src_object, ui_key)

	if (ui)
		// The UI is already open
		if (!force_open)
			ui.push_data(data)
			return ui
		else
			ui.reinitialise(new_initial_data=data)
			return ui

	return null

/**
 * Get an open /nanoui ui for the current user, src_object and ui_key
 *
 * * user - The `/mob` who opened/owns the ui
 * * src_object - The `/obj` or `/mob` which the ui belongs to
 * * ui_key - A string key used for the ui
 */
/datum/controller/subsystem/processing/nanoui/proc/get_open_ui(mob/user, src_object, ui_key)
	var/src_object_key = SOFTREF(src_object)
	if (!LAZYLEN(open_uis[src_object_key]) || !LAZYLEN(open_uis[src_object_key][ui_key]))
		return null

	for (var/datum/nanoui/ui in open_uis[src_object_key][ui_key])
		if (ui.user == user)
			return ui

	//testing("nanomanager/get_open_ui mob [user.name] [src_object:name] [ui_key] - ui not found")
	return null

/**
 * Update all `/nanoui` uis attached to src_object
 *
 * * src_object - The `/obj` or `/mob` which the uis are attached to
 *
 * Returns the number of UIs updated
 */
/datum/controller/subsystem/processing/nanoui/proc/update_uis(src_object)
	var/src_object_key = SOFTREF(src_object)
	if (!LAZYLEN(open_uis[src_object_key]))
		return 0

	. = 0
	var/list/obj_uis = open_uis[src_object_key]
	for (var/ui_key in obj_uis)
		for (var/thing in obj_uis[ui_key])
			var/datum/nanoui/ui = thing
			if(ui && ui.src_object && ui.user && ui.src_object.ui_host())
				ui.process(1)
				.++

/**
 * Close all `/nanoui` uis attached to src_object
 *
 * * src_object - The `/obj` or `/mob` which the uis are attached to
 *
 * Returns the number of UIs closed
 */
/datum/controller/subsystem/processing/nanoui/proc/close_uis(src_object)
	var/src_object_key = SOFTREF(src_object)
	if (!open_uis[src_object_key] || !islist(open_uis[src_object_key]))
		return 0

	. = 0
	var/list/obj_uis = open_uis[src_object_key]
	for (var/ui_key in obj_uis)
		for (var/thing in obj_uis[ui_key])
			var/datum/nanoui/ui = thing
			if(ui && ui.src_object && ui.user && ui.src_object.ui_host())
				ui.close()
				.++

/**
 * Update /nanoui uis belonging to user
 *
 * * user - The `/mob` who owns the uis
 * * src_object - An `/obj` or `/mob` that, if is provided, only update uis which are attached to it (optional)
 * * ui_key - A string, if ui_key is provided, only update uis with a matching ui_key (optional)
 *
 * Returns the number of UIs updated
 */
/datum/controller/subsystem/processing/nanoui/proc/update_user_uis(mob/user, src_object, ui_key)
	if (!LAZYLEN(user.open_uis))
		return 0 // has no open uis

	. = 0
	for (var/thing in user.open_uis)
		var/datum/nanoui/ui = thing
		if (NULL_OR_EQUAL(src_object, ui.src_object) && NULL_OR_EQUAL(ui_key, ui.ui_key))
			ui.process(1)
			.++

/datum/controller/subsystem/processing/nanoui/proc/close_user_uis(mob/user, src_object, ui_key)
	if (!LAZYLEN(user.open_uis))
		return 0

	for (var/thing in user.open_uis)
		var/datum/nanoui/ui = thing
		if (NULL_OR_EQUAL(src_object, ui.src_object) && NULL_OR_EQUAL(ui_key, ui.ui_key))
			ui.close()
			.++

	//testing("nanomanager/close_user_uis mob [user.name] closed [open_uis.len] of [.] uis")

/**
 * Add a /nanoui ui to the list of open uis
 * This is called by the /nanoui open() proc
 *
 * * ui - The `/nanoui` ui to add
 */
/datum/controller/subsystem/processing/nanoui/proc/ui_opened(datum/nanoui/ui)
	var/src_object_key = SOFTREF(ui.src_object)
	LAZYINITLIST(open_uis[src_object_key])

	LAZYADD(ui.user.open_uis, ui)
	LAZYADD(open_uis[src_object_key][ui.ui_key], ui)
	START_PROCESSING(SSnanoui, ui)
	//testing("nanomanager/ui_opened mob [ui.user.name] [ui.src_object:name] [ui.ui_key] - user.open_uis [ui.user.open_uis.len] | uis [uis.len] | processing_uis [processing_uis.len]")

/**
 * Remove a /nanoui ui from the list of open uis
 * This is called by the /nanoui close() proc
 *
 * * ui - A `/nanoui` to remove
 *
 * Returns FALSE if no ui was removed, TRUE if removed successfully
 */
/datum/controller/subsystem/processing/nanoui/proc/ui_closed(datum/nanoui/ui)
	var/src_object_key = SOFTREF(ui.src_object)
	var/ui_key = ui.ui_key
	var/list/obj_uis = open_uis[src_object_key]

	if (!LAZYLEN(obj_uis) || !obj_uis[ui_key])
		return 0	// Wasn't open.

	STOP_PROCESSING(SSnanoui, ui)
	if(ui.user)	// Sanity check in case a user has been deleted (say a blown up borg watching the alarm interface)
		LAZYREMOVE(ui.user.open_uis, ui)

	obj_uis[ui_key] -= ui

	if (!LAZYLEN(obj_uis[ui_key]))
		obj_uis -= ui_key

	if (!LAZYLEN(obj_uis))
		open_uis -= src_object_key

	//testing("nanomanager/ui_closed mob [ui.user.name] [ui.src_object:name] [ui.ui_key] - user.open_uis [ui.user.open_uis.len] | uis [uis.len] | processing_uis [processing_uis.len]")

	return 1

/**
 * This is called on user logout
 * Closes/clears all uis attached to the user's `/mob`
 *
 * * user - The user's `/mob`
 */
/datum/controller/subsystem/processing/nanoui/proc/user_logout(mob/user)
	return close_user_uis(user)

/**
 * This is called when a player transfers from one mob to another
 * Transfers all open UIs to the new mob
 *
 * * oldMob - The user's old `/mob`
 * * newMob - The user's new `/mob`
 */
/datum/controller/subsystem/processing/nanoui/proc/user_transferred(mob/oldMob, mob/newMob)
	//testing("nanomanager/user_transferred from mob [oldMob.name] to mob [newMob.name]")
	if (!oldMob || !LAZYLEN(oldMob.open_uis) || !LAZYLEN(open_uis))
		//testing("nanomanager/user_transferred mob [oldMob.name] has no open uis")
		return 0 // has no open uis

	for (var/thing in oldMob.open_uis)
		var/datum/nanoui/ui = thing
		ui.user = newMob
		LAZYADD(newMob.open_uis, ui)

	oldMob.open_uis = null

	return 1 // success

/datum/asset/nanoui
	var/list/common = list()

	var/list/common_dirs = list(
		"nano/css/",
		"nano/js/",
		"nano/images/",
		"nano/images/status_icons/",
		"nano/templates/"
	)
	var/list/uncommon_dirs = list()

/datum/asset/nanoui/register()
	// Crawl the directories to find files.
	for (var/path in common_dirs)
		var/list/filenames = flist(path)
		for(var/filename in filenames)
			if(copytext(filename, length(filename)) != "/") // Ignore directories.
				if(fexists(path + filename))
					common[filename] = fcopy_rsc(path + filename)
					SSassets.transport.register_asset(filename, common[filename])
	for (var/path in uncommon_dirs)
		var/list/filenames = flist(path)
		for(var/filename in filenames)
			if(copytext(filename, length(filename)) != "/") // Ignore directories.
				if(fexists(path + filename))
					SSassets.transport.register_asset(filename, fcopy_rsc(path + filename))

/datum/asset/nanoui/send(client, uncommon)
	if(!islist(uncommon))
		uncommon = list(uncommon)

	SSassets.transport.send_assets(client, uncommon)
	SSassets.transport.send_assets(client, common)