#define MAP_VOTE_CACHE_LOCATION "data/map_vote_cache.json"

SUBSYSTEM_DEF(map_vote)
	name = "Map Vote"
	flags = SS_NO_FIRE

	/// Has an admin specifically set a map.
	var/admin_override = FALSE

	/// Have we already done a vote.
	var/already_voted = FALSE

	/// The map that has been chosen for next round.
	var/datum/map_config/next_map_config

	/// Stores the current map vote cache, so that players can look at the current tally.
	var/list/map_vote_cache

	/// Stores the previous map vote cache, used when a map vote is reverted.
	var/list/previous_cache

	/// Stores a formatted html string of the tally counts
	var/tally_printout = span_red("Loading...")

/datum/controller/subsystem/map_vote/Initialize()
	if(rustg_file_exists(MAP_VOTE_CACHE_LOCATION))
		map_vote_cache = json_decode(file2text(MAP_VOTE_CACHE_LOCATION))
		var/carryover = CONFIG_GET(number/map_vote_tally_carryover_percentage)
		for(var/map_id in map_vote_cache)
			map_vote_cache[map_id] = round(map_vote_cache[map_id] * (carryover / 100))
		sanitize_cache()
	else
		map_vote_cache = list()
	update_tally_printout()
	return SS_INIT_SUCCESS

/datum/controller/subsystem/map_vote/proc/write_cache()
	rustg_file_write(json_encode(map_vote_cache), MAP_VOTE_CACHE_LOCATION)

/datum/controller/subsystem/map_vote/proc/sanitize_cache()
	var/max = CONFIG_GET(number/map_vote_maximum_tallies)
	for(var/map_id in map_vote_cache)
		if(!(map_id in config.maplist))
			map_vote_cache -= map_id
		var/count = map_vote_cache[map_id]
		if(count > max)
			map_vote_cache[map_id] = max

/datum/controller/subsystem/map_vote/proc/send_map_vote_notice(...)
	var/static/last_message_at
	if(last_message_at == world.time)
		message_admins("Call to send_map_vote_notice twice in one game tick. Yell at someone to condense messages.")
	last_message_at = world.time

	var/list/messages = args.Copy()
	to_chat(world, span_purple(examine_block("Map Vote\n<hr>\n[messages.Join("\n")]")))

/datum/controller/subsystem/map_vote/proc/finalize_map_vote(datum/vote/map_vote/map_vote)
	if(already_voted)
		message_admins("Attempted to finalize a map vote after a map vote has already been finalized.")
		return
	already_voted = TRUE

	var/flat = CONFIG_GET(number/map_vote_flat_bonus)
	previous_cache = map_vote_cache.Copy()
	for(var/map_id in map_vote.choices)
		var/datum/map_config/map = config.maplist[map_id]
		map_vote_cache[map_id] += (map_vote.choices[map_id] * map.voteweight) + flat
	sanitize_cache()
	write_cache()
	update_tally_printout()

	if(admin_override)
		send_map_vote_notice("Admin Override is in effect. Map will not be changed.", "Tallies are recorded and saved.")
		return

	var/list/valid_maps = filter_cache_to_valid_maps()
	if(!length(valid_maps))
		send_map_vote_notice("No valid maps.")
		return

	var/winner
	var/winner_amount = 0
	for(var/map in valid_maps)
		if(!winner_amount)
			winner = map
			winner_amount = map_vote_cache[map]
			continue
		if(map_vote_cache[map] <= winner_amount)
			continue
		winner = map
		winner_amount = map_vote_cache[map]

	ASSERT(winner, "No winner found in map vote.")
	set_next_map(config.maplist[winner])
	var/list/messages = list("Map Selected - [span_bold(next_map_config.map_name)]")
	messages += "Tallies at the time of selection:"
	messages += tally_printout

	// do not reset tallies if only one map is even possible
	if(length(valid_maps) > 1)
		map_vote_cache[winner] = CONFIG_GET(number/map_vote_minimum_tallies)
		write_cache()
		update_tally_printout()
	else
		messages += "Only one map was possible, tallies were not reset."

	send_map_vote_notice(arglist(messages))

/// Returns a list of all map options that are invalid for the current population.
/datum/controller/subsystem/map_vote/proc/get_valid_map_vote_choices()
	var/list/valid_maps = list()

	// Fill in our default choices with all of the maps in our map config, if they are votable and not blocked.
	var/list/maps = shuffle(global.config.maplist)
	for(var/map in maps)
		var/datum/map_config/possible_config = config.maplist[map]
		if(!possible_config.votable || (possible_config.map_name in SSpersistence.blocked_maps))
			continue
		valid_maps += possible_config.map_name

	var/filter_threshold = 0
	if(SSticker.HasRoundStarted())
		filter_threshold = get_active_player_count(alive_check = FALSE, afk_check = TRUE, human_check = FALSE)
	else
		filter_threshold = length(GLOB.clients)

	for(var/map in valid_maps)
		var/datum/map_config/possible_config = config.maplist[map]
		if(possible_config.config_min_users > 0 && filter_threshold < possible_config.config_min_users)
			valid_maps -= map

		else if(possible_config.config_max_users > 0 && filter_threshold > possible_config.config_max_users)
			valid_maps -= map

	return valid_maps

/datum/controller/subsystem/map_vote/proc/filter_cache_to_valid_maps()
	var/connected_players = length(GLOB.player_list)
	var/list/valid_maps = list()
	for(var/map_id in map_vote_cache)
		var/datum/map_config/map = config.maplist[map_id]
		if(!map.votable)
			continue
		if(map.config_min_users > 0 && (connected_players < map.config_min_users))
			continue
		if(map.config_max_users > 0 && (connected_players > map.config_max_users))
			continue
		valid_maps[map_id] = map_vote_cache[map_id]
	return valid_maps

/datum/controller/subsystem/map_vote/proc/set_next_map(datum/map_config/change_to)
	if(!change_to.MakeNextMap())
		message_admins("Failed to set new map with next_map.json for [change_to.map_name]!")
		return FALSE

	next_map_config = change_to
	return TRUE

/datum/controller/subsystem/map_vote/proc/revert_next_map()
	if(!next_map_config)
		return
	if(previous_cache)
		map_vote_cache = previous_cache
		previous_cache = null

	already_voted = FALSE
	admin_override = FALSE
	send_map_vote_notice("Next map reverted. Voting re-enabled.")

#undef MAP_VOTE_CACHE_LOCATION

/datum/controller/subsystem/map_vote/proc/update_tally_printout()
	var/list/data = list()
	for(var/map_id in map_vote_cache)
		var/datum/map_config/map = config.maplist[map_id]
		data += "[map.map_name] - [map_vote_cache[map_id]]"
	tally_printout = examine_block("Current Tallies\n<hr>\n[data.Join("\n")]")