// Generates cave systems for the asteroid, and places ore tiles.
var/global/list/random_maps = list()
var/global/list/map_count = list()

/datum/random_map

	// Strings.
	var/name                        // Set in New()
	var/descriptor = "random map"   // Display name.

	// Locator/value vars.
	var/initial_wall_cell = 100     // % Chance that a cell will be seeded as a wall.
	var/max_attempts = 5            // Fail if a sane map isn't generated by this point.
	var/origin_x = 1                // Origin point, left.
	var/origin_y = 1                // Origin point, bottom.
	var/origin_z = 1                // Target Z-level.
	var/limit_x = 128               // Default x size.
	var/limit_y = 128               // Default y size.
	var/auto_apply = 1

	// Turf paths.
	var/wall_type =  /turf/simulated/wall
	var/floor_type = /turf/simulated/floor
	var/target_turf_type

	// Storage for the final iteration of the map.
	var/list/map = list()           // Actual map.

	// If set, all sleep(-1) calls will be skipped.
	// Test to see if rand_seed() can be used reliably.
	var/priority_process

/datum/random_map/New(var/seed, var/tx, var/ty, var/tz, var/tlx, var/tly, var/do_not_apply, var/do_not_announce)

	// Store this for debugging.
	if(!map_count[descriptor])
		map_count[descriptor] = 1
	else
		map_count[descriptor]++
	name = "[descriptor] #[map_count[descriptor]]"
	random_maps[name] = src

	// Get origins for applying the map later.
	origin_x = (!isnull(tx) ? tx : 1)
	origin_y = (!isnull(ty) ? ty : 1)
	origin_z = (!isnull(tz) ? tz : 1)
	if(tlx) limit_x = tlx
	if(tly) limit_y = tly

	if(do_not_apply)
		auto_apply = null

	// Initialize map.
	set_map_size()

	var/start_time = world.timeofday
	if(!do_not_announce) admin_notice("<span class='danger'>Generating [name].</span>", R_DEBUG)
	sleep(-1)

	// Testing needed to see how reliable this is (asynchronous calls, called during worldgen), DM ref is not optimistic
	if(seed)
		rand_seed(seed)
		priority_process = 1

	for(var/i = 0;i<max_attempts;i++)
		if(generate())
			if(!do_not_announce) admin_notice("<span class='danger'>[capitalize(name)] generation completed in [round(0.1*(world.timeofday-start_time),0.1)] seconds.</span>", R_DEBUG)
			return
	if(!do_not_announce) admin_notice("<span class='danger'>[capitalize(name)] failed to generate ([round(0.1*(world.timeofday-start_time),0.1)] seconds): could not produce sane map.</span>", R_DEBUG)

/datum/random_map/proc/get_map_cell(var/x,var/y)
	var/cell = ((y-1)*limit_x)+x
	if((cell < 1) || (cell > map.len))
		return null
	else
		return cell

/datum/random_map/proc/get_map_char(var/value)
	switch(value)
		if(WALL_CHAR)
			return "#"
		if(FLOOR_CHAR)
			return "."
		if(DOOR_CHAR)
			return "D"
		if(ROOM_TEMP_CHAR)
			return "+"
		if(MONSTER_CHAR)
			return "M"
		if(ARTIFACT_TURF_CHAR)
			return "_"
		if(ARTIFACT_CHAR)
			return "A"
		else
			return " "

/datum/random_map/proc/display_map(atom/user)

	if(!user)
		user = world

	var/dat = "<code>+------+<br>"
	for(var/x = 1, x <= limit_x, x++)
		for(var/y = 1, y <= limit_y, y++)
			var/current_cell = get_map_cell(x,y)
			if(within_bounds(current_cell))
				dat += get_map_char(map[current_cell])
		dat += "<br>"
	user << "[dat]+------+</code>"

/datum/random_map/proc/within_bounds(var/val)
	if(!islist(map))
		set_map_size()
	return (val>0) && (val<=map.len)

/datum/random_map/proc/set_map_size()
	map = list()
	map.len = limit_x * limit_y

/datum/random_map/proc/seed_map()
	for(var/x = 1, x <= limit_x, x++)
		for(var/y = 1, y <= limit_y, y++)
			var/current_cell = get_map_cell(x,y)
			if(prob(initial_wall_cell))
				map[current_cell] = WALL_CHAR
			else
				map[current_cell] = FLOOR_CHAR

/datum/random_map/proc/clear_map()
	for(var/x = 1, x <= limit_x, x++)
		for(var/y = 1, y <= limit_y, y++)
			map[get_map_cell(x,y)] = 0

/datum/random_map/proc/generate()
	seed_map()
	generate_map()
	if(check_map_sanity())
		cleanup()
		if(auto_apply)
			apply_to_map()
		return 1
	return 0

// Unused for basic map.
/datum/random_map/proc/generate_map()
	return 1

/datum/random_map/proc/check_map_sanity()
	return 1

/datum/random_map/proc/apply_to_map(var/tx, var/ty, var/tz)
	if(!tx) tx = isnull(origin_x) ? 1 : origin_x
	if(!ty) ty = isnull(origin_y) ? 1 : origin_y
	if(!tz) tz = isnull(origin_z) ? 1 : origin_z

	for(var/x = 1, x <= limit_x, x++)
		for(var/y = 1, y <= limit_y, y++)
			if(!priority_process) sleep(-1)
			apply_to_turf((tx-1)+x,(ty-1)+y,tz)

/datum/random_map/proc/apply_to_turf(var/x,var/y,var/z)
	var/current_cell = get_map_cell(x,y)
	if(!within_bounds(current_cell))
		return 0
	var/turf/T = locate(x,y,z)
	if(!T || (target_turf_type && !istype(T,target_turf_type)))
		return 0
	var/newpath = get_appropriate_path(map[current_cell])
	if(newpath)
		T.ChangeTurf(newpath)
	get_additional_spawns(map[current_cell],T)
	return T

/datum/random_map/proc/get_appropriate_path(var/value)
	switch(value)
		if(FLOOR_CHAR)
			return floor_type
		if(WALL_CHAR)
			return wall_type

/datum/random_map/proc/get_additional_spawns(var/value, var/turf/T)
	if(value == DOOR_CHAR)
		new /obj/machinery/door/airlock(T)

/datum/random_map/proc/cleanup()
	return

/datum/random_map/proc/overlay_with(var/datum/random_map/target_map, var/tx, var/ty)
	if(!map.len || !istype(target_map))
		return
	tx-- // Update origin so that x/y index
	ty-- // doesn't push it off-kilter by one.
	for(var/x = 1, x <= limit_x, x++)
		for(var/y = 1, y <= limit_y, y++)
			var/current_cell = get_map_cell(x,y)
			if(!within_bounds(current_cell))
				continue
			if(tx+x > target_map.limit_x)
				continue
			if(ty+y > target_map.limit_y)
				continue
			target_map.map[target_map.get_map_cell(tx+x,ty+y)] = map[current_cell]
	handle_post_overlay_on(target_map,tx,ty)

/datum/random_map/proc/handle_post_overlay_on(var/datum/random_map/target_map, var/tx, var/ty)
	return