-- If true, the Perlin test nodes will support color
-- (set to false in case of performance problems)
local COLORIZE_NODES = true
-- The number of available test node colors is divided by this number.
-- A number between 1 to 256
-- * 1 = Full 256 palette.
-- * 2 = 128 colors.
-- * 4 = 64 colors.
-- etc.
-- Higher values lead to less colors but increased performance.
-- This value is only used for performance reason, because Minetest
-- has a sharp performance drop when there are many different node colors on screen.
-- Consider removing this one when Minetest's performance problem has been solved.
local COLOR_PRECISION = 4

-- Time to wait in seconds before checking and generating new nodes in autobuild mode.
local AUTOBUILD_UPDATE_TIME = 1.0

-- x/y/z size of chunks to generate in autobuild mode.
local AUTOBUILD_SIZE = 16
-- Amount of chunks to generate around player
local AUTOBUILD_CHUNKDIST = 2


-- Color of the formspec box[] element
local FORMSPEC_BOX_COLOR = "#00000080"
-- Color for the section titles in the formspec
local FORMSPEC_HEADER_COLOR = "#000000FF"

local S = minetest.get_translator("perlin_explorer")
local F = minetest.formspec_escape

-- Per-player formspec states (mostly for remembering checkbox states)
local formspec_states = {}

-- List of noise parameters profiles
local np_profiles = {}

local default_noiseparams = {
	offset = 0.0,
	scale = 1.0,
	spread = vector.new(10, 10, 10),
	seed = 0,
	octaves = 2,
	persistence = 0.5,
	lacunarity = 2.0,
	flags = "noeased,noabsvalue",
}

-- Holds the currently used Perlin noise
local current_perlin = {}
-- holds the current PerlinNoise object
current_perlin.noise = nil
current_perlin.noiseparams = table.copy(default_noiseparams)
table.insert(np_profiles, current_perlin.noiseparams)
-- Side length of calculated perlin area
current_perlin.size = 64
-- Theoretical min and max values for Perlin noise (for colorization)
current_perlin.min = -1
current_perlin.max = 1

-- dimensions of current Perlin noise (2 or 3)
current_perlin.dimensions = 2
-- If greater than 1, the Perlin noise values are "pixelized". Noise values at
-- coordinates not divisible by sidelen will be set equal to the noise value
-- of the nearest number (counting downwards) that is divisible by sidelen.
-- This is (kind of) analogous to the "sidelen" parameter of mapgen decorations.
current_perlin.sidelen = 1
current_perlin.pos = {}

current_perlin.auto_build = true
current_perlin.loaded_areas = {}

------------

-- Helper functions
-- Reduce the pos coordinates down to the closest numbers divisible by sidelen
local sidelen_pos = function(pos, sidelen)
	local newpos = table.copy(pos)
	if sidelen <= 1 then
		return newpos
	end
	newpos.x = newpos.x - newpos.x % sidelen
	newpos.y = newpos.y - newpos.y % sidelen
	newpos.z = newpos.z - newpos.z % sidelen
	return newpos
end

-- Sets the currently active Perlin noise.
-- * noiseparams: NoiseParams table (see Minetest's Lua API documentation)
local set_perlin_noise = function(noiseparams)
	current_perlin.noise = PerlinNoise(noiseparams)
	current_perlin.noiseparams = noiseparams
end

-- Test nodes to generate a map based on a perlin noise
local paramtype2
if COLORIZE_NODES then
	paramtype2 = "color"
end
minetest.register_node("perlin_explorer:node", {
	description = S("Perlin Test Node"),
	paramtype = "light",
	sunlight_propagates = true,
	paramtype2 = paramtype2,
	tiles = {"perlin_explorer_node.png"},
	palette = "perlin_explorer_node_palette.png",
	groups = { dig_immediate = 3 },
	-- Force-drop without metadata to avoid spamming the inventory
	drop = "perlin_explorer:node",
})
minetest.register_node("perlin_explorer:node_negative", {
	description = S("Negative Perlin Test Node"),
	paramtype = "light",
	sunlight_propagates = true,
	paramtype2 = paramtype2,
	tiles = {"perlin_explorer_node_neg.png"},
	palette = "perlin_explorer_node_palette_neg.png",
	groups = { dig_immediate = 3 },
	-- Force-drop without metadata to avoid spamming the inventory
	drop = "perlin_explorer:node_negative",
})
minetest.register_tool("perlin_explorer:getter", {
	description = S("Perlin Value Getter"),
	_tt_help = S("Punch a node to display the Perlin noise value at this position"),
	inventory_image = "perlin_explorer_getter.png",
	wield_image = "perlin_explorer_getter.png",
	groups = { disable_repair = 1 },
	on_use = function(itemstack, user, pointed_thing)
		if not user then
			return
		end
		local privs = minetest.get_player_privs(user:get_player_name())
		if not privs.server then
			minetest.chat_send_player(user:get_player_name(), S("Insufficient privileges! You need the @1 privilege to use this tool.", "server"))
			return
		end
		if current_perlin.noise then
			if pointed_thing.type ~= "node" then
				-- No-op for non-nodes
				return
			end
			local pos = pointed_thing.under
			local getpos = sidelen_pos(pos, current_perlin.sidelen)
			local val
			if current_perlin.dimensions == 2 then
				val = current_perlin.noise:get_2d({x=getpos.x, y=getpos.z})
			elseif current_perlin.dimensions == 3 then
				val = current_perlin.noise:get_3d(getpos)
			else
				minetest.chat_send_player(user:get_player_name(), S("Unknown/invalid number of Perlin noise dimensions. Use /generate_perlin first!"))
			end
			minetest.chat_send_player(user:get_player_name(), S("pos=@1, value=@2", minetest.pos_to_string(pos), val))
		else
			local msg = S("No Perlin noise set. Set one first!")
			minetest.chat_send_player(user:get_player_name(), msg)
		end
	end,
})
minetest.register_tool("perlin_explorer:seeder", {
	description = S("Random Perlin seed setter"),
	_tt_help = S("Set a random Perlin seed for the current Perlin noise params"),
	inventory_image = "perlin_explorer_seeder.png",
	wield_image = "perlin_explorer_seeder.png",
	groups = { disable_repair = 1 },
	on_use = function(itemstack, user, pointed_thing)
		if not user then
			return
		end
		local privs = minetest.get_player_privs(user:get_player_name())
		if not privs.server then
			minetest.chat_send_player(user:get_player_name(), S("Insufficient privileges! You need the @1 privilege to use this tool.", "server"))
			return
		end
		if current_perlin.noise then
			local noiseparams = table.copy(current_perlin.noiseparams)
			noiseparams.seed = math.random(0, 2^32-1)
			set_perlin_noise(noiseparams)
			current_perlin.loaded_areas = {}
			local msg = S("New random seed set!")
			minetest.chat_send_player(user:get_player_name(), msg)
		else
			local msg = S("No Perlin noise set. Set one first!")
			minetest.chat_send_player(user:get_player_name(), msg)
		end
	end,
})

local CONTENT_TEST_NODE = minetest.get_content_id("perlin_explorer:node")
local CONTENT_TEST_NODE_NEGATIVE = minetest.get_content_id("perlin_explorer:node_negative")

local update_map = function(pos, set_nodes)
	local stats
	if not current_perlin.noise then
		return
	end
	local size_v = vector.new(current_perlin.size, current_perlin.size, current_perlin.size)

	local startpos = pos
	local endpos = vector.add(startpos, current_perlin.size-1)

	local y_max = endpos.y - startpos.y
	if current_perlin.dimensions == 2 then
		y_max = 0
		startpos.y = pos.y
		endpos.y = pos.y
	end

	local vmanip, emin, emax, vdata, vdata2, varea
	if set_nodes then
		vmanip = VoxelManip(startpos, endpos)
		emin, emax = vmanip:get_emerged_area()
		vdata = vmanip:get_data()
		vdata2 = vmanip:get_param2_data()
		varea = VoxelArea:new({MinEdge = emin, MaxEdge = emax})
	end

	stats = {}
	stats.avg = 0
	local sum_of_values = 0
	local value_count = 0
	for x=0, endpos.x - startpos.x do
	for y=0, y_max do
	for z=0, endpos.z - startpos.z do
		-- Get Perlin value at current pos
		local relpos = vector.new(x,y,z)
		local abspos = vector.add(startpos, relpos)
		local abspos_get = sidelen_pos(abspos, current_perlin.sidelen)
		local perlin_value
		if current_perlin.dimensions == 2 then
			perlin_value = current_perlin.noise:get_2d({x=abspos_get.x, y=abspos_get.z})
		elseif current_perlin.dimensions == 3 then
			perlin_value = current_perlin.noise:get_3d(abspos_get)
		else
			error("[perlin_explorer] Unknown/invalid number of Perlin noise dimensions!")
			return
		end

		-- Statistics
		if not stats.min then
			stats.min = perlin_value
		elseif perlin_value < stats.min then
			stats.min = perlin_value
		end
		if not stats.max then
			stats.max = perlin_value
		elseif perlin_value > stats.max then
			stats.max = perlin_value
		end
		sum_of_values = sum_of_values + perlin_value
		value_count = value_count + 1

		-- Calculate color (param2) for node
		local zeropoint = 0
		local min_size = zeropoint - current_perlin.min
		local max_size = current_perlin.max - zeropoint
		local node_param2
		if perlin_value >= zeropoint then
			node_param2 = (math.abs(perlin_value) / max_size) * 255
		else
			node_param2 = (math.abs(perlin_value) / min_size) * 255
		end
		node_param2 = math.floor(math.abs(node_param2))
		node_param2 = math.max(0, math.min(255, node_param2))
		if node_param2 < 255 then
			node_param2 = node_param2 - (node_param2 % COLOR_PRECISION)
		end

		if set_nodes then
			-- Get vmanip index
			local index = varea:indexp(abspos)
			if not index then
				return
			end

			-- Set node and param2
			if perlin_value >= zeropoint then
				vdata[index] = CONTENT_TEST_NODE
				vdata2[index] = node_param2
			else
				if current_perlin.show_negative == true then
					vdata[index] = CONTENT_TEST_NODE_NEGATIVE
					vdata2[index] = node_param2
				else
					vdata[index] = minetest.CONTENT_AIR
					vdata2[index] = 0
				end
			end
		end
	end
	end
	end
	stats.avg = sum_of_values / value_count

	if set_nodes then
		-- Set vmanip, return stats
		vmanip:set_data(vdata)
		vmanip:set_param2_data(vdata2)
		vmanip:write_to_map()
	end
	return stats
end

-- Creates and demonstrates a Perlin noise.
-- * pos: Where the Perlin noise starts
-- * options: table with:
-- 	* dimensions: number of Perlin noise dimensions (2 or 3)
-- 	* size: side length of area/volume to calculate)
-- 	* show_negative: if true, places nodes for negative Perlin values (default: true for 2 dimensions and false for 3 dimensions)
-- 	* set_nodes: if true, will set nodes, otherwise it's a "dry run"
local create_perlin = function(pos, options)
	if not current_perlin.noise then
		return false
	end
	current_perlin.dimensions = options.dimensions
	current_perlin.size = options.size
	current_perlin.show_negative = options.show_negative
	if current_perlin.show_negative == nil then
		if current_perlin.dimensions == 2 then
			current_perlin.show_negative = true
		elseif current_perlin.dimensions == 3 then
			current_perlin.show_negative = false
		end
	end
	local cpos = table.copy(pos)
	local mpos = vector.round(cpos)
	current_perlin.pos = mpos
	local set_nodes = options.set_nodes ~= false
	local stats = update_map(mpos, set_nodes)

	-- Show a particle in the center of the newly generated area
	local center = vector.new()
	center.x = mpos.x + options.size/2
	center.y = mpos.y + options.size/2
	center.z = mpos.z + options.size/2
	minetest.add_particle({
		pos = center,
		expirationtime = 4,
		size = 16,
		texture = "perlin_explorer_new_chunk_particle.png",
		glow = minetest.LIGHT_MAX,
	})
	if stats then
		return string.format("Perlin noise created! Stats: min. value=%.3f, max. value=%.3f, avg. value=%.3f", stats.min, stats.max, stats.avg)
	end
end

minetest.register_chatcommand("perlin_set_options", {
	privs = { server = true },
	description = S("Set Perlin options"),
	params = S("<dimensions> <sidelen> <minval> <maxval>"),
	func = function(name, param)
		local dimensions, sidelen, min, max = string.match(param, "([23]) ([0-9]+) ([0-9.-]+) ([0-9.-]+)")
		if not dimensions then
			return false
		end
		dimensions = tonumber(dimensions)
		sidelen = tonumber(sidelen)
		min = tonumber(min)
		max = tonumber(max)
		if not dimensions or not sidelen or not min or not max then
			return false, S("Invalid parameter type.")
		end
		current_perlin.dimensions = dimensions
		current_perlin.sidelen = sidelen
		current_perlin.min = min
		current_perlin.max = max
		current_perlin.loaded_areas = {}
		return true, S("Perlin options set!")
	end,
})

minetest.register_chatcommand("perlin_set_noise", {
	privs = { server = true },
	description = S("Set Perlin noise parameters"),
	params = S("<octaves> <offset> <scale> <spread_x> <spread_y> <spread_z> <persistence> <lacunarity> <seed>"),
	func = function(name, param)
		local octaves, offset, scale, sx, sy, sz, persistence, lacunarity, seed = string.match(param, string.rep("([0-9.-]+) ", 8) .. "([0-9.-]+)")
		if not octaves then
			return false
		end
		octaves = tonumber(octaves)
		offset = tonumber(offset)
		sx = tonumber(sx)
		sy = tonumber(sy)
		sz = tonumber(sz)
		persistence = tonumber(persistence)
		lacunarity = tonumber(lacunarity)
		seed = tonumber(seed)
		if not octaves or not offset or not sx or not sy or not sz or not persistence or not lacunarity or not seed then
			return false, S("Invalid parameter type.")
		end
		set_perlin_noise({
			octaves = octaves,
			offset = offset,
			scale = scale,
			spread = { x = sx, y = sy, z = sz },
			persistence = persistence,
			lacunarity = lacunarity,
			seed = seed,
		})
		current_perlin.loaded_areas = {}
		return true, S("Perlin noise set!")
	end,
})

minetest.register_chatcommand("perlin_generate", {
	privs = { server = true },
	description = S("Generate Perlin noise"),
	params = S("<pos> <size>"),
	func = function(name, param)
		local x, y, z, size = string.match(param, "([0-9.-]+) ([0-9.-]+) ([0-9.-]+) ([0-9]+)")
		if not x then
			return false
		end
		x = tonumber(x)
		y = tonumber(y)
		z = tonumber(z)
		size = tonumber(size)
		if not x or not y or not z or not size then
			return false
		end
		if not x or not y or not z or not size then
			return false, S("Invalid parameter type.")
		end
		local pos = vector.new(x, y, z)

		minetest.chat_send_player(name, S("Creating Perlin noise, please wait …"))
		local msg = create_perlin(pos, {dimensions=current_perlin.dimensions, size=size})
		if msg == false then
			return false, S("No Perlin noise set. Set one with '/perlin_set_noise' first!")
		end
		return true, msg
	end,
})

local build_flags_string = function(eased, absvalue)
	local flags = ""
	if eased then
		flags = "eased"
	else
		flags = "noeased"
	end
	if absvalue then
		flags = flags .. ",absvalue"
	else
		flags = flags .. ",noabsvalue"
	end
	return flags
end
local parse_flags_string = function(flags)
	local ftable = string.split(flags, ",")
	local eased, absvalue = false, false
	for f=1, #ftable do
		local s = string.trim(ftable[f])
		if s == "eased" then
			eased = true
		elseif s == "absvalue" then
			absvalue = true
		end
	end
	return { eased = eased, absvalue = absvalue }
end

local show_formspec = function(player, noiseparams, profile_id)
	local np
	if noiseparams then
		np = noiseparams
	else
		np = current_perlin.noiseparams
	end
	if not profile_id then
		profile_id = 1
	end
	local offset = tostring(np.offset or "")
	local scale = tostring(np.scale or "")
	local seed = tostring(np.seed or "")
	local sx, sy, sz = "", "", ""
	if np.spread then
		sx = tostring(np.spread.x or "")
		sy = tostring(np.spread.y or "")
		sz = tostring(np.spread.z or "")
	end
	local octaves = tostring(np.octaves or "")
	local persistence = tostring(np.persistence or "")
	local lacunarity = tostring(np.lacunarity or "")

	local size = tostring(current_perlin.size or "")
	local sidelen = tostring(current_perlin.sidelen or "")
	local pos_x = tostring(current_perlin.pos.x or "")
	local pos_y = tostring(current_perlin.pos.y or "")
	local pos_z = tostring(current_perlin.pos.z or "")
	local value_min = tostring(current_perlin.min or "")
	local value_max = tostring(current_perlin.max or "")

	local flags = np.flags
	local flags_table = parse_flags_string(flags)
	local eased = tostring(flags_table.eased)
	local absvalue = tostring(flags_table.absvalue)

	local noiseparams_list = {}
	for i=1, #np_profiles do
		table.insert(noiseparams_list, S("Profile @1", i))
	end
	local noiseparams_list_str = table.concat(noiseparams_list, ",")

	local dimensions_index = (current_perlin.dimensions or 2) - 1

	local delete_btn = ""
	if #np_profiles > 1 then
		delete_btn = "button[7.25,0.5;2.0,0.5;delete_np_profile;"..F(S("Delete")).."]"
	end
	local form = [[
		formspec_version[4]size[10,12.5]
		container[0.25,0.25]
		box[0,0;9.5,5.5;]]..FORMSPEC_BOX_COLOR..[[]
		box[0,0;9.5,0.4;]]..FORMSPEC_HEADER_COLOR..[[]
		label[0.15,0.2;]]..F(S("Noise parameters"))..[[]
		container[0.0,0.5]
		dropdown[0.25,0;2,0.5;np_profiles;]]..noiseparams_list_str..[[;]]..profile_id..[[;true]
		button[3.25,0;2.0,0.5;add_np_profile;]]..F(S("Add"))..[[]
		button[5.25,0;2.0,0.5;load_np_profile;]]..F(S("Load"))..[[]
		]]..delete_btn..[[
		container_end[]
		container[0.0,1.5]
		field[0.25,0;2,0.75;offset;]]..F(S("Offset"))..[[;]]..offset..[[]
		field[3.25,0;2,0.75;scale;]]..F(S("Scale"))..[[;]]..scale..[[]
		field[6.25,0;2,0.75;seed;]]..F(S("Seed"))..[[;]]..seed..[[]
		image_button[8.35,0.0;0.75,0.75;perlin_explorer_seeder.png;set_random_seed;]
		field[0.25,1.2;2,0.75;spread_x;]]..F(S("X Spread"))..[[;]]..sx..[[]
		field[3.25,1.2;2,0.75;spread_y;]]..F(S("Y Spread"))..[[;]]..sy..[[]
		field[6.25,1.2;2,0.75;spread_z;]]..F(S("Z Spread"))..[[;]]..sz..[[]
		field[0.25,2.4;2,0.75;octaves;]]..F(S("Octaves"))..[[;]]..octaves..[[]
		field[3.25,2.4;2,0.75;persistence;]]..F(S("Persistence"))..[[;]]..persistence..[[]
		field[6.25,2.4;2,0.75;lacunarity;]]..F(S("Lacunarity"))..[[;]]..lacunarity..[[]
		checkbox[0.25,3.55;eased;]]..F(S("eased"))..[[;]]..eased..[[]
		checkbox[3.25,3.55;absvalue;]]..F(S("absvalue"))..[[;]]..absvalue..[[]
		container_end[]

		field_close_on_enter[offset;false]
		field_close_on_enter[scale;false]
		field_close_on_enter[seed;false]
		field_close_on_enter[spread_x;false]
		field_close_on_enter[spread_y;false]
		field_close_on_enter[spread_z;false]
		field_close_on_enter[octaves;false]
		field_close_on_enter[persistence;false]
		field_close_on_enter[lacunarity;false]
		field_close_on_enter[sidelen;false]
		field_close_on_enter[pos_x;false]
		field_close_on_enter[pos_y;false]
		field_close_on_enter[pos_z;false]
		field_close_on_enter[value_min;false]
		field_close_on_enter[value_max;false]

		tooltip[set_random_seed;]]..F(S("Random seed"))..[[]
		container_end[]


		container[0.25,6.0]
		box[0,0;9.5,1.6;]]..FORMSPEC_BOX_COLOR..[[]
		box[0,0;9.5,0.4;]]..FORMSPEC_HEADER_COLOR..[[]
		label[0.15,0.2;]]..F(S("Noise options"))..[[]
		dropdown[0.25,0.7;1,0.75;dimensions;]]..F(S("2D"))..[[,]]..F(S("3D"))..[[;]]..dimensions_index..[[;true]
		field[2.25,0.7;2,0.75;sidelen;]]..F(S("Pixelization"))..[[;]]..sidelen..[[]
		tooltip[sidelen;]]..F(S("If higher than 1, Perlin values will be repeated along all axes every x nodes, for a ‘pixelized’ effect."))..[[]
		container_end[]


		container[0.25,7.85]
		box[0,0;9.5,2.9;]]..FORMSPEC_BOX_COLOR..[[]
		box[0,0;9.5,0.4;]]..FORMSPEC_HEADER_COLOR..[[]
		label[0.15,0.2;]]..F(S("Node generation"))..[[]
		field[0.25,0.75;2,0.75;value_min;]]..F(S("Min. color at"))..[[;]]..value_min..[[]
		field[2.35,0.75;2,0.75;value_max;]]..F(S("Max. color at"))..[[;]]..value_max..[[]
		field[0.25,1.95;2,0.75;pos_x;]]..F(S("X"))..[[;]]..pos_x..[[]
		field[2.35,1.95;2,0.75;pos_y;]]..F(S("Y"))..[[;]]..pos_y..[[]
		field[4.45,1.95;2,0.75;pos_z;]]..F(S("Z"))..[[;]]..pos_z..[[]
		field[6.55,1.95;2,0.75;size;]]..F(S("Size"))..[[;]]..size..[[]
		tooltip[value_min;]]..F(S("The Perlin value at which the node color gradient begins. Must be lower than 0."))..[[]
		tooltip[value_max;]]..F(S("The Perlin value at which the node color gradient ends. Must be higher than 0."))..[[]
		container_end[]


		container[0,10.95]
		button[0.5,0;3,1;apply;]]..F(S("Apply"))..[[]
		button[3.5,0;3,1;create;]]..F(S("Apply and create"))..[[]
		button_exit[6.5,0;3,1;close;]]..F(S("Close"))..[[]
		container_end[]
	]]
	minetest.show_formspec(player:get_player_name(), "perlin_explorer:creator", form)
end

minetest.register_on_player_receive_fields(function(player, formname, fields)
	if formname ~= "perlin_explorer:creator" then
		return
	end
	-- Require 'server' priv
	local privs = minetest.get_player_privs(player:get_player_name())
	if not privs.server then
		return
	end

	-- Handle checkboxes
	local name = player:get_player_name()
	local flags_touched = false
	if fields.eased == "true" then
		formspec_states[name].eased = true
		return
	elseif fields.eased == "false" then
		formspec_states[name].eased = false
		return
	end
	if fields.absvalue == "true" then
		formspec_states[name].absvalue = true
		return
	elseif fields.absvalue == "false" then
		formspec_states[name].absvalue = false
		return
	end

	-- Deleting a profile does not require any other field
	if fields.delete_np_profile then
		if #np_profiles <= 1 then
			return
		end
		local profile_to_delete = tonumber(fields.np_profiles)
		table.remove(np_profiles, profile_to_delete)
		local new_id = math.max(1, profile_to_delete - 1)
		show_formspec(player, default_noiseparams, new_id)
		return
	end
	-- Handle other fields
	local do_apply = fields.apply ~= nil
	local do_create = fields.create ~= nil or fields.key_enter_field ~= nil
	if (do_create or do_apply or fields.add_np_profile or fields.np_profiles) then
		if fields.offset and fields.scale and fields.seed and fields.spread_x and fields.spread_y and fields.spread_z and fields.octaves and fields.persistence and fields.lacunarity then

			current_perlin.loaded_areas = {}
			local offset = tonumber(fields.offset)
			local scale = tonumber(fields.scale)
			local seed = tonumber(fields.seed)
			local sx = tonumber(fields.spread_x)
			local sy = tonumber(fields.spread_y)
			local sz = tonumber(fields.spread_z)
			if not sx or not sy or not sz then
				return
			end
			local spread = vector.new(sx, sy, sz)
			local octaves = tonumber(fields.octaves)
			local persistence = tonumber(fields.persistence)
			local lacunarity = tonumber(fields.lacunarity)
			local dimensions = tonumber(fields.dimensions)
			local sidelen = tonumber(fields.sidelen)
			local px = tonumber(fields.pos_x)
			local py = tonumber(fields.pos_y)
			local pz = tonumber(fields.pos_z)
			local size = tonumber(fields.size)
			local value_min = tonumber(fields.value_min)
			local value_max = tonumber(fields.value_max)
			if (offset and scale and spread and octaves and persistence) then
				local eased = formspec_states[name].eased
				local absvalue = formspec_states[name].absvalue
				local noiseparams = {
					offset = offset,
					scale = scale,
					seed = seed,
					spread = spread,
					octaves = octaves,
					persistence = persistence,
					lacunarity = lacunarity,
					flags = build_flags_string(eased, absvalue),
				}
				-- Change NP profile selection
				if fields.load_np_profile and fields.np_profiles then
					local profile = tonumber(fields.np_profiles)
					local loaded_np = np_profiles[profile]
					-- Load new profile
					show_formspec(player, loaded_np, profile)
					minetest.log("action", "[perlin_explorer] Loaded perlin noise profile "..profile)
					return
				-- Add new profile and save current noiseparams to it
				elseif fields.add_np_profile then
					table.insert(np_profiles, noiseparams)
					local new_profile = #np_profiles
					minetest.log("action", "[perlin_explorer] Perlin noise profile "..new_profile.." added!")
					show_formspec(player, noiseparams, new_profile)
					return
				elseif fields.set_random_seed then
					-- Randomize seed
					local profile = tonumber(fields.np_profiles)
					noiseparams.seed = math.random(0, 2^32-1)
					show_formspec(player, noiseparams, profile)
					return
				end

				if not (dimensions and sidelen and size and value_min and value_max) then
					return
				end
				-- Convert dropdown index to actual dimensions number
				dimensions = dimensions + 1
				-- Spread is used differently in 2D
				if dimensions == 2 then
					spread.y = spread.z
				end
				set_perlin_noise(noiseparams)
				minetest.log("action", "[perlin_explorer] Perlin noise set!")
				current_perlin.dimensions = dimensions
				current_perlin.size = size
				current_perlin.sidelen = sidelen
				current_perlin.min = value_min
				current_perlin.max = value_max
				if do_create then
					if not px or not py or not pz then
						return
					end
					local place_pos = vector.new(px, py, pz)
					local msg = S("Creating Perlin noise, please wait …")
					minetest.chat_send_player(name, msg)
					msg = create_perlin(place_pos, {dimensions=dimensions, size=size})
					if msg then
						minetest.chat_send_player(name, msg)
					elseif msg == false then
						minetest.log("error", "[perlin_explorer] Error generating Perlin noise nodes!")
					end
				end
			end
		end
	end
end)

minetest.register_tool("perlin_explorer:creator", {
	description = S("Perlin Noise Creator"),
	_tt_help = S("Punch to open the Perlin noise creation menu"),
	inventory_image = "perlin_explorer_creator.png",
	wield_image = "perlin_explorer_creator.png",
	groups = { disable_repair = 1 },
	on_use = function(itemstack, user, pointed_thing)
		if not user then
			return
		end
		local privs = minetest.get_player_privs(user:get_player_name())
		if not privs.server then
			minetest.chat_send_player(user:get_player_name(), S("Insufficient privileges! You need the @1 privilege to use this tool.", "server"))
			return
		end
		show_formspec(user)
	end,
})

local timer = 0
minetest.register_globalstep(function(dtime)
	timer = timer + dtime
	if timer < AUTOBUILD_UPDATE_TIME then
		return
	end
	timer = 0
	if current_perlin.noise and current_perlin.auto_build then
		local player = minetest.get_player_by_name("singleplayer")
		if not player then
			return
		end
		local build = function(pos, player_name)
			if not pos or not pos.x or not pos.y or not pos.z then
				minetest.log("error", "[perlin_explorer] build(): Invalid pos!")
				return
			end
			local hash = minetest.hash_node_position(pos)
			if not current_perlin.loaded_areas[hash] then
				local msg = create_perlin(pos, {
					dimensions = current_perlin.dimensions,
					size = AUTOBUILD_SIZE,
				})
				minetest.chat_send_player(player_name, msg)
				current_perlin.loaded_areas[hash] = true
			end
		end

		local pos = vector.round(player:get_pos())
		pos = sidelen_pos(pos, AUTOBUILD_SIZE)
		local neighbors = { vector.new(0, 0, 0) }
		local c = AUTOBUILD_CHUNKDIST
		local cc = c
		if current_perlin.dimensions == 2 then
			cc = 0
		end
		for cx=-c, c do
		for cy=-cc, cc do
		for cz=-c, c do
			table.insert(neighbors, vector.new(cx, cy, cz))
		end
		end
		end
		for n=1, #neighbors do
			local offset = vector.multiply(neighbors[n], AUTOBUILD_SIZE)
			local npos = vector.add(pos, offset)
			build(npos, player:get_player_name())
		end
	end
end)

minetest.register_on_joinplayer(function(player)
	local name = player:get_player_name()
	formspec_states[name] = {
		eased = false,
	}
end)
minetest.register_on_leaveplayer(function(player)
	local name = player:get_player_name()
	formspec_states[name] = nil
end)