-- Some global variables (don't overwrite them!)
mcl_vars = {}

minetest.log("action", "World seed = " .. minetest.get_mapgen_setting("seed"))

mcl_vars.redstone_tick = 0.1

-- GUI / inventory menu settings
mcl_vars.gui_slots = "listcolors[#9990;#FFF7;#FFF0;#000;#FFF]"

-- nonbg is added as formspec prepend in mcl_formspec_prepend
mcl_vars.gui_nonbg = table.concat({
	mcl_vars.gui_slots,
	"style_type[image_button;border=false;bgimg=mcl_inventory_button9.png;bgimg_pressed=mcl_inventory_button9_pressed.png;bgimg_middle=2,2]",
	"style_type[button;border=false;bgimg=mcl_inventory_button9.png;bgimg_pressed=mcl_inventory_button9_pressed.png;bgimg_middle=2,2]",
	"style_type[field;textcolor=#323232]",
	"style_type[label;textcolor=#323232]",
	"style_type[textarea;textcolor=#323232]",
	"style_type[checkbox;textcolor=#323232]",
})

-- Background stuff must be manually added by mods (no formspec prepend)
mcl_vars.gui_bg_color = "bgcolor[#00000000]"
mcl_vars.gui_bg_img = "background9[1,1;1,1;mcl_base_textures_background9.png;true;7]"

-- Tool wield size
mcl_vars.tool_wield_scale = vector.new(1.8, 1.8, 1)

-- Mapgen variables
local mg_name = minetest.get_mapgen_setting("mg_name")
local minecraft_height_limit = 256
local superflat = mg_name == "flat" and minetest.get_mapgen_setting("mcl_superflat_classic") == "true"
local singlenode = mg_name == "singlenode"

-- Calculate mapgen_edge_min/mapgen_edge_max
mcl_vars.chunksize = math.max(1, tonumber(minetest.get_mapgen_setting("chunksize")) or 5)
mcl_vars.MAP_BLOCKSIZE = math.max(1, minetest.MAP_BLOCKSIZE or 16)
mcl_vars.mapgen_limit = math.max(1, tonumber(minetest.get_mapgen_setting("mapgen_limit")) or 31000)
mcl_vars.MAX_MAP_GENERATION_LIMIT = math.max(1, minetest.MAX_MAP_GENERATION_LIMIT or 31000)

-- Central chunk is offset from 0,0,0 coordinates by 32 nodes (2 blocks)
-- See more in https://git.minetest.land/VoxeLibre/VoxeLibre/wiki/World-structure%3A-positions%2C-boundaries%2C-blocks%2C-chunks%2C-dimensions%2C-barriers-and-the-void
local central_chunk_offset = -math.floor(mcl_vars.chunksize / 2)

mcl_vars.central_chunk_offset_in_nodes = central_chunk_offset * mcl_vars.MAP_BLOCKSIZE
mcl_vars.chunk_size_in_nodes = mcl_vars.chunksize * mcl_vars.MAP_BLOCKSIZE

local central_chunk_min_pos = central_chunk_offset * mcl_vars.MAP_BLOCKSIZE
local central_chunk_max_pos = central_chunk_min_pos + mcl_vars.chunk_size_in_nodes - 1
local ccfmin = central_chunk_min_pos - mcl_vars.MAP_BLOCKSIZE -- Fullminp/fullmaxp of central chunk, in nodes
local ccfmax = central_chunk_max_pos + mcl_vars.MAP_BLOCKSIZE
local mapgen_limit_b = math.floor(math.min(mcl_vars.mapgen_limit, mcl_vars.MAX_MAP_GENERATION_LIMIT) /
	mcl_vars.MAP_BLOCKSIZE)
local mapgen_limit_min = -mapgen_limit_b * mcl_vars.MAP_BLOCKSIZE
local mapgen_limit_max = (mapgen_limit_b + 1) * mcl_vars.MAP_BLOCKSIZE - 1
local numcmin = math.max(math.floor((ccfmin - mapgen_limit_min) / mcl_vars.chunk_size_in_nodes), 0) -- Number of complete chunks from central chunk
local numcmax = math.max(math.floor((mapgen_limit_max - ccfmax) / mcl_vars.chunk_size_in_nodes), 0) -- fullminp/fullmaxp to effective mapgen limits.

mcl_vars.mapgen_edge_min = central_chunk_min_pos - numcmin * mcl_vars.chunk_size_in_nodes
mcl_vars.mapgen_edge_max = central_chunk_max_pos + numcmax * mcl_vars.chunk_size_in_nodes

---@param x integer
---@return integer
local function coordinate_to_block(x)
	return math.floor(x / mcl_vars.MAP_BLOCKSIZE)
end

---@param x integer
---@return integer
local function coordinate_to_chunk(x)
	return math.floor((coordinate_to_block(x) - central_chunk_offset) / mcl_vars.chunksize)
end

---@param pos Vector
---@return Vector
function mcl_vars.pos_to_block(pos)
	return vector.new(
		coordinate_to_block(pos.x),
		coordinate_to_block(pos.y),
		coordinate_to_block(pos.z)
	)
end

---@param pos Vector
---@return Vector
function mcl_vars.pos_to_chunk(pos)
	return vector.new(
		coordinate_to_chunk(pos.x),
		coordinate_to_chunk(pos.y),
		coordinate_to_chunk(pos.z)
	)
end

local k_positive = math.ceil(mcl_vars.MAX_MAP_GENERATION_LIMIT / mcl_vars.chunk_size_in_nodes)
local k_positive_z = k_positive * 2
local k_positive_y = k_positive_z * k_positive_z

---@param pos Vector
---@return integer
function mcl_vars.get_chunk_number(pos) -- unsigned int
	local c = mcl_vars.pos_to_chunk(pos)
	return (c.y + k_positive) * k_positive_y +
		(c.z + k_positive) * k_positive_z +
		c.x + k_positive
end

if not superflat and not singlenode then
	-- Normal mode
	--[[ Realm stacking (h is for height)
	- Overworld (h>=256)
	- Void (h>=1000)
	- Realm Barrier (h=11), to allow escaping the End
	- End (h>=256)
	- Void (h>=1000)
	- Nether (h=128)
	- Void (h>=1000)
	]]

	-- Overworld
	mcl_vars.mg_overworld_min = -62
	mcl_vars.mg_overworld_max_official = mcl_vars.mg_overworld_min + minecraft_height_limit
	mcl_vars.mg_bedrock_overworld_min = mcl_vars.mg_overworld_min
	mcl_vars.mg_bedrock_overworld_max = mcl_vars.mg_bedrock_overworld_min + 4
	mcl_vars.mg_lava_overworld_max = mcl_vars.mg_overworld_min + 10
	mcl_vars.mg_lava = true
	mcl_vars.mg_bedrock_is_rough = true

elseif singlenode then
	mcl_vars.mg_overworld_min = -66
	mcl_vars.mg_overworld_max_official = mcl_vars.mg_overworld_min + minecraft_height_limit
	mcl_vars.mg_bedrock_overworld_min = mcl_vars.mg_overworld_min
	mcl_vars.mg_bedrock_overworld_max = mcl_vars.mg_bedrock_overworld_min
	mcl_vars.mg_lava = false
	mcl_vars.mg_lava_overworld_max = mcl_vars.mg_overworld_min
	mcl_vars.mg_bedrock_is_rough = false
else
	-- Classic superflat
	local ground = tonumber(minetest.get_mapgen_setting("mgflat_ground_level")) or 8

	mcl_vars.mg_overworld_min = ground - 3
	mcl_vars.mg_overworld_max_official = mcl_vars.mg_overworld_min + minecraft_height_limit
	mcl_vars.mg_bedrock_overworld_min = mcl_vars.mg_overworld_min
	mcl_vars.mg_bedrock_overworld_max = mcl_vars.mg_bedrock_overworld_min
	mcl_vars.mg_lava = false
	mcl_vars.mg_lava_overworld_max = mcl_vars.mg_overworld_min
	mcl_vars.mg_bedrock_is_rough = false
end

mcl_vars.mg_overworld_max = mcl_vars.mapgen_edge_max

-- The Nether (around Y = -29000)
mcl_vars.mg_nether_min = -29067 -- Carefully chosen to be at a mapchunk border
mcl_vars.mg_nether_max = mcl_vars.mg_nether_min + 128
mcl_vars.mg_bedrock_nether_bottom_min = mcl_vars.mg_nether_min
mcl_vars.mg_bedrock_nether_top_max = mcl_vars.mg_nether_max
mcl_vars.mg_nether_deco_max = mcl_vars.mg_nether_max -11 -- this is so ceiling decorations don't spill into other biomes as bedrock generation calls minetest.generate_decorations to put netherrack under the bedrock
if not superflat then
	mcl_vars.mg_bedrock_nether_bottom_max = mcl_vars.mg_bedrock_nether_bottom_min + 4
	mcl_vars.mg_bedrock_nether_top_min = mcl_vars.mg_bedrock_nether_top_max - 4
	mcl_vars.mg_lava_nether_max = mcl_vars.mg_nether_min + 31
else
	-- Thin bedrock in classic superflat mapgen
	mcl_vars.mg_bedrock_nether_bottom_max = mcl_vars.mg_bedrock_nether_bottom_min
	mcl_vars.mg_bedrock_nether_top_min = mcl_vars.mg_bedrock_nether_top_max
	mcl_vars.mg_lava_nether_max = mcl_vars.mg_nether_min + 2
end
if mg_name == "flat" then
	if superflat then
		mcl_vars.mg_flat_nether_floor = mcl_vars.mg_bedrock_nether_bottom_max + 4
		mcl_vars.mg_flat_nether_ceiling = mcl_vars.mg_bedrock_nether_bottom_max + 52
	else
		mcl_vars.mg_flat_nether_floor = mcl_vars.mg_lava_nether_max + 4
		mcl_vars.mg_flat_nether_ceiling = mcl_vars.mg_lava_nether_max + 52
	end
end

-- The End (surface at ca. Y = -27000)
mcl_vars.mg_end_min = -27073 -- Carefully chosen to be at a mapchunk border
mcl_vars.mg_end_max_official = mcl_vars.mg_end_min + minecraft_height_limit
mcl_vars.mg_end_max = mcl_vars.mg_overworld_min - 2000
mcl_vars.mg_end_platform_pos = { x = 100, y = mcl_vars.mg_end_min + 64, z = 0 }
mcl_vars.mg_end_exit_portal_pos = vector.new(0, mcl_vars.mg_end_min + 71, 0)

-- Realm barrier used to safely separate the End from the void below the Overworld
mcl_vars.mg_realm_barrier_overworld_end_max = mcl_vars.mg_end_max
mcl_vars.mg_realm_barrier_overworld_end_min = mcl_vars.mg_end_max - 11

-- Use VoxeLibre-style dungeons
mcl_vars.mg_dungeons = true

-- Set default stack sizes
minetest.nodedef_default.stack_max = 64
minetest.craftitemdef_default.stack_max = 64

-- Set random seed for all other mods (Remember to make sure no other mod calls this function)
math.randomseed(os.time())

local chunks = {} -- intervals of chunks generated

---@param pos Vector
function mcl_vars.add_chunk(pos)
	local n = mcl_vars.get_chunk_number(pos) -- unsigned int
	local prev
	for i, d in pairs(chunks) do
		if n <= d[2] then -- we've found it
			if (n == d[2]) or (n >= d[1]) then return end -- already here
			if n == d[1] - 1 then -- right before:
				if prev and (prev[2] == n - 1) then
					prev[2] = d[2]
					table.remove(chunks, i)
					return
				end
				d[1] = n
				return
			end
			if prev and (prev[2] == n - 1) then --join to previous
				prev[2] = n
				return
			end
			table.insert(chunks, i, { n, n }) -- insert new interval before i
			return
		end
		prev = d
	end
	chunks[#chunks + 1] = { n, n }
end

---@param pos Vector
---@return boolean
function mcl_vars.is_generated(pos)
	local n = mcl_vars.get_chunk_number(pos) -- unsigned int
	for i, d in pairs(chunks) do
		if n <= d[2] then
			return (n >= d[1])
		end
	end
	return false
end

---"Trivial" (actually NOT) function to just read the node and some stuff to not just return "ignore", like mt 5.4 does.
---@param pos Vector Position, if it's wrong, `{name="error"}` node will return.
---@param force? boolean Optional (default: `false`), Do the maximum to still read the node within us_timeout.
---@param us_timeout? number Optional (default: `244 = 0.000244 s = 1/80/80/80`), set it at least to `3000000` to let mapgen to finish its job
---@return node # Node definition, eg. `{name="air"}`. Unfortunately still can return `{name="ignore"}`.
---@nodiscard
function mcl_vars.get_node(pos, force, us_timeout)
	-- check initial circumstances
	if not pos or not pos.x or not pos.y or not pos.z then return { name = "error" } end

	-- try common way
	local node = minetest.get_node(pos)
	if node.name ~= "ignore" then
		return node
	end

	-- copy vector to get sure it won't changed by other threads
	local pos_copy = vector.copy(pos)

	-- try LVM
	minetest.get_voxel_manip():read_from_map(pos_copy, pos_copy)
	node = minetest.get_node(pos_copy)
	if node.name ~= "ignore" or not force then
		return node
	end

	-- all ways failed - need to emerge (or forceload if generated)
	if mcl_vars.is_generated(pos_copy) then
		minetest.chat_send_all("IMPOSSIBLE! Please report this to MCL2 issue tracker!")
		minetest.forceload_block(pos_copy)
	else
		minetest.emerge_area(pos_copy, pos_copy)
	end

	local t = minetest.get_us_time()

	node = minetest.get_node(pos_copy)

	while (not node or node.name == "ignore") and (minetest.get_us_time() - t < (us_timeout or 244)) do
		node = minetest.get_node(pos_copy)
	end

	return node
	-- it still can return "ignore", LOL, even if force = true, but only after time out
end
