local modname = minetest.get_current_modname()
local modpath = minetest.get_modpath(modname)
local S = minetest.get_translator(modname)
local F = minetest.formspec_escape

local table = table

-- Load the characters map (characters.txt)
--[[ File format of characters.txt:
It's an UTF-8 encoded text file that contains metadata for all supported characters. It contains a sequence of info blocks, one for each character. Each info block is made out of 3 lines:
Line 1: The literal UTF-8 encoded character
Line 2: Name of the texture file for this character minus the “.png” suffix; found in the “textures/” sub-directory
Line 3: Currently ignored. Previously this was for the character width in pixels

After line 3, another info block may follow. This repeats until the end of the file.

All character files must be 5 or 6 pixels wide (5 pixels are preferred)
]]

local chars_file = io.open(modpath.."/characters.txt", "r")
-- FIXME: Support more characters (many characters are missing). Currently ASCII and Latin-1 Supplement are supported.
local charmap = {}
if not chars_file then
	minetest.log("error", "[mcl_signs] : character map file not found")
else
	while true do
		local char = chars_file:read("*l")
		if char == nil then
			break
		end
		local img = chars_file:read("*l")
		chars_file:read("*l")
		charmap[char] = img
	end
end

-- CONSTANTS
local SIGN_WIDTH = 115

local LINE_LENGTH = 15
local NUMBER_OF_LINES = 4

local LINE_HEIGHT = 14
local CHAR_WIDTH = 5


-- Helper functions
local function round(num, idp)
	local mult = 10^(idp or 0)
	return math.floor(num * mult + 0.5) / mult
end

local function string_to_array(str)
	local tab = {}
	for i=1,string.len(str) do
		table.insert(tab, string.sub(str, i,i))
	end
	return tab
end

local function string_to_line_array(str)
	local tab = {}
	local current = 1
	local linechar = 1
	tab[1] = ""
	for _,char in ipairs(string_to_array(str)) do
		-- New line
		if char == "\n" then
			current = current + 1
			tab[current] = ""
			linechar = 1
		else
			tab[current] = tab[current]..char
			linechar = linechar + 1
		end
	end
	return tab
end

local function create_lines(text)
	local line_num = 1
	local tab = {}
	for _, line in ipairs(string_to_line_array(text)) do
		if line_num > NUMBER_OF_LINES then
			break
		end
		table.insert(tab, line)
		line_num = line_num + 1
	end
	return tab
end

local function generate_line(s, ypos)
	local i = 1
	local parsed = {}
	local width = 0
	local chars = 0
	local printed_char_width = CHAR_WIDTH + 1
	while chars < LINE_LENGTH and i <= #s do
		local file
		-- Get and render character
		if charmap[s:sub(i, i)] then
			file = charmap[s:sub(i, i)]
			i = i + 1
		elseif i < #s and charmap[s:sub(i, i + 1)] then
			file = charmap[s:sub(i, i + 1)]
			i = i + 2
		else
			-- No character image found.
			-- Use replacement character:
			file = "_rc"
			i = i + 1
			minetest.log("verbose", "[mcl_signs] Unknown symbol in '"..s.."' at "..i)
		end
		if file then
			width = width + printed_char_width
			table.insert(parsed, file)
			chars = chars + 1
		end
	end
	width = width - 1

	local texture = ""
	local xpos = math.floor((SIGN_WIDTH - width) / 2)
	for i = 1, #parsed do
		texture = texture..":"..xpos..","..ypos.."="..parsed[i]..".png"
		xpos = xpos + printed_char_width
	end
	return texture
end

local function generate_texture(lines, signnodename)
	local texture = "[combine:"..SIGN_WIDTH.."x"..SIGN_WIDTH
	local ypos
	if signnodename == "mcl_signs:wall_sign" then
		ypos = 30
	else
		ypos = 0
	end
	for i = 1, #lines do
		texture = texture..generate_line(lines[i], ypos)
		ypos = ypos + LINE_HEIGHT
	end
	return texture
end

local n = 23/56 - 1/128

local signtext_info_wall = {
	{delta = {x = 0, y = 0, z = n}, yaw = 0},
	{delta = {x = n, y = 0, z = 0}, yaw = math.pi / -2},
	{delta = {x = 0, y = 0, z = -n}, yaw = math.pi},
	{delta = {x = -n, y = 0, z = 0}, yaw = math.pi / 2},
}

local signtext_info_standing = {}

local m = -1/16 + 1/64

for rot=0, 15 do
	local yaw = math.pi*2 - (((math.pi*2) / 16) * rot)
	local delta = vector.multiply(minetest.yaw_to_dir(yaw), m)
	-- Offset because sign is a bit above node boundaries
	delta.y = delta.y + 2/28
	table.insert(signtext_info_standing, { delta = delta, yaw = yaw })
end

local function get_rotation_level(facedir, nodename)
	local rl = facedir * 4
	if nodename == "mcl_signs:standing_sign22_5" then
		rl = rl + 1
	elseif nodename == "mcl_signs:standing_sign45" then
		rl = rl + 2
	elseif nodename == "mcl_signs:standing_sign67_5" then
		rl = rl + 3
	end
	return rl
end

local function get_wall_signtext_info(param2, nodename)
	local dir = minetest.wallmounted_to_dir(param2)
	if dir.x > 0 then
		return 2
	elseif dir.z > 0 then
		return 1
	elseif dir.x < 0 then
		return 4
	else
		return 3
	end
end

local sign_groups = {handy=1,axey=1, deco_block=1, material_wood=1, attached_node=1, dig_by_piston=1, flammable=-1}

local function destruct_sign(pos)
	local objects = minetest.get_objects_inside_radius(pos, 0.5)
	for _, v in ipairs(objects) do
		local ent = v:get_luaentity()
		if ent and ent.name == "mcl_signs:text" then
			v:remove()
		end
	end
	local players = minetest.get_connected_players()
	for p=1, #players do
		if vector.distance(players[p]:get_pos(), pos) <= 30 then
			minetest.close_formspec(players[p]:get_player_name(), "mcl_signs:set_text_"..pos.x.."_"..pos.y.."_"..pos.z)
		end
	end
end

local function update_sign(pos, fields, sender, force_remove)
	local meta = minetest.get_meta(pos)
	if not meta then
		return
	end
	local text = meta:get_string("text")
	if fields and (text == "" and fields.text) then
		meta:set_string("text", fields.text)
		text = fields.text
	end
	if text == nil then
		text = ""
	end

	local sign_info
	local n = minetest.get_node(pos)
	local nn = n.name
	if nn == "mcl_signs:standing_sign" or nn == "mcl_signs:standing_sign22_5" or nn == "mcl_signs:standing_sign45" or nn == "mcl_signs:standing_sign67_5" then
		sign_info = signtext_info_standing[get_rotation_level(n.param2, nn) + 1]
	elseif nn == "mcl_signs:wall_sign" then
		sign_info = signtext_info_wall[get_wall_signtext_info(n.param2)]
	end
	if sign_info == nil then
		minetest.log("error", "[mcl_signs] Missing sign_info!")
		return
	end

	local objects = minetest.get_objects_inside_radius(pos, 0.5)
	local text_entity
	for _, v in ipairs(objects) do
		local ent = v:get_luaentity()
		if ent and ent.name == "mcl_signs:text" then
			if force_remove then
				v:remove()
			else
				text_entity = v
				break
			end
		end
	end

	if not text_entity then
		text_entity = minetest.add_entity({
			x = pos.x + sign_info.delta.x,
			y = pos.y + sign_info.delta.y,
			z = pos.z + sign_info.delta.z}, "mcl_signs:text")
	end
	text_entity:get_luaentity()._signnodename = nn
	text_entity:set_properties({textures={generate_texture(create_lines(text), nn)}})

	text_entity:set_yaw(sign_info.yaw)
end

local function show_formspec(player, pos)
	minetest.show_formspec(
		player:get_player_name(),
		"mcl_signs:set_text_"..pos.x.."_"..pos.y.."_"..pos.z,
		"size[6,3]textarea[0.25,0.25;6,1.5;text;"..F(S("Enter sign text:"))..";]label[0,1.5;"..F(S("Maximum line length: 15")).."\n"..F(S("Maximum lines: 4")).."]button_exit[0,2.5;6,1;submit;"..F(S("Done")).."]"
	)
end

minetest.register_on_player_receive_fields(function(player, formname, fields)
	if formname:find("mcl_signs:set_text_") == 1 then
		local x, y, z = formname:match("mcl_signs:set_text_(.-)_(.-)_(.*)")
		local pos = {x=tonumber(x), y=tonumber(y), z=tonumber(z)}
		if not pos or not pos.x or not pos.y or not pos.z then return end
		update_sign(pos, fields, player)
	end
end)

local node_sounds
if minetest.get_modpath("mcl_sounds") then
	node_sounds = mcl_sounds.node_sound_wood_defaults()
end

minetest.register_node("mcl_signs:wall_sign", {
	description = S("Sign"),
	_tt_help = S("Can be written"),
	_doc_items_longdesc = S("Signs can be written and come in two variants: Wall sign and sign on a sign post. Signs can be placed on the top and the sides of other blocks, but not below them."),
	_doc_items_usagehelp = S("After placing the sign, you can write something on it. You have 4 lines of text with up to 15 characters for each line; anything beyond these limits is lost. Not all characters are supported. The text can not be changed once it has been written; you have to break and place the sign again."),
	inventory_image = "default_sign.png",
	walkable = false,
	is_ground_content = false,
	wield_image = "default_sign.png",
	node_placement_prediction = "",
	paramtype = "light",
	sunlight_propagates = true,
	paramtype2 = "wallmounted",
	drawtype = "mesh",
	mesh = "mcl_signs_signonwallmount.obj",
	selection_box = {type = "wallmounted", wall_side = {-0.5, -7/28, -0.5, -23/56, 7/28, 0.5}},
	tiles = {"mcl_signs_sign.png"},
	use_texture_alpha = minetest.features.use_texture_alpha_string_modes and "opaque" or false,
	groups = sign_groups,
	stack_max = 16,
	sounds = node_sounds,

	on_place = function(itemstack, placer, pointed_thing)
		local above = pointed_thing.above
		local under = pointed_thing.under

		-- Use pointed node's on_rightclick function first, if present
		local node_under = minetest.get_node(under)
		if placer and not placer:get_player_control().sneak then
			if minetest.registered_nodes[node_under.name] and minetest.registered_nodes[node_under.name].on_rightclick then
				return minetest.registered_nodes[node_under.name].on_rightclick(under, node_under, placer, itemstack) or itemstack
			end
		end

		local dir = vector.subtract(under, above)

		-- Only build when it's legal
		local abovenodedef = minetest.registered_nodes[minetest.get_node(above).name]
		if not abovenodedef or abovenodedef.buildable_to == false then
			return itemstack
		end

		local wdir = minetest.dir_to_wallmounted(dir)

		--local placer_pos = placer:get_pos()

		local fdir = minetest.dir_to_facedir(dir)

		local sign_info
		local nodeitem = ItemStack(itemstack)
		-- Ceiling
		if wdir == 0 then
			--how would you add sign to ceiling?
			return itemstack
		-- Floor
		elseif wdir == 1 then
			-- Standing sign

			-- Determine the sign rotation based on player's yaw
			local yaw = math.pi*2 - placer:get_look_horizontal()

			-- Select one of 16 possible rotations (0-15)
			local rotation_level = round((yaw / (math.pi*2)) * 16)

			if rotation_level > 15 then
				rotation_level = 0
			elseif rotation_level < 0 then
				rotation_level = 15
			end

			-- The actual rotation is a combination of predefined mesh and facedir (see node definition)
			if rotation_level % 4 == 0 then
				nodeitem:set_name("mcl_signs:standing_sign")
			elseif rotation_level % 4 == 1 then
				nodeitem:set_name("mcl_signs:standing_sign22_5")
			elseif rotation_level % 4 == 2 then
				nodeitem:set_name("mcl_signs:standing_sign45")
			elseif rotation_level % 4 == 3 then
				nodeitem:set_name("mcl_signs:standing_sign67_5")
			end
			fdir = math.floor(rotation_level / 4)

			-- Place the node!
			local _, success = minetest.item_place_node(nodeitem, placer, pointed_thing, fdir)
			if not success then
				return itemstack
			end
			if not minetest.is_creative_enabled(placer:get_player_name()) then
				itemstack:take_item()
			end
			sign_info = signtext_info_standing[rotation_level + 1]
		-- Side
		else
			-- Wall sign
			local _, success = minetest.item_place_node(itemstack, placer, pointed_thing, wdir)
			if not success then
				return itemstack
			end
			sign_info = signtext_info_wall[fdir + 1]
		end

		-- Determine spawn position of entity
		local place_pos
		if minetest.registered_nodes[node_under.name].buildable_to then
			place_pos = under
		else
			place_pos = above
		end

		local text_entity = minetest.add_entity({
			x = place_pos.x + sign_info.delta.x,
			y = place_pos.y + sign_info.delta.y,
			z = place_pos.z + sign_info.delta.z}, "mcl_signs:text")
		text_entity:set_yaw(sign_info.yaw)
		text_entity:get_luaentity()._signnodename = nodeitem:get_name()

		minetest.sound_play({name="default_place_node_hard", gain=1.0}, {pos = place_pos}, true)

		show_formspec(placer, place_pos)
		return itemstack
	end,
	on_destruct = destruct_sign,
	on_punch = function(pos, node, puncher)
		update_sign(pos)
	end,
	on_rotate = function(pos, node, user, mode)
		if mode == screwdriver.ROTATE_FACE then
			local r = screwdriver.rotate.wallmounted(pos, node, mode)
			node.param2 = r
			minetest.swap_node(pos, node)
			update_sign(pos, nil, nil, true)
			return true
		else
			return false
		end
	end,
	_mcl_hardness = 1,
	_mcl_blast_resistance = 1,
})

-- Standing sign nodes.
-- 4 rotations at 0°, 22.5°, 45° and 67.5°.
-- These are 4 out of 16 possible rotations.
-- With facedir the remaining 12 rotations are constructed.

-- 0°
local ssign = {
	paramtype = "light",
	use_texture_alpha = minetest.features.use_texture_alpha_string_modes and "opaque" or false,
	sunlight_propagates = true,
	walkable = false,
	is_ground_content = false,
	paramtype2 = "facedir",
	drawtype = "mesh",
	mesh = "mcl_signs_sign.obj",
	selection_box = {type = "fixed", fixed = {-0.2, -0.5, -0.2, 0.2, 0.5, 0.2}},
	tiles = {"mcl_signs_sign.png"},
	groups = sign_groups,
	drop = "mcl_signs:wall_sign",
	stack_max = 16,
	sounds = node_sounds,

	on_destruct = destruct_sign,
	on_punch = function(pos, node, puncher)
		update_sign(pos)
	end,
	on_rotate = function(pos, node, user, mode)
		if mode == screwdriver.ROTATE_FACE then
			node.name = "mcl_signs:standing_sign22_5"
			minetest.swap_node(pos, node)
		elseif mode == screwdriver.ROTATE_AXIS then
			return false
		end
		update_sign(pos, nil, nil, true)
		return true
	end,

	_mcl_hardness = 1,
	_mcl_blast_resistance = 1,
}

minetest.register_node("mcl_signs:standing_sign", ssign)

-- 22.5°
local ssign22_5 = table.copy(ssign)
ssign22_5.mesh = "mcl_signs_sign22.5.obj"
ssign22_5.on_rotate = function(pos, node, user, mode)
	if mode == screwdriver.ROTATE_FACE then
		node.name = "mcl_signs:standing_sign45"
		minetest.swap_node(pos, node)
	elseif mode == screwdriver.ROTATE_AXIS then
		return false
	end
	update_sign(pos, nil, nil, true)
	return true
end
minetest.register_node("mcl_signs:standing_sign22_5", ssign22_5)

-- 45°
local ssign45 = table.copy(ssign)
ssign45.mesh = "mcl_signs_sign45.obj"
ssign45.on_rotate = function(pos, node, user, mode)
	if mode == screwdriver.ROTATE_FACE then
		node.name = "mcl_signs:standing_sign67_5"
		minetest.swap_node(pos, node)
	elseif mode == screwdriver.ROTATE_AXIS then
		return false
	end
	update_sign(pos, nil, nil, true)
	return true
end
minetest.register_node("mcl_signs:standing_sign45", ssign45)

-- 67.5°
local ssign67_5 = table.copy(ssign)
ssign67_5.mesh = "mcl_signs_sign67.5.obj"
ssign67_5.on_rotate = function(pos, node, user, mode)
	if mode == screwdriver.ROTATE_FACE then
		node.name = "mcl_signs:standing_sign"
		node.param2 = (node.param2 + 1) % 4
		minetest.swap_node(pos, node)
	elseif mode == screwdriver.ROTATE_AXIS then
		return false
	end
	update_sign(pos, nil, nil, true)
	return true
end
minetest.register_node("mcl_signs:standing_sign67_5", ssign67_5)

-- FIXME: Prevent entity destruction by /clearobjects
minetest.register_entity("mcl_signs:text", {
	pointable = false,
	visual = "upright_sprite",
	textures = {},
	physical = false,
	collide_with_objects = false,

	_signnodename = nil, -- node name of sign node to which the text belongs

	on_activate = function(self, staticdata)
		if staticdata and staticdata ~= "" then
			local des = minetest.deserialize(staticdata)
			if des then
				self._signnodename = des._signnodename
			end
		end
		local meta = minetest.get_meta(self.object:get_pos())
		local text = meta:get_string("text")
		self.object:set_properties({
			textures={generate_texture(create_lines(text), self._signnodename)},
		})
		self.object:set_armor_groups({ immortal = 1 })
	end,
	get_staticdata = function(self)
		local out = { _signnodename = self._signnodename }
		return minetest.serialize(out)
	end,
})

minetest.register_craft({
	type = "fuel",
	recipe = "mcl_signs:wall_sign",
	burntime = 10,
})

if minetest.get_modpath("mcl_core") then
	minetest.register_craft({
		output = "mcl_signs:wall_sign 3",
		recipe = {
			{"group:wood", "group:wood", "group:wood"},
			{"group:wood", "group:wood", "group:wood"},
			{"", "mcl_core:stick", ""},
		}
	})
end

if minetest.get_modpath("doc") then
	doc.add_entry_alias("nodes", "mcl_signs:wall_sign", "nodes", "mcl_signs:standing_sign")
	doc.add_entry_alias("nodes", "mcl_signs:wall_sign", "nodes", "mcl_signs:standing_sign22_5")
	doc.add_entry_alias("nodes", "mcl_signs:wall_sign", "nodes", "mcl_signs:standing_sign45")
	doc.add_entry_alias("nodes", "mcl_signs:wall_sign", "nodes", "mcl_signs:standing_sign67_5")
end

minetest.register_alias("signs:sign_wall", "mcl_signs:wall_sign")
minetest.register_alias("signs:sign_yard", "mcl_signs:standing_sign")

minetest.register_lbm({
	name = "mcl_signs:respawn_entities",
	label = "Respawn sign text entities",
	run_at_every_load = true,
	nodenames = { "mcl_signs:wall_sign", "mcl_signs:standing_sign", "mcl_signs:standing_sign22_5", "mcl_signs:standing_sign45", "mcl_signs:standing_sign67_5" },
	action = function(pos, node)
		update_sign(pos)
	end,
})
