-- signs_lib api, backported from street_signs

local S = signs_lib.S
local FS = function(...) return minetest.formspec_escape(S(...)) end
local has_default_mod = minetest.get_modpath("default")

local function log(level, messagefmt, ...)
	minetest.log(level, "[signs_lib] " .. messagefmt:format(...))
end

local function get_sign_formspec() end

signs_lib.glow_item = "basic_materials:energy_crystal_simple"

signs_lib.lbm_restore_nodes = {}
signs_lib.old_fenceposts = {}
signs_lib.old_fenceposts_replacement_signs = {}
signs_lib.old_fenceposts_with_signs = {}

-- Settings used for a standard wood or steel wall sign
signs_lib.standard_lines = 6
signs_lib.standard_hscale = 1
signs_lib.standard_vscale = 1
signs_lib.standard_lspace = 1
signs_lib.standard_fsize = 16
signs_lib.standard_xoffs = 4
signs_lib.standard_yoffs = 0
signs_lib.standard_cpl = 35

signs_lib.standard_wood_groups = table.copy(has_default_mod and minetest.registered_items["default:sign_wall_wood"].groups or {})
signs_lib.standard_wood_groups.attached_node = nil

signs_lib.standard_steel_groups = table.copy(has_default_mod and minetest.registered_items["default:sign_wall_steel"].groups or {})
signs_lib.standard_steel_groups.attached_node = nil

signs_lib.standard_wood_sign_sounds  = table.copy(has_default_mod and minetest.registered_items["default:sign_wall_wood"].sounds or {})
signs_lib.standard_steel_sign_sounds = table.copy(has_default_mod and minetest.registered_items["default:sign_wall_steel"].sounds or {})

signs_lib.default_text_scale = {x=10, y=10}

signs_lib.old_widefont_signs = {}

signs_lib.block_list = {}
signs_lib.totalblocks = 0

signs_lib.standard_yaw = {
	0,
	math.pi / -2,
	math.pi,
	math.pi / 2,
}

signs_lib.wallmounted_yaw = {
	nil,
	nil,
	math.pi / -2,
	math.pi / 2,
	0,
	math.pi,
}

signs_lib.fdir_to_back = {
	{  0, -1 },
	{ -1,  0 },
	{  0,  1 },
	{  1,  0 },
}

signs_lib.wall_fdir_to_back = {
	nil,
	nil,
	{  0,  1 },
	{  0, -1 },
	{ -1,  0 },
	{  1,  0 },
}

signs_lib.fdir_flip_to_back = {
	[0] = {  0,  2 },
	[1] = {  2,  0 },
	[2] = {  0, -2 },
	[3] = { -2,  0 }
}

signs_lib.wall_fdir_flip_to_back = {
	[2] = {  2,  0 },
	[3] = { -2,  0 },
	[4] = {  0,  2 },
	[5] = {  0, -2 },
}

signs_lib.fdir_to_back_left = {
	[0] = { -1,  1 },
	[1] = {  1,  1 },
	[2] = {  1, -1 },
	[3] = { -1, -1 }
}

signs_lib.wall_fdir_to_back_left = {
	[2] = {  1,  1 },
	[3] = { -1, -1 },
	[4] = { -1,  1 },
	[5] = {  1, -1 }
}

signs_lib.rotate_walldir = {
	[0] = 4,
	[1] = 0,
	[2] = 5,
	[3] = 1,
	[4] = 2,
	[5] = 3
}

signs_lib.rotate_walldir_simple = {
	[0] = 4,
	[1] = 4,
	[2] = 5,
	[3] = 4,
	[4] = 2,
	[5] = 3
}

signs_lib.rotate_facedir = {
	[0] = 1,
	[1] = 2,
	[2] = 3,
	[3] = 4,
	[4] = 6,
	[5] = 6,
	[6] = 0
}

signs_lib.rotate_facedir_simple = {
	[0] = 1,
	[1] = 2,
	[2] = 3,
	[3] = 0,
	[4] = 0,
	[5] = 0
}

signs_lib.flip_facedir = {
	[0] = 2,
	[1] = 3,
	[2] = 0,
	[3] = 1,
	[4] = 6,
	[5] = 4,
	[6] = 4
}

signs_lib.flip_walldir = {
	[0] = 1,
	[1] = 0,
	[2] = 3,
	[3] = 2,
	[4] = 5,
	[5] = 4
}

-- Initialize character texture cache
local ctexcache = {}
local ctexcache_wide = {}

-- entity handling

minetest.register_entity("signs_lib:text", {
	initial_properties = {
		collisionbox = { 0, 0, 0, 0, 0, 0 },
		visual = "mesh",
		mesh = "signs_lib_standard_sign_entity_wall.obj",
		textures = {},
		static_save = true,
		backface_culling = false,
	},
	on_activate = function(self)
		local node = minetest.get_node(self.object:get_pos())
		if minetest.get_item_group(node.name, "sign") == 0 then
			self.object:remove()
		end
	end,
	on_blast = function(self, damage)
		return false, false, {}
	end,
})

function signs_lib.delete_objects(pos)
	local objects = minetest.get_objects_inside_radius(pos, 0.5)
	for _, v in ipairs(objects) do
		if v then
			local e = v:get_luaentity()
			if e and string.match(e.name, "sign.*text") then
				v:remove()
			end
		end
	end
end

function signs_lib.spawn_entity(pos, texture, glow)
	local node = minetest.get_node(pos)
	local def = minetest.registered_items[node.name]
	if not def or not def.entity_info then return end

	local text_scale = (node and node.text_scale) or signs_lib.default_text_scale
	local objects = minetest.get_objects_inside_radius(pos, 0.5)
	local obj

	if #objects > 0 then
		for _, v in ipairs(objects) do
			if v then
				local e = v:get_luaentity()
				if e and e.name == "signs_lib:text" then
					obj = v
				end
			end
		end
	end

	if not obj then
		obj = minetest.add_entity(pos, "signs_lib:text")
	end

	local yaw = def.entity_info.yaw[node.param2 + 1]
	local pitch = 0

	if not string.find(node.name, "onpole") and not string.find(node.name, "hanging") then
		local rot90 = math.pi/2

		if def.paramtype2 == "wallmounted" then
			if node.param2 == 1 then -- on floor
				pitch = -rot90
				yaw = 0
			elseif node.param2 == 0 then -- on ceiling
				pitch = rot90
				yaw = math.pi
			end
		elseif def.paramtype2 == "facedir" then
			if node.param2 == 4 then
				pitch = -rot90
				yaw = 0
			elseif node.param2 == 6 then
				pitch = rot90
				yaw = math.pi
			end
		end
	end

	if glow ~= "" then
		obj:set_properties( {glow = tonumber(glow * 5)} )
	end

	if yaw then
		obj:set_rotation({x = pitch, y = yaw, z=0})

		if not texture then
			obj:set_properties({
				mesh = def.entity_info.mesh,
				visual_size = text_scale,
			})
		else
			obj:set_properties({
				mesh = def.entity_info.mesh,
				visual_size = text_scale,
				textures={texture},
			})
		end
	end
end

function signs_lib.set_obj_text(pos, text, glow)
	local split = signs_lib.split_lines_and_words
	local text_ansi = signs_lib.Utf8ToAnsi(text)
	signs_lib.delete_objects(pos)
	-- only create sign entity for actual text
	if text_ansi and text_ansi ~= "" then
		signs_lib.spawn_entity(pos,
				signs_lib.make_sign_texture(split(text_ansi), pos), glow)
	end
end

-- rotation

function signs_lib.handle_rotation(pos, node, user, mode)
	if not signs_lib.can_modify(pos, user)
	  or mode ~= screwdriver.ROTATE_FACE then
		return false
	end
	local newparam2
	local tpos = pos
	local def = minetest.registered_items[node.name]

	if string.match(node.name, "_onpole") then
		if not string.match(node.name, "_horiz") then
			newparam2 = signs_lib.rotate_walldir_simple[node.param2] or 4
			local t = signs_lib.wall_fdir_to_back_left

			if def.paramtype2 ~= "wallmounted" then
				newparam2 = signs_lib.rotate_facedir_simple[node.param2] or 0
				t  = signs_lib.fdir_to_back_left
			end

			tpos = {
				x = pos.x + t[node.param2][1],
				y = pos.y,
				z = pos.z + t[node.param2][2]
			}
		else
			-- flip the sign to the other side of the horizontal pole
			newparam2 = signs_lib.flip_walldir[node.param2] or 4
			local t = signs_lib.wall_fdir_flip_to_back

			if def.paramtype2 ~= "wallmounted" then
				newparam2 = signs_lib.flip_facedir[node.param2] or 0
				t  = signs_lib.fdir_flip_to_back
			end

			tpos = {
				x = pos.x + t[node.param2][1],
				y = pos.y,
				z = pos.z + t[node.param2][2]
			}
		end
		local node2 = minetest.get_node(tpos)
		local def2 = minetest.registered_items[node2.name]
		if not def2 or not def2.buildable_to then return true end -- undefined, or not buildable_to.

		minetest.set_node(tpos, {name = node.name, param2 = newparam2})
		minetest.get_meta(tpos):from_table(minetest.get_meta(pos):to_table())
		minetest.remove_node(pos)
		signs_lib.delete_objects(pos)
	elseif string.match(node.name, "_hanging") or string.match(node.name, "yard") then
		minetest.swap_node(tpos, { name = node.name, param2 = signs_lib.rotate_facedir_simple[node.param2] or 0 })
	elseif minetest.registered_items[node.name].paramtype2 == "wallmounted" then
		minetest.swap_node(tpos, { name = node.name, param2 = signs_lib.rotate_walldir[node.param2] or 0 })
	else
		minetest.swap_node(tpos, { name = node.name, param2 = signs_lib.rotate_facedir[node.param2] or 0 })
	end

	signs_lib.update_sign(tpos)
	return true
end

-- infinite stacks

if not minetest.settings:get_bool("creative_mode") then
	signs_lib.expect_infinite_stacks = false
else
	signs_lib.expect_infinite_stacks = true
end

-- CONSTANTS

-- Path to the textures.
local TP = signs_lib.path .. "/textures"
-- Font file formatter
local CHAR_FILE = "%s_%02x.png"
local CHAR_FILE_WIDE = "%s_%s.png"
local UNIFONT_TEX = "signs_lib_uni%02x.png\\^[sheet\\:16x16\\:%d,%d"
-- Fonts path
local CHAR_PATH = TP .. "/" .. CHAR_FILE
local CHAR_PATH_WIDE = TP .. "/" .. CHAR_FILE_WIDE

-- Lots of overkill here. KISS advocates, go away, shoo! ;) -- kaeza

local PNG_HDR = string.char(0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A)

-- check if a file does exist
-- to avoid reopening file after checking again
-- pass TRUE as second argument
local function file_exists(name, return_handle, mode)
	mode = mode or "r";
	local f = io.open(name, mode)
	if f ~= nil then
		if (return_handle) then
			return f
		end
		io.close(f)
		return true
	else
		return false
	end
end

-- Read the image size from a PNG file.
-- Returns image_w, image_h.
-- Only the LSB is read from each field!
function signs_lib.read_image_size(filename)
	local f = file_exists(filename, true, "rb")
	-- file might not exist (don't crash the game)
	if (not f) then
		return 0, 0
	end
	f:seek("set", 0x0)
	local hdr = f:read(string.len(PNG_HDR))
	if hdr ~= PNG_HDR then
		f:close()
		return
	end
	f:seek("set", 0x13)
	local ws = f:read(1)
	f:seek("set", 0x17)
	local hs = f:read(1)
	f:close()
	return ws:byte(), hs:byte()
end

-- 4 rows, max 80 chars per, plus a bit of fudge to
-- avoid excess trimming (e.g. due to color codes)

local MAX_INPUT_CHARS = 400

-- helper functions to trim sign text input/output

local function trim_input(text)
	return text:sub(1, math.min(MAX_INPUT_CHARS, text:len()))
end

local function build_char_db(font_size)

	local cw = {}
	local cw_wide = {}

	-- To calculate average char width.
	local total_width = 0
	local char_count = 0

	for c = 32, 255 do
		local w, h = signs_lib.read_image_size(CHAR_PATH:format("signs_lib_font_"..font_size.."px", c))
		if w and h then
			local ch = string.char(c)
			cw[ch] = w
			total_width = total_width + w
			char_count = char_count + 1
		end
	end

	for i = 1, #signs_lib.wide_character_codes do
		local ch = signs_lib.wide_character_codes[i]
		local w, h = signs_lib.read_image_size(CHAR_PATH_WIDE:format("signs_lib_font_"..font_size.."px", ch))
		if w and h then
			cw_wide[ch] = w
			total_width = total_width + w
			char_count = char_count + 1
		end
	end

	local cbw, cbh = signs_lib.read_image_size(TP.."/signs_lib_color_"..font_size.."px_n.png")
	assert(cbw and cbh, "error reading bg dimensions")
	return cw, cbw, cbh, (total_width / char_count), cw_wide
end

signs_lib.charwidth16,
signs_lib.colorbgw16,
signs_lib.lineheight16,
signs_lib.avgwidth16,
signs_lib.charwidth_wide16 = build_char_db(16)

signs_lib.charwidth32,
signs_lib.colorbgw32,
signs_lib.lineheight32,
signs_lib.avgwidth32,
signs_lib.charwidth_wide32 = build_char_db(32)


-- some local helper functions

local math_max = math.max

local function fill_line(x, y, w, c, font_size, colorbgw)
	c = c or "0"
	local tex = { }
	for xx = 0, math.max(0, w), colorbgw do
		table.insert(tex, (":%d,%d=signs_lib_color_"..font_size.."px_%s.png"):format(x + xx, y, c))
	end
	return table.concat(tex)
end

-- make char texture file name
-- if texture file does not exist use fallback texture instead
local function char_tex(font_name, ch)
	if ctexcache[font_name..ch] then
		return ctexcache[font_name..ch], true
	else
		local c = ch:byte()
		local exists = file_exists(CHAR_PATH:format(font_name, c))
		local tex
		if exists and c ~= 14 then
			tex = CHAR_FILE:format(font_name, c)
		else
			tex = CHAR_FILE:format(font_name, 0x0)
		end
		ctexcache[font_name..ch] = tex
		return tex, exists
	end
end

local function char_tex_wide(font_name, ch)
	if ctexcache_wide[font_name..ch] then
		return ctexcache_wide[font_name..ch], true
	else
		local exists = file_exists(CHAR_PATH_WIDE:format(font_name, ch))
		local tex
		if exists then
			tex = CHAR_FILE_WIDE:format(font_name, ch)
		else
			tex = CHAR_FILE:format(font_name, 0x5f)
		end
		ctexcache_wide[font_name..ch] = tex
		return tex, exists
	end
end

local function make_line_texture(line, lineno, pos, line_width, line_height, cwidth_tab, font_size, colorbgw, cwidth_tab_wide, force_unicode_font)
	local width = 0
	local maxw = 0
	local font_name = "signs_lib_font_"..font_size.."px"

	local words = { }
	local node = minetest.get_node(pos)
	local def = minetest.registered_items[node.name]
	local default_color = def.default_color or 0

	local cur_color = tonumber(default_color, 16)

	-- We check which chars are available here.
	for word_i, word in ipairs(line) do
		local chars = { }
		local ch_offs = 0
		local word_l = #word
		local i = 1
		local escape = 0
		while i <= word_l  do
			local wide_type, wide_c = string.match(word:sub(i), "^&#([xu])(%x+);")
			local c = word:sub(i, i)
			local c2 = word:sub(i+1, i+1)

			if escape > 0 then escape = escape - 1 end
			if c == "^" and escape == 0 and c2:find("[1-8a-h]") then
				c = string.char(tonumber(c2,18)+0x80)
				i = i + 1
			end

			local wide_skip = 0
			if force_unicode_font then
				if wide_c then
					wide_skip = #wide_c + 3
					wide_type = "u"
				elseif c:byte() < 0x80 or c:byte() >= 0xa0 then
					wide_type = "u"
					local uchar = signs_lib.AnsiToUtf8(c)
					local code
					if #uchar == 1 then
						code = uchar:byte()
					else
						code = uchar:byte() % (2 ^ (7 - #uchar))
						for j = 1, #uchar do
							code = code * (2 ^ 6) + uchar:byte(j) - 0x80
						end
					end
					wide_c = string.format("%04x", code)
				end
			elseif wide_c then
				wide_skip = #wide_c + 3
			end

			if c == "#" and escape == 0 and c2:find("[0-9A-Fa-f#^]") then
				if c2 == "#" or c2 == "^" then
					escape = 2
				else
					i = i + 1
					cur_color = tonumber(c2, 16)
				end
			elseif wide_c then
				local w, code
				if wide_type == "x" then
					w = cwidth_tab_wide[wide_c]
				elseif wide_type == "u" and #wide_c <= 4 then
					w = font_size
					code = tonumber(wide_c, 16)
					if signs_lib.unifont_halfwidth[code] then
						w = math.floor(w / 2)
					end
				end
				if w then
					width = width + w + 1
					if width >= (line_width - cwidth_tab[" "]) then
						width = 0
					else
						maxw = math_max(width, maxw)
					end
					if #chars < MAX_INPUT_CHARS then
						local tex
						if wide_type == "u" then
							local page = math.floor(code / 256)
							local idx = code % 256
							local x = idx % 16
							local y = math.floor(idx / 16)
							tex = UNIFONT_TEX:format(page, x, y)
							if font_size == 32 then
								tex = tex .. "\\^[resize\\:32x32"
							end
						else
							tex = char_tex_wide(font_name, wide_c)
						end
						table.insert(chars, {
							off = ch_offs,
							tex = tex,
							col = ("%X"):format(cur_color),
						})
					end
					ch_offs = ch_offs + w
				end
				i = i + wide_skip
			else
				local w = cwidth_tab[c]
				if w then
					width = width + w + 1
					if width >= (line_width - cwidth_tab[" "]) then
						width = 0
					else
						maxw = math_max(width, maxw)
					end
					if #chars < MAX_INPUT_CHARS then
						table.insert(chars, {
							off = ch_offs,
							tex = char_tex(font_name, c),
							col = ("%X"):format(cur_color),
						})
					end
					ch_offs = ch_offs + w
				end
			end
			i = i + 1
		end
		width = width + cwidth_tab[" "] + 1
		maxw = math_max(width, maxw)
		table.insert(words, { chars=chars, w=ch_offs })
	end

	-- Okay, we actually build the "line texture" here.

	local texture = { }

	local start_xpos = math.floor((line_width - maxw) / 2) + def.x_offset

	local xpos = start_xpos
	local ypos = (line_height + def.line_spacing)* lineno + def.y_offset

	cur_color = nil

	for word_i, word in ipairs(words) do
		local xoffs = (xpos - start_xpos)
		if (xoffs > 0) and ((xoffs + word.w) > maxw) then
			table.insert(texture, fill_line(xpos, ypos, maxw, "n", font_size, colorbgw))
			xpos = start_xpos
			ypos = ypos + line_height + def.line_spacing
			lineno = lineno + 1
			if lineno >= def.number_of_lines then break end
			table.insert(texture, fill_line(xpos, ypos, maxw, cur_color, font_size, colorbgw))
		end
		for ch_i, ch in ipairs(word.chars) do
			if ch.col ~= cur_color then
				cur_color = ch.col
				table.insert(texture, fill_line(xpos + ch.off, ypos, maxw, cur_color, font_size, colorbgw))
			end
			table.insert(texture, (":%d,%d=%s"):format(xpos + ch.off, ypos, ch.tex))
		end
		table.insert(
			texture,
			(":%d,%d="):format(xpos + word.w, ypos) .. char_tex(font_name, " ")
		)
		xpos = xpos + word.w + cwidth_tab[" "]
		if xpos >= (line_width + cwidth_tab[" "]) then break end
	end

	table.insert(texture, fill_line(xpos, ypos, maxw, "n", font_size, colorbgw))
	table.insert(texture, fill_line(start_xpos, ypos + line_height, maxw, "n", font_size, colorbgw))

	return table.concat(texture), lineno
end

function signs_lib.make_sign_texture(lines, pos)
	local node = minetest.get_node(pos)
	local meta = minetest.get_meta(pos)

	local def = minetest.registered_items[node.name]
	if not def or not def.entity_info then return end

	local font_size
	local line_width
	local line_height
	local char_width
	local char_width_wide
	local colorbgw
	local widemult = meta:get_int("widefont") == 1 and 0.5 or 1
	local force_unicode_font = meta:get_int("unifont") == 1

	if def.font_size and (def.font_size == 32 or def.font_size == 31) then
		font_size = 32
		line_width = math.floor(signs_lib.avgwidth32 * def.chars_per_line) * (def.horiz_scaling * widemult)
		line_height = signs_lib.lineheight32
		char_width = signs_lib.charwidth32
		char_width_wide = signs_lib.charwidth_wide32
		colorbgw = signs_lib.colorbgw32
	else
		font_size = 16
		line_width = math.floor(signs_lib.avgwidth16 * def.chars_per_line) * (def.horiz_scaling * widemult)
		line_height = signs_lib.lineheight16
		char_width = signs_lib.charwidth16
		char_width_wide = signs_lib.charwidth_wide16
		colorbgw = signs_lib.colorbgw16
	end

	local texture = { ("[combine:%dx%d"):format(line_width, (line_height + def.line_spacing) * def.number_of_lines * def.vert_scaling) }

	local lineno = 0
	for i = 1, #lines do
		if lineno >= def.number_of_lines then break end
		local linetex, ln = make_line_texture(lines[i], lineno, pos, line_width, line_height, char_width, font_size, colorbgw, char_width_wide, force_unicode_font)
		table.insert(texture, linetex)
		lineno = ln + 1
	end
	table.insert(texture, "^[makealpha:0,0,0")
	return table.concat(texture, "")
end

function signs_lib.split_lines_and_words(text)
	if not text then return end
	local lines = { }
	for _, line in ipairs(text:split("\n", true)) do
		table.insert(lines, line:split(" "))
	end
	return lines
end

function signs_lib.rightclick_sign(pos, node, player, itemstack, pointed_thing)

	if not player or not signs_lib.can_modify(pos, player) then return end
	if not player.get_meta then return end

	player:get_meta():set_string("signslib:pos", minetest.pos_to_string(pos))
	minetest.show_formspec(player:get_player_name(), "signs_lib:sign", get_sign_formspec(pos, node.name))
end

function signs_lib.destruct_sign(pos)
	local meta = minetest.get_meta(pos)
	local glow = meta:get_string("glow")
	if glow ~= "" and not minetest.is_creative_enabled("") then
		local num = tonumber(glow)
		minetest.add_item(pos, ItemStack(signs_lib.glow_item .. " " .. num))
	end
	signs_lib.delete_objects(pos)
end

function signs_lib.blast_sign(pos, intensity)
	if signs_lib.can_modify(pos, "") then
		local node = minetest.get_node(pos)
		local drops = minetest.get_node_drops(node, "tnt:blast")
		minetest.remove_node(pos)
		return drops
	end
end

local function make_infotext(text)
	text = trim_input(text)
	local lines = signs_lib.split_lines_and_words(text) or {}
	local lines2 = { }
	for _, line in ipairs(lines) do
		table.insert(lines2, (table.concat(line, " "):gsub("#[0-9a-fA-F#^]", function (s)
			return s:sub(2):find("[#^]") and s:sub(2) or ""
		end)))
	end
	return table.concat(lines2, "\n")
end

function signs_lib.glow(pos, node, puncher)
	local name = puncher:get_player_name()
	if minetest.is_protected(pos, name) then
		return
	end
	local tool = puncher:get_wielded_item()
	if tool:get_name() == signs_lib.glow_item then
		local meta = minetest.get_meta(pos)
		local glow = tonumber(meta:get_string("glow"))
		if not glow then
			glow = 1
		elseif glow < 3 then
			glow = glow + 1
		else
			return -- already at brightest level
		end
		if not minetest.is_creative_enabled(name) then
			tool:take_item()
			puncher:set_wielded_item(tool)
		end
		meta:set_string("glow", glow)
	end
end

function signs_lib.update_sign(pos, fields)
	local meta = minetest.get_meta(pos)

	-- legacy udpate
	if meta:get_string("formspec") ~= "" then
		meta:set_string("formspec", "")
	end

	local text = fields and fields.text or meta:get_string("text")
	text = trim_input(text)

	local owner = meta:get_string("owner")
	local ownstr = ""
	if owner ~= "" then ownstr = S("Locked sign, owned by @1\n", owner) end

	meta:set_string("text", text)
	meta:set_string("infotext", ownstr..make_infotext(text).." ")

	local glow = meta:get_string("glow")
	signs_lib.set_obj_text(pos, text, glow)
end

function signs_lib.can_modify(pos, player)
	local meta = minetest.get_meta(pos)
	local owner = meta:get_string("owner")
	local playername
	if type(player) == "userdata" then
		playername = player:get_player_name()

	elseif type(player) == "string" then
		playername = player

	else
		playername = ""
	end

	if minetest.is_protected(pos, playername) then
		minetest.record_protection_violation(pos, playername)
		return false
	end

	if owner == ""
	  or playername == owner
	  or minetest.get_player_privs(playername)[signs_lib.edit_priv]
	  or (playername == minetest.settings:get("name")) then
		return true
	end
	minetest.record_protection_violation(pos, playername)
	return false
end

-- make selection boxes
-- sizex/sizey specified in inches because that's what MUTCD uses.

function signs_lib.make_selection_boxes(sizex, sizey, foo, xoffs, yoffs, zoffs, is_facedir)

	local tx = (sizex * 0.0254 ) / 2
	local ty = (sizey * 0.0254 ) / 2
	local xo = xoffs and xoffs * 0.0254 or 0
	local yo = yoffs and yoffs * 0.0254 or 0
	local zo = zoffs and zoffs * 0.0254 or 0

	if not is_facedir then
		return {
			type = "wallmounted",
			wall_side =   { -0.5 + zo, -ty + yo, -tx + xo, -0.4375 + zo, ty + yo, tx + xo },
			wall_top =    { -tx - xo, 0.5 + zo, -ty + yo, tx - xo, 0.4375 + zo, ty + yo},
			wall_bottom = { -tx - xo, -0.5 + zo, -ty + yo, tx - xo, -0.4375 + zo, ty + yo }
		}
	else
		return {
			type = "fixed",
			fixed = { -tx + xo, -ty + yo, 0.5 + zo, tx + xo, ty + yo, 0.4375 + zo}
		}
	end
end

function signs_lib.check_for_pole(pos, pointed_thing)
	local ppos = minetest.get_pointed_thing_position(pointed_thing)
	local pnode = minetest.get_node(ppos)
	local pdef = minetest.registered_items[pnode.name]

	if not pdef then return end

	if signs_lib.check_for_ceiling(pointed_thing) or signs_lib.check_for_floor(pointed_thing) then
		return false
	end

	if type(pdef.check_for_pole) == "function" then
		local node = minetest.get_node(pos)
		local def = minetest.registered_items[node.name]
		return pdef.check_for_pole(pos, node, def, ppos, pnode, pdef)
	elseif pdef.check_for_pole
	  or pdef.drawtype == "fencelike"
	  or string.find(pnode.name, "_post")
	  or string.find(pnode.name, "fencepost") then
		return true
	end
end

function signs_lib.check_for_horizontal_pole(pos, pointed_thing)
	local ppos = minetest.get_pointed_thing_position(pointed_thing)
	local pnode = minetest.get_node(ppos)
	local pdef = minetest.registered_items[pnode.name]

	if not pdef then return end

	if signs_lib.check_for_ceiling(pointed_thing) or signs_lib.check_for_floor(pointed_thing) then
		return false
	end

	if type(pdef.check_for_horiz_pole) == "function" then
		local node = minetest.get_node(pos)
		local def = minetest.registered_items[node.name]
		return pdef.check_for_horiz_pole(pos, node, def, ppos, pnode, pdef)
	end
end

function signs_lib.check_for_ceiling(pointed_thing)
	if pointed_thing.above.x == pointed_thing.under.x
	  and pointed_thing.above.z == pointed_thing.under.z
	  and pointed_thing.above.y < pointed_thing.under.y then
		return true
	end
end

function signs_lib.check_for_floor(pointed_thing)
	if pointed_thing.above.x == pointed_thing.under.x
	  and pointed_thing.above.z == pointed_thing.under.z
	  and pointed_thing.above.y > pointed_thing.under.y then
		return true
	end
end

function signs_lib.after_place_node(pos, placer, itemstack, pointed_thing, locked)
	local playername = placer:get_player_name()

	local controls = placer:get_player_control()

	local signname = itemstack:get_name()
	local no_wall_name = string.gsub(signname, "_wall", "")

	local def = minetest.registered_items[signname]

	if def.allow_onpole and signs_lib.check_for_pole(pos, pointed_thing) and not controls.sneak then
		local newparam2
		local lookdir = minetest.yaw_to_dir(placer:get_look_horizontal())
		if def.paramtype2 == "wallmounted" then
			newparam2 = minetest.dir_to_wallmounted(lookdir)
		else
			newparam2 = minetest.dir_to_facedir(lookdir)
		end
		minetest.swap_node(pos, {name = no_wall_name.."_onpole", param2 = newparam2})
	elseif def.allow_onpole_horizontal and signs_lib.check_for_horizontal_pole(pos, pointed_thing) and not controls.sneak then
		local newparam2
		local lookdir = minetest.yaw_to_dir(placer:get_look_horizontal())
		if def.paramtype2 == "wallmounted" then
			newparam2 = minetest.dir_to_wallmounted(lookdir)
		else
			newparam2 = minetest.dir_to_facedir(lookdir)
		end
		minetest.swap_node(pos, {name = no_wall_name.."_onpole_horiz", param2 = newparam2})
	elseif def.allow_hanging and signs_lib.check_for_ceiling(pointed_thing) and not controls.sneak then
		local newparam2 = minetest.dir_to_facedir(placer:get_look_dir())
		minetest.swap_node(pos, {name = no_wall_name.."_hanging", param2 = newparam2})
	elseif def.allow_yard and signs_lib.check_for_floor(pointed_thing) and not controls.sneak then
		local newparam2 = minetest.dir_to_facedir(placer:get_look_dir())
		minetest.swap_node(pos, {name = no_wall_name.."_yard", param2 = newparam2})
	elseif def.paramtype2 == "facedir" and signs_lib.check_for_ceiling(pointed_thing) then
		minetest.swap_node(pos, {name = signname, param2 = 6})
	elseif def.paramtype2 == "facedir" and signs_lib.check_for_floor(pointed_thing) then
		minetest.swap_node(pos, {name = signname, param2 = 4})
	end

	if locked then
		local meta = minetest.get_meta(pos)
		meta:set_string("owner", playername)
		meta:set_string("infotext", S("Locked sign, owned by @1\n", playername))
	end
end

function signs_lib.register_fence_with_sign()
	log("warning", "Attempt to call no longer used function signs_lib.register_fence_with_sign()")
end

local use_glow = function(pos, node, puncher, pointed_thing)
	if puncher then -- if e.g. a machine tries to punch; only a real person should change the lighting
		signs_lib.glow(pos, node, puncher)
	end
	return signs_lib.update_sign(pos)
end

local glow_drops = function(pos, oldnode, oldmetadata, digger)
	if digger and minetest.is_creative_enabled(digger:get_player_name()) then
		return
	end
	local glow = oldmetadata and oldmetadata.fields and oldmetadata.fields.glow
	if glow then
		minetest.add_item(pos, ItemStack(signs_lib.glow_item .. " " .. glow))
	end
end

function signs_lib.register_sign(name, raw_def)
	local def = table.copy(raw_def)
	def.is_ground_content = false

	if raw_def.entity_info == "standard" then
		def.entity_info = {
			mesh = "signs_lib_standard_sign_entity_wall.obj",
			yaw = signs_lib.wallmounted_yaw
		}
	elseif raw_def.entity_info then
		def.entity_info = raw_def.entity_info
	end

	def.after_place_node = raw_def.after_place_node or signs_lib.after_place_node
	def.on_blast         = raw_def.on_blast         or signs_lib.blast_sign

	if raw_def.entity_info then

		if def.allow_glow ~= false then
			def.on_punch        = raw_def.on_punch            or use_glow
			def.after_dig_node  = raw_def.after_dig_node      or glow_drops
		else
			def.on_punch        = raw_def.on_punch            or signs_lib.update_sign
		end

		def.on_rightclick       = raw_def.on_rightclick       or signs_lib.rightclick_sign
		def.on_destruct         = raw_def.on_destruct         or signs_lib.destruct_sign
		def.number_of_lines     = raw_def.number_of_lines     or signs_lib.standard_lines
		def.horiz_scaling       = raw_def.horiz_scaling       or signs_lib.standard_hscale
		def.vert_scaling        = raw_def.vert_scaling        or signs_lib.standard_vscale
		def.line_spacing        = raw_def.line_spacing        or signs_lib.standard_lspace
		def.font_size           = raw_def.font_size           or signs_lib.standard_fsize
		def.x_offset            = raw_def.x_offset            or signs_lib.standard_xoffs
		def.y_offset            = raw_def.y_offset            or signs_lib.standard_yoffs
		def.chars_per_line      = raw_def.chars_per_line      or signs_lib.standard_cpl
		def.default_color       = raw_def.default_color       or "0"
		if raw_def.locked and not raw_def.after_place_node then
			def.after_place_node = function(pos, placer, itemstack, pointed_thing)
				signs_lib.after_place_node(pos, placer, itemstack, pointed_thing, true)
			end
		end
	end

	def.paramtype           = raw_def.paramtype           or "light"
	def.drawtype            = raw_def.drawtype            or "mesh"
	def.mesh                = raw_def.mesh                or "signs_lib_standard_sign_wall.obj"
	def.wield_image         = raw_def.wield_image         or def.inventory_image
	def.drop                = raw_def.drop                or name
	def.sounds              = raw_def.sounds              or signs_lib.standard_wood_sign_sounds
	def.paramtype2          = raw_def.paramtype2          or "wallmounted"
	def.on_rotate           = raw_def.on_rotate           or signs_lib.handle_rotation

	if raw_def.groups then
		def.groups = raw_def.groups
	else
		def.groups = signs_lib.standard_wood_groups
	end

	-- force all signs into the sign group
	def.groups.sign = def.groups.sign or 1

	local cbox = signs_lib.make_selection_boxes(35, 25)

	def.selection_box = raw_def.selection_box or cbox
	def.node_box      = table.copy(raw_def.node_box or raw_def.selection_box or cbox)

	if def.sunlight_propagates ~= false then
		def.sunlight_propagates = true
	end

	def.tiles[3] = "signs_lib_blank.png"
	def.tiles[4] = "signs_lib_blank.png"
	def.tiles[5] = "signs_lib_blank.png"
	def.tiles[6] = "signs_lib_blank.png"

	minetest.register_node(":"..name, def)
	table.insert(signs_lib.lbm_restore_nodes, name)

	local no_wall_name = string.gsub(name, "_wall", "")

	local othermounts_def = table.copy(def)

	if raw_def.allow_onpole or raw_def.allow_onpole_horizontal then

		local offset = 0.3125
		if othermounts_def.uses_slim_pole_mount then
			offset = 0.35
		end

		othermounts_def.selection_box = raw_def.onpole_selection_box or othermounts_def.selection_box
		othermounts_def.node_box = raw_def.onpole_node_box or othermounts_def.selection_box

		if othermounts_def.paramtype2 == "wallmounted" then
			othermounts_def.node_box.wall_side[1] = def.node_box.wall_side[1] - offset
			othermounts_def.node_box.wall_side[4] = def.node_box.wall_side[4] - offset

			othermounts_def.selection_box.wall_side[1] = def.selection_box.wall_side[1] - offset
			othermounts_def.selection_box.wall_side[4] = def.selection_box.wall_side[4] - offset
		else
			othermounts_def.node_box.fixed[3] = def.node_box.fixed[3] + offset
			othermounts_def.node_box.fixed[6] = def.node_box.fixed[6] + offset

			othermounts_def.selection_box.fixed[3] = def.selection_box.fixed[3] + offset
			othermounts_def.selection_box.fixed[6] = def.selection_box.fixed[6] + offset
		end

		othermounts_def.groups.not_in_creative_inventory = 1
		othermounts_def.mesh = raw_def.onpole_mesh or string.gsub(othermounts_def.mesh, "wall.obj$", "onpole.obj")

		if othermounts_def.entity_info then
			othermounts_def.entity_info.mesh = string.gsub(othermounts_def.entity_info.mesh, "entity_wall.obj$", "entity_onpole.obj")
		end
	end

	-- setting one of item 3 or 4 to a texture and leaving the other "blank",
	-- reveals either the vertical or horizontal pole mount part of the model

	if raw_def.allow_onpole then
		othermounts_def.tiles[3] = raw_def.tiles[3] or "signs_lib_pole_mount.png"
		othermounts_def.tiles[4] = "signs_lib_blank.png"
		othermounts_def.tiles[5] = "signs_lib_blank.png"
		othermounts_def.tiles[6] = "signs_lib_blank.png"

		minetest.register_node(":"..no_wall_name.."_onpole", othermounts_def)
		table.insert(signs_lib.lbm_restore_nodes, no_wall_name.."_onpole")
	end

	if raw_def.allow_onpole_horizontal then
		local onpole_horiz_def = table.copy(othermounts_def)

		onpole_horiz_def.tiles[3] = "signs_lib_blank.png"
		onpole_horiz_def.tiles[4] = raw_def.tiles[3] or "signs_lib_pole_mount.png"
		onpole_horiz_def.tiles[5] = "signs_lib_blank.png"
		onpole_horiz_def.tiles[6] = "signs_lib_blank.png"

		minetest.register_node(":"..no_wall_name.."_onpole_horiz", onpole_horiz_def)
		table.insert(signs_lib.lbm_restore_nodes, no_wall_name.."_onpole_horiz")
	end

	if raw_def.allow_hanging then

		local hanging_def = table.copy(def)
		hanging_def.paramtype2 = "facedir"

		local hcbox = signs_lib.make_selection_boxes(35, 32, nil, 0, 3, -18.5, true)

		hanging_def.selection_box = raw_def.hanging_selection_box or hcbox
		hanging_def.node_box = raw_def.hanging_node_box or raw_def.hanging_selection_box or hcbox

		hanging_def.groups.not_in_creative_inventory = 1
		hanging_def.tiles[3] = raw_def.tiles[4] or "signs_lib_hangers.png"
		hanging_def.tiles[4] = "signs_lib_blank.png"
		hanging_def.tiles[5] = "signs_lib_blank.png"
		hanging_def.tiles[6] = "signs_lib_blank.png"

		hanging_def.mesh = raw_def.hanging_mesh or string.gsub(string.gsub(hanging_def.mesh, "wall.obj$", "hanging.obj"), "_facedir", "")

		if hanging_def.entity_info then
			hanging_def.entity_info.mesh = string.gsub(string.gsub(hanging_def.entity_info.mesh, "entity_wall.obj$", "entity_hanging.obj"), "_facedir", "")
			hanging_def.entity_info.yaw = signs_lib.standard_yaw
		end

		minetest.register_node(":"..no_wall_name.."_hanging", hanging_def)
		table.insert(signs_lib.lbm_restore_nodes, no_wall_name.."_hanging")
	end

	if raw_def.allow_yard then

		local ydef = table.copy(def)
		ydef.paramtype2 = "facedir"

		local ycbox = signs_lib.make_selection_boxes(35, 34.5, false, 0, -1.25, -19.69, true)

		ydef.selection_box = raw_def.yard_selection_box or ycbox
		ydef.tiles[3] = raw_def.tiles[5] or "default_wood.png"
		ydef.tiles[4] = "signs_lib_blank.png"
		ydef.tiles[5] = "signs_lib_blank.png"
		ydef.tiles[6] = "signs_lib_blank.png"

		ydef.node_box = raw_def.yard_node_box or raw_def.yard_selection_box or ycbox

		ydef.groups.not_in_creative_inventory = 1
		ydef.mesh = raw_def.yard_mesh or string.gsub(string.gsub(ydef.mesh, "wall.obj$", "yard.obj"), "_facedir", "")

		if ydef.entity_info then
			ydef.entity_info.mesh = string.gsub(string.gsub(ydef.entity_info.mesh, "entity_wall.obj$", "entity_yard.obj"), "_facedir", "")
			ydef.entity_info.yaw = signs_lib.standard_yaw
		end

		minetest.register_node(":"..no_wall_name.."_yard", ydef)
		table.insert(signs_lib.lbm_restore_nodes, no_wall_name.."_yard")
	end

	if raw_def.allow_widefont then
		table.insert(signs_lib.old_widefont_signs, name.."_widefont")
		table.insert(signs_lib.old_widefont_signs, name.."_widefont_onpole")
		table.insert(signs_lib.old_widefont_signs, name.."_widefont_hanging")
		table.insert(signs_lib.old_widefont_signs, name.."_widefont_yard")
	end
end

-- restore signs' text after /clearobjects and the like, the next time
-- a block is reloaded by the server.

minetest.register_lbm({
	nodenames = signs_lib.lbm_restore_nodes,
	name = "signs_lib:restore_sign_text",
	label = "Restore sign text",
	run_at_every_load = true,
	action = function(pos, node)
		signs_lib.update_sign(pos,nil,nil,node)
	end
})

-- Convert old signs on fenceposts into signs on.. um.. fence posts :P

minetest.register_lbm({
	nodenames = signs_lib.old_fenceposts_with_signs,
	name = "signs_lib:fix_fencepost_signs",
	label = "Change single-node signs on fences into normal",
	run_at_every_load = true,
	action = function(pos, node)

		local fdir = node.param2 % 8
		local signpos = {
			x = pos.x + signs_lib.fdir_to_back[fdir+1][1],
			y = pos.y,
			z = pos.z + signs_lib.fdir_to_back[fdir+1][2]
		}

		if minetest.get_node(signpos).name == "air" then
			local new_wmdir = minetest.dir_to_wallmounted(minetest.facedir_to_dir(fdir))
			local oldfence =  signs_lib.old_fenceposts[node.name]
			local newsign =   signs_lib.old_fenceposts_replacement_signs[node.name]

			signs_lib.delete_objects(pos)

			local oldmeta = minetest.get_meta(pos):to_table()
			minetest.set_node(pos, {name = oldfence})
			minetest.set_node(signpos, { name = newsign, param2 = new_wmdir })
			local newmeta = minetest.get_meta(signpos)
			newmeta:from_table(oldmeta)
			signs_lib.update_sign(signpos)
		end
	end
})

-- Convert widefont sign nodes to use one base node with meta flag to select wide mode

minetest.register_lbm({
	nodenames = signs_lib.old_widefont_signs,
	name = "signs_lib:convert_widefont_signs",
	label = "Convert widefont sign nodes",
	run_at_every_load = false,
	action = function(pos, node)
		local basename = string.gsub(node.name, "_widefont", "")
		minetest.swap_node(pos, {name = basename, param2 = node.param2})
		local meta = minetest.get_meta(pos)
		meta:set_int("widefont", 1)
		signs_lib.update_sign(pos)
	end
})

-- Maintain a list of currently-loaded blocks
minetest.register_lbm({
	nodenames = {"group:sign"},
	name = "signs_lib:update_block_list",
	label = "Update list of loaded blocks, log only those with signs",
	run_at_every_load = true,
	action = function(pos, node)
		-- yeah, yeah... I know I'm hashing a block pos, but it's still just a set of coords
		local hash = minetest.hash_node_position(vector.floor(vector.divide(pos, minetest.MAP_BLOCKSIZE)))
		if not signs_lib.block_list[hash] then
			signs_lib.block_list[hash] = true
			signs_lib.totalblocks = signs_lib.totalblocks + 1
		end
	end
})

minetest.register_chatcommand("regen_signs", {
	params = "",
	privs = {server = true},
	description = S("Skims through all currently-loaded sign-bearing mapblocks, clears away any entities within each sign's node space, and regenerates their text entities, if any."),
	func = function(player_name, params)
		local allsigns = {}
		local totalsigns = 0
		for b in pairs(signs_lib.block_list) do
			local blockpos = minetest.get_position_from_hash(b)
			local pos1 = vector.multiply(blockpos, minetest.MAP_BLOCKSIZE)
			local pos2 = vector.add(pos1, minetest.MAP_BLOCKSIZE - 1)
			if minetest.get_node_or_nil(vector.add(pos1, minetest.MAP_BLOCKSIZE/2)) then
				local signs_in_block = minetest.find_nodes_in_area(pos1, pos2, {"group:sign"})
				allsigns[#allsigns + 1] = signs_in_block
				totalsigns = totalsigns + #signs_in_block
			else
				signs_lib.block_list[b] = nil -- if the block is no longer loaded, remove it from the table
				signs_lib.totalblocks = signs_lib.totalblocks - 1
			end
		end
		if signs_lib.totalblocks < 0 then signs_lib.totalblocks = 0 end
		if totalsigns == 0 then
			minetest.chat_send_player(player_name, S("There are no signs in the currently-loaded terrain."))
			signs_lib.block_list = {}
			return
		end

		minetest.chat_send_player(player_name, S("Found a total of @1 sign nodes across @2 blocks.", totalsigns, signs_lib.totalblocks))
		minetest.chat_send_player(player_name, S("Regenerating sign entities ..."))

		for _, b in pairs(allsigns) do
			for _, pos in ipairs(b) do
				signs_lib.delete_objects(pos)
				local node = minetest.get_node(pos)
				local def = minetest.registered_items[node.name]
				if def and def.entity_info then
					signs_lib.update_sign(pos)
				end
			end
		end
		minetest.chat_send_player(player_name, S("Finished."))
	end
})

minetest.register_on_mods_loaded(function()
	if not minetest.registered_privileges[signs_lib.edit_priv] then
		minetest.register_privilege("signslib_edit", {})
	end
end)



--
-- local functions
--

function get_sign_formspec(pos, nodename)

	local meta = minetest.get_meta(pos)
	local txt = meta:get_string("text")
	local state = meta:get_int("unifont") == 1 and "on" or "off"

	local formspec = {
		"size[6,4]",
		"background[-0.5,-0.5;7,5;signs_lib_sign_bg.png]",
		"image[0.1,2.4;7,1;signs_lib_sign_color_palette.png]",
		"textarea[0.15,-0.2;6.3,2.8;text;;" .. minetest.formspec_escape(txt) .. "]",
		"button_exit[3.7,3.4;2,1;ok;" .. S("Write") .. "]",
		"label[0.3,3.4;"..FS("Unicode font").."]",
		"image_button[0.6,3.7;1,0.6;signs_lib_switch_" .. state .. ".png;uni_"
			.. state .. ";;;false;signs_lib_switch_interm.png]",
	}

	if minetest.registered_nodes[nodename].allow_widefont then
		state = meta:get_int("widefont") == 1 and "on" or "off"
		formspec[#formspec+1] = "label[2.1,3.4;"..FS("Wide font").."]"
		formspec[#formspec+1] = "image_button[2.3,3.7;1,0.6;signs_lib_switch_" .. state .. ".png;wide_"
				.. state .. ";;;false;signs_lib_switch_interm.png]"
	end

	return table.concat(formspec, "")
end


minetest.register_on_player_receive_fields(function(player, formname, fields)

	if formname ~= "signs_lib:sign" then return end

	local pos_string = player:get_meta():get_string("signslib:pos")
	local pos = minetest.string_to_pos(pos_string)
	local playername = player:get_player_name()

	if fields.text and fields.ok then
		log("action", "%s wrote %q to sign at %s",
			(playername or ""),
			fields.text:gsub("\n", "\\n"),
			pos_string
		)
		signs_lib.update_sign(pos, fields)
	elseif fields.wide_on or fields.wide_off or fields.uni_on or fields.uni_off then
		local node = minetest.get_node(pos)
		local meta = minetest.get_meta(pos)
		local change_wide
		local change_uni

		if fields.wide_on and meta:get_int("widefont") == 1 then
			meta:set_int("widefont", 0)
			change_wide = true
		elseif fields.wide_off and meta:get_int("widefont") == 0 then
			meta:set_int("widefont", 1)
			change_wide = true
		end
		if fields.uni_on and meta:get_int("unifont") == 1 then
			meta:set_int("unifont", 0)
			change_uni = true
		elseif fields.uni_off and meta:get_int("unifont") == 0 then
			meta:set_int("unifont", 1)
			change_uni = true
		end

		if change_wide then
			log("action", "%s flipped the wide-font switch to %q at %s",
				(playername or ""),
				(fields.wide_on and "off" or "on"),
				minetest.pos_to_string(pos)
			)
			signs_lib.update_sign(pos, fields)
			minetest.show_formspec(playername, "signs_lib:sign", get_sign_formspec(pos, node.name))
		end
		if change_uni then
			log("action", "%s flipped the unicode-font switch to %q at %s",
				(playername or ""),
				(fields.uni_on and "off" or "on"),
				minetest.pos_to_string(pos)
			)
			signs_lib.update_sign(pos, fields)
			minetest.show_formspec(playername, "signs_lib:sign", get_sign_formspec(pos, node.name))
		end
	end
end)