local p = {}

local Latn_pattern = table.concat {
	'[',																	-- this is a set so include opening bracket
	'\n\32-\127',															-- C0 Controls and Basic Latin			U+0020–U+007E (20 - 7E) + (U+0010 and U+007F <poem>...</poem> support)
	'\194\160-\194\172',													-- C1 Controls and Latin-1 Supplement	U+00A0-U+00AC (C2 A0 - C2 AC)
	'\195\128-\195\191',													-- (skip shy)							U+00C0–U+00FF (C3 80 - C3 BF)
	'\196\128-\197\191',													-- Latin Extended-A						U+0100–U+017F (C4 80 - C5 BF)
	'\198\128-\201\143',													-- Latin Extended-B						U+0180–U+024F (C6 80 - C9 8F)
	'\225\184\128-\225\187\191',											-- Latin Extended Additional			U+1E00-U+1EFF (E1 B8 80 - E1 BB BF)
	'\226\177\160-\226\177\191',											-- Latin Extended-C						U+2C60–U+2C7F (E2 B1 A0 - E2 B1 BF)
	'\234\156\160-\234\159\191',											-- Latin Extended-D						U+A720-U+A7FF (EA 9C A0 - EA 9F BF)
	'\234\172\176-\234\173\175',											-- Latin Extended-E						U+AB30-U+AB6F (EA AC B0 - EA AD AF)
	'\239\172\128-\239\172\134',											-- Alphabetic Presentaion Forms			U+FB00-U+FB06 (EF AC 80 - EF AC 86)
	'\239\188\129-\239\188\188',											-- Halfwidth and Fullwidth Forms		U+FF01-U+FF3C (EF BC 81 - EF BC BC)
	'–',																	-- ndash
	'—',																	-- mdash
	'«', '»',																-- guillemets commonly used in several 'Latn' languages
	']',																	-- close the set
};

local function expand_range(start, ending)
	local lower, higher = get_codepoint(start), get_codepoint(ending)
	if higher < lower then
		return nil
	end
	local chars = {}
	local i = 0
	for codepoint = lower, higher do
		i = i + 1
		chars[i] = mw.ustring.char(codepoint)
	end
	return table.concat(chars)
end

local fun = require "Module:Fun"
local m_table = require "Module:Table"

local script_to_count_mt = {
	__index = function (self, key)
		self[key] = 0
		return 0
	end,
	__call = function (self, ...)
		return setmetatable({}, self)
	end
}
setmetatable(script_to_count_mt, script_to_count_mt)

local function show_scripts(str)
	local script_to_count = script_to_count_mt()
	for codepoint in mw.ustring.gcodepoint(str) do
		local script = Unicode_data.lookup_script(codepoint)
		script_to_count[script] = script_to_count[script] + 1
	end
	return table.concat(
		fun.mapIter(
			function (count, script)
				return ("%s (%d)"):format(script, count)
			end,
			m_table.sortedPairs(
				script_to_count,
				function (script1, script2)
					return script_to_count[script1] > script_to_count[script2]
				end)),
		", ")
end

function p.show(frame)
	local expanded_pattern = Latn_pattern:gsub('%[(.-)%]', '%1'):gsub(
		'([%z\1-\127\194-\244][\128-\191]*)%-([%z\1-\127\194-\244][\128-\191]*)',
		function (char1, char2)
			local codepoint1, codepoint2 =
				mw.ustring.codepoint(char1), mw.ustring.codepoint(char2)
			return expand_range(codepoint1, codepoint2)
		end)
	
	return ("%s<br>%s"):format(expanded_pattern, show_scripts(expanded_pattern))
end

return p