local p = {}

local words = mw.loadData('Module:A or an/words')



local lcVChars = 'aeiouà-æè-ïò-öø-üāăąēĕėęěĩīĭįıijōŏőœũūŭůűų'

local ucVvChars = 'AEFHILMNORSXÀ-ÆÈ-ÏÒ-ÖØĀĂĄĒĔĖĘĚĨĪĬĮıIJŌŎŐŒÑĤĦĹĻĽĿŁŃŅŇŊŔŖŘŚŜŞ'



local article = {

	a = "a",

	an = "an",

}



local function findWord(text, array)

	for _, v in ipairs(array) do

		if mw.ustring.find(text, '^' .. v .. '$') then

			return true

		end

	end

end



local function get_article_from_acronym(text)

	if mw.ustring.find(text, '^[' .. ucVvChars .. ']')

		and not findWord(text, words.cvAcronyms) -- Exclude 'NASA' etc.

		or findWord(text, words.vvAcronyms) -- 'UNRWA' etc.

	then

		return article.an

	end

	return article.a

end



local function get_article_from_number_word(text)

	text = mw.ustring.match(text, '^[0-9]+') -- Extract the number

	if findWord(text, words.vNums) then -- '18' etc.

		return article.an

	end

	return article.a

end



local function clean_text(text)

	text = mw.ustring.gsub(text, '</?[A-Za-z][^>]->', '') -- Remove HTML tags

	text = mw.ustring.gsub(text, '%[%[[^%|]+%|(..-)%]%]', '%1') -- Remove wikilinks

	text = mw.ustring.gsub(mw.ustring.gsub(text, '%[%[', ''), '%]%]', '')

	text = mw.ustring.gsub(text, '^["%$\'%(<%[%{¢-¥₠-₿]+', '') -- Strip some symbols at the beginning

	text = mw.ustring.match(text, '^%.?[0-9%u%l]+') or text -- Extract the first word

	return text

end



function p._main(args)

	local original_text = args1 and mw.text.trim(args1])

	local text = original_text

	local article = article.a

	local ret = ''



	if text and text ~= '' then

		text = clean_text(text)



		if mw.ustring.find(text, '^[0-9]') then -- It begins with a number

			article = get_article_from_number_word(text)

		elseif mw.ustring.match(text, '^[0-9%u]+$') then -- It looks like an acronym

			article = get_article_from_acronym(text)

		else

			text = mw.ustring.lower(text) -- Uncapitalize

			if mw.ustring.find(text, '^['.. lcVChars .. ']') then -- It begins with a vowel

				if not findWord(text, words.vcWords) -- Exclude 'euro' etc.

					or findWord(text, words.vvWords) -- But not 'Euler' etc.

				then

					article = article.an

				end

			elseif args.variety and mw.ustring.lower(args.variety) == 'us' -- 'herb' etc.

				and findWord(text, words.cvWordsUS)

				or findWord(text, words.cvWords) -- 'hour' etc.

			then

				article = article.an

			end

		end

		ret = article .. ' ' .. original_text

	end

	

	return ret

end



function p.main(frame)

	return p._main(frame:getParent().args)

end



return p