Modul:Formatnum

local p = {}


-- this function receives a number, tries to guess the layout and returns the 
-- same number with the thousand separator stripped and the decimal separator
-- converted to English format
p._stripSeparators = function(input)
	local comma = ','
	local dot = '%.'
	local _, commaCount = string.gsub(input, comma, comma)
	local _, dotCount = string.gsub(input, dot, dot)
	if dotCount == 0 then
		if commaCount == 0 then --plain old integer
			return tonumber(input)
		elseif commaCount == 1 then -- floating point, Romanian format
			--TODO better guesswork
			return tonumber(string.gsub(input, comma, dot), 10)
		else -- integer with thousand separator
			return tonumber(string.gsub(input, comma, ""), 10)
		end
	elseif dotCount == 1 then
		if commaCount == 0 then  --floating point, English format
			--TODO better guesswork
			return tonumber(input, 10)
		elseif commaCount == 1 then --one each; the last one is decimal sep
			local commaIndex = mw.ustring.find(input, comma)
			local dotIndex = mw.ustring.find(input, dot)
			if commaIndex > dotIndex then
				return tonumber(string.gsub(string.gsub(input, dot, ""), comma, dot), 10)
			else
				return tonumber(string.gsub(input, comma, ""), 10)
			end
		else -- float with thousand separator comma
			return tonumber(string.gsub(input, comma, ""), 10)
		end
	else
		if commaCount == 0 then  --integer with thousand separator
			return tonumber(string.gsub(input, dot, ""), 10)
		elseif commaCount == 1 then -- float with thousand separator dot
			return tonumber(string.gsub(string.gsub(input, dot, ""), comma, dot), 10)
		else -- invalid
			return nil
		end
	end
end

function p.stripSeparators(frame)
	ret = p._stripSeparators(frame.args[1])
	if ret then return ret else return "" end
end

function p._formatNum(number, lang, prec, compact)
	if lang ~= nil and mw.language.isKnownLanguageTag(lang) == true then 
		lang = mw.getLanguage(lang) 
	end
	if lang == nil or lang == {} or mw.text.trim(lang) == '' then
		lang = mw.getContentLanguage()
	end
	processed = p._stripSeparators(number)
	if processed == nil then return number else number = processed end

    -- TODO: do something with prec
    if compact then
        number = lang:formatNum(number, { noCommafy = 'y' }) -- caveat: can load localized resources for up to 20 languages
    else
        number = lang:formatNum(number) -- caveat: can load localized resources for up to 20 languages
    end
    return number
end

function p.formatNum(frame)
	local args = require("Modul:Arguments").getArgs(frame)
    local prec    = args.prec or ''
    local sep     = args.sep or ''
    local number  = args[1] or args.number or ''
    local lang    = args[2] or args.lang or ''
    return p._formatNum(number, lang, prec, sep ~= '')
end

return p